Volume 2 - Annexes 1-17

INTERNATIONAL COURT OF JUSTICE
DISPUTE OVER THE STATUS AND USE OF THE
WATERS OF THE SILALA
(CHILE v. BOLIVIA)
COUNTER-MEMORIAL OF
THE PLURINATIONAL STATE OF BOLIVIA
ANNEXES 1 - 17
VOLUME 2
3 SEPTEMBER 2018

LIST OF ANNEXES TO THE COUNTER-MEMORIAL
OF THE PLURINATIONAL STATE OF BOLIVIA
ANNEX N° TITLE PAGE N°
United Nations Documents (Annexes 1 - 3)
VOLUME 2
ANNEXES 1 - 17
Documentation from the Bolivia-Chile Silala Working Group
and Political Consultation Mechanism (Annexes 4 - 10)
United Nations, Sixth Committee, Summary Record of
the 23rd meeting, 17 October 1996, A/C.6/51/SR.23, p.
11, para. 78
(Original in English)
United Nations, Sixth Committee, Summary Record of
the 53rd meeting, 31 March 1997, A/C.6/51/SR.53, p. 8,
para. 47 and p. 9, para. 53
(Original in English)
United Nations, Sixth Committee, Summary Record
of the Second Part of the 62nd meeting, 4 April 1997,
A/C.6/51/SR.62/ Add.1, pp. 6-7, para. 24
(Original in English)
Joint Study Profile submitted by Chile in August 2004
(Original in Spanish, English translation)
Minutes of the II Meeting of the Bolivia-Chile Working
Group on the Silala Issue, 20 January 2005
(Original in Spanish, English translation)
Minutes of the XVIII Meeting of the Bolivia-Chile
Political Consultation Mechanism, 17 June 2008
(Original in Spanish, English translation)
Annex 1
Annex 2
Annex 3
Annex 4
Annex 5
Annex 6
3
19
39
55
105
115
Bolivia – Chile Diplomatic Correspondence (Annexes 11 - 12)
Bolivian Official Documents (Annex 13)
Minutes of the IV Meeting of the Bolivia-Chile Working
Group on the Silala Issue, 14 November 2008
(Original in Spanish, English translation)
Initial Agreement [Silala or Siloli], Agreed Draft, 28
July 2009
(Original in Spanish, English translation)
Initial Agreement [Silala or Siloli], Agreed Draft,
Santiago,13 November 2009
(Original in Spanish, English translation)
Minutes of the First Part of the VIII Meeting of the
Bolivia-Chile Working Group on the Silala Issue,
October 2010 (unsigned)
(Original in Spanish, English translation)
Note Nº VRE-DGRB-UAM-018880/2011 from the
Ministry of Foreign Affairs of Bolivia to the General
Consulate of Chile in La Paz, 29 August 2011
(Original in Spanish, English translation)
Note Nº VRE-DGRB-UAM-009901/2012 from the
Ministry of Foreign Affairs of Bolivia to the General
Consulate of Chile in La Paz, 24 May 2012
(Original in Spanish, English translation)
Bolivian Supreme Decree N° 24660, 20 June 1997
(Original in Spanish, English translation)
Annex 7
Annex 8
Annex 9
Annex 10
Annex 11
Annex 12
Annex 13
143
157
175
195
211
215
223
Press Articles (Annexes 14 - 16)
El Diario, “The Silala is not a matter of discussion” for
Chile, La Paz, 28 May 1996
(Original in Spanish, English translation)
El Mercurio, “Clarification from the Chilean
Chancellery: There is no conflict with Bolivia over the
Silala River”, Santiago, 17 May 1997
(Original in Spanish, English translation)
La Razón, “Everything will be done after signing
the initial agreement”, La Paz, 30 August 2009
(Original in Spanish, English translation)
Annex 14
Annex 15
Annex 16
231
237
243
Annex 17 Danish Hydraulic Institute (DHI), Study of the Flows in
the Silala Wetlands and Springs System, 2018
(Original in English)
255
Annex A: The Silala Catchment
Annex B: Climate Analysis
Annex C: Surface Waters
Technical Documents (Annex 17)
313
331
357

1
United Nations Documents
(Annexes 1 - 3)
2
3
Annex 1
United Nations, Sixth Committee, Summary Record of the 23rd
meeting, 17 October 1996, A/C.6/51/SR.23, p. 11, para. 78
(Original in English)
4
5
UNITED NATIONS
General 9Assembly
FIFTY-FIRST SESSION
Official Records
SIXTH COMMITTEE
23rd meeting
held on
Thursday , 17 October 1996
at 3 p .m.
New York
SUMMARY RECORD OF THE 23rd MEETING
Chairman : Mr . YAMADA
(Chairman of the Working Group of the Whole on the
Elaboration of a Framework Convention on the Law of
the Non-Navigational Uses of International Watercourses)
CONTENTS
AGENDA ITEM 144 : CONVENTION ON THE LAW OF THE NON-NAVIGATIONAL USES OF
INTERNATIONAL WATERCOURSES (continued)
(Japan)
This record is subject to correction. Corrections should be sent under the signature of a member of the
delegation concerned within one week of the dale of the p11hlicatim1 to the Chief of the Official Records Editing
Section, room DC2-794, 2 United Nations Plaza, and incoflX)rated in a copy of the record.
Distr . GENERAL
A/C.6/51/SR . 23
4 December 1996
Corrections will be issued after the end of the session, in a separate corrigendum for each Committee.
ORIGINAL: ENGLISH
96-81469 (E) / .. .
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Mr. Yamada (Chairman of the Working Group of the Whole
on the Elaboration of a Framework Convention on the
Law of the Non- Navigational Uses of International
Watercourses) took the Chair .
The meeting was called to order at 3 . 05 p .m.
AGENDA ITEM 144 : CONVENTION ON THE LAW OF THE NON-NAVIGATIONAL USES OF
INTERNATIONAL WATERCOURSES (continued)
Elaboration of a framework convention on the law of the non-navigational uses of
international watercourses on the basis of the draft articles adopted by the
International Law Commission in the light of the written comments and
observations of States and views expressed in the debate at the forty-ninth
session (continued) (A/49/10 and A/49/335 ; A/51/275 and Corr.land Add.l)
Cluster IV (articles 20-28) (continued)
Article 28
1 . Mr . PAZARCI (Turkey) said that the definition of "emergency" in article 28
was so wide-ranging that it might pose a problem for developing countries, and
he therefore suggested that the definition should be narrowed down.
2 . Mr . CROOK (United States of America) , Mr . KASSEM (Syrian Arab Republic) ,
Mr . PRANDLER (Hungary) and Mr . AKBAR (Pakistan) wished to retain the article as
drafted.
3 . Ms. MATROOS (Botswana) said she understood that "when necessary " in
paragraph 4 implied that the obligation to develop contingency plans jointly was
optional , and yet as the sentence progressed it appeared to be dealing with a
mandatory measure .
4. Mr . PRANDLER (Hungary ) explained that the qualification "when necessary "
meant that when an emergency occurred, it was obligatory to develop contingency
plans , as it was imperative that States should cooperate .
5. Mr . SMEJKAL (Czech Republic) pointed out that there was no provision in the
article for the equitable sharing of the cost of measures necessitated by an
emergency .
6. Mrs. FERNANDEZ de GURMENDI (Argentina) asked the Expert Consultant to
clarify the implications of the inclusion of "other States " as well as
'' watercourse States '' in paragraph 1 .
7. Mr. ROSENSTOCK (Expert Consultant) referred to paragraph (2) of the
commentary to the article (A/49/10) , where it was pointed out that "other
States " would usually refer to coastal States suffering from the effects of ,
say , a chemical spill . Similarly, floods or diseases originating in a
watercourse State could spread to other States , which was why the definition of
an emergency was extended to cover non-watercourse States . It was true that
there were no specific provisions in the article on the question of sharing the
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costs of dealing with an emergency, although the contingency plans mentioned in
paragraph 4 could include prior agreements on burden-sharing . The point was
that when a catastrophe struck , action had to be taken immediately, with no
delay for wrangling over the sharing of costs.
8 . Mr . LAVALLE VALDES (Guatemala) inquired whether the reference to
non-watercourse States referred only to States parties to the convention or
applied also to States that were not parties to the convention ; if the latter ,
it would not be necessary to change the text to refer specifically to States
parties to the convention .
9. Mr . ROSENSTOCK (Expert Consultant) replied that the hope was that not only
watercourse States, but others too , would adopt the convention .
Cluster V (articles 29-32 and article 2)
Article 29
10 . Mr . CROOK (United States of America) drew attention to the amendment
proposed by the United States in document A/C.6/51/NUW/WG/CRP . l . The commentary
to the article made it clear that the text was intended t o be without prejudice
to existing international law and was not to lay down any new rules . However ,
despite purporting not to extend the applicability of any instrument to States
not party to that instrument , the article could be interpreted as making States
parties to the watercourse convention subject to certain rules contained in
Protocol I of 1977 Additional to the Geneva Conventions , which the United States
did not accept as customary law . He therefore called on the Working Group to
address that matter in the preamble or to revise article 29 in line with the
amendment proposed by his delegation.
11 . Speaking on behalf of the United Kingdom delegation , he said that it , too ,
had similar reservations about article 29 , considering that the matter belonged
to the area covered by the laws of armed conflict. It the matter was to be
addressed in the watercourse convention , the United Kingdom delegation would
like it to be done by means of a clause making explicit the intention that the
article was without prejudice to the application to international watercourses
of the principles and rules of international law on armed conflict .
12 . Mr. SABEL (Israel) and Mr. LEE (Republic of Korea) said that they supported
the United States amendment .
13 . Mr . ENAYAT (Islamic Republic of Iran) said the draft proposed by the
International Law Commission was well balanced . The essential point was that
article 29 was not an enunciation of existing rules. The accompanying
commentary made it quite clear that the article was without prejudice to
existing law and that it did not "purport to extend the applicability of any
instrument to States not parties to that instrument ". To limit the scope of the
article to watercourse States , as had been suggested, would be an a contrario
interpretation, which would permit illegal acts . Besides , watercourse States
were already bound by article 26 , which dealt with terrorism and sabotage .
14 . Ever since the International Law Commission had begun its consideration of
the matter , it had sought to apply the provisions not only to watercourse States
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but also to other States , although , as was again made clear in the commentary, a
State not party to the convention would not be bound by its provisions ~He
pointed out that that part of the commentary could also be found on page 77
of volume II of the 1991 Yearbook of the International Law Commission , that the
original idea had been included in a resolut ion adopted at the 1976 conference
of the International Law Association , and that it was also to be found in the
sixth report of the Special Rapporteur , Mr . Mccaffrey . Lastly , he cited the
view of the Chairman of the Drafting Committee in 1991 , Mr . Pawlak, that the
inclusion of a reference to t he principles and rules of international law was
vital , and that the provisions should not be confined to watercourse States ,
since an attack could be carried out by a State that was not a watercourse
State .
15 . Mr . PRANDLER (Hungary ) said that the article was formulated in general
terms and did not prejudge the positions of respective States , and therefore his
delegation could accept the current draft . However , he would be prepared to
look at any new drafting suggestions if the concerns expressed about protocols
to the Geneva Conventions were not sufficiently allayed by the remarks in the
commentary that certain fundamental protections were afforded by the "Martens
clause ", which had achieved the status of general international l aw .
16 . Mr . ROSENSTOCK (Expert Consultant) , observing that the United States
amendment sought to reflect the commentary more adequately , said that the only
potentially substantive difference bore on the scope of the article , namely ,
whether it referred , as the amendment stat ed, only to watercourse St at es , or to
all States or all States parties . The rest of the changes proposed were merely
drafting changes .
17 . Mr . CALERO RODRIGUES (Brazil ) said he agreed that there was virtually no
difference between the two texts . The United States amendment reflected the
idea in paragraph (2) of the commentary that the principles and rules of
international law that applied were those that were binding on the States
concerned . Article 29 as it stood focused on what was to be protected, whi le
the United States proposal focused on who must provide protection . The only
substantive difference was that the amendment made the article applicable to
watercourse States only , whereas the Commission ' s text could be interpreted as
imposing an obligation of protection on non-watercourse States , a debatable
point . Brazil could accept either proposal .
18 . Mr . RAO (India) said that he had an open mind on that matter , but
definitely thought the word "internal " should be replaced by
"non-international ", as proposed by the United States .
19 . Ms . DASKALOPOULOU-LIVADA (Greece) , Mr . CAFLISCH (Observer for Switzerland)
and Mr . SANCHEZ (Spain) endorsed the existing text .
20. Ms. MEKHEMAR (Egypt) said that she supported the existing text because it
was general and balanced .
21 . Mr . KASSEM (Syrian Arab Republic) said that , since the United States
amendment limited the scope of the article , he preferred to reta i n the
Commission ' s text , which was in keeping with existing international and treaty
law .
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22 . Mr. CROOK (United States of America) said that the problem for his
delegation had been that there was no general agreement as to the content of the
principles and rules of international law that applied in armed conflicts ; the
amendment sought to make it clear that the only applicable rules were those that
bound the particular State that was protecting a watercourse. The use of the
term "watercourse States " had not been meant to exclude other countries , and he
could agree to different language , such as "Parties shall . . . ". He did not
regard that as a point of substance but as a drafting question .
23 . Mr . AKBAR (Pakistan) said he preferred the existing text because it did not
lay down any new rules but simply referred to existing rules .
24 . Mr. HAMDAN (Lebanon) said that if there was no real difference between the
two texts it was preferable to keep article 29 as drafted .
25 . The CHAIRMAN said that since there was no difference in substance between
the draft text and the United States amendment , article 29 could be referred to
the Drafting Committee .
Article 30
26 . The CHAIRMAN said that no written amendments to article 30 had thus far
been received .
Article 31
27 . Mr . CROOK (United States of America) , speaking on behalf of the United
Kingdom, said that the article as it stood was not acceptable in the view of the
British delegation. The exception to the obligation to provide information was
too narrowly drawn : it should also exempt data that should be confidential on
industrial and commercial grounds , as had been done , for instance, in article 8
of the Helsinki Convention on the Protection and Use of Transboundary
Watercourses and International Lakes and article 2 of the Espoo Convention on
Environmental Impact Assessment in a Transboundary Context .
Article 32
28 . Mr . CANELAS de CASTRO (Portugal) , supported by Mr. CALERO RODRIGUES
(Brazil) and Mr . CAFLISCH (Observer for Switzerland) , said that since the first
part of the article referred to two possibilities - the suffering of
transboundary harm and the threat of suffering such harm - it would be more
consistent to replace "occurred" by "occurs or may occur ".
29 . Mr . de VILLENEUVE (Netherlands) said that the scope of the article should
perhaps be extended to make it incumbent upon a State party actually to
introduce adequate administrative and legal procedures and not simply to provide
equal treatment under the law. He would submit an amendment to that effect.
30 . Mr . RAO (India) said that his delegation could not accept the article ,
because it interjected prematurely into the watercourse context a still-evolving
principle drawn from the broad field of the environment. It should be either
deleted or included in an optional protocol.
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31 . The problems referred to in article 32 would generally affect private
individuals within a State ' s own territory , in contrast to a liability
convention where problems such as air pollution might have implications beyond a
State' s borders . The mechanisms whereby individuals could take legal action
against a State were not universally uniform, but differed according to the law
of the region concerned . The European region had a highly developed system
allowing individuals to make claims against their own and other countries ,
through common institutions and common conventions and with freedom of movement
and free access for all - an ideal situation which did not exist elsewhere . In
any case , access to the courts by foreigners was never an easy matter , requiring
much expense , a knowledge of languages and an understanding of alien laws and
regulations . If the intent of the article was that individuals should be left
to fend for themselves to press a claim against a State , it was meaningless .
Even where class actions were involved, especially by poor people, the State had
to intervene to assist them to obtain justice.
32 . Moreover , conflict of laws was a very complicated matter in itself . There
was also the further question of how justifiable it was for any individual or
group of individuals , on either side of a border, to seek to frustrate , through
long court delays , an international agreement struck between two watercourse
States regarding protection against significant harm .
33 . Mr . AKBAR (Pakistan) said that he , too , had many reservations regarding
article 32 and through it should be deleted.
34 . Mr . CALERO RODRIGUES (Brazil) said that the very divergent reactions to the
text by the Netherlands and India showed that it probably struck the proper
balance. Its aim was to set out what non-discrimination should mean and it
expressed a widely accepted principle in very fair terms . His delegation
believed it should be retained as drafted .
35 . Mr. SVIRIDOV (Russian Federation) said that a very complicated issue was
involved : the article went beyond establishing a State ' s obligation to provide
individuals with access to legal procedures , for it obliged a State to provide
foreign legal entities with equal legal and procedural protection . Article 32
was based on a very broad interpretation of a principle for which there were
some precedents but which had not yet been developed in international customary
law. His delegation could not support the text as it stood, and intended to
propose a compromise text .
36 . Mr . CAFLISCH (Observer for Switzerland) said that article 32 was probably
based on the 1909 Treaty relating to boundary waters between the United States
and Canada , a frequent source in treaty law . Switzerland supported the
principle in article 32 , which it felt must be included in the convention
proper . The article would allow for the normal application of the rule
regarding exhaustion of domestic remedies . It provided both for material
non-discrimination and for non-discriminat ion in access to the courts , and his
delegation did not see what needed to be added .
37 . Mr . LAVALLE VALDES (Guatemala) said that article 32 tried to say too much
in one paragraph. The expression "shall not discriminate " was a problem : the
usual pejorative connotation of the word "discriminate " - which could in fact
also mean the making of perfectly justifiable legal distinctions - made it
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somewhat disconcerting when coupled with the proviso that States might agree
otherwise . Also , the use of the conjunction "or" between "access to judicial or
other procedures " and "a right to claim compensation or other relief" implied
that they were mutually exclusive concepts although that was not necessarily the
case.
38 . Mr . MAZILU (Romania) , supported by Mr . LEE (Republic of Korea) , suggested
that, in view of the objections raised to article 32 , informal consultations
should be held between the delegations concerned, as it was important to ensure
that the framework convention was acceptable to the great majority .
39 . Mr . EPOTE (Cameroon) said that it might be helpful if the Expert Consultant
were to give an exact explanation of the meaning of article 32 with a view to
eliminating any problems of comprehension . As he understood it , watercourse
States which caused harm to natural or juridical persons that were not nationals
or residents of watercourse States should not discriminate against such persons .
40 . Mr . REYES (Mexico) said that his delegation was willing to consider the
Portuguese proposal and pointed out that , as stated in paragraph (3) of the
commentary to article 32 , the rule concerning non-discrimination was a residual
one.
41 . Mr . ROSENSTOCK (Expert Consultant) confirmed the residual nature of the
rule and said that the article had been properly interpreted by the
representative of Cameroon. In his view , its meaning was clear , but he
clarified that meaning further by giving examples and added that consideration
could be given to the drafting issue raised by the representative of Guatemala .
42 . Mrs. DASKALOPOULOU-LIVADA (Greece) said that her delegation had no
objection to the provisions contained in article 32 , which were standard in
legal assistance agreements .
43. Mr. NUSSBAUM (Canada) said that the principle of non- discrimination was
important to his delegation , which viewed it as a significant factor in the
growing trend to rely on civil liability as a remedy for transboundary harm.
However , given the comments of the representative of India and others , he
supported the Romanian proposal for informal consultations.
44 . Mr. VARSO (Slovakia) said that article 32 contained too many elements in a
single sentence and was also contradictory, since it appeared to suggest that
States could agree to discriminate . He therefore suggested that it should be
divided into four sentences , covering in turn respect for the principle of
non-discrimination , agreement otherwise reached between watercourse States ,
access to judicial or other procedures , and compensation .
Cluster V (article 2)
45 . Mr. PAZARCI (Turkey) said that , as defined in paragraph (a) , the term
'' international watercourses" did not cover the link between watercourses and the
territory of watercourse States . With a view to drawing a distinction between
international watercourses , he therefore proposed the following definition :
"International watercourses are divided into the following two categories:
watercourses which form a boundary; transboundary watercourses which flow
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successively through two or more States ". Since a framework convention should
deal only with surface waters , he also proposed that the words "and
groundwaters" should be deleted from subparagraph (b).
46 . Mrs. DASKALOPOULOU-LIVADA (Greece) supported the definition proposed by the
representative of Turkey .
47 . Mr . TAMRAT (Ethiopia) , Mrs . VARGAS de LOSADA (Colombia) and Mr . AKBAR
(Pakist an) support ed the Turkish proposal concerning subparagraph (b) .
48 . Mrs . FERNANDEZ de GURMENDI (Argentina) said that in the Spanish text the
term "aquas subterraneas " in subparagraph (b) was inappropriate , as such waters
did not always flow into the common terminus of a watercourse . It would be
preferable to use the term "aquas subalveas " . Furthermore , the term "physical
relationship" in subparagraph (b) was insufficiently clear , as it could refer to
canals or basins. Her delegation would therefore prefer the term "physical or
natural relationship " or "physical or geographical relationship ".
49 . Mr . SANCHEZ (Spain) supported the Argentine proposal concerning the use of
the term "aquas subc3.lveas ".
50 . Mrs . MEKHEMAR (Egypt) expressed disagreement with the proposal to delete
the word "groundwaters ", as it referred to a whole water system that could
affect other parts of a watercourse . She also proposed that subparagraph (b)
should be expanded to read : . . . "groundwaters forming an integral part of the
surface waters and constituting ... ", as the definition would then include
groundwaters which did not flow into a common terminus , but which were just as
important .
51 . Mrs. DASKALOPOULOU-LIVADA (Greece) and Mr . PULVENIS (Venezuela) said they ,
too , were opposed to the deletion of the word "groundwaters " from
subparagraph (b).
52 . Mr . de VILLENEUVE (Netherlands) said he was opposed to the deletion of the
word "groundwaters " and supported the Egyptian proposal concerning the expansion
of subparagraph (b) .
53 . Mr . ROSENSTOCK (Expert Consultant) said he wondered whether the problem
raised by the representative of Argentina was caused by a poor translation into
Spanish of the word "groundwaters ".
54 . Mrs. FERNANDEZ de GURMENDI (Argentina) said that the Spanish term "aquas
subalveas " referred to waters t hat were linked to a river and flowed t o the
mouth of that river , whereas the term "aquas subterraneas " covered a much
broader concept .
55 . Mr . ROSENSTOCK (Expert Consultant) said that , in isolation, the term
"groundwaters " in English could also encompass a much broader definition than
that contained in subparagraph (b) , which referred to a system and did not
include confined groundwater . Deletion of the word "groundwaters " was a
different matter.
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56 . Mr. AKBAR (Pakistan) proposed that , throughout the framework convention,
the word "watercourse " should be replaced by the word "river ", as it was
universally recognized and used in all engineering literature and relevant
agreements on the subject .
57 . Mr . de VILLENEUVE (Netherlands) said that his delegation was against use of
the word "river "; in his country , it was difficult to differentiate between a
river and a canal .
58 . Mr . PULVENIS (Venezuela) said that his delegation was prepared to consider
a shorter version of the Turkish proposal if it was felt that the issue which it
addressed had a bearing on the standards and principles under discussion . He
disagreed with t he Pakistani proposal to use the word "river" and emphasized
that the proposed use of the term "aquas sub6lveas" in the Spanish text should
not be interpreted as minimizing or limiting the concept of groundwaters as
reflected in the other languages .
59 . Mr . CAFLISCH (Observer for Switzerland) said that his delegation could go
along with article 2 as drafted and with the reference in subparagraph (bl of
that article to "groundwaters constituting .. . a unitary whole "; like the
Commission , however , his delegation would be opposed to including confined
groundwater in the definition .
60 . The question arose whether definitions given in other parts of the
convention should be included in article 2; if so , the definition of
"regulation " in article 25 , paragraph 3, should be transferred to article 2 .
61 . Lastly , his delegation wished to know why the Commission had chosen to
define '' international watercourse '' before defining "watercourse '' .
62 . Mr . ROSENSTOCK (Expert Consultant) , replying to the previous question , said
that the order in which the terms were defined was intended to make it clear
that the convention dealt only with transboundary situations . As to the
possible inclusion in article 2 of definitions found in other articles , the
Commission had decided that terms used in more than one article would be defined
in article 2, while definitions of terms occurring in only one article would be
left in that article .
63 . Mr. KASSEM (Syrian Arab Republic) said that article 2, subparagraph (a) ,
was acceptable as drafted, especially since both contiguous and successive
watercourses were governed by the same legal regime . Likewise , his delegation
could accept the Commission ' s definition of "groundwater ".
64 . As to the possibility of including in article 2 definitions of terms used
in other articles , his delegation had proposed a definition of the term "optimal
utilization " found in article 5, and had agreed to defer consideration of that
amendment to the discussion of article 2. In view of the criteria just out l ined
by the Expert Consultant , and the fact that "optimal utilization " occurred in at
least two articles , he requested the Chairman to clarify whether the Syrian
delegation ' s amendment should be incorporated into article 5 or article 2 .
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65 . The CHAIRMAN said that all proposed amendments would be referred to the
Drafting Committee; the Syrian delegation would have an opportunity to discuss
the placement of its proposal in the context of that Committee .
66 . Mr . McCAFFREY (United States of America) said that his delegation
associated itself with the comments made by the Syrian representative ; the same
principles applied to both contiguous and successive international watercourses .
While the distinction between the two types of watercourse had long been
recognized in St at e practice , many watercourses were both contiguous and
successive at different points along their courses . The question was one of
emphasis ; references to contiguous and successive watercourses tended to omit
other, related parts of the system, such as tributaries and groundwater . In
that connection , knowledge of hydrology had increased in recent years , to the
point where it was recognized that groundwater and surface water were usually
interrelated . Attempts to regulate surface water alone could prove futile ,
because water that was extracted from the ground would reduce the amount of
related surface water , and surface water that fed aquifers would, when
extracted, reduce the amount of water available in the aquifer . Similarly,
pollution of an aquifer would eventually seep into a surface stream .
Accordingly , surface water and groundwater could not easily be separated, either
physically or conceptually .
67 . There were , of course , instances of confined groundwater; however , the
Commission had concluded that it was essential to include groundwater in the
definition of a watercourse , precisely because of its relationship to surface
water . For those reasons , his delegation supported the Commission ' s text as
drafted .
68 . Mr . EPOTE (Cameroon) said that his delegation endorsed the statement made
by the United States representative . Since the actions taken by one watercourse
State could affect the groundwater of another watercourse State , deleting the
term "groundwaters " might make it impossible to impute legal liability in the
case of harm caused to a third State .
69 . Mr . TANZI (Italy) said that , while his delegation could accept article 2 as
drafted, it had no objections to the Turkish proposal to distinguish between
watercourses that formed and those that crossed an international boundary ; such
a distinction was appropriately made in article 1 of the 1992 Convention on the
Protect ion and Use of Transboundary Watercourses and International Lakes .
70 . The proposed deletion of the term "groundwaters " would be a step backwards
from established international treaty practice, and would diminish the impact
and relevance of t he future convention.
71 . Mr . MANONGI (United Republic of Tanzania) said that it was difficult to see
how the term "groundwaters " could be deleted unless an appropriate alternative
was found : a watercourse or river must be viewed as part of a systemic whole.
His delegation supported the Egyptian proposal and the earlier proposal by
Israel for the inclusion in article 2 of a definition of "watercourse
agreements ".
72 . Mr . PAZARCI (Turkey) said that his delegation ' s proposal concerned the
distinction among contiguous watercourses , watercourses that formed a boundary
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and those that crossed a boundary; as recognized by the United States
representative , such a distinction had long been accepted in State practice .
The definition of the term "international watercourse " should clearly encompass
all of those categories .
73 . His delegation disagreed with the Syrian view that the legal regime
applying to contiguous and successive watercourses was identical . While the
convention itself did not make a clear distinction in that regard, its rules
might be applied differently in one or the other case ; for example , article 6
(Factors relevant to equitable and reasonable utilization) , paragraph 1 (a) ,
referred to "geographic ... and other factors of a natural character" which must
be taken into account , while paragraph 1 (d) of the same article referred to
"the effects of the use or uses of the watercourse in one watercourse State on
other watercourse States ". Those provisions made it clear that practice
differed in respect of watercourse that formed and those that crossed a
boundary .
74 . Mr . KASSEM (Syrian Arab Republic) said that the definition of "watercourse"
contained in the Commission ' s draft encompassed both watercourses that formed
and those that crossed a boundary; in that connection, he drew attention to
paragraph (2) of t he Commission ' s commentary to article 2 (A/49/10) . The lack
of distinction between the two types of rivers or streams - not in respect of
their definition , but of the legal regime applying to them - was well
established in both treaty law and customary law, and had been confirmed by the
International Court of Justice in a celebrated opinion.
75 . Mr . LALLIOT (France) said that his delegation had no difficulties with the
term "groundwaters " as used in article 2, subparagraph (b) , provided that it did
not apply to "confined" groundwaters , but only to groundwaters having a physical
relationship to an international watercourse. He requested the Expert
Consultant to confirm his understanding of the term .
76 . Mr. ROSENSTOCK (Expert Consultant) said that the French representative ' s
understanding of the term "groundwaters ", as used in the Commission ' s draft , was
correct : it referred to groundwaters that interacted with surface waters and
were part of a system .
77 . Mr . NGUYEN DUY CHIEN (Viet Nam) said that , while every watercourse
undoubtedly had specific characteristics , that did not imply that the definition
must include each and every distinguishing feature . His delegation agreed with
the Syrian and United States delegations that the definitions of "watercourse "
and "international watercourse " were sufficiently clear in the Commission ' s
draft.
78 . Mr . CRISOSTOMO (Chile ) said that the term "watercourse " was confusing, as
shown by the fact that some delegations wished to replace it with "river ", which
was far too restrictive a term. His delegation proposed that "watercourse "
should be replaced by "hydrographic system", "international watercourse " by
'' hydrographic system with shared water resources '' and '' watercourse State '' by
"State belonging to a hydrographic system with shared water resources ".
79 . Mr. HABIYAREMYE (Rwanda) said that his delegation welcomed the Turkish
proposal , as it made for a more complete distinction between contiguous
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watercourses and those that formed a boundary . His delegation was also among
those which felt that the term "groundwaters " was superfluous ; it would not ,
however , insist on its deletion . Lastly , his delegation believed that it would
have been more logical to define "watercourse " first and then "international
watercourse ".
80 . Mr . MORSHED (Bangladesh ) endorsed the views expressed by the United States
representative.
81 . Mr . MANNER (Finland) , reiterating his delegation ' s comments , contained in
document A/51/275 , on the term "international watercourse ", drew attention to
the alternative expression "transboundary waters ", which was used in the 1992
ECE Convention on the Protection and Use of Transboundary Watercourses and
International Lakes .
82. Mr. REYES (Mexico) said that his delegation too was in favour of the
Commission ' s text and had little to add to the comments by the United States
representative . From the technical standpoint the term "international
watercourse " was used correctly in article 2 because the source of the waters
must always be distinguished from the waters themselves .
83 . Mr . LAVALLE VALDES (Guatemala) asked the Expert Consultant to say whether a
river , for simplicity ' s sake one without tributaries , which throughout its
course ran between two States but with the State frontier established along only
one of its banks , would constitute an international watercourse .
84 . Mr . ROSENSTOCK (Expert Consultant) said that it was hard to give an answer
on such a theoretical situation. It was inconceivable that a river could be so
clearly demarcated, lacking any tributaries or distributaries or groundwater
flows , that the State frontier could be established along a line at the river ' s
edge . However , in such a situation he supposed that the river would not
constitute an international watercourse .
Article 33
85 . Mr . MAZILU (Romania) said that his delegation supported the French
proposals concerning article 33 (A/C . 6/51/NUW/WG/CRP . 55) .
86 . Mr . KASSEM (Syrian Arab Republic) said that it would be possible for States
to settle disputes under article 33 , but unless the article was made compulsory
they would not be obliged to do so . His delegation had therefore submitted an
amendment to make all recourse under the article compulsory .
87 . Mrs. MEKHEMAR (Egypt) said that the article was too detailed for a
framework convention . It should be left to the parties to a dispute to find a
peaceful solution under specific agreements .
88 . Mr . SMEJKAL (Czech Republic) said that his delegation supported the French
proposals , preferring the first option therein .
89 . Mr. LAVALLE VALDES (Guatemala) said that his delegation would prefer
provisions concerning a settlement dispute system drafted along the lines of
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such instruments as the Framework Convention on Climate Change . It would submit
an amendment to that end .
90 . Mr . RAO (India) said that his country had always taken the position that
disputes should be settled by peaceful means but also by means acceptable to all
the parties , a principle established in the Charter of the United Nations . No
one party to a dispute must be allowed to impose any specific means of
settlement on the other parties . That point was recognized in article 33 , but
recourse to a fact-finding commission was made compulsory and that might create
more problems than it solved . The French proposals were helpful but did not
resolve that particular issue . An article such as article 33 should have been
avoided in a framework convention .
91 . The CHAIRMAN said he took it that the Working Group wished all the
proposals on clusters IV and V to be referred to the Drafting Committee .
92 . It was so decided .
93 . The CHAIRMAN said that there appeared to be two or three groups of
delegations with differing positions on the policy issues . Some delegations had
i nitiat ed coor dination work wi t hin t hose groups and had begun to negot iate with
the other groups . He hoped that that approach would be vigorously pursued .
Such efforts could not of course replace the work of the Drafting Committee but
would help to narrow the differences and pave the way to a generally acceptable
text.
The meeting rose at 5 . 40 p .m.
18
19
Annex 2
United Nations, Sixth Committee, Summary Record of the 53rd
meeting, 31 March 1997, A/C.6/51/SR.53, p. 8, para. 47 and
p. 9, para. 53
(Original in English)
20
21
UNITED NATIONS
General. Assembly
Chairman :
FIFTY-FIRST SESSION
Official Records
SUMMARY RECORD OF THE 53rd MEETING
Mr . YAMADA
SIXTH COMMITTEE
53rd meeting
held on
Monday , 31 March 1997
at 10 a .m.
New York
(Japan)
(Chairman of the Working Group of the Whole on the
Elaboration of a Framework Convention on the Law
of the Non-Navigational Uses of International
Watercourses)
CONTENTS
AGENDA ITEM 144 : CONVENTION ON THE LAW OF THE NON-NAVIGATIONAL USES OF
INTERNATIONAL WATERCOURSES (continued)
Elaboration of a framework convention on the law of the non-navigational
uses of international watercourses on the basis of the draft articles
adopted by the International Law Commission in the light of the written
comments and observations of States and views expressed in the debate of
the forty-ninth session of the General Assembly (continued )
(A/C . 6/51/NUW/WG/L.l/Rev.l and Add . l )
This record is subject to correction. Corrections should be sent under the signature of a member of the
delegation concerned within one week of the ,late of 1he publication to the Chief of !he Offi cial Records
Editing Section, room DC2-750, 2 United Nations Plaza, and incorpomted in a copy of the record.
Corrections will be issued after the end of the session, in a separate corrigendum for each Committee.
Distr. GENERAL
A/C.6/51/SR . 53
5 September 1997
ENGLISH
ORIGINAL: SPANISH
97-80954 IE) / ...
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Page 2
Mr . Yamada (Chairman of the Working Group of the Whole
on t he Elaborat ion of a Framework Convent ion on the
Law of the Non-Navigational Uses of International
Watercourses) took the Chair .
The meeting was called to order at 10.20 a.m.
AGENDA ITEM 144 : CONVENTION ON THE LAW OF THE NON-NAVIGATIONAL USES OF
INTERNATIONAL WATERCOURSES (continued)
Elaboration of a framework convention on the law of the non-navigational
uses of international watercourses on the basis of the draft articles
adopted by the International Law Commission in the light of the written
comments and observations of States and views expressed in the debate of
the fort y-ninth session of the General Assembly (continued)
(A/C . 6/51/NUW/WG/L . l/Rev . l and Add . l)
1. The CHAIRMAN invited the Chairman of the Drafting Committee to introduce
that Committee ' s report contained in document A/C . 6/51/NUW/WG/L . 1/Rev . l/Add . l .
Report of the Drafting Committee
2. Mr. LAMMERS (Chairman of the Drafting Committee ) , introducing the second
report of the Drafting Committee contained in document
A/C.6/51/NUW/WG/L.l/Rev.l/Add.l , said that at the second session of the Working
Group the Drafting Committee had held six meetings from 24 to 27 March 1997 .
3 . Before i nt roducing the report , he expressed his sincere thanks to all the
delegations for their cooperation and support. He also thanked the Expert
Consultant , Mr . Rosenstock , for his contribution in advising the Committee
whenever necessary . He also expressed his appreciation to the coordinators for
their efforts to bridge gaps and bring together diverse views .
4. The pending issues before the Drafting Committee had been article 3,
paragraph 3, articles 7 and 33 , the preamble and the final clauses . The
Drafting Committee, despite the best effort of everyone , had not been able to
recommend a generally agreed text on all t he pending issues . During the current
week , work would continue on article 7 concerning the obligation not to cause
significant harm and article 33 concerning dispute settlement .
5. The set of draft articles prepared by t he Internat ional Law Commission
(ILC) had not contained a preamble . General Assembly resolution 49/52 had
therefore requested the Drafting Committee to prepare the text of a draft
preamble and to submit it to the Wo r king Group. That text was contained in
document A/C.6/51/NUW/WG/L . l/Rev . l/Add.l and consisted of 13 paragraphs .
6. The first sentence of the preamble made reference to the "Parties " to the
Convention and not to "States Parties " . The generic term "Parties" had been
used because it had been envisaged that not only States but also regional
economic integration organizations might become Parties to the Convention .
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7 . The first preambular paragraph was meant to provide a very general
introduction to the text of the Convention. It should be noted that there were
two expressions between square brackets. The placing of the expression "the
non-navigational uses of" between square brackets reflected the fact that , while
some delegations had believed that a general introductory preambular paragraph
should make reference to the importance of international watercourses in
general , irrespective of the specific subject matter of the Convention, others
had considered that the Convention ' s precise scope should be made clear already
in the first preambular paragraph . The expression "and their ecosystems " had
been placed between square brackets pending the outcome of the discussions on
similar expressions found in articles 5 and 8, which were also between square
bracket s for the t ime being .
8 . The second preambular paragraph was also of a general nature and simply
restated the provision of Article 13 , paragraph 1 (a ), of the Charter of the
United Nations relat ing to the progressive development of internat i onal law and
its codification .
9. The third preambular paragraph linked the first two together in that it
addressed the effect s of successful codification and development of rules of
international law not from a general standpoint , but in connection with the
subject matter of the Convention , namely , the non-navigational uses of
international watercourses . The paragraph highlighted the contri bution of such
exercise in the promotion and implementation of the purposes and principles set
forth in Articles 1 and 2 of the Charter of the United Nations .
10 . The fourth preambular paragraph drew attention to the problems affecting
the viability of many international watercourses . It also listed two important
sources of such problems : increasing demands and pollution . However , it was
clear from the words "among other things ", that the short list was only
indicative .
11 . The fifth preambular paragraph dealt with the intended concrete effects of
the Convention : they were to "ensure the utilization , development ,
conservation , management and protection of international watercourses and the
promotion of the optimal [and sustainable] utilization thereo f for present and
future generations ". It should be noted, in that connect ion , that the words
"and sustainable " were between square brackets , pending t he conc l usion of the
discussions on article 5 where that expression also appeared between square
brackets . It should also be noted that the term "framework " had been inserted
before the word "Convention". It would be recalled that , in paragraphs 2 and 4
of the ILC comment ary t o article 3, as well as in paragraph 3 of General
Assembly resolution 49/52 , references had been made to "framework agreement " and
"framework convention ". The Drafting Committee had found it appropriate to
simply recall those references without taking a position on their meaning .
12 . The sixth preambular paragraph affirmed the importance of two general
principles which were particularly relevant with regard to the non-navigational
uses of international watercourses : international cooperation and goodneighbourliness
. The seventh preambular paragraph was self-explanat ory , since
it called attention to the special situation and needs of developing countries .
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13 . The eighth preambular paragraph was placed between square brackets .
Indeed, delegations had expressed different views on that matter. Some had
argued that it was important to recall that the sovereignty of States extended
over the parts of international watercourses situated in their territory - to
the extent that the exercise of such sovereignty was in conformity with
international law - as well as to stress t he ensuing direct responsibility of
such St ates to take appropriate action in that area. Other delegations had felt
that such emphasis on the sovereignty of States could be misleading , as the
purpose of the Convention was precisely to impose certain limitations on the
freedom of States regarding the non-navigational uses of international
watercourses .
14 . The ninth preambular paragraph recalled the provisions and principles of
the Rio Declaration on Environment and Development and Agenda 21 . It had been
considered relevant to include such reference since the Convention addressed,
among other things , the question of the protection and preservation of
international watercourses .
15 . The tenth preambular paragraph recognized the fact that a number of
bilateral and multilateral agreements existed already regarding the
non-navigational uses of international watercourses . The eleventh preambular
paragraph recalled the work done in that field in other forums . The twelfth
preambular paragraph recognized the fact that the draft convention under
elaboration was based on the draft articles prepared by the International Law
Commission . The Assembly would, by means of that paragraph, express its
appreciation to the Commission for its contribution .
16 . Finally, the thirteenth preambular paragraph made reference to General
Assembly resolution 49/52 , whereby the Working Group had been established . That
paragraph was followed by the standard phrase which concluded a preamble ,
namely , "Have agreed as follows " .
17 . As for article 3, paragraph 3, the Drafting Committee recommended no
changes in the text as proposed by the International Law Commission . That meant
that the square brackets around the words "apply and adjust " in paragraph 3 of
the text contained on page 3 of document A/C . 6/51/NUW/WG/L . l/Rev . l should be
removed . As a consequence , the bracketed words "adjustment or application" in
paragraph 5 should read "adjust ment and application" without any square
brackets.
18. The Drafting Committee , however , wished to place on record a very clear
underst anding regarding that paragraph . That understanding read :
"It is understood that the present Convention will serve as a
guideline for future watercourse agreements and that , once such agreements
are concluded, it will not alter the rights and obligations provided
therein , unless such agreements provide otherwise .''
19 . The Committee had been unable to agree on whether that understanding , which
had been recorded verbatim in t he summary records , would be sufficient , or
whether it should be reflected elsewhere . Consultations were continuing on the
subject .
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20 . Article 7 was an important article . Both the Working Group of the Whole
and the Drafting Committee had devoted days to discussing it and consulting on
it. At the current session, Canada had been appointed as the coordinator on
that article , and had continued its consultations with the delegations during
the Drafting Committee' s second session . Canada had reported, however , that the
consultations were not completed and should continue .
21 . As for article 33 , the Drafting Committee was unfortunately unable to
submit a text to the Working Group of the Whole. It would be recalled that the
debate on that article in the Working Group of the Whole had shown that the
delegations had very diverse views. The same views had been expressed in the
Draft ing Committee . Some delegations had favoured a simple provision providing
only that disputes arising from the implementation of the Convention should be
settled peacefully . In their view , States should be left entirely free to
choose their own method of dispute settlement. Any obligatory compulsory
binding procedure was not only devoid of any practical utility for the
effectiveness of the Convention, but also was counter-productive by discouraging
a number of States from joining the Convention . On the other hand, some other
delegations had preferred a clearly spelled out compulsory and binding dispute
settlement procedure . In the view of those delegations , the Convention would
not be effective unless it was clear that , if parties did not comply with its
terms , there would be a compulsory and binding dispute settlement procedure.
Those delegations also felt that a number of issues in the Convention were
stated in general terms and that , if parties could not agree on their exact
meanings , there must be certainty that , at the last stage, the issue would be
resolved through a compulsory and binding procedure . There had been yet another
group of delegations which felt that many States would not agree to a compulsory
and binding dispute settlement procedure. In their view , in order not to keep
the Convention hostage to compulsory and binding dispute settlement procedures ,
it might be more appropriate to design a dispute settlement procedure with
flexibility , allowing the parties to choose their own mode of settlement with an
addition of compulsory non-binding procedure such as compulsory fact-finding or
conciliation . Such a procedure could also provide for an opt-in procedure .
Accordingly , at the time of ratification or later , States could choose a method
of binding dispute settlement . That approach , indeed, was a middle ground
between the two earlier approaches. It was his feeling that that approach would
have the support of the majority of the delegations. Taking that approach as
the basis , he had proposed a text for article 33 contained in document
WG/CRP . 83 . He would continue his consultations on that and hoped to be able to
report on the subject within a few days .
22 . Articles 34 t o 37 dealt with final clauses. It would be recalled that the
draft proposed by the International Law Commission had not had any provisions on
final clauses . During the discussion in the Working Group of the Whole on a
number of proposals , Ireland , on behalf of the European Union and its member
States , had submit ted a draft allowing for t he regional economic integration
organizations to become parties to the Convention . The Drafting Committee had
been amenable to that proposal . The text of articles 34 to 37 as agreed by the
Drafting Committee had therefore left the possibility open for such
organizations to become parties to the Convention.
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23 . Article 34 , on signature , allowed all States and regional economic
integration organi zations to sign the Convention . Because the term "regional
economic integration organization" had not been defined in the Convention , the
Drafting Committee had agreed that a definition for "regional economic
integration organization '' should be included in article 2 on ''use of terms ''.
24 . It would also be noted that the date for signature was left open . The
Drafting Committee had agreed to follow the general practice of opening the
Convention for signature for one year at United Nations Headquarters in
New York. The dates would have to be completed during the adoption of the
Convention in the General Assembly .
25 . Article 35 was on "Ratification , acceptance , approval or accession ". The
Drafting Committee had decided that , instead of having two articles - one on
ratification , acceptance and approval and one on accession - there should be a
single article to deal with all those matters. That was the practice followed
in recent treaties to simplify drafting and reduce the number of articles.
Article 35 followed standard form .
26 . Paragraph 1 provided that the Convention was subject to ratification ,
acceptance , approval or accession by States and by regional economic integration
organizations . It would be open for accession from the day after the date upon
which the Convention was closed for signature. The Secretary-General of the
United Nations would act as the depositary for the instruments of ratification ,
acceptance , approval or accession .
27 . Paragraph 2 addressed the relationship between a regional economic
integration organization and its member States and third States . It provided
that where such an organization became a party to the Convention without any of
its member States being a party, the organization should be bound by all the
obligations under the Convention . However , in the case of such an organization ,
one or more of whose member States was a party to the Convention , the
organization and its member States would decide on their respective
responsibilities for the performance of their obligations under the Convention .
In such cases , the organization and the member States would not be entitled to
exercise rights under the Convention concurrently.
28 . Paragraph 3 also dealt wi t h the particular situation of regional economic
integration organizations becoming parties to the Convention . It provided that
such organizations , in their instruments of ratification , acceptance , approval
or accession , should declare the extent of their competence with respect to the
matters governed by the Convent ion. Those organizations would a l so inform the
Secretary-General of the United Nations of any substantial modification in the
extent of their competence .
29 . Article 36 dealt with the entry into force of the Convention . Paragraph 1
addressed two issues : the date of entry into force and the number of
instruments of ratification , acceptance , approval or accession necessary for its
entry into force . It was evident that the Drafting Committee had been unable to
agree on the number of instruments of ratification necessary for the Convention
to enter into force . Three views had been expressed . One was that the
Convention should enter into force as soon as possible , which would require a
/ ...
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low number of instruments to be deposited . That would allow the Convention to
come into force for those States that wanted to be bound by the Convention .
According to that view, those States that did not wish the Convention to have
binding effect on them would simply not become parties to it . According to the
second view , the requirement of a large number of instruments of ratification ,
acceptance , approval or accession would not only ensure that many watercourse
States would become parties to the Convention but also increase the likelihood
that watercourse States of the same watercourse would be bound by the
Convention. According to the third view , it was more realistic to take a middle
ground between the two opposing views , namely , that the Convention would enjoy
great er support if the required number of instruments of rati f ication was
neither too low nor too high . It had been impossible t o reconci l e those views
in the Drafting Committee . The number 22 represented the views of those who
supported a low number of ratifications ; the number 60 represented the views of
those who preferred a high number; and the numbers 30 and 35 represented the
views of those who preferred the middle ground .
30 . With respect to the date of entry into force , the Drafting Committee had
agreed on the ninetieth day following the date of deposit of the required number
of inst ruments of ratification , acceptance , etc ., with the Secretary-General of
the United Nations .
31 . Paragraph 2 dealt with a State or regional economic integration
organization that ratified , accepted or approved the Convention or acceded
thereto after the deposit of the required number of instruments of ratification ,
acceptance , etc . For such a State or regional economic integration
organization , the Convention would enter into force on the ninet i eth day
following the date of deposit by such State or regional economic integration
organization of its instrument of ratification , acceptance , approval or
accession .
32 . Paragraph 3 avoided double counting by providing that any instrument
deposited by a regional economic integration organization would not be counted
as additional to those deposited by Member States .
33 . Article 37 dealt with authentic texts . It was the standard text in such
cases and was self-explanatory .
34 . The CHAIRMAN said that the statement by the Chairman of the Drafting
Committee was an integral part of the report of the Drafting Committee , and it
should therefore be reproduced in extenso in the summary record .
35 . I t was so decided .
36 . The CHAIRMAN invited the Working Group to consider the first report of the
Draft ing Committ ee (A/C . 6/51/NUW/WG/L . l/Rev . l) which had been submitted at the
Commit t ee ' s 24th meeting .
37 . Mr . GONZALEZ (France ) said that some of the articles to be discussed -
art icles 3 and 7 in particular - were related to each other, a fact that should
be taken into account in the final decision .
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38 . The CHAIRMAN said he agreed that they were related and that a solution must
be found that took into account the articles as a whole. He urged delegations
to streamline the debate and avoid repetition. The discussion on article 10
would be deferred at the request of the representative of South Africa .
Part III. PLANNED MEASURES
Article 11 . Information concerning planned measures
39 . Mr. AMARE (Ethiopia) recalled that Ethiopia had reserved its position on
all of part III (articles 11 to 19) .
40 . The CHAIRMAN said he took it that the Working Group wished to adopt
article 11 ad referendum .
41 . It was so decided .
Article 12. Notification concerning planned measures with possible adverse
effects
42 . The CHAIRMAN said that Turkey had reserved its position on articles 12
to 19 and had proposed that articles 12 to 15 should be changed . The positions
of delegations had already been stated and could be found in summary records
A/C.6/51/SR . 20 and 21 for the meetings held on 14 October 1996 .
43 . Mr. AMARE (Ethiopia) proposed that the title of article 12 should be
changed to read "Notification of planned measures which may have a significant
adverse effect" in order to make it agree with the text of the article .
44 . Mr. ISKIT (Turkey) said that his delegation maintained its reservation on
part III as a whole . It had proposed that articles 12 to 19 should be replaced,
and could not accept the adoption ad referendum of those articles .
45 . Ms . FAHMI (Egypt) said that her delegation supported the title of
article 12 as it appeared in the report of the Drafting Committee and would
prefer to change the word "significant " in the text.
46 . Mr . ROSENSTOCK (Expert Consultant) said that the best way to solve the
problems posed by titles was to recognize that they were established for the
sake of convenience and had no normative effect .
47 . Mr . SALINAS (Chile) said t hat his delegation had no objections regarding
the text of article 12 , although the title did not match the content .
Therefore, he suggested that "significant " should be inserted before "adverse
effects ".
48 . Mr . HABIYAREMYE (Rwanda ) said that the title of article 12 should agree
with its text ; therefore , he supported the inclusion of the adjective
"significant ".
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49 . Mr . HAMID (Pakistan) said that he supported the suggestion of the
representative of Egypt that "significant " should be deleted before "adverse
effect " in the text of the article.
50 . Mr . DEKKER (Netherlands) said that the text should not be changed, and
proposed that the phrase "with possible adverse effects " should be deleted from
the title . The proposed new title would be "Notification concerning planned
measures ", which would be in agreement with article 11 , "Information concerning
planned measures ", and with the text of article 13 , which referred to "planned
measures ".
51. Ms . LADGHAM (Tunisia) said that the word "significant " should not be
included in the title , and that the Netherlands proposal was worth considering .
52 . Mr. LOIBL (Austria) supported the proposal of the Netherlands and other
delegat ions that t he text should not be changed and that the title should be
shortened .
53 . Mr. SALINAS (Chile) said that the Netherlands proposal did not agree
exact ly with the content of the articles . Article 11 referred to planned
measures without qualifying the possible adverse effects , while article 12
stipulated the obligation to give notification of planned measures that might
have a significant adverse effect . Therefore , he maintained his proposal that
"significant " should be added to the title .
54 . Mr . LAMMERS (Chairman of the Drafting Committee) recalled that the word
"significant " appeared in two ways in the text of the Convention : in article 4,
paragraph 2, where it had been agreed to leave that word , and in other articles
dealing with "significant damage ". He referred to the footnote on page 31 . The
Drafting Committee had decided not to consider that question because it was
related to article 7 and would have to be revised in the light of that article .
55 . Mr . RAO (India) , supported by Mr . BOCALANDRO (Argentina) and Mr . LOGIZA
(Bolivia) , said he preferred the text recommended by the Drafting Committee and
the Netherlands proposal to shorten the title .
56 . Mr . KASME (Syrian Arab Republic) supported Egypt ' s position. The title
should match the t ext of the article . The word "significant " was not as
important in the context of notification as in the context of "significant
harm" . He therefore suggested using the words "possible effects" or "possible
adverse effects " in the text .
57 . Mr . ZHOU Jian (China) said that it would be appropriate to shorten the
title of article 12 , as the Netherlands had proposed . The obligation to notify
was clearly expressed in the original title ; if that were changed, the content
would also change , and China would then have reservations .
58 . Mr . HARRIS (United States of America) agreed with the comment by India , and
drew attention to two other issues : firstly , he favoured retain i ng the words
chosen by the Drafting Commit tee and, secondly, he made a distinction between
planned measures which might have a significant adverse effect and those which
actually caused a significant effect . The International Law Commission had
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established a lower threshold for notification than that contained in article 7 .
As for the quest ion raised by China, titles did not creat e normative obligations
or rights ; they were chosen as a matter of convenience . However , in response to
the concern expressed by certain delegations , the title proposed by the
Netherlands could be rephrased as "Notification concerning certain planned
measures ".
59 . Mr . SVIRIDOV (Russian Federation ) said he had no objection to retaining the
title recommended by the Drafting Committee or to shortening it as proposed by
the Netherlands , since the text of the article was quite self-explanatory. His
delegation did not object to changing the title to "Notification concerning
certain planned measures .
60 . Mr. Sung-Kyu LEE (Republic of Korea) supported the position of the
Netherlands .
61 . The CHAIRMAN said that the word "significant " appeared throughout the text
of the Convention , and the issue of the terminology of each article could not be
settled until the end of the consultations currently under way , particularly on
article 7 . Consequently , he suggested leaving the word "significant " until work
on the other articles had been finalized . As for the titles , the issue was not
very important , and he asked the representative of China to clarify his
statement in that regard .
62 . Mr . ZHOU Jian (China) said he agreed with the proposal of the United States
of America that the title should read "Notification concerning planned
measures ".
63 . Mr . ISKIT (Turkey) drew attention to the alternative text proposed by
Turkey in footnote 18 to document A/C . 6/51/NUW/WG/ L.l /Rev . l and recalled that
Turkey had reserved its position on articles 12 to 19 .
64 . The CHAIRMAN said he took it that the Working Group had noted the Turkish
position , and asked the representative of Turkey to inform him of the results of
his consultations with other delegations concerning his proposal .
65 . Mr. KASME (Syrian Arab Republic) said that the proposal of the United
States of America on the title of article 12 would cause confusion and make the
text of the article inconsistent with its title.
66. Ms. LADGHAM (Tunisia ) agreed with the statement by the Syrian Arab
Republic .
67 . Mr . CANELAS de CASTRO (Portugal) said that the United States proposal did
not enjoy the consensus support which had been growing in favour of the
Netherlands proposal . He wondered whether t he delegation of the Netherlands
itself would be prepared to accept the United States proposal ; his own
delegation supported the Netherlands proposal.
68 . Mr . ROSENSTOCK (Expert Consultant) emphasized that t he titles of articles
had no normative effect .
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69 . Mr . NGUYEN QUY BINH (Viet Nam) said he failed to understand the reason for
insisting on using the word "certain " , which would limit the number of measures
referred to , if the title was not an operative part of the article. He
supported the Netherlands proposal .
70 . Mr . PASTOR RIDRUEJO (Spain) said that Spain would be flexible as to the
title of the article , and supported the Netherlands proposal .
71 . Mr . PRANDLER (Hungary ) said that using the word "certain" woul d be
meaningless , and supported the proposal of the Netherlands .
72 . Mr . ADAM (Sudan) said that , in light of the fact t hat the t i t l e of the
article had no normative effect , it would be better to concentrate on adopting
its contents .
73 . Mr . NGUYEN QUY BINH (Viet Nam) said t hat , although t he Netherlands proposal
had not been accepted unanimously , it was supported by a broader consensus than
that of the United States of America . The issue should be considered again
later .
74 . Mr . ZHOU Jian (China) said that the phrase which the Nether l ands proposed
to delete restricted the measures to those that were being referred to ; the
delet ion of the phrase would therefore require the use of the word "certain"
before the word "measures " to maintain the restrictive nature of the sentence .
His delegation opposed any change to the original text .
75 . The CHAIRMAN took it that the Working Group wished to postpone the adoption
of the title of article 12 in order to hold consultations on the subject , and
that it wished to adopt the text of that article ad referendum .
76 . It was so decided .
Article 13
77 . The CHAIRMAN took it that the Working Group wished to adopt the text of
article 13 ad referendum .
78 . It was so decided .
Article 14
79 . Mr . PREDA (Romania) introduced two proposals concerning article 14 . The
first was to insert in subparagraph (a) , after the phrase "accurate evaluation ",
the words "of the planned measures ". The second was to delete subparagraph (b)
in its entirety because , on the one hand, its content was already summarized in
art icle 17 (3) , and on the ot her hand, it did not appear to take int o account
the provisions of article 8, which had already been adopted, concerning
cooperation in good faith among watercourse States , but rather cast doubt upon
the good faith of those States and, in particular, that of the not i fying State .
80 . Mr . LAMMERS (Chairman of the Drafting Committee ) said that the Drafting
Committee had not deemed it necessary to make article 14 (a ) any more specific,
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since it had been considered that it was obviously a continuation of article 13 ,
in which explicit reference was made to "planned measures ".
81 . Mr . KASME (Syrian Arab Republic) supported the statement by the Chairman of
the Drafting Committee . Also , the missing conjunction should be added at the
end of the Arabic text of article 14 (a) to bring it into line with the English
version .
82 . Mr . DEKKER (Netherlands ), Mr . NGUYEN QUY BINH (Viet Nam) and Mr . HANAFY
(Egypt) supported the statement by the Chairman of the Drafting Committee.
83 . Mr . PREDA (Romania ) said that he wished to withdraw his first proposal .
84 . Mr. AMARE (Ethiopia) endorsed the second proposal of the Romanian
delegation. In his view , the text of article 14 , subparagraph (b) , suggested
that the implementation of the planned measures was left in the hands of the
notified State instead of stressing cooperation and negotiation between the
notifying and notified States .
85 . Mr. MANONGI (United Republic of Tanzania) said that he also endorsed the
second proposal of the Romanian delegation , since he felt that notified States
could easily abuse the rights and privileges they were granted under article 14 ,
subparagraph (b). Moreover , that subparagraph gave cause for concern in that
there were bound to be situations in which States would have to implement
measures arising from other already existing agreements covered by the draft
Convention .
86 . Mr. ROSENSTOCK (Expert Consultant) said that , in preparing the draft
Convention , special care had been taken not to grant a veto to notified States .
Article 14 , subparagraph (b) , was aimed at helping watercourse States to ensure
that any planned measure was compatible with their obligations under draft
articles 5 and 7 . Furthermore , article 14 , subparagraph (b), and article 17 ,
paragraph 3, dealt with different situations and different periods of time . In
that regard , the present title of article 14 had been carefully drafted to
explain that its subparagraph (b) applied only to the period referred to in
article 13 , namely , the first six months of the period for reply .
87 . Mr . NGUYEN QUY BINH (Viet Nam) , Mr . KASME (Syrian Arab Republic) ,
Mr . CANCHOLA (Mexico) , Mr . HARRIS (United States of America) , Mr . HANAFY
(Egypt) , Mr . AL-WITRI (Iraq) , Mr . P. S. RAO (India) , Mr . SABEL (Israel),
Mr. BOCALANDRO (Argentina), Mr. SALINAS (Chile) and Mr. PULVENIS (Venezuela)
expressed support for retaining the current version of article 14 ,
subparagraph (b).
88 . Ms. KALEMA (Uganda) said that , if subparagraph (b) applied only to the
period of six mont hs referred t o in article 13 , she was in favour of retaining
it . However , should its application extend beyond that period, she would be in
favour of its deletion .
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89 . The CHAIRMAN said he took it that the Working Group wished to adopt ,
ad referendum, the present version of the text of article 14 as a whole .
90 . It was so decided .
Article 15
91 . The CHAIRMAN said he took it that the Working Group wished to adopt the
text of draft article 15 of the Convention ad referendum .
92 . It was so decided .
Article 16
93 . Mr. HAMID (Pakistan) said that his delegation could not accept the text of
article 16 , in particular its paragraph l ; t he text of that paragraph was
dangerous because it permitted any State to proceed with the impl ementation of
the planned measures by invoking reasons of emergency . Moreover , that provision
to some extent ran counter to article 14 , subparagraph (bl , and article 17 ,
paragraph 3, which prohibited t he implementation of the planned measures without
the consent of the notified State .
94 . Mr. ROSENSTOCK (Expert Consultant) explained that article 16, paragraph 1,
was int ended solely to prevent the notified State from invoking the absence of a
reply to exercise a veto , which was unacceptable . In his view , that paragraph
was unrelated to emergency situations and did not run counter to article 17 ,
paragraph 3 .
95 . Mr . KASME (Syrian Arab Republic) said that he agreed with the text of
article 16 . Referring to articles 5 and 7, he said that in order to be properly
understood, the concepts of "equitable participation" and "significant harm",
which had not been clearly defined , would have to be defined . That was equally
crucial to understanding article 6.
96 . The CHAIRMAN , supported by the Chairman of the Drafting Committee, said
that , in his view , when a watercourse State implemented the planned measures , it
had t o comply with t he principles governing the present Convention, including
those provided for in articles 5, 6 and 7 . Furthermore , he took it that , since
Pakistan had accepted the text of article 16 following the explanation of the
Expert Consultant , the Working Group wished to adopt article 16 ad referendum .
97 . It was so decided .
Article 17
98 . Mr . AMER (Egypt) , noting t hat he had reserved his position on art icle 17 ,
paragraph 3, said that a proposal was now being made in that paragraph linking
the period of suspension of the implementation of planned measures to the
peaceful resolution of the dispute in question . Since that link was based on
objective realit y, he was now prepared to enter into negotiations on t hat
proposal .
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99 . The CHAIRMAN said he took it that the Working Group wished to adopt
ad referendum article 17 , paragraphs 1 and 2 .
100 . It was so decided .
101 . The CHAIRMAN , referring to article 17 , paragraph 3, said that there was an
alternative proposal by Portugal in square brackets. An informal survey of
delegat ions had showed that there were more delegations against than in favour
of that proposal . The paragraph was basically aimed at dealing with cases where
a fact - finding commission was used ; it was t herefore related to article 33
concerning the settlement of disputes . Since the Chairman of the Drafting
Committ ee was cont inuing his consultations on that article , he suggest ed
deferring the adoption of any decision on that paragraph until the results of
those consultations were known .
102 . It was so decided .
Article 18
103 . The CHAIRMAN said he took it that the Working Group wished to adopt
ad referendum article 18 , paragraphs 1 and 2 .
104 . I t was so decided .
105 . The CHAIRMAN , referring to article 18 , paragraph 3, noted that there was a
Portuguese proposal in square brackets , which had not enjoyed wide acceptance
among members of the Drafting Committee . Since that paragraph a l so referred to
the fact-finding issue , he suggested deferring the adoption of a decision until
the Chairman of the Drafting Committee had concluded the consultations
concerning the settlement of disputes .
106 . It was so decided .
Article 19
107 . The CHAIRMAN said he took it that the Working Group wished to adopt
ad referendum article 19 .
108 . I t was so decided .
Article 20
109 . The CHAIRMAN , referring to article 20 , said that there was a proposal by
the representative of China to replace the words "preserve the ecosystems" by
"maintain the ecological balance ". That proposal was reflected in the summary
record of the 21st meeting .
110. Mr . SVIRIDOV (Russian Federation ) , Mr . PASTOR RIDRUEJO (Spa i n) , Mr . ISKIT
(Turkey) , Mr. CHIRANOND (Thailand) , Mr. EL-MUFTI (Sudan) and Mr . AMARE
(Et hiopia ) said that they supported the Chinese proposal .
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111 . Mr . DEKKER (Netherlands ) said that the Chinese proposal restri cted the
concept of preservat ion of ecosystems . According to the de f inition in the
Convent ion on Biological Diversity, "ecosyst em" meant a dynamic complex of
plant , animal and micro-organism communities and their non-living environment
interacting as a functional unit . The current text referred to a broader
concept of protect ion than the mere maintenance of the ecologica l balance. He
was t herefore in favour of the original text.
112 . Mr . TANZI (Italy) and Mr . PRANDLER (Hungary ) said that they supported the
proposal by the representative of the Netherlands.
113 . Ms . LEHID (Finland) said that she supported the original text and wished to
retain it for the reasons explained by the representatives of the Netherlands
and Hungary .
114. Mr . RAMEOS (Malaysia) , Ms . VARGAS de LOSADA (Colombia) , Mr . JABER
(Lebanon) , Mr . PRIFTER (Switzerland) and Mr . HABIYAREMYE (Rwanda) said that they
supported the Chinese proposal .
115 . Mr. NGUYEN QUY BINH (Viet Nam) , Mr . PATRONAS (Greece ), Ms . LADGHAM
(Tunisia) , Mr . SALINAS (Chile ) and Mr . LEE (Republic of Korea) said that they
supported the current wording of article 20.
116. Ms. BARRETT (United Kingdom) said that she supported the current text for
the reasons explained by the representative of the Netherlands .
117 . Mr . PULVENIS (Venezuela ) said that , like the representative of the United
Kingdom, his delegation would prefer to retain the reference to ecosystems , as
in the current text .
118. Mr . CANELAS de CASTRO (Portugal) said that he supported the original text
and recalled that his delegation had referred several times to the systematic
approach which had been endorsed at the United Nations Conference on Environment
and Development .
119 . Ms . GAO Yanping (China) said that , after an in- depth study , her delegation
felt that the ob jective of the Convention was to make better use of
international watercourses . It was not a convention on t he protection of the
environment , and it would therefore be better to use a more precise definition
which would facilitate acceptance of the Convention by the largest possible
number of States.
120 . Mr . P. S. RAO (India ) said that he supported the view expressed by the
representative of China and suggested that the words "preserve the ecosystems"
should be replaced by "maintain the ecological balance " .
121 . The CHAIRMAN said that the proposal to replace the words "preserve the
ecosystems" by "maintain the ecological balance" had been put forward by the
representative of China at the Working Group ' s meeting on 15 October 1996 and
had been taken up by the Draft ing Committee . Paragraph 2 of the commentary of
the Int ernational Law Commission contained an explanation of the terminology
used . He believed that there was general support for article 20 and suggested
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that action on article 20 should be deferred until consultations were held on
terminology .
122. Ms . GAO Yanping (China) said that the decision to defer action on
article 20 was well-founded, although she did not feel that there was general
agreement on the article . Most delegations had supported her delegation ' s
proposal.
123 . Mr . ROSENSTOCK (Expert Consultant) said that he was concerned that there
had been no explanation of the difference between "ecosystems " and "ecological
balance "; if one term was to be replaced by another , there should be a reason.
If the International Law Commission preferred to use the words "preserve the
ecosystems" it was because those words were the most appropriate and had been
selected for that reason .
124. The CHAIRMAN , referring to the comments made by the representative of
China, said that there was general agreement on the current text because it came
from the Drafting Committee .
Article 21
Paragraph
125. The CHAIRMAN said that there were no amendments to paragraph 1 .
126 . Paragraph was adopted .
Paragraph 2
127 . The CHAIRMAN said that paragraph 2 included a note on the term "significant
harm" which would be reviewed in the light of the text of article 7; the Working
Group would therefore return to that paragraph after holding the relevant
consultations .
128 . Mr . HARRIS (United States of America) said that , judging from the
commentary by the International Law Commission on article 21 , paragraph 2,
article 22 and article 23 , the obligation established was an obligation of due
diligence . In t he articles t hemselves , however , it was not clear whether an
obligation of due diligence or another type of obligation was imposed . His
delegation felt that , in order to avoid ambiguities which could cause problems
later , it should be made clear that the articles under consideration imposed an
obligat ion of due diligence .
129. Mr . LAMMERS (Chairman of the Drafting Committee ) said that although the
Drafting Committee had not agreed to make a specific reference to that effect ,
the Drafting Committ ee had agreed that it was not an absolute obligation or an
obligation of guarantee which was being imposed , but an obligation of due
diligence .
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130. The CHAIRMAN said that he took it that the Working Group wished to adopt
article 21 , paragraph 2 ad referendum on t he understanding that it would revert
later to the question of "significant harm " .
131 . It was so decided .
Paragraph 3
132 . The CHAIRMAN drew attention to the two variants of article 21 , paragraph 3;
one referred to measures and methods in general , and the other included
examples.
133 . Mr . LAMMERS (Chairman of the Drafting Committee) said that the correct
punctuation to reflect the two positions was as follows: the brackets should
open at the beginning of the paragraph and also after the word "watercourse" in
the third line ; then both brackets should be closed at the end of the paragraph .
134. The CHAIRMAN , Mr. HARRIS (United States of America) and Mr . SVIRIDOV
(Russian Federation) made statements about organizational matters .
The meeting rose at 1.03 p.m.
38
39
Annex 3
United Nations, Sixth Committee, Summary Record of the
Second Part of the 62nd meeting, 4 April 1997, A/C.6/51/SR.62/
Add.1, pp. 6-7, para. 24
(Original in English)
40
41
UNITED NATIONS
General. Assembly
FIFTY-FIRST SESSION
Official Records
SIXTH COMMITTEE
62nd meeting
held on
Friday, April 1997
at 3 p .m.
New York
SUMMARY RECORD OF THE SECOND PART* OF THE 62nd MEETING
Chairman : Mr . YAMADA (Japan)
(Chairman of the Working Group of the Whole on the
Elaboration of a Framework Convention on the Law
of the Non-Navigational Uses of International
Watercourses)
CONTENTS
AGENDA ITEM 144 : CONVENTION ON THE LAW OF THE NON-NAVIGATIONAL USES OF
INTERNATIONAL WATERCOURSES (continued)
* The summary record of the first part of the meeting appears as document
A/C.6/51/SR . 62.
This record is subject to correction. Corrections should be sent under the signature of a member of the
delegation concerned within one week of the ,late of 1he publication to the Chief of !he Offi cial Records
Editing Section, room DC2-750, 2 United Nations Plaza, and incorpomted in a copy of the record.
Corrections will be issued after the end of the session, in a separate corrigendum for each Committee.
Distr . GENERAL
A/C . 6/51/SR . 62/Add . l
29 August 1997
ENGLISH
ORIGINAL : SPANISH
97-81090 IE) / ...
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Page 2
The meeting was resumed at 6. 15 p. m.
AGENDA ITEM 144 : CONVENTION ON THE LAW OF THE NON-NAVIGATIONAL USES OF
INTERNATIONAL WATERCOURSES (continued)
1 . The CHAIRMAN said that , although the representative of France had cited
rule 120 of the rules of procedure of the General Assembly , which provided that ,
as a general rule , no proposal should be put to the vote at any meeting of a
committee unless copies of it had been circulated not later than the day
preceding the meet ing , that requirement was usually waived when negotiations
were prolonged and there was a deadline for the conclusion of the discussion .
After noting that each of the articles had been adopted separately, on the
understanding that the document had been read in its entirety, he said that a
vote would be taken on the draft convention as a whole and that a recorded vote
had been requested .
2. A recorded vote was taken on the draft convention as a whole .
In favour : Algeria , Austria , Bangladesh, Belgium, Brazil , Cambodia ,
Canada , Chile, Czech Republic , Denmark , Ethiopia, Finland,
Germany , Greece , Holy See , Hungary , Iran (Islamic Republic
of ), Italy , Jordan , Liechtenstein , Malawi , Malaysia , Mexico ,
Mozambique , Namibia , Netherlands , Nigeria , Norway , Portugal ,
Romania , South Africa , Sudan, Switzerland, Syrian Arab
Republic , Thailand, the former Yugoslav Republic of Macedonia ,
Tunisia , United Kingdom of Great Britain and Northern Ireland,
United States of America , Venezuela , Viet Nam, Zimbabwe
Against: China , France, Turkey
Abstaining : Argentina , Bolivia , Bulgaria, Colombia , Ecuador , Egypt , India ,
Israel , Japan , Lebanon , Lesotho , Mali , Pakistan , Russian
Federation , Rwanda , Slovakia, Spain , United Republic of
Tanzania , Uruguay
3. The draft convention as a whole was adopted by 42 votes to 3, with
19 abst entions .
4 . Mr . RAO (India) , speaking in explanation of vote , said that his delegation
had done its best to promote the adoption of a convention by consensus and
without a vote . As that had not been possible, India unfortunately had had to
abstain .
5 . From the outset , the Governments had been considering the draft convention
within the framework and parameters which the International Law Commission had
recommended for its adoption . The Commission had taken years to prepare the
draft , and no delegation had had the opportunity to conduct the necessary indepth
study of the various issues raised . Articles 5, 6 and 7 should have been
retained as proposed by the Commission , since it had been impossible to improve
on the care with which they had been drafted and the balance achieved in their
provisions . In particular , article 5, which was the only one that clearly
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established the principles of equitable and reasonable utilization , had been
weakened and obscured by the introduction of undefinable concepts that were not
even relevant to its implementation .
6 . Article 7 had also lost the balance achieved in the Commission ' s proposal
and was therefore unsatisfactory . India did not oppose the idea of paying due
attention to environmental considerations in the management and use of river
resources ; however , like other environmental issues , they could not be separated
from other development considerations , the need for transfers of technical
resources and the need for capacity-building in all States , particularly
developing ones . Sustainable development , protection, preservation and
management were basically guiding principles and could not be considered
specific and enforceable international standards .
7. India felt that article 32 on non-discrimination was inappropriate in a
framework convention, since t he application of that principle depended on the
economic , political and legal integration of the States of each region . In any
event , agreements concluded between States would always take precedence.
Likewise , problems concerning private international law had no place in the
Convent ion.
8. Lastly , the Indian delegation was fundamentally opposed to the inclusion of
any provision on dispute settlement in the framework Convention, since the
parties to a dispute should be free to choose the means of settling it . A
convention of that type should set forth the basic standards and general
principles for the negotiation of agreements between neighbouring States ,
without going into details which would only hamper such negotiations . The
opportunity to adopt an instrument of high persuasive value had been lost .
9 . Mr . AMER (Egypt) said that , although his delegation had taken part in the
debates of the Sixth Committee with the greatest possible interest and
effectiveness , it had abstained from voting. It believed, first of all , that
the Convention codified only some of the customary rules of international law
and that some of its provisions constituted new rules which departed from
established customary law . In that regard, the new provisions which departed
from international standards and with respect to which his delegation had
reservations could not be used against the Arab Republic of Egypt in the future ,
even if other States adopted them . The framework Convent ion could not affect
the legal validity of customs which had always existed and would always exist
and which reflected established international standards . Likewise , it could not
adversely affect bilateral , multilateral or international agreements on rivers
or watercourses because such agreements reflected the general provisions of
international contracts and because that would cause incalculable harm in many
parts of the world . In Egypt ' s view , the expression "international
watercourses" neither contravened nor formed part of the concept of an
"international drainage basin "; consequent ly , the use of that new term could not
in any way affect the rights or obligations deriving from other bi l ateral ,
regional or international agreements or from customs established in the
relations between riparian States .
10 . Given the importance it attached to the equitable sharing of international
watercourses , Egypt had reservations about the establishment of a rigid formula
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in article 5 linking that principle to the obligation of riparian States not to
cause harm to ot her States or making the t wo principles equivalent. The
standards of equitable utilization that appeared in article 6 could not cancel
or replace other standards established under international customary law . With
respect to the wording of article 7, he felt that it added nothing to the
customary principles already established and set forth by the Commission since
the beginning of its work . The principle of the right to use international
watercourses without harming other States was the cornerstone of any legal
regime on international watercourses agreed upon between States .
11 . Lastly , he stressed that the document was a framework convention , meaning
that it contained a set of principles and general rules on the non-navigational
uses of international watercourses , but that those principles and rules and
their partial or full application to any given international river basin would
depend on the mutual consent of all the States that shared that watercourse .
Therefore, the Convention could not be applied directly to the resources of
river basins unless the riparian States had concluded a special agreement
governing their use . Special agreements would take into account the particular
nature of the river in question and other bilateral or multilateral conventions ,
as well as the customs established with respect to the use of its waters , and
their provisions would take precedence over the Convention .
12 . Since the dawn of its civilization , Egypt had used the Nile and had
cooperated with other basin States under international customary rules. It
hoped that the Convention just adopted would promote constructive cooperation
and help to guarantee the use of the Nile as a source of life for all the
peoples of the region .
13 . Mr . HARRIS (United States of America) said that the Convention was the
outcome of a lengthy process , particularly in the International Law Commission,
and that although it was not perfect , it had established a framework that could
foster a common understanding among the majority of countries . Not all of its
provisions were part of international customary law, but even the new ones
served a vital function by forming a set of reasonable standards for the parties
to the Convention which would help to settle disputes and to improve
communication and cooperation between watercourse States .
14 . Mr . SABEL (Israel) , speaking in explanation of vote , said that although the
Convention represented an effort to strike a balance among different interests ,
his country still had reservations about various aspects , and had therefore
abstained from voting on the draft convention as a whole.
15 . Mr . CHIMIMBA (Malawi) said that , while his delegation had voted in favour
of the draft Convention as a whole , he wished to place on record its
reservations concerning article 2 (c) ; article 3, paragraph 4; article 32 ; and
article 33.
16 . Mr . CAFLISCH (Observer for Switzerland) , speaking in explanation of vote ,
said that his delegation had voted in favour of the Convention as a whole in the
belief that it could be a useful instrument for the international community and
that it represented the codification of a fundamental principle of the law on
the uses of international watercourses , namely , equitable and reasonable
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utilization . Nonetheless , his delegation was concerned, first of all , at the
lack of a preambular paragraph recalling the sovereignty of watercourse States
over the part of the watercourse situated in their territory , even though the
exercise of such sovereignty was subject to the norms of international law .
Second, paragraphs 2 and 5 and the ambiguity of article 3, paragraph 4, gave
cause for concern . Third, it was concerned at the wording of article 7,
paragraph 2 for the reasons it had outlined previously. Lastly , it was not
opposed to article 33 , which was preferable to having no means of settling
disputes , even though it believed that the Convention, in particular, should
include the option of seeking binding court decisions as a last resort .
17 . Ms . GAO Yanping (China) , speaking in explanation of vote , said that her
delegation had voted against the Convention for reasons that fell into two
categories . First , it had voted against it for procedural reasons : her
delegation had not had a 24-hour period to inform its Government of the outcome
of the negotiations on the draft Convention and to request instructions ; nor had
it received the official translation of the instrument . While articles 3, 5, 6,
7 and 33 had been adopted by a vote , many other articles that had been adopted
without a vote had given rise to reservations by numerous States . Clearly, the
Convent ion had not been adopted by consensus of the international community,
contrary to United Nations practice, which would hinder its implementation .
Second, her delegation had opposed the Convention for reasons of content . In
its view , there was no balance between the rights and obligations of watercourse
States . Nor did the Convention reflect the principle of national sovereignty,
recognized by both the Charter of the United Nations and international law .
Moreover , its provisions on the settlement of disputes did not conform to the
provisions of Chapter VI of the Charter . Lastly , her delegation continued to
have reservations with regard to the first and fifth preambular paragraphs and
articles 5, 7, 20 , 22 , 33 and 36 .
18 . Ms. VARGAS DE LOSADA (Colombia) , speaking in explanation of vote , said that
her delegation had abstained because the basic provisions of the Convention were
not sufficiently balanced; such an agreement , particularly its basic provis i ons ,
should have enjoyed wider acceptance . Moreover , she wished to place on record
that , owing to the circumstances surrounding the negotiations on the text of the
Convention , there had been no time to compare the versions in the various
official languages , which would all be equally authentic .
19 . Mr . PASTOR RIDRUEJO (Spain) , speaking in explanation of vote , said that his
delegation had abstained because the content of article 7, paragraph 2, of the
Convention was highly unsatisfactory. In his view , the provision, which was the
backbone of the Convention , was not sufficiently balanced .
20 . Mr . GONZALEZ (France) , speaking in explanation of vote , said that his
delegation had voted against the Convention because the point of order it had
raised had been ignored; speakers had been denied the opportunity to explain
their vote before the voting ; and the Convention had been adopted without the
two-thirds majority specified in the rules of procedure . His delegation had
also voted against it because of the manner in which the work had been carried
out , the procedure used to negotiate the adoption of the draft Convention and
the ambiguities of some of its basic provisions , particularly those relating to
the scope of the draft . There were also a number of articles which had given
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rise to numerous reservations , indicating that the Sixth Committee could not
consider that i t had completed its work ; t herefore , it could not submit a report
on the question to the General Assembly . Lastly , he noted that the number of
votes in favour of adopting the draft Convention was barely over the minimum of
35 States required for its entry into force ; that would impede its general
acceptance and its contribution to the development of international law and to
the strengthening of international peace and security .
21 . Mr . NUSSBAUM (Canada) , speaking in explanation of vote , said that his
delegation had voted in favour of adopting the draft Convention for a number of
reasons. First , according to its interpretation, article 3, paragraph 1, of the
Convention provided that agreements already in force could not be affected by
the implementation of the Convention . Second, according to its interpretat ion ,
article 3, paragraph 2, implied no legal or other obligation whatsoever for the
parties to harmonize agreements already concluded and in force with the
principles of the Convention . Lastly , it supported the codification of
international law in general and believed that it would help to strengthen peace
and security at a time when many international watercourses and many sources of
drinking water in general were being increasingly threatened by greater
consumption and pollution .
22. Mr. SVIRIDOV (Russian Federation) , speaking in explanation of vote , said
that his delegation had abstained because it deemed article 32 of the Convention
unacceptable .
23 . Mr. SMEJKAL (Czech Republic) , speaking in explanation of vote , said that
his delegation had voted in favour of adopting the draft Convention because it
was interested in promoting the process of codification and progressive
development of international law . Nonetheless , it had reservations concerning a
number of provisions of the Convention. First , it was difficult to accept the
text of article 7, paragraph 2. Second, the fifth preambular paragraph and
article 5 referred to "optimal [and sustainable] utilization "; in his
delegation ' s view , the adjective "sustainable" was inappropriate . Equally
unsatisfactory was the fact that the preamble lacked a paragraph recognizing the
sovereignty of watercourse States over the watercourse in question . Lastly , it
was regrettable that the approach taken in article 3 in order to resolve the
problem of relations between the Convention and watercourse agreements concluded
prior or subsequent to it was lacking in clarity and unnecessarily complicated .
24 . Mr . SALINAS (Chile) , speaking in explanation of vote , said that his
delegation had voted in favour of the draft Convention , despite its reservations
with regard to some of its provisions . For example , the deletion of the
reference to the sovereignty of the watercourse States over the part of the
watercourse situated in their national territory was a serious omission , since
the principle of State sovereignty was the point of departure for the whole
process . Nonetheless , the draft which had been adopted was a useful guideline
for States insofar as it laid down , in a balanced fashion , the basic principles
governing the question , namely , the principle of equitable and reasonable
utilization and participation, the principle of not causing sign i f i cant harm,
the principle of cooperation and the principle of environmental protection . The
Convention was also a useful instrument because it established a binding
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procedure for the settlement of disputes , particularly through the mechanism of
fact-finding .
25 . Mr . KASME (Syrian Arab Republic) said that his delegation had voted in
favour of the draft convention because it considered it an important step
forward . However , he had reservations on three of the articles . With regard to
article 5, he endorsed the clarification which the International Law Commission
had made in paragraph (3) of the commentary on article 5 in its report on the
work of its forty-si xth session (A/49/10) : "Attaining optimal uti l ization and
benefits does not mean achieving the ' maximum' use , the most technologically
efficient use , or the most monetarily valuable use much less short-term gain at
the cost of long-t erm loss . Nor does it imply that the State capable of making
the most efficient use of a watercourse - whether economically, in terms of
avoiding waste , or in any other sense - should have a superior cl aim to the use
thereof . Rather , it implies attaining maximum possible benefits for all
watercourse Stat es and achieving the great est possible satisfaction of all their
needs , while minimizing the detriment to , or unmet needs of , each ." With
regard to article 7, he endorsed the observations of the Commission in
paragraph (14 ) of the relevant commentary : "A use which causes significant harm
to human health and safety is understood t o be inherent ly inequitable and
unreasonable ." Finally, with regard to article 33 , his delegation was certain
that the establishment of a compulsory procedure for the settlement of disputes
regarding the application and i nterpretation of the Convention was the best way
to make that instrument effective and prevent deadlocks .
26 . Mr . BENITEZ SAENZ (Uruguay) said that his delegation had abstained in the
vote because , although it supported the principles contained in the Convention
as adopted, it believed that the figure of 35 States established in article 36
for its entry into force was not sufficiently representative for such a
framework convention .
27 . Mr . LOAYZA (Bolivia) said that his delegation had abstained because of its
previously stated reservations concerning the Convention as adopted , in
particular concerning article 7, paragraph 2 .
28 . Mr . BOCALANDRO (Argentina) said he did not wish to restate the reservations
which his delegation had already expressed concerning certain articles of the
Convent ion , which could be found in the summary records . His de l egation had
abstained because the Convention as adopted presented some problems with regard
to key elements which had not been resolved satisfactorily .
29 . Mr . CANELAS DE CASTRO (Portugal) said t hat his delegation had vot ed in
favour of the Convention because it represented a milestone in the process of
the codification and progressive development of international law relating to
the uses of international watercourses and to the uses of water in general , as
well as to cooperation in that field , bearing in mind in particular the
limitat ions , both quantitative and qualitative , to which waters and their
ecosystems were subject . The instrument just adopted should be applied without
prejudice to the principles , norms and general concepts of applicable
int ernational environmental law .
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30 . Mr. DEKKER (Netherlands) said that his country maintained watercourse
cooperation agreements with t he riparian States of the rivers Scheldt , Moselle
and Rhine - Germany , Belgium, France , Luxembourg and Switzerland . Those
agreements dealt with flood prevention , pollution control and restoration of
aquatic ecosystems . His delegation had voted in favour of the Convention
because it hoped that , notwithstanding the reservations expressed by France and
Switzerland, which , like the Netherlands , were parties to the aforementioned
agreements , existing watercourse agreements would be respected under the
provisions of article 3 .
31 . Mr . AL-WITRI (I raq) , said that his delegation had voted in favour of the
Convention because it allowed the codification of international law on the uses
of international watercourses . Riparian States of such watercourses should
cooperate constructively to meet the needs of all in accordance with existing
agreements , the Convention and international law, whether or not they were
parties to the Convention . The modification made to the definition of the term
"watercourse State" by the International Law Commission in article 2,
subparagraph (c ) , was unnecessary . A provision should have been added to
article 33 concerning arbitration and binding legal solutions to disputes
between watercourse States which could not be resolved by other means . Finally,
his delegation feared that the number of 35 States established for the entry
into force of the Convention would be insufficient to guarantee its application .
32 . Mr. AMARE (Ethiopia) said that although his delegation had made some
reservations , it had voted in favour of the adoption of the draft convention as
a whole , since it contained the basic norms for regulating the use of
international watercourses on the basis of the principle of equitable use , which
was fully recognized in articles 5, 6 and 7 . It was to be hoped, however , that
the ambiguous doctrines some States had cited regarding the use of watercourses
would not be taken into account . The Convention would be highly useful in cases
where no agreement had been made to regulate the joint use of an international
watercourse . No State could claim an exclusive right on the basis of outmoded
principles established unilaterally for its own benefit . The Convention would
provide an appropriate framework within which watercourse States could negotiate
in good faith an equitable allocation of water resources .
33. Mr. HABIYAREMYE (Rwanda) said that his delegation had abstained in the vote
because the preamble to the Convention contained no reference to State
sovereignty .
34. Mr. LAVALLE (Guatema la) said it was regrettable that it had not been
possible to include in the preamble the proposed paragraph on State sovereignty
and that the version of article 7 contained in the report of the International
Law Commission, which established an adequate balance between upstream and
downstream watercourse States , had not been adopted . It was also regrettable
that it had not been possible to compare the different language versions ,
particularly as oral amendments had been made only to the English version of
article 7 .
35 . Mr. NGUYEN QUY BINH (Viet Nam) said that his delegation had voted in favour
of the adoption of the draft convention because it believed in the codification
of international law . However , it had made a reservation because the principle
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of State sovereignty was not fully reflected in the Convention. In any event ,
the principle of State sovereignty did not absolve States of their liability for
transboundary harm. In addition , the text adopted , although it constituted a
framework convention, did provide for a minimum dispute-settlement mechanism .
Therefore, his delegation had voted in favour of its adoption .
36 . Ms. FLORES (Mexico) said that although it had , unfortunately , not been
possible to adopt the Convention without a vote , the text represented a
significant step forward in the codification and progressive development of
international law and would help to improve cooperation and communication
between States and promote the conservation and preservation of international
watercourses to the benefit of current and future generat ions .
37 . Mr . PRANDLER (Hungary ) said that his delegation had voted in favour of the
draft convention even though it had placed on record reservations concerning
articles 5, 6, 7 and 33 . The t ext as prepared truly represented a compromise ,
and thus it was regrettable that some countries had voted against its adoption
or had abstained . The Convention would contribute to the progressive
development and codification of international law , as the International Law
Commission had ant icipated .
38 . Mr . VARSO (Slovakia) said that his delegation had abstained in the vote on
the draft convention because it believed that there was a lack of balance
between articles 5 and 7 . Article 5 should allow the equitable and reasonable
use of international watercourses , while article 7 should place limits on such
utilization . Its abstention did not mean that Slovakia was against the
codification and progressive development of international law . Cooperation
among States was essential in order to strike a balance between the interests of
upstream and downstream watercourse States .
39 . Mr . PULVENIS (Venezuela ) said that he would have preferred the Convention
to have been adopted by consensus . His delegation had voted in favour of
adoption because it believed that the best compromise solution within the
limitations imposed by the negotiating process had been achieved . Despite those
limitations , an important step had been taken in the direction of the
codification and progressive development of international law .
40 . Mr . MANONGI (United Republic of Tanzania) said that the Convention had been
adopted not as a result of comprehensive negotiations , but because the Working
Group had run out of time . The provisions of article 3, paragraph 2, and of
articles 5, 7 and 32 did not represent a balance of interests between riparian
St ates insofar as the equitable use of wat ercourse was concerned . Consequently,
an ins t rument had been adopted which did not enjoy the confidence of a
considerable number of States .
41 . The CHAIRMAN int roduced the draft report of the Working Group of the Whole
to the General Assembly (A/C . 6/51/NUW/WG/L.4 and Add . l) .
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Part I . Introduction
42 . The CHAIRMAN said he took it that the Working Group wished to adopt Part I
of the draft report .
43 . It was so decided .
44 . Mr . GONZALEZ (France) said that the articles had been adopted with a number
of reservations , which meant that the drafting process was not over . For that
reason , the report of the Working Group could not be submitted to the General
Assembly; instead, the work that had been done should be reported to the Sixth
Committee .
Part II : Consideration of proposals
Paragraphs 6 and 7
45 . The CHAIRMAN said he took it that the Working Group wished to adopt
paragraphs 6 and 7 of the draft report.
46 . It was so decided .
Paragraph 8
47 . Mr . SVIRIDOV (Russian Federation) proposed that , in the statement of
understanding pertaining to article 1, the words "conservation and management "
should be replaced by the word "utilization ".
48 . The CHAIRMAN said he took it that the Working Group wished to adopt
paragraphs (a ) and (b) of the statement of understanding pertaining to
article 1, as orally amended by the representative of the Russian Federation .
49 . It was so decided .
50 . The CHAIRMAN said he took it that the Working Group wished to adopt the
paragraph of the statement of understanding pertaining to article 2,
subparagraph c.
51 . It was so decided .
52. The CHAIRMAN took it that the Working Group wished to adopt paragraph (a)
of the statement of understanding pertaining to article 3 .
53 . It was so decided .
54 . The CHAIRMAN said that one delegation had proposed t hat the phrase "in this
article or elsewhere" should be added after the word "used" in the first line of
paragraph (b) pertaining to article 3 . He took it that the Working Group wished
to adopt the paragraph with the proposed amendment .
55 . It was so decided .
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56 . The CHAIRMAN said he took it that the Working Group wished to adopt the
paragraph pertaining to article 6, paragraph 1 (e) .
57 . It was so decided .
58 . The CHAIRMAN read out a paragraph pertaining to article 7, paragraph 2,
which was to be incorporated into the statement of understanding contained in
document A/C.6/51/NUW/WG/L . 4/Add . l and which read : "In the event such steps as
are required by article 7 (2) do not eliminate the harm, such steps as are
required by article 7 (2) shall then be taken to mitigate the harm". He took it
that the Working Group wished to adopt the paragraph.
59 . It was so decided .
60. The CHAIRMAN said he took it that the Working Group wished to adopt the
paragraphs pertaining to article 10 , articles 21 , 22 and 23 , article 28 and
article 29 .
61. It was so decided.
62 . The CHAIRMAN noted that throughout the consideration of the articles of the
draft convention, reference had been made to the relevant comments which the
International Law Commission had made to clarify its content.
Paragraphs 9 and 10
63. Mr. ISKIT (Turkey) said that , in order to place on record what had really
happened during the meeting , it would be necessary to add a phrase in
paragraph 9 after the word "adopted" to indicate that the Working Group had
failed to reach consensus on the most important articles , nor had it adopted the
draft as a whole by consensus.
64 . The CHAIRMAN pointed out that the Working Group had adopted the draft
convent ion as a whole after putting it to a vote . He suggested that , if
delegations agreed, the results of that vote should be included in paragraph 9
of the draft report .
65 . Mr . ISKIT (Turkey) said it would suffice to say that the draft convention
had been put to a vote .
66 . The CHAIRMAN said he took it that the Working Group wished to adopt
paragraphs 9 and 10 of the report as amended by the representative of Turkey .
67 . It was so decided .
68 . The CHAIRMAN said he took it that the Working Group wished to adopt the
draft report (A/C . 6/51/NUW/WG/L .4 and Add . l) as a whole .
69 . It was so decided .
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70 . The CHAIRMAN said that the Working Group had concluded its work on adopting
the draft convention, which represented the culmination of nearly 25 years of
work. He thanked delegations , the Chairman of the Drafting Commi ttee , the
Expert Consultant , the Secretary and the Secretariat for their assistance .
The meeting rose at 8.05 p. m.
53
Documentation from the Bolivia-Chile Silala Working
Group and Political Consultation Mechanism
(Annexes 4 - 10)
54
55
Annex 4
Joint Study Profile submitted by Chile in August 2004
(Original in Spanish, English translation)
56
Perfil de estudio conjunto
La naturaleza y caracteristicas de los recursos hidricos del Silala
1. INTRODUCCION
Conforme se desprende del Acta del 6 de mayo de 2004,
correspondient e a la primera reunion de trabajo de la Comisi6n Tecnica
Mixta dispuesta por los Cancilleres de Chile y Bolivia para tratar
materias atingentes a las aguas del Silala, y conforme al intercambio de
Notas de fecha 7 de abril de 2004 de Chile y 4 de mayo de 2004 de
Bolivia, se determin6 necesario reafizar estudios tecnico- cientificos que
permitiesen determinar fa natura/eza, origen y f/ujos de las aguas de/
Si/ala para, de esa manera, establecer una base cientffica que sea
puesta a disposici6n de los respectivos Gobiernos.
Para dicho prop6sito, se acord6 que organismos tecnicos de ambos
pafses realicen estudios conjuntos sobre las materias que indica el
presente documento.
Se consider6 en el Acta que los estudios que comprendieran
investigaciones con tecnicas isot6picas, hidroqufmicas y otras, podrian
ser encomendados a organismos y entidades calificados, solventes y de
reconocida reputaci6n, los que deberfan ser definidos en su oportunidad.
Conforme a esos lineamientos, el presente documento comprende una
proposici6n de\ perfil para llevar adelante esos cometidos.
Par lo tanto, desde el punto de vista cientifico y tecnico, y en funci6n de
una adecuada organizaci6n del tiempo y los recursos a emplear, el perfil
que propone Chile esta orientado a dilucidar el asunto que se ha
planteado entre ambos paises, segun diversos documentos
intercambiados.
2. CARACTERIZACION ESPACIAL y TERRITORIAL
En relaci6n a este cap ftulo, se requiere que el estudio consldere una
introduccl6n al area que sera sometida a investigaci6n, la cual
incorporara una descripci6n del marco geografico de la cuenca del rfo
Sila la, contemplando los siguientes aspectos:
2.1 Ubicaci6n
57
Joint Study Profile
The nature and characteristics of Silala’s water resources
1. INTRODUCTION
As is clear from the Act of 6 May 2004, corresponding to the first work meeting
of the Joint Technical Commission arranged by the Foreign Ministers of Chile
and Bolivia to deal with matters relevant to the Silala waters, and according to
the Exchange of Notes dated 7 April 2004 of Chile and 4 May 2004 of Bolivia,
it was determined necessary to carry out technical-scientific studies that would
allow to determine the nature, origin and flows of the Silala waters, in order to
establish a scientific base that is made available to the respective Governments.
For this purpose, it was agreed that technical organisms from both countries
conduct joint studies on the matters indicated in this document.
It was considered in the Act that the studies that included investigations
with isotopic, hydro-chemical and other techniques, could be entrusted to
organizations and entities qualified, solvent and of recognized reputation,
which should be defined in due course.
In accordance with these guidelines, this document includes a profile proposal
to carry out these tasks.
Therefore, from the scientific and technical point of view, and in function of an
adequate organization of the time and resources to be used, the profile proposed
by Chile is aimed at elucidating the issue that has been raised between the two
countries, according to various documents exchanged.
2. SPATIAL AND TERRITORIAL CHARACTERIZATION
In relation to this chapter, it is required that the study consider an introduction to
the area that will be submitted to research, which will incorporate a description
of the geographical framework of the Silala River basin, contemplating the
following aspects:
2.1 Location
1
58
Dentro de esta parte se debera efectuar una descripci6n que
contenga lo siguiente:
- Ubicaci6n polftica administrativa
- Superficie del area de estudio
- Accidentes relevantes identificables y toponimia inherente
- Entldades pobladas ubicadas en el area
- Actividades productivas en el area
- Accesibilidad y distancias
2.2 Descripci6n fisiografica de la zona
En esta parte introductoria, el estudio debera incorporar una
descripci6n de los principales rasgos ffsicos del area, con los
siguientes aspectos:
a) A nivel de relieve:
- Rasgos volcanicos: Considera la identificaci6n de accidentes,
disposici6n de estructuras, alturas y denominaci6n toponfmica.
- Rasgos hidrograficos: Considera una caracterizaci6n del sistema
de drenaje que configuran la hoya hidrografica, la clasificaci6n de
la cuenca y la identificaci6n de su via exutoria de acuerdo a la
topografia del area.
- Alturas relevantes: Considera la identificaci6n de las alturas
maximas a nivel de cerros y volcanes, como tambien mfnimas a
nivel de base (m.s.n.m.). Considera la identificaci6n de alturas en
el umbral oriental de la cuenca, en las nacientes Orientales, en las
nacientes de Cajon yen el cruce del lfmite Internacional.
- Pendlentes general y locales: El estudio debera hacer referenda
a los resultados de las pendientes del terreno en grades y
porcentajes. Las pendientes locales, confonne se describe en la
parte topografica, responderan a perfiles representativos del area,
incluyendo el eje longitudinal de la quebrada de Cajones, desde su
umbral oriental hasta el lfmite Internacional.
La referenda a la pendiente general se fundamentara en un perfil
especial que comprendera desde el umbra! oriental de la cuenca,
pasando por las nacientes Orientales, la quebrada Oriental y el
lfmite internacional.
b) Rasgos vegetacionales
2
59
Within this part, a description must be made that contains the following:
- Political-administrative location
- Surface of the study area
- Identifiable relevant accidents and inherent toponymy
- Populated entities located in the area
- Productive activities in the area
- Accessibility and distances
2.2 Physiographic description of the area
In this introductory part, the study should incorporate a description of the
main physical features of the area, with the following aspects:
a) At the topography level:
- Volcanic features: Considers the identification of accidents, structure
layout, heights and toponymic denomination.
- Hydrographic features: It considers a characterization of the drainage
system that make up the hydrographic basin, the classification of the basin
and the identification of its drainage path according to the topography of the
area.
- Relevant heights: It considers the identification of the maximum heights
at the level of hills and volcanoes, as well as minimum heights at the base
level (meters above sea level). It considers the identification of heights in the
Eastern threshold of the basin, in the Oriental springs, in the Cajon springs
and in the crossing of the international boundary.
- General and local slopes: The study should refer to the results of the
terrain slopes in degrees and percentages. The local slopes, as described
in the topographic part, will respond to representative profiles of the area,
including the longitudinal axis of the Cajones ravine, from its eastern
threshold to the international boundary.
The reference to the general slope will be based on a special profile that will
include from the Eastern threshold of the basin, passing through the Oriental
springs, the Oriental ravine and the international boundary.
b) Vegetation features
2
60
Comprende la identificaci6n de especies y superficies de cobertura
c) Fauna
Comprende informaci6n sobre fauna silvestre e introducida.
d) Rasgos climaticos
El informe debera contemplar en este factor una breve
caracterizaci6n general del area de estudio en base a los
slguientes fundamentos:
- Precipitaciones: Sobre la base de estadfsticas disponibles del
area.
-Temperaturas: maximas y min1mas sobre la base de la
informaci6n disponible y aplicables con fundamento cientffico.
- Clasificaci6n general climatica aplicable conforrne a los
indicadores de localizaci6n regional, vertiente andina de
pertenencia, alturas, temperaturas y precipitaciones1.
e) Cartograffa introductoria
Este capftulo debera incorporar un mapa de ubicaci6n del area de
estudio a nivel de escala pafs, un mapa de ubicaci6n a nivel local regional
y un mapa a nivel del area a estudiar con los detalles de
ubicaci6n de los principales accidentes, top6nirnos, caminos y
senderos debidamente georreferenciados. Podran utilizarse
graficos y perfiles de ser necesarios.
2. 3 Caracterizaci6n topografica y geodesica:
El capftulo debera caracterizar topograficamente el area de
estudio. Comprende tanto los antecedentes disponibles, como
aquellos que deberan obtenerse en terreno para complementar
la informaci6n del area. Esto se reflejara en la cartografia que
1 La clasificaci6n climatica aplicable debe fundamentarse con indicadores cientfficos de
incidencia en el area, como los senalados, y no en base a interpolaciones deducidas de
una division politico administrativa donde predominan factores no vinculantes con el
area de estudio.
3
61
It includes the identification of species and coverage areas.
c) Fauna
It includes information about wildlife and introduced fauna.
d) Climatic features
The report should contemplate in this factor a brief general characterization
of the study area based on the following fundaments:
- Precipitation: Based on available statistics of the area.
- Temperatures: Maximum and minimum on the basis of the information
available and applicable with scientific basis.
- General climatic classification applicable according to the indicators of
regional location, Andean spring of relevance, heights, temperatures and
rainfall1.
e) Introductory cartography
This Chapter should incorporate a location map of the study area at the
country scale level, a map of local regional level and a map at the level of
the area to be studied with the location details of the main accidents, place
names, roads and trails, properly geo-referenced. Graphics and profiles may
be used if necessary.
2.3 Topographic and geodesic characterization:
The Chapter should topographically characterize the study area. It includes
both the available background information and the information that must
be obtained in the terrain in order to complement the information of the
area. This will be reflected in the cartography that will support the various
works that will be carried out in the framework of this study.
_____________________________
1 The applicable climatic classification must be based on scientific indicators of incidence in the area, such as those
indicated, and not based on interpolations derived from a political-administrative division where non-binding
factors predominate with the study area.
3
62
respaldara los diversos trabajos que se realizaran en el marco de
este estudio.
En este capitulo, se debera interpretar la documentaci6n de
gabinete y terreno seflalada precedentemente (informes,
levantamientos, mediciones, perfiles, cartas y pianos).
Espedficamente se requiere documentar y realizar los siguientes
trabajos:
2.3.1 Recopilaci6n de antecedentes topograficos, cartograficos y
geodesicos del area
Se debera efectuar una completa recopilaci6n y revision de los
antecedentes existentes a nivel de:
- Comisi6n Mixta de Lfmites
- Organismos oficiales de cada pais (Geograficos militares,
mineros y similares)
2.3.2 Trabajos cartograficos y geodesicos.a realizar:
- Apoyo de terreno para la confecci6n de la cartografia a escala 1:
10.000 de la cuenca, con curvas de nivel cada 5 m. Para este
trabajo se cuenta con el levantamiento aerofotogrametrico
binaclonal efectuado en noviembre de 2001.
- Levantamientos de detalle del terreno para la confecci6n de
pianos a escala 1: 1.000 de las nacientes Orientales y Cajones, con
curvas de nivel cada 1 m. o 50 cm.
- Levantamientos de detalle a escala 1: 500 de las secciones con
mayor y menor pendiente hidraulica entre las nacientes
Orientales, Cajones y el Hmite Internacional.
- Medici6n de perfiles geodesicos de las quebradas Orientales y
Cajones, con detalle de los accfdentes del terreno, de las obras
existentes y del escurrimiento de las aguas, desde los umbrales,
pasando por las nacientes hasta el If mite internacional.
- Medici6n de uno o mas perfiles transversales al sentido de las
quebradas Cajones y Orientales. Dichos perfiles deberan ser
representativos para conocer el caracter colector de esta parte de
la cuenca.
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various works that will be carried out in the framework of this study.
In this Chapter, the office and terrain documents indicated above must be
interpreted (reports, surveys, measurements, profiles, letters and maps).
Specifically, it is necessary to document and perform the following tasks:
2.3.1 Collection of topographic, cartographic and geodetic information of
the area
A complete compilation and review should be carried out of the existing
background information at the level of:
- Joint Boundary Commission
- Official organizations of each country (military, mining and similar
geographic organizations)
2.3.2 Cartographic and geodetic works to be carried out:
- Field support for the preparation of cartography at a 1:10.000 scale of the
basin, with level curves every 5 m. For this work, we have the binational
air-photogrammetric survey carried out in November 2001.
- Detailed terrain surveys for the preparation of 1:1.000 scale maps of the
Orientales and Cajones springs, with level curves every meter or 50 cm.
- Detail surveys at 1:500 scale of the sections with the highest and lowest
hydraulic gradients between the Orientales and Cajones springs and the
international border.
- Measurement of geodetic profiles of the Orientales and Cajones ravines,
with details of the accidents of the terrain, of the existing works and of the
runoff of waters, from the thresholds, passing through the springs up to the
international border.
- Measurement of one or more profiles transversal to the direction of the
Cajones and Orientales ravines. These profiles must be representative in
order to know the collector character of this part of the basin.
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64
- Levantamiento detallado de las obras hidraulicas para la
confecci6n de pianos constructivos por secciones.
- Confecci6n de los pianos de detalle de las obras hidraulicas,
considerando extension de los canales; caracteristicas
constructivas; materiales utilizados; secciones de pendiente;
mediciones de talud, sello, anchos, altura y profundidades;
indicaci6n de estado de las obras y rebalses.
2.3.3 Plan de actividades
- Los trabajos topograficos y geodesicos de terreno seran
efectuados por las Cornisiones de Lirn ites de arnbos paises
(Comisi6n Mixta Chile - Bolivia de Urnites) y se llevaran a cabo
entre septiernbre y diciernbre de 2004, conforme al cronograrna de
trabajo que para este prop6sito la propia Comisi6n Mixta
determinara.
- Las cartas, pianos y perfiles que se originen en los trabajos que
realizara la Comisi6n Mixta, estaran disponibles para su utilizaci6n
en ,las demas actividades considerados en este estudio.
- El desarrollo de las demas labores de terreno requeridas en las
otras actividades consideradas en este estudio, se programara
estableciendo un cronograma o carta Gantt, el cual debera generar
un plan de trabajo que armonice el conjunto de las labores.
2.3.4 Caracterizaci6n del limite Internacional
- La Comisi6n Mixta de limites precisara en terreno el If mite
internacional en el fondo de la garganta - caf\ad6n del Silala . .
- Dicha ubicaci6n y trazado general en la cuenca, debera
representarse en la cartografia, pianos y perfiles sef\alados
precedentemente.
- Se informara sobre las caracteristicas del If mite en el sector.
2.3.5 Interpretaci6n de los antecedentes topograficos,
cartograficos y geodesicos
El Presente punto debera concluir los siguientes aspectos de
acuerdo al resultado de los trabajos efectuados:
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65
- Detailed survey of hydraulic works for the preparation of construction
plans by sections.
- Preparation of detail plans for hydraulic works, considering the extension
of the canals, construction characteristics, materials used, slope sections,
slope measurements, seals, widths, heights and depths, and the indication of
the condition of the works and overflow tanks.
2.3.3 Activity plan
- Topographic and geodetic terrain work will be carried out by the Boundary
Commissions of both countries (Joint Boundary Commission Chile-Bolivia)
and will be carried out between September and December 2004, according
to the work schedule that for this purpose the Joint Commission itself will
determine.
- Letters, maps and profiles that originate in the work that the Joint
Commission will carry out, will be available for use in the other activities
considered in this study.
- The development of the other field tasks required in the other activities
considered in this study, will be scheduled establishing a chronogram or
Gantt chart, which should generate a work plan that harmonizes the set of
tasks.
2.3.4 Characterization of the international border
- The Joint Boundary Commission will specify the international border at
the bottom of the ravine - Silala Ravine.
- Said location and general layout in the basin, shall be represented in the
cartography, maps and profiles indicated above.
- There will be a report about the characteristics of the border in the sector.
2.3.5 Interpretation of topographic, cartographic and geodetic background
information
This point must conclude the following aspects according to the result of the
works carried out:
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66
- Uniformidad de la cuenca en base a las pendientes y topografia
local.
- Existencia de depresiones topograficas cerradas y de umbrales
que afecten a la pendiente, y al
drenaje general de la cuenca, en sentido este - oeste (desde
Bolivia a Chile).
- Sentido del escurrimiento de las aguas de acuerdo a la pendiente
natural del terreno.
Los trabajos a cargo de la Comisi6n Mixta de Limites se
programaran de manera que contribuyan con antecedentes para
avanzar en el tema global.
3. CARACTERIZACION HIDROLOGICA
3.1 Labores de medici6n y obtenci6n de datos
3.1.1 Recopilaci6n de antecedentes
Una primera fase de este trabajo corresponde a la exhaustiva
recopllaci6n de la lnformaci6n hidrol6gica existente en la zona de
estudio, e incluira un area de influencia mas amplia con el
prop6sito de permitir a posteriori la definici6n de patrones de
comportamiento de caracter hidrometeorol6gico. Por otra parte
debera recopilarse fotografias aereas e imagenes satelitales
(hist6ricas y actuales) destinadas a conocer la cobertura nival y
las formaciones vegetacionales relevantes para establecer su
variabilidad en el tlempo.
Para tal efecto se debera revlsar los antecedentes consignados en
estudios existentes en instituciones publicas, prlvadas y entes
academicos.
La informacl6n a recabar dice relaci6n con a lo menos lo siguiente:
Precipitaciones
Temperatura del aire
Evaporaci6n
Caudales superficiales que cruzan la frontera.
Niveles de aguas subterraneas vinculados con las aguas
superficiales que cruzan la frontera
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67
- Uniformity of the basin based on the slopes and local topography.
- Existence of closed topographic depressions and thresholds that affect the
slope, and the general drainage of the basin, in an east–west direction (from
Bolivia to Chile).
- Water runoff direction according to the natural slope of the terrain.
The works in charge of the Joint Boundary Commission will be programmed
in such a way that they contribute with background information in order
to move forward in the global issue.
3. HIDROLOGICAL CHARACTERIZATION
3.1 Measurement and data collection
3.1.1 Gathering of background information
A first phase of this work corresponds to the exhaustive compilation of
hydrological information existing in the study area, and will include a broader
area of influence with the purpose of allowing a posteriori the definition
of hydro-meteorological behavior patterns. On the other hand, aerial
photographs and satellite images (historical and current) must be collected
in order to know the snow cover and the relevant vegetation formations to
establish their variability over time.
For this purpose, the background information recorded in existing studies
in public and private institutions and academic entities should be reviewed.
The information to be collected relates to at least the following:
Precipitation
Air temperature
Evaporation
Surface flows that cross the border.
Levels of underground water linked to surface waters that cross the border.
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68
Calidad de las aguas superficiales que cruzan la Frontera
El ambito espacial para este case debe considerar una zona mas
amplia que el area del rio Silala, de forma de poder contar con
informaci6n vinculante que permita establecer relaciones
hidrol6gicas orientadas a la ampliaci6n de la estadisticas, o para
realizar un analisis de caracter mas regional a traves de indices
hidrol6gicos. En este sentido es necesario que se obtenga
informaci6n de precipitaciones, caudales, evaporaci6n,
temperaturas y calidad del agua.
La ampliaci6n debe considerar zonas geograficamente vinculantes
desde el punto de vista climatico e hidrol6gico.
Se debera diferenciar y distinguir la informaci6n de caracter
sistematico y de caracter no sistematico o esporadico. En relaci6n
con las mediciones sistematicas debera distinguirse aquellas de
registro continua y aquellas de caracter directa. Respecto a la
informaci6n de caracter esporadico debera establecerse con
claridad todos las antecedentes para su adecuada identificaci6n y
posterior empleo.
Toda la informaci6n recopilada debera organizarse en tablas en
formate adecuado para las posteriores procesos de
homogenizaci6n, validaci6n y utilizaci6n.
3.1.2 Plan de medici6n hidrol6gica
Se contempla el desarrollo de un plan de mediciones con el objeto
de generar la informaci6n de caracter hidrol6gico e hidrometrico
necesaria para cumplir las objetivos de evaluaci6n planteados. Se
considera que coma minima debe contarse con mediciones que
cubran un ano complete de forma de disponer de antecedentes
que representen la variaci6n estacional.
El monitoreo estara destinado a complementar la informaci6n
existente de forma de disponer de una base o plataforma de
informaci6n suficientemente adecuada para realizar las analisis
hidrol6gicos y evaluaciones que se contemplan en el presente
perfil de estudio conjunto. Lo anterior sabre la base de analisis
hidrol6gicos directos si la informaci6n disponible lo permite o bien,
en forma alternativa o complementaria, sabre la base de metodos
hidrol6gicos indirectos de caracter convencional.
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Quality of surface waters that cross the border
The spatial scope for this case must consider a wider area than the Silala
River area, in order to have binding information that allows establishing
hydrological relations oriented to the expansion of statistics, or to carry
out a more regional analysis through hydrological indexes. In this sense,
it is necessary to obtain information on precipitation, flows, evaporation,
temperatures and water quality.
The extension must consider geographically binding areas from the climatic
and hydrological point of view.
The information of a systematic nature and of a non-systematic or sporadic
nature should be differentiated and distinguished. In relation to systematic
measurements, those of continuous recording and those of a direct nature
must be distinguished. Regarding the information of sporadic nature,
all the background information must be clearly established for its proper
identification and subsequent use.
All the information collected must be organized in tables in an appropriate
format for the subsequent processes of homogenization, validation and use.
3.1.2 Hydrological measurement plan
The development of a measurement plan is contemplated in order to
generate the hydrological and hydrometric information necessary to meet
the proposed assessment objectives. It is considered that, as a minimum,
measurements that cover a full year should be available in order to have the
background information that represents the seasonal variation.
The monitoring will be aimed at complementing the existing information
in order to have a base or information platform sufficiently adequate to
carry out the hydrological analyzes and evaluations contemplated in this
joint study profile. The above must be performed on the basis of direct
hydrological analyzes if the available information allows it or alternatively
or complementary, on the basis of indirect hydrological methods of a
conventional nature.
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El plan de mediciones debe incluir - en la forma que se indica a
continuaci6n - la medici6n de precipitaciones, caudales, niveles de
aguas subterraneas, calidad de aguas e is6topos, temperatura y
evaporaci6n. Este plan, que tiene el caracter de sistematico, debe
contemplar como minimo lo sigufente:
a) Precipitaciones
Al menos 4 puntos donde se localicen pluvi6gratos que permitan
acumular o registrar informaci6n por lo menos durante tres meses
debido a las condiciones de acceso.
Dos puntos ubicados en la zona de cabecera de la cuenca, uno en
la vertiente oeste y otro en la vertiente este a cotas def orden de
4750 msnm.
En la zona del cruce de Frontera a una cota no superior a 4500
msnm
En la zona mas al oriente de las nacientes Orientales para
caracterizar la variabilidad este-oeste
Los pluvi6grafos deben contar con un sistema para la medici6n de
precipitaci6n en forma de nieve y su acumulaci6n
b) Caudales
Se contempla el control sfstematico de caudales en los siguientes
puntos2:
Quebrada Oriental en cruce camino
Quebrada Cajones antes de Quebrada Silala
Quebrada Oriental antes Quebrada Cajones
Quebrada Silala despues de Quebrada Cajones
Rio Silala en cruce de frontera
2 El termlno Quebrada Silc1la se refiere a la incision que continua aguas c1bajo de la
confluencia de las quebradas Ori entales y Cajones. Estas ultimas se refleren a la
bic.aci6n de las vertientes del mismo nombre.
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The measurement plan should include –in the form indicated below– the
measurement of rainfall, flow rates, underground water levels, water and
isotope quality, temperature and evaporation. This plan, which has the
character of systematic, must contemplate at least the following:
a) Precipitation
At least 4 points where pluviographs are located that allow gathering or
registering information for at least three months due to access conditions.
Two points located in the headwaters of the basin, one on the western slope
and another on the eastern slope at heights of the order of 4,750 masl.
In the area of the border crossing at an elevation no higher than 4,500 masl.
In the easternmost area of the Orientales springs in order to characterize the
east-west variability
The pluviographs must have a system for the measurement of precipitation
in the form of snow and its accumulation.
b) Flows
The systematic control of flows is contemplated in the following points2:
Oriental Ravine at the crossroad
Cajones Ravine before the Silala Ravine
Oriental Ravine before the Cajones Ravine
Silala Ravine after the Cajones Ravine
Silala River at the border crossing
______________________________
2 The term Silala Ravine refers to the incision that continues downstream from the confluence of the Orientales and
Cajones ravines. These latter refer to the location of the springs of the same name.
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Se considera la realizaci6n de aforos mensuales, por un periodo de
un ano, en dichos puntos. Se realizaran siguiendo las norrnas
hidrometricas y se debe entregar toda la informaci6n detallada
generada en dichos aforos as[ coma la topografia de la secci6n de
control en el caso de que se haga un levantamiento espedfico.
Sera necesario realizar trimestralmente una serie aforos a lo largo
del dia dichos puntos para conocer la variabilidad del caudal por
efecto de la temperatura, se debera desarrollar a lo menos 4
medicfones adecuadamente distribuidas trimestralmente.
b.1 Campanas detalladas
Adiciona lmente debera realizarse a lo menos tres campafias de
mediciones detalladas, las cuales deberan espaciarse
adecuadamente a lo largo del presente trabajo de forma de
obtener informaci6n representativa.
En estas campaiias se realizara el aforo del caudal de todos los
flujos superfi cia les identificados, ya sean rfos, esteros, vertientes o
manantiales y cualquier otro flujo o afloramiento que genere
escorrent [a superficial que no este contemplada dentro del
programa sistematico. En especial debe considerarse la realizaci6n
de aforos en puntos intermedios de los cauces con el fin de
determinar el balance de los aportes laterales y determinar los
caudales de recuperaci6n o perdida por tramos de cauces. Del
mismo modo debera efectuarse el aforo del caudal de aguas en la
zona de ubicaci6n de obras de captaci6n, considerando aforar el
caudal aguas arriba, aguas abajo y el captado por dicha obra. La
cantidad de puntos a aforar en total se estima en un numero no
inferior a 30.
c) Calidad de aquas
Se considera el monitoreo de la calidad del agua, con frecuencia
mensual en los mismos puntos de control de caudales indicados
anteriormente.
Ademas debera considerarse el control de la calidad de las aguas
en los puntos donde se realizaran aforos de caudal cuatrimestral,
estas mediciones y muestreos se haran simultaneamente con
dichos aforos. Las muestras deberan tener el tratamiento
correspondiente, de acuerdo a los metodos estandares, para la
debida preservaci6n para su analisis en laboratorio. En forma
adicional se obtendran muestras de lluvias y nieve segun lo
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It is considered to carry out monthly stream-gauging, for a period of one
year, at said points. They will be carried out following the hydrometric
standards and all the detailed information generated in said gauging should
be provided, as well as the topography of the control section in case a specific
survey is made. It will be necessary to perform a series of exercises quarterly
throughout the day at these points in order to know the variability of the flow
due to the effect of temperature. At least 4 measurements must be carried
out, properly distributed quarterly.
b.1. Detailed campaigns
Additionally, at least three detailed measurements campaigns should be
carried out, which should be appropriately spaced throughout this work in
order to obtain representative information.
In these campaigns the gauging of the flow of all identified surface flows
will be carried out, whether rivers, estuaries, springs or streams and any
other flow or outcrop that generates surface runoff that is not contemplated
within the systematic program. Particularly, the carrying out of gauging
at intermediate points of the channels should be considered in order to
determine the balance of the lateral contributions and determine the recovery
or loss flows by sections of channels. In the same way, the capacity of the
water flow in the area where the catchments are located must be measured,
considering the flow upstream, downstream and the volume abstracted by
said works. The quantity of points to be gauged in total is estimated at a
number not less than 30.
c) Water quality
It is considered to carry out the monitoring of water quality with monthly
frequency in the same flow control points indicated above.
In addition, the control of the water quality at the points where quarterly
flow gauging will be carried out should be considered. These measurements
and sampling will be done simultaneously with said gauging. The samples
must have the corresponding treatment, according to standard methods, for
the proper preservation in order to analyze it in the laboratory. In addition,
samples of rain and snow will be obtained as
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indicado en el punto 3.5.2. Las muestras deberan estar
debidamente rotuladas indicando fecha, lugar para su debida
correlaci6n con caudales, precipitaciones, etc.
El monitoreo contempla que se rnida in situ el pH, conductividad
electrica, temperatura del agua y oxigeno disuelto. Valores que
ademas deberan medirse en laboratorio al momento de efectuar el
analisis del resto de los parametros. El analisis debera entregar la
totalidad de las macroelementos, ademas microelementos tales
coma: Baro, Fluor, Arsenico, Litio, Cobre, Silice y otras necesarias
para log rar el adecuado estudio hidrogeoquimico.
Los analisis seran aceptables si el balance i6nico de los
macroelementos presenta un error de cierre menor a 5%, de lo
contrario deberan repetirse; por lo tanto las muestras deberan ser
de volumen suficiente para ta l efecto.
3.2 Ana lisis de precipltaciones
A partir de los antecedentes obtenidos, tanto en terreno como de
la recopilaci6n, se procedera a efectuar lo siguiente:
3.2.1 Analisis de la calidad de la informaci6n
Se debera efectuar un completo anal isls de la informaci6n con el
objeto de disponer de estadisticas adecuadas, compatibles y
confiables. Para tal efecto se revisara los registros y veri fica ra que
los valores registrados no presenten distorsiones . .
Para dicho prop6sito, se deberan aplicar procedirnientos
convenclonales que permitan verificar la homogeneidad y validez
de la lnformaci6n.
Asimismo, se debera considerar corno alternativa la completacion
o extension de la serie estadistica a partir de dates existentes en
otras zonas que permitan fundadamente representar a escala
regional un comportamiento similar. La escala de relleno para este
proceso debe ser analizada y fundamentada adecuadamente.
El proceso debera concluir con la confecci6n de estadfsticas de
precipitaclones corregidas y validadas de extension apropiada para
los fines que se persiguen (mensual, anual, etc.)
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indicated in point 3.5.2. The samples must be properly labeled, indicating
the date, the place for its proper correlation with flows, precipitation, etc.
The monitoring contemplates that the pH, electrical conductivity, water
temperature and dissolved oxygen are measured in situ. These values must
also be measured in the laboratory when analyzing the rest of the parameters.
The analysis must deliver all the macro-elements, in addition to the microelements
such as: Boron, Fluorine, Arsenic, Lithium, Copper, Silica and
others necessary to achieve the appropriate hydro-geochemical study.
The analysis will be acceptable if the ionic balance of the macro-elements
presents a closing error of less than 5%, otherwise they must be repeated.
Therefore, the samples must be of sufficient volume for this purpose.
3.2 Precipitation analysis
Based on the information obtained, both in the field and in the compilation,
the following will be carried out:
3.2.1 Analysis of the quality of information
A complete analysis of the information should be carried out in order to have
adequate, compatible and reliable statistics. For this purpose, the records
will be reviewed and the registered values will be checked for distortions.
For this purpose, conventional procedures should be applied in order to
verify the homogeneity and validity of the information.
Likewise, the completion or extension of the statistical series should be
considered as an alternative, based on existing data in other areas that allow
a similar behavior to be represented on a regional scale. The filling scale for
this process must be analyzed and properly founded.
The process must conclude with the preparation of corrected and validated
precipitation statistics of appropriate extension for the purposes pursued
(monthly, annual, etc.).
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Sabre la base de las series confeccionadas, se estableceran fndices
que permitan describir la variabilidad de la precipitaci6n a traves
de indicadores caracterfsticos para tal efecto (varianza, coeficiente
asimetrfa, etc.)
3.2.2 Caracterizaci6n de la precipitaci6n
Sabre la base de lo anterior debera efectuarse una caracterizaci6n
del regimen de precipitaciones que permita conocer lo siguiente:
- Variabilidad temporal de la precipitaci6n (estacionalidad,
variaci6n interanual)
- Variabilidad espacial (gradientes, area de precipitaci6n nival,
etc.)
- Precipitaci6n media anual para diferentes zonas definidas segun
rangos de elevaci6n
- Precipitaci6n media anual para diferentes probabilidades de
excedencia
Corna resultado de lo anterior debera generarse mapas de
isolfneas de precipitaci6n media (isoyetas) para la cuenca en
estudio.
3.3 Analisis de caudales
En primer lugar, se procedera a efectuar un analisis de las datos
recopilados y generados. Como arte de este trabajo, el analisis
debera orientarse a la verificaci6n y validaci6n de la informaci6n.
A partir de lo anterior debera efectuarse un proceso de extension
de las estadfsticas generadas considerando la necesidad de
generar series de caudales mensuales y anuales. Para tal efecto
debera considerarse la necesidad de recurrir a datos existentes en
zonas o cuencas vinculantes desde el punto de vista de vecindad y
de condiciones hidrometeorol6gicas. Dichas zonas deben presentar
indicadores de regimen similar en el caso de abordar este trabajo
a partir de metodos indirectos.
La serie de caudales mensuales generados debera entregarse en
una tabla indicando las valores rellenados y el metodo usado as[
coma las valores extendidos y el metodo aplicado.
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Based on the series prepared, indices will be established to describe the
variability of precipitation through characteristic indicators for this purpose
(variance, coefficient of asymmetry, etc.).
3.2.2 Characterization of precipitation
On the basis of the above, a characterization of the precipitation regime
should be carried out, which allows knowing the following:
- Temporal variability of precipitation (seasonality, inter-annual variation).
- Spatial variability (gradients, snow precipitation area, etc.).
- Average annual precipitation for different areas defined according to
elevation ranges.
- Average annual precipitation for different exceedance probabilities.
As a result of the above, it will be necessary to generate maps of isolines of
average precipitation (isohyets) for the basin under study.
3.3 Flow analysis
First, an analysis of the data collected and generated will be carried out.
As part of this work, the analysis should be oriented to the verification and
validation of the information.
Based on the above, a process must be carried out in order to extend the
statistics generated, considering the need to generate series of monthly and
annual flows. To this end, consideration should be given to the need to resort
to existing data in areas or basins that are binding from the point of view
of neighborhood and hydro-meteorological conditions. These areas should
present similar regime indicators in the case of approaching this work from
indirect methods.
The series of monthly flows generated should be delivered in a table,
indicating the values filled and the method used as well as the extended
values and the applied method.
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El tratamiento de los datos de aforos puntuales, dada la escasa
informaci6n existente, es de la mayor lmportancia por lo que debe
efectuarse un analisis en profundidad de esta informaci6n.
Sobre la base de dicha estadistica se procedera a efectuar un
analisis de los caudales cuyo primer prop6sito sera la
determinaci6n de lo siguiente:
- Caudales medics mensuales
- Caudales medias anuales segun probabilidad de excelencia.
- Caudales espedficos anuales medios (m3/seg. y m3/s/km2/mm)
En Segundo termino es de interes efectuar una caracterlzaci6n del
regimen hidrol6gico distinguiendo regimen nival y pluvial, en la
medida que sea pertinente.
Los resultados deben entregarse, siguiendo el orden de aguas
arriba hacia agua abajo, en los siguientes puntos:
- Puntos donde se encuentran las estaciones de control de
caudales indicadas en el punto 3.1.2 letra b.
- Junta de otras quebradas afluentes a la quebrada Silala
- Rio Silala en el cruce de Frontera
3.4 Caracterizaci6n de la calidad de las aguas
En este caso es necesario efectuar un analisis de la consistencia y
coherencia de la informaci6n, verificando a traves de criterios de
validaci6n ranges admisibles o ffsicos de los parametros que se
controlan (cuando ello proceda)
Del mismo modo, para el caso de los macroelementos se debe
verificar el error de cierre del balance i6nico segun lo indicado en
el punto 3.1.2 letra c.
Sabre la base de la informaci6n validada y corregida, se procedera
a caracterizar el tipo de aguas en los puntos de control. Es de
interes que se realice una caracterizaci6n respecto a la variabilidad
temporal y espacial de la calidad. Adicionalmente se debe
proceder a relacionar la calidad de las aguas con las caracteristicas
geol6gicas de la zona y las caracteristicas de la recarga, teniendo
en cuenta la informaci6n hist6rica dlsponible antes y despues de la
construcci6n de las obras.
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The treatment of the data of detailed gauges –given the scarce existing
information– is of the greatest importance for which an in-depth analysis of
this information must be carried out.
On the basis of said statistics, an analysis of the flows will be carried out
whose first purpose will be the determination of the following:
- Monthly average flows
- Annual average flows according to probability of excellence.
- Annual average specific flows (m3/sec and m3/s/ km2/mm)
Secondly, it is of interest to carry out a characterization of the hydrological
regime, distinguishing the snow regime and the rainfall regime, insofar as
is relevant.
The results must be delivered, following the order of upstream to downstream,
in the following points:
- Points where the flow control stations are located indicated in point 3.1.2
letter b.
- Joint of other streams tributaries to the Silala ravine.
- Silala River at the border crossing.
3.4 Characterization of water quality
In this case it is necessary to carry out an analysis of the consistency and
coherence of the information, verifying through validation criteria the
admissible or physical ranges of the parameters that are controlled (when
applicable).
In the same way, for the case of the macro-elements, the closing error of the
ionic balance must be verified as indicated in point 3.1.2 letter c.
On the basis of the validated and corrected information, the type of water in
the control points will be characterized. It is of interest that a characterization
is made regarding the temporal and spatial variability of the quality.
Additionally, the quality of the water must be related to the geological
characteristics of the area and the characteristics of the recharge, taking into
account the historical information available before and after the construction
of the works.
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3.5 Caracterizacl6n isot6pica
Se procedera a efectuar una caracterizaci6n isot6pica de los flujos
que confluyen hacia la frontera, para lo cual se procedera a lo
siguiente:
3.5.1 Recopilaci6n de datos existentes
Se efectuara una completa recopilaci6n de la informaci6n del
contenido isot6pico existentes en estudios, publicaciones
cientfficas y en informes. La informaci6n debera contener los
antecedentes que permitan su adecuada identificaci6n (fecha,
ubicaci6n, tipo de agua muestreada, etc.)
Se debera recopilar informaci6n sobre is6topos ambientales
(deuterio, oxigeno18, tritio, carbono 13 y 14) de la cuenca
hidrografica y de una zona suficientemente amplia de modo de
disponer los antecedentes que permitan conocer su
comportamiento regional. Para ta l efecto se considerara
informaci6n existente de aguas lluvias, nieve, lagunas o lagos,
vertientes, aguas subterraneas, etc.
3.5.2 Muestreos y mediciones
Se debera establecer un programa de muestreo y analisis de
is6topos ambientales para la obtenci6n de datos cuatrimestrales
de aguas superficiales (dos, lagunas y vertientes), aguas
subterraneas aguas lluvias y nieve. El muestreo para aguas
superficiales se realizara conjuntamente con las campafias de
aforo mencionadas anteriormente; se incluira tambien muestreo
en lagunas en los mismos puntos donde se controle calidad del
agua. El muestreo de aguas lluvias se realizara en los puntos
definldos para medici6n de precipitaciones. El muestreo para
aguas subterraneas se hara en los sondajes a perforar, segun se
indica mas adelante en el punto 4.2.1, siguiendo los estandares
convencionales para este caso. Las muestras de nieve se
obtendran en puntos localizados en las vertientes norte y sur de la
zona de cabecera de la cuenca considerando a 10 menos 4 puntos
adecuadamente distribuidos para obtener buena
representatividad. Para el caso de lluvias y nieve se tomaran
muestras ad icionales para el analisis de calidad de aguas segun el
protocolo establecido en el punto 3.2.1 letra c.
3.5.3 Resultados
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3.5 Isotopic characterization
An isotopic characterization of the flows that converge towards the border
will be carried out, for which the following will be done:
3.5.1 Collection of existing data
A complete compilation of the information regarding the isotopic content
existing in studies, scientific publications and reports will be carried out.
The information must contain the background information that allows its
proper identification (date, location, type of water sampled, etc.)
Information on environmental isotopes (deuterium, oxygen 18, tritium,
carbon 13 and 14) must be collected from the hydrographic basin and a
sufficiently large area in order to provide the background information to
know their regional behavior. For this purpose, the existing information on
precipitation, snow, lagoons or lakes, springs, underground water, etc., will
be considered.
3.5.2 Sampling and measurements
A program of sampling and analysis of environmental isotopes should
be established in order to obtain quarterly data on surface water (rivers,
lakes and springs), underground water, rainwater and snow. Sampling for
surface water will be carried out in conjunction with the capacity assessment
campaigns mentioned above. Sampling in lakes will also be included in
the same points where water quality is controlled. Rainwater sampling
will be done at the points established for precipitation measurement. The
sampling for underground water will be made in the holes to be drilled, as
indicated below in point 4.2.1, following the conventional standards for this
case. The snow samples will be obtained at points located on the north and
south slopes of the headwaters of the basin, considering at least 4 points
properly distributed in order to obtain good representativeness. In the case
of precipitation and snow, additional samples will be taken for water quality
analysis according to the protocol established in point 3.2.1 letter c.
3.5.3 Results
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A partlr de los antecedentes debera reallzarse un analisls
orientado a determlnar la dinamica del sistema. En particular se
orientara a identificar la relaci6n entre la precipitaci6n, los
caudales superficiales y los flujos subterraneos vinculados con las
aguas del rio Silala que cruzan la frontera.
Se consulta analisls de tritio y carbono con el objeto de conocer la
dinamica de las aguas subterraneas que confluyen hacia la
frontera y que se vinculan con los flujos superficiales pasantes.
Adicionalmente se debera tener en cuenta el analisis que permita
conocer la influencia de las zonas de humedales sobre los flujos
superficiales, atendlendo su poslble diferenciaci6n evaporativa y/o
sus caracterlsticas hidrogeoqufmicas espedficas.
4. CARACTERIZACION HIDROGEOLOGICA
4.1 Marco Geomorfol6gico, Geol6gico, Estructural y Tect6nlco
Regional.
En lo referente a la geomorfologfa se debera efectuar una
definici6n y caracterizaci6n de las formas del relieve mas
destacadas. En relaci6n con la geologfa se debera realizar una
identificaci6n, delimitaci6n y caracterlzaci6n de todas las unidades
de suelos o dep6sitos no consolidados y rocas: En relaci6n con los
elementos estructurales se debera identiflcar, delimitar y
caracterizar los princlpales elementos estructurales, es decir,
lineamientos y fallas de alcance regional, reconocidas en torno a la
zona ocupada por la hoya hidrografica del rfo Silala, como
consecuencia de la evoluci6n geodinamica ne6gena de este sector
andino.
Se sustentara en la recopilaci6n de todos los antecedentes
relacionados con estudios e investigaciones geol6gicas realizadas
en la zona, ya sea de caracter regional o local, debiendose
desarrollar trabajos en el propio terreno orientados a
complementar las actividades conducentes a la elaboraci6n de la
cartografia geol6gica final.
4.1.1 Geologfa de Detalle.
a) Definici6n y caracterlzaci6n de las formas del relieve:
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From the background information, an analysis should be conducted in
order to determine the dynamics of the system. In particular, it will focus
on identifying the relationship between precipitation, surface flows and
underground flows linked to the Silala River waters that cross the border.
Tritium and carbon analyzes are consulted in order to know the dynamics of
the underground water that converge towards the border and that is linked to
the superficial through-flows.
Additionally, the analysis that allows to know the influence of the wetland
areas on the superficial flows, taking into account their possible evaporative
differentiation and/or their specific hydro-geochemical characteristics,
should be taken into account.
4. HYDROGEOLOGICAL CHARACTERIZATION
4.1 Regional Geomorphological, Geological, Structural and Tectonic
Framework
With regard to geomorphology, a definition and characterization of the
most important topographical forms should be carried out. In relation to
geology, an identification, delimitation and characterization of all soil
units or unconsolidated deposits and rocks must be carried out. In relation
to the structural elements, the main structural elements must be identified,
delimited and characterized, that is, guidelines and faults of regional scope,
recognized around the area occupied by the hydrographic basin of the Silala
River, as a consequence of the neo-dynamic geodynamic evolution of this
Andean sector.
It will be based on the compilation of all the background information related
to geological studies and investigations carried out in the area, whether of
a regional or local nature, having to develop works in the field oriented to
complement the activities leading to the elaboration of the final geological
cartography.
4.1.1 Detail Geology
a) Definition and characterization of topographical forms:
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- "tierras bajas": superficies peniplanicies altiplanfcas-conos
aluviales - zonas depresionarias (lagunas. salares)- sistemas
fluviales (dos, quebradas, esteros, vertientes, incisiones
menores);
- "tierras altas": estructuras volcanicas, (edificios volcanicos,
domos, flujos de lavas e ignimbritas).
- rasgos asociados a procesos glaciales (remanentes morrenlcos y
periglaciales) y remociones en masa: deslizamientos,
desprendimlentos, flujos de barro o detritos.
b) Identificaci6n, dellmitaci6n y caracterizaci6n de todas las
unidades de suelos o dep6sitos no consolidados y rocas, en todo el
ambito de la hoya hidrogriifica comprometida por el flujo de las
aguas del Silala que cruzan por la frontera.
- Definlci6n y relaciones estratigraficas
- Distribuci6n y litologfa.
- Espesores.
- Edades, (realizaci6n de dataciones radiometricas), correlaciones
y mecanismos geneticos: intrusives, extrusivos o actividad
volciinica, sedimentaria (fluvial, coluvial, e61ica, glacial, aluvlonal) .
Para estos efectos se deberii recurrlr al procesamiento de
imagenes satelitales y la interpretacl6n fotogeol6gica de
fotografias aereas de la zona.
4.1.2 Esctructura y tect6nica
Identiflcaci6n de los principales elementos estructurales presentes
en la zona de interes: lineamientos, fotolineamientos mayores;
fallas; patrones locales de fracturamiento; plegamientos y
dlscorda ncias.
Para estos efectos, del mismo modo que en el caso anterior, se
deberii recurrir al procesamiento de imiigenes satelitales y el
aniillsls de fotograffas aereas.
En este caso y el correspondiente al punto 4.1.1 se debe
desarrollar trabajos en el proplo terreno orientados a
complementar las actividades conducentes a la elaboraci6n de la
cartografia geol6gica final.
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- “Lowlands”: Altiplanic peneplain surfaces – alluvial cones – depressions
(lakes, salt flats) – river systems (rivers, ravines, estuaries, springs, minor
incisions);
- “Highlands”: Volcanic structures, (volcanic buildings, domes, lava flows
and ignimbrites).
- Features associated with glacial processes (morainic and paraglacial
remnants) and mass removals: landslides, mudslides, mud flows or debris.
b) Identification, delimitation and characterization of all units of
unconsolidated soils or deposits and rocks, in the entire area of the
hydrographic basin compromised by the flow of the Silala waters that cross
the border.
- Definition and stratigraphic relationships
- Distribution and lithology.
- Thicknesses
- Ages (radiometric dating), correlations and genetic mechanisms: intrusive,
extrusive or volcanic activity, sedimentary (fluvial, colluvial, wind, glacial,
alluvial).
For these purposes, it will be necessary to resort to the processing of satellite
images and the interpretation of aerial photographs of the area.
4.1.2 Structure and tectonics
Identification of the main structural elements present in the area of interest:
guidelines, major photo guidelines, faults, local patterns of fracturing,
refolding and unconformity.
For these purposes, in the same way as in the previous case, it will be
necessary to resort to the processing of satellite images and the analysis of
aerial photographs.
In this case and the one corresponding to point 4.1.1, work must be carried
out in the field itself in order to complement the activities leading to the final
geological cartography.
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4.1.3 Escalas de trabajo.
Para el punto 4.1.1 se requiere generar y entregar la informaci6n
a escala 1 : 50.000 para el otro caso se requiere una escala 1:
25.000.
4.2 Labores prospectivas y de exploraci6n
Se debera mejorar y/o complementar el conocimiento geol6gico
subsuperficial actual; en terminos del caracter, continuidad lateral
y profundidad, espesores, relaciones infra y suprayacente de las
diversas unidades identificadas en superficie. Para estos efectos se
debera realizar una serie de actividades de exploraci6n,
empleando dos procedimientos:
4.2.1 Metodos de prospecci6n hidrogeol6gica.
Dos alternativas pueden ser consideradas.
a) Geofisica .
Habida cuenta de los elevados costos de los sondajes de
prospecci6n, se recomienda considerar, en una primera etapa,
este tipo de procedimiento prospective. Con sus resultados sera
posible acotar la posterior localizaci6n de sondajes y determinar
sus respectivas profundidades.
Para este prop6sito es recomendable emplear el metodo de
Transiente Electro Magnetico, TEM, en atenci6n a la experiencia en
prospecciones en ambientes como el de la zona en estudio.
Para la zona objeto del estudio, la aplicaci6n de este metodo
permitirfa:
- Estimar el espesor de los cuerpos acuiferos sedimentarios
- Estimar la situaci6n de los niveles de agua
- Detectar la presencia y geometria del basamento rocoso del
relleno sedimentario
Para los efectos del presente estudio se debera efectuar perfiles
geofisicos (TEM, etc) que permitan definir dos perfiles tranversales
en los sectores siguientes:
- Sector de junta Quebrada Oriental con Quebrada Cajones
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4.1.3 Work scales
For point 4.1.1, it is required to generate and deliver information at a scale
of 1:50.000; for the other case, a scale of 1:25.000 is required.
4.2 Prospective and exploration work
The current sub-surface geological knowledge should be improved and/
or complemented; in terms of the character, lateral continuity and depth,
thicknesses, infra and superjacent relationships of the various units identified
on the surface. For these purposes, a series of exploration activities must be
carried out, using two procedures:
4.2.1 Methods of hydrogeological prospecting
Two alternatives can be considered.
a) Geophysics
Given the high costs of prospecting drilling, it is recommended to consider,
in a first stage, this type of prospective procedure. With its results it will
be possible to limit the subsequent drilling location and determine their
respective depths.
For this purpose, it is advisable to use the Electromagnetic Transient (EMT)
method, based on the experience in prospecting in environments such as the
area under study.
For the area under study, the application of this method would allow:
- Estimate the thickness of the sedimentary aquifer water bodies.
- Estimate the situation of water levels.
- Detect the presence and geometry of the rocky basement of the sedimentary
fill.
For the purposes of this study, geophysical profiles (EMT, etc.) should be
carried out in order to define two transversal profiles in the following sectors:
- Joint sector of the Oriental ravine with the Cajones ravine
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- Sector intermedio entre Quebrada Cajones y el cruce de frontera
- Sector del cruce de frontera
b) Sondajes
Los sondajes a realizar deben ser disenados para satisfacer los
siguientes prop6sftos:
- Generar informaci6n geol6gica e hidrogeol6gica
- Mejorar y compfementar la informaci6n geofisica obtenida.
- Ajustar los resultados previos de la geoffsica
Respecto de la geo!ogia, la informaci6n generada comprende tipo,
relaciones de contacto, espesores. continuldad lateral y en
profundidad de las secuencias ignimbriticas. Respecto de la
hidrogeologia se orienta a detectar la presencia de aguas
subterraneas, tipos de acuiferos, situaci6n de sus niveles,
caudales, permitir la extracci6n de muestras para determinaciones
fisico - quimicas e isot6picas. Lo anterior con el objeto de obtener
una adecuada explicaci6n de la interrelaci6n de las aguas
subterraneas que confluyen a la frontera e interactuan con los
flujos superficiales pasantes en este sector.
Cada sondaje debe tener una descripci6n estratigrafica detallada
que permita identificar los diferentes estratos encontrados durante
la perforaci6n. La localizaci6n de las cribas debera quedar
claramente definida. En el caso de encontrarse unidades acuiferas
distintas, debera seiialarse la ubicaci6n de las crlbas en cada una
de ellas.
Se debera reafizar pruebas de bombeos en cada sondaje,
considerando gasto variable y de gasto constante, esta ultima con
al menos una duraci6n de 24 hr. o una duraci6n mayor si la
estabilizaci6n lo requiere. El trabajo incluye el analisis que permita
el calculo de los principales parametros elasticos del sistema
acuifero ( coeficientes de transmisibilidad y almacenamiento ).
Ademas al inicio de la prueba, en la mitad y en la parte final se
tomaran muestras para calidad de aguas y analisis isot6pico.
En todos los sondajes se debera realizar una determinaci6n de la
cota del nivel de la napa con una precision que permita determinar
el gradiente hidraulico. En caso de encontrarse mas de una unidad
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- Intermediate sector between the Cajones ravine and the border crossing
- Sector of the border crossing.
b) Drilling
The drillings to be performed must be designed to meet the following
purposes:
- Generate geological and hydrogeological information
- Improve and complement the obtained geophysical information
- Adjust the previous results of geophysics
Regarding geology, the information generated includes type, contact
relations, thicknesses, lateral and in-depth continuity of ignimbrite
sequences. Regarding hydrogeology, it is aimed at detecting the presence
of underground water, types of aquifers, situation of their levels, flow rates,
allowing the extraction of samples for physical-chemical and isotopic
determinations. The foregoing in order to obtain an adequate explanation
of the interrelation of underground water that converge to the border and
interact with superficial through-flows in this sector.
Each drilling must have a detailed stratigraphic description in order to
identify the different strata found during drilling. The location of the screens
must be clearly defined. In the case of finding different aquifer units, the
location of the screens in each of them should be indicated.
Pumping tests must be carried out in each drill hole, considering the variable
expense and the constant expense, the latter with at least a duration of 24
hours or a longer duration if the stabilization requires it. The work includes
the analysis that allows the calculation of the main elastic parameters of the
aquifer system (coefficients of transmissibility and storage). In addition to
the start of the test, in the middle and in the final part samples will be taken
in order to see the water quality and carry out an isotopic analysis.
In all drillings, a determination of the elevation level of the underground
water must be made with a precision that allows determining the hydraulic
gradient. If more than one aquifer unit
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acuffera en el relleno sedimentario los sondajes deberan
habilitarse de forma de poder efectuar mediciones, muestreos,
pruebas de bombeo en forma independiente para cada uno de
ellos.
En una primera etapa, independiente de los resultados de la
geofisica, se deber(a considerar la realizaci6n en cada costado de
rfo Silala de por lo menos 3 sondajes someros cuya localizaci6n y
profundidad permlta reconocer el relleno sedimentario donde se
desarrolla el rio Silala. Asociado a cada sondaje debe construirse a
lo menos un piez6metro que permita observar niveles y permitir
conocer gradientes, estos tambien deben tener la nivelaci6n de la
cota del nivel de la napa.
La localizaci6n de estos sondajes sera:
- La quebrada Oriental aguas abajo del cruce del camino;
- Aguas abajo de la confluencia de las quebradas Orientales y
Cajones;
- Aguas arriba de las proximidades del cruce de frontera.
De estimarse necesario debera considerarse dos sondajes
adicionales, uno en las nacientes de la quebrada Orientales y otro
en las nacientes de la quebrada Cajones.
4.3 Caracterizaci6n de unidades acufferas y su geometrfa
En este punto, con ajuste al conocimiento geol6gico de superficie
(mapeos y perfiles) y subsuperficie (sondajes y prospecciones
geofisicas), se debera efectuar una caracterizaci6n de las unidades
acuiferas existentes aguas arriba del limite internacional,
considerando lo siguiente:
- Caracterizaci6n litol6glca de las secuencias volcanicas y clasticas
reconocidas
- Determinar su continuldad lateral y en profundidad
- Establecer relaciones infra y suprayacentes
- Definir espesores
Como resu ltado del trabajo se debera entregar perfiles y mapas de
planta donde se identifiquen las secciones reconocidas, tanto por
sondajes como a traves de geofisica, ademas de las secciones
inferidas en base a la informaci6n de superficie.
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is found in the sedimentary fill, the drilling must be enabled in order to be
able to carry out measurements, sampling, and pumping tests independently
for each of them.
In a first stage, independent of the results of geophysics, the realization on
each side of the Silala River of at least 3 shallow holes should be considered,
whose location and depth allow to recognize the sedimentary fill where the
Silala River develops. Associated to each drilling must be built at least one
piezometer that allows to observe levels and allow knowing gradients, these
must also be leveled to the elevation of the groundwater layer.
The location of these drillings will be:
- The Orientales ravine downstream of the road junction;
- Downstream from the confluence of the Orientales and Cajones ravines;
- Upstream from the vicinity of the border crossing.
If necessary, two additional drillings should be considered, one in the
headwaters of the Orientales ravine and another in the headwaters of the
Cajones ravine.
4.3 Characterization of aquifer units and their geometry
At this point, with adjustment to geological knowledge of surface (maps
and profiles) and sub-surface (drilling and geophysical surveys), a
characterization of the existing aquifer units upstream of the international
border should be carried out, considering the following:
- Lithological characterization of recognized volcanic and elastic sequences
- Determine its lateral and in-depth continuity
- Establish infra and supra-lying relationships
- Define thicknesses
As a result of the work, profiles and plant maps should be submitted where
recognized sections are identified, both by drilling and through geophysics,
as well as inferred sections based on surface information.
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Tamblen se deberan indicar los sectores en los cuales la
determinaci6n de espesores, o de localizaci6n del basamento, se
estlma incierta para los efectos de establecer volumenes de
almacenamiento.
4.4 Caracterizaci6n de parametros elasticos
Sobre la base de los antecedentes generados se deflniran los
coeficientes de transmisibilldad y almacenamiento. Este trabajo
debera establecer por zonas consideradas similares, la definici6n
de parametros que sean representatives. Para esto debera
conslderarse lo siguiente:
- Revision de la informacion estratigrafica existente
- Pruebas de bombeo en los sondajes que se realicen.
En base a lo anterior, se debera definir los coeficientes de
transmisibilidad y de almacenamiento para las distintas unidades
(si se establecen) y ademas determinar areas con coeficientes
representatives efectuandose, para tal efecto debera
confeccionarse un mapa a escala 1:50.000 o de mayor detalle si
es necesario para obtener una adecuada representaci6n.
4.5 Interacci6n aguas superficiales y subterraneas
El anallsls tiene come objetivo establecer la potencial interacci6n
existente entre el escurrimiento superficial y la unidad acuifera
que esta directamente vinculado con este en la zona de cruce de
la frontera.
Para tal efecto debera considerarse la realizaci6n de aforos antes y
durante la realizaci6n de las pruebas de bombeos, asf coma
muestreos de calidad de agua natural antes de la prueba en el
cauce y en el sondaje. Debera considerarse la realizaci6n de
pruebas con trazadores tales como sal, fluoresceina u otro no
radiactivo y conservativo que permita establecer el grado de
conexi6n entre el rio y la unidad acuffera.
A partir de los parametros elasticos podran aplicarse relaciones
indirectas para estudiar la interrelaci6n rio-acuifero las cuales
requeriran su validacion con los datos de terreno anteriormente
mencionados.
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It should also indicate the sectors in which the determination of the
thickness, or location of the base, is considered uncertain for the purposes of
establishing storage volumes.
4.4 Characterization of elastic parameters
On the basis of the generated background information the coefficients of
transmissibility and storage will be defined. This work should establish, by
zones considered similar, the definition of parameters that are representative.
For this, the following should be considered:
- Review of existing stratigraphic information.
- Pumping tests in the drillings that are made.
Based on the above, the transferability and storage coefficients for the
different units should be defined (if they are established) and also determine
areas with representative coefficients. A map at a scale of 1:50.000 or more
is made for that purpose if is necessary in order to obtain an adequate
representation.
4.5 Interaction of surface and underground water
The objective of the analysis is to establish the potential interaction existing
between surface runoff and the aquifer unit that is directly linked to it in the
border crossing area.
For this purpose, carrying out drillings before and during the pumping tests
should be considered, as well as natural water quality sampling before the
test in the channel and in the drill hole. Tracers such as salt, fluorescein
or other non-radioactive and conservative tracers should be considered to
establish the degree of connection between the river and the aquifer unit.
From the elastic parameters, indirect relationships can be applied to study
the aquifer-river interrelation, which will require their validation with the
aforementioned terrain data.
19
94
5. IMPACTO DE LA INFRAESTRUCTURA HIDRAULICA EXISTENTE
5.1 Descripci6n de las obras hidraulicas
Se consulta un trabajo de ldentlflcaci6n y anallsls de las obras
hldraullcas exlstentes en el cauce aguas arrlba del Hmite
Internacional. Este trabajo, considerando las labores indicadas en el
punto 2.3.2 de este documento, considera lo siguiente:
- Descrlpci6n del tipo de obra (Tlpo de estructura, estado de
conservaci6n, fecha de c construcci6n, dimenslones, materlales)
- Descripci6n hlst6rica referlda a su funcionamiento lncluyendo
antecedentes prevlos y posterlores a su construcci6n (fotograffas,
mapas, pianos, cotas, dimensiones, etc)
- Ubicaci6n precisa en coordenadas
- Capacidad de porteo y rebase
- Flnalidad de la obra
- Vlnculaci6n con aportes laterales
Para tal efecto se elaborara una ficha para cada obra, en un formato
deflnldo, el cual contendra la lnformaci6n lndlcada ademas de un
croquls y una fotograffa a color.
5.2 Interacci6n de las obras y los recursos hidrlcos
Tomando en consideraci6n las aguas superflclales, se procedera a lo
siguiente:
- Determinar el area de drenaje o aportante a cada obra hldraulica
- Determlnar los caudales captados por cada obra
- Establecer los caudales superficiales en regimen natural aguas
arriba de las obras hidraulicas en anallsis
- Establecer los caudales sobrantes aguas abajo de dlcha obra
En el caso de las aguas subterraneas debera analizarse los efectos de
cada obra sobre la inreacci6n del rlo con el acuifero directamente
llgado con ella. Para tal efecto debera analizarse los posibles camblos
en la recarga o recuperaclones desde los cauces naturales hasta el
cruce de frontera.
Sobre la base de los antecedentes topograficos, hidrol6gicos,
hidrogeol6gicos y caracteristicas de las obras hidraulicas, el analisis
20
95
5. IMPACT OF THE EXISTING HYDRAULIC INFRASTRUCTURE
5.1 Description of hydraulic works
A work of identification and analysis of the hydraulic works existing in
the channel upstream of the international border is consulted. This work,
considering the tasks indicated in point 2.3.2 of this document, includes the
following:
- Description of the type of work (type of structure, state of conservation,
date of construction, dimensions, materials).
- Historical description referring to its operation including background
information prior and after its construction (photographs, maps, plans,
elevations, dimensions, etc.)
- Accurate location in coordinates
- Carrying capacity and overflow
- Purpose of the work
- Linkage with lateral contributions
For this purpose, a datasheet will be prepared for each work, in a defined
format, which will contain the indicated information as well as a sketch and
a color photograph.
5.2 Interaction of works and water resources
Taking into consideration the surface waters, the following will be done:
- Determine the drainage or contributor area for each hydraulic work
- Determine the flows abstracted by each work
- Establish the surface flows in natural regime upstream of the hydraulic
works in analysis
- Establish the surplus flows downstream of said work
In the case of underground water, the effects of each work on the interaction
of the river with the aquifer directly linked to it must be analyzed. For this
purpose, the possible changes in recharge or recoveries from the natural
channels up to the border crossing should be analyzed.
On the basis of the topographic, hydrological, hydrogeological background
information and the characteristics of the hydraulic works, the analysis
20
96
debera pronunciarse sobre la existencia de modificaciones del
sistema de drenaje, rupturas de pendientes. Del mismo modo debera
indicar la existencia de sistemas de elevacl6n electromecanicas de
aguas y trasvase de aguas de una cuenca a otra.
6. CARACTERIZACION DE FLUJOS Y SU BALANCE
6.1 Caracterizaci6n de flujos superficiales
Contempla la identificaci6n de los flujos que genera la red de
drenaje superficial a nivel de caudales medics y volumenes,
asociados, que cruzan la frontera. Del mismo modo deberan
caracterizarse los flujos generados por afloramientos de
vertientes.
Lo anterior debe considerar la variaci6n estacional
correspondiente, asf como los valores asociados a diferentes
probabilidades de excelencia.
Los flujos deberan definirse a nivel de caudal rnedio anual y
caudales mensuales, para puntos relevantes del sistema hidrico,
puntos que deben corresponder a lo menos a cuatro puntos del
cierre oriental de la cuenca o sub- subcuenca, desde el punto de
vista del balance hfdrlco, incluyendo el cruce de frontera.
6.2 Caracterizaci6n de flujos subterraneos y zonas de recarga
En base a la inforrnaci6n de precipltaciones y de los flujos
superficlales, se procedera a establecer las zonas de recarga,
atendiendo las caracterfsticas hidrogeol6gicas de cada zona de
estudio. El analisis de la recarga debe ser compatible con los flujos
superficiales que se establecen, habida consideraci6n de los
aspectos relacionados con los flujos evaporativos y
evapotranspirativos que se determinen.
Asimismo a partir de la informaci6n de aguas subterraneas, se
procedera a estimar los flujos subterraneos pasantes de forma de
asociar dichos flujos con sus zonas de recarga o alirnentaci6n. En
este contexto se debera estimar los flujos pasantes en los sectores
ubicados aguas arriba de la quebrada Cajones; en la zona
intermedia situada entre la quebrada Cajones y el ltmite
Internacional, yen la zona de cruce de frontera.
6.3 Interacci6n de las aguas superficiales y subterraneas
21
97
will have to pronounce itself on the existence of modifications of the drainage
system, ruptures of slopes. In the same way, it should indicate the existence of
electromechanical water elevation systems and water transfer from one basin
to another.
6. CHARACTERIZATION OF FLOWS AND THEIR BALANCE
6.1 Characterization of surface flows
It includes the identification of the flows generated by the surface drainage
network at the level of associated average flows and volumes that cross the
border. In the same way, the flows generated by outcrops of springs should
be characterized.
The above must consider the corresponding seasonal variation, as well as
the values associated with different probabilities of excellence.
The flows should be defined at the level of average annual flow and monthly
flows, for relevant points of the water system, points that must correspond
to at least four points of the eastern end of the basin or sub-basin, from the
point of view of the water balance, including the border crossing.
6.2 Characterization of underground flows and recharge zones
Based on the information on rainfall and surface flows, the recharge zones
will be established, taking into account the hydrogeological characteristics
of each study area. The analysis of the recharge must be compatible with the
surface flows that are established, taking into account the aspects related to
evaporative and evapotranspiration flows that are determined.
Likewise, based on the information of underground water, we will proceed
to estimate the underground through-flows to be able to associate these
flows with their recharge or feeding zones. In this context, the though-flows
located in the sectors upstream of the Cajones ravine should be estimated,
also in the intermediate zone located between the Cajones ravine and the
international border, and in the border crossing area.
6.3 Interaction of surface and underground water
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98
El analisis debera orientarse a establecer los flujos entre ambos
sistemas conslderando que debera realizarse lo siguiente:
- Identificar tramos de cauce superficiales donde pudiere
producirse cambio en el caudal debido a la interacci6n entre el rio
y el acuffero directamente relacionado con este. Para ello, se
podra considerar el desarrollo especial de corridas de aforos para
la cuantificaci6n de los flujos involucrados.
- Identificar las zonas de aporte o drenaje hacia las vertientes,
determinar la recarga pluvial asociada y los flujos subterraneos
estimados. En este sentido es de lmportancia relaclonar la
variabilidad de los flujos con las precipitaciones e identificar la
posible variabilidad dentro del dfa, lo que puede indicar el grado
de relaci6n con su area de drenaje o con zonas de vegas que
pudieran estar asociadas.
- Establecer los consumos evapotranspirativos en zonas de vegas
y bofedales (humedales), los flujos superficiales y subterraneos de
alimentaci6n que llegan a ellos. Debe considerarse la variaci6n
diaria y estacional que genera condiciones de temperatura muy
diferentes en este analisis. Para tal efecto debera efectuarse una
detallada descripci6n de las unidades vegetacionales (superficie,
tipo de vegetacl6n, distribuci6n de la vegetaci6n, etc.) que permita
cuantiflcar los consumos evapotranspirativos. Para tal efecto
debera considerarse la necesidad de disponer de datos de
evaporaci6n de tanque en torno a estas zonas, para lo cual sera
necesario que se contemple el control de esta variable durante el
desarrollo de las actividades de terreno. En forma adicional debera
conocerse su funcionamiento a traves de la medici6n de los niveles
de agua subsuperficial (micropiezometros) de forma tal de
caracterizar direcci6n y cuantia de los flujos superficiales y
subsuperficiales someros.
Como resultado del analisis se establecera los posibles flujos de
interacci6n entre el cauce superficial y la unidad acuifera vinculada
acumulados en la zona de interes hasta su confluencia en la zona de
frontera.
6.4 Determinaci6n de flujos que cruzan la frontera
En forma especffica debera efectuarse una evaluaci6n de los flujos en
frontera, conslderando:
22
99
The analysis should be oriented to establish the flows between both systems,
considering that the following should be done:
- Identify sections of the surface channel where change in flow could occur
due to the interaction between the river and the aquifer directly related to it.
For this, the special development of gauging runs for the quantification of
the flows involved may be considered.
- Identify the zones of contribution or drainage towards the slopes,
determine the associated pluvial recharge and the estimated underground
flows. In this sense, it is important to relate the variability of the flows with
the precipitations and identify the possible variability within the day, which
may indicate the degree of relationship with their drainage area or with areas
of fertile plains that could be associated.
- Establish the evapotranspiration consumption in areas of fertile plains and
bofedales (wetlands), the superficial and underground recharge flows that
reach them. The daily and seasonal variation that generates very different
temperature conditions in this analysis should be considered. For this
purpose, a detailed description of the vegetation units (surface, vegetation
type, vegetation distribution, etc.) should be carried out in order to quantify
the evapotranspiration consumption. For this purpose, the need to have
tank evaporation data around these areas should be considered, for which
it will be necessary to contemplate the control of this variable during the
development of field activities. In addition, its operation should be known
through the measurement of sub-surface water levels (micro-piezometers)
in order to characterize the direction and amount of shallow surface and subsurface
flows.
As a result of the analysis, the possible interaction flows between the surface
channel and the linked aquifer unit accumulated in the area of interest up to its
confluence in the border area will be established.
6.4 Determination of flows that cross the border
Specifically, an assessment of border flows should be carried out, considering:
22
100
- Flujos superficiales
Caudales medics anuales de largo plazo
Caudales medias anuales de invierno y verano
Caudales medics rnensuales promedio
Variabilidad interanual del caudal anual
- Flujos subterraneos en el cruce de frontera
Caudal medic de largo plazo
Caudales o volumenes anuales
6.5 Determfnaci6n de las componentes del balance hidrico
Se consulta la integraci6n de las componentes obtenldas en los puntos
anteriores desde la perspectiva del balance hidrico de largo plazo. Las
componentes del balance deberan establecerse a lo menos para los
puntos donde se implementara ef monitoreo de caudales.
Se incluye lo siguiente:
- Precipitaci6n
- Evaporaci6n y evapotranspiraci6n
- Escorrentfa superficial
- Escorrentla subterranea
- Estimaci6n del error de cierre
6.5.1 Situaci6n pre-existente
Se contempla en esta fase la integracf6n de las componentes del
balance hfdrico de largo plazo en condiciones de regimen natural, es
decir las condiciones previas a la materfalizaci6n de las obras
hldraulicas.
6.5.2 Sltuaci6n actual
En este caso se contempla reallzar el balance considerando la existencia
de las obras y usos actuales dentro de la cuenca.
7, CONCLUSION ES
Como resultado del estudio se presentaran conclusiones orientadas a lo
slguiente:
23
101
- Surface flows
Annual long-term average flows
Annual average flows of winter and summer
Average monthly average flows
Year-to-year variability of the annual flow
- Underground flows at the border crossing
Average long-term flow
Flows or annual volumes
6.5 Determination of water balance components
The integration of the components obtained in the previous points is consulted
from the perspective of the long-term water balance. The components of the
water balance should be established at least for the points where flow monitoring
will be implemented.
The following is included:
- Precipitation
- Evaporation and evapotranspiration
- Surface runoff
- Underground runoff
- Estimation of closing error
6.5.1 Pre-existing situation
The integration of the components of the long-term water balance under natural
regime conditions, that is, the conditions prior to the materialization of the
hydraulic works, is contemplated in this phase.
6.5.2 Current situation
In this case, the water balance is carried out by considering the existence of
works and current uses within the basin.
7. CONCLUSIONS
As a result of the study, conclusions will be presented oriented to the following:
23
102
- Caracteristicas generales del regimen hidrol6gico existente en la zona
- Areas de alimentaci6n de vertientes
- Consumos evapotranspirativos
- Caudales superficiales generados en el sector de la cuenca boliviana
- Efectos de las obras hidraulicas en el drenaje y escurrimiento de las
aguas
- Sentido del flujo y escurrimiento natural de las aguas
- Localizaci6n del cauce
8. BIBLIOGRAFiA
Se indlcara la bibliografia consultada tanto para la presentaci6n de la
proposici6n para realizar el estudio como en la fase de su ejecuci6n.
Todas las referencias indicadas deberan quedar consignadas
debidamente para permitir su verificaci6n.
24
103
- General characteristics of the existing hydrological regime in the area
- Spring feeding areas
- Evapotranspiration consumption
- Surface flows generated in the sector of the Bolivian basin
- Effects of hydraulic works on the drainage and runoff of waters
- Direction of flow and natural runoff of waters
- Channel location
8. BIBLIOGRAPHY
The bibliography consulted will be indicated both for the presentation of the
proposal to carry out the study and in the implementation phase. All references
indicated must be duly registered to allow verification.
24
104
105
Annex 5
Minutes of the II Meeting of the Bolivia-Chile Working Group
on the Silala Issue, 20 January 2005
(Original in Spanish, English translation)
106
• REPUR LICA DE ROLIVIA
MINISTERIO DE RELACIONES
EXTERIORES Y CULTO
ACTA DE LA II REUNl6N DEL GRUPO DE TRABAJO BOLIVIA- CHILE:
SOBRE EL TEMA DEL $!LALA
En la ciudad de La Paz, Republica de Bolivia, el dia 20 de enero de 2005, se
reunieron las Delegaciones de Bolivia y Chile, presididas por D. William Torres
Armas, Director de la Unidad de Analisis de Politica Exterior (UDAPEX), del
Ministerio de Relaciones Exteriores y Culto de Bolivia, y la Embajadora Maria
Teresa Infante, Directora Nacional de Fronteras y Limites del Estado, del
Ministerio de Relaciones Exteriores de Chile, con el objeto de intercambiar
opiniones y criterios acerca de las aguas de! Silala y los recurses hidricos.
La n6mina de las Delegaciones de ambos paises se anexa a la presente Acta.
Ambas Delegaciones expresaron que se mantiene la voluntad politica de alcanzar
importantes acuerdos para cooperar en el tema de recurses hidricos compartidos
y contar con un marco util y practice para este efecto. Un acuerdo satisfactorio
para ambas partes sabre el tema del Silala servira de valioso antecedente para
avanzar en la cooperaci6n mutua sobre dichos recurses.
Conforme al espiritu cooperative que une a ambas Delegaciones y de acuerdo a lo
establecido en la I Reunion del Grupo de Trabajo Bolivia - Chile sobre el tema del
Silala, reiteraron su compromise de avanzar en un programa de trabajo conjunto
que abarcara estudios tecnico-cientificos en ambos lados de la frontera,
necesarios para determinar la naturaleza, origen y flujos de las aguas del Silala,
tanto a nivel superficial como subterraneo.
En su intervencion, la parte chilena recordo la entrega con fecha 2 de agosto de
2004, de un perfil de estudio conjunto sobre "La naturaleza y caracterfsticas de los Cf recurses hidricos del Silala", como fuese concordado en la reunion de 6 de mayo
del mismo afio. Al respecto, la Delegacion boliviana se comprometi6 a presentar
una contrapropuesta del perfil de estudio conjunto acerca de la naturaleza de los
recurses hidricos compartidos.
V
En esta oportunidad, se concuerda actuar mediante una subcomisi6n de caracter
tecnico-cientffico, que dirigira o supervisara los seis aspectos delineados en la
reunion de 6 de mayo de 2004, priorizandose los siguientes:
1. Realizer los trabajos geodesicos y topograficos. Para ese efecto se
recuerda el mandato a la Comisi6n Mixta de Umites.
107
MINUTES OF THE II MEETING OF THE BOLIVIA-CHILE
WORKING GROUP ON THE SILALA ISSUE
In the city of La Paz, Republic of Bolivia, on 20 January 2005, the Delegations
of Bolivia and Chile met, presided over by Mr. William Torres Armas, Director
of the Foreign Policy Analysis Unit (UDAPEX), Ministry of Foreign Affairs and
Worship of Bolivia, and Ambassador Maria Teresa Infante, National Director
of State Borders and Limits, of the Ministry of Foreign Affairs of Chile, with
the purpose of exchanging opinions and criteria about the Silala waters and the
water resources.
The list of the Delegations of both countries is attached to this Minutes.
Both Delegations expressed that they maintain the political will to reach
important agreements to cooperate in the issue of shared water resources and
have a useful and practical framework for this purpose. A satisfactory agreement
for both Parties on the Silala issue will serve as a valuable precedent to move
forward in the mutual cooperation regarding these resources.
In accordance with the cooperative spirit that unites both Delegations and in
accordance with the provisions of the I Meeting of the Bolivia–Chile Working
Group on the Silala issue, they reiterated their commitment to move forward in
a joint work program that will include technical-scientific studies on both sides
of the border, necessary to determine the nature, origin and flows of the waters
of Silala, both on the surfece and underground.
In his speech, the Chilean side recalled the delivery on 2 August 2004, of a
joint study profile on “The nature and characteristics of the water resources
of Silala”, as agreed at the meeting of May 6th of the same year. In this regard,
the Bolivian Delegation undertook to present a counterproposal of the joint
study profile regarding the nature of shared water resources. In this regard, the
Bolivian Delegation undertook to present a counterproposal of the joint study
profile on the nature of shared water resources.
On this occasion, it is agreed to act through a technical-scientific subcommission,
which will direct or supervise the six aspects outlined in the
meeting of 6 May 2004, prioritizing the following:
1. Carry out the geodesic and topographic works. For this purpose, the mandate
of the Joint Boundary Commission is recalled.
108
REPUBLJCA DE BOLIVIA
MINISTERIO DE RELACIONES
EXTERIORES Y CULTO
2. Definir los parametros del estudio conjunto y de complementar los estudios
existentes en cada pais, identificando las areas en que se desarrollara
cada actividad.
3. Construir una base de dates conjunta con la informacion disponible en
ambos paises.
La subcomision mixta constituida procedera en el mas breve plaza posible, a
concordar el perfil definitivo del estudio conjunto, de acuerdo a las diez aspectos
senalados en la reunion de 6 de mayo de 2004 y otros que pudieran concordarse.
En !al sentido ambas Oelegaciones acordaron la celebracion de una reunion
dentro del primer cuatrimestre de 2005, en una ciudad a convenir.
Ambas Delegaciones podran solicitar conjuntamente, apoyo tecnico de
organismos internacionales especializados coma el Organismo Internacional de
Energia Atomica de las Naciones Unidas (OIEA) y el Programa de Recursos
Hfdricos de la UNESCO entre otros, para beneficiar, facilitar y complementar las
trabajos de la subcomision mixta. Los estudios conjuntos a que lleguen las partes,
serviran de base para las acuerdos a las que arriben Bolivia y Chile.
La Delegacion boliviana manifesto la importancia del manejo racional y sostenible
de los recurses hidricos compartidos, en virtud de que dichos recurses tienen un
caracter finito.
Al termino de la Reunion la Presidenta de la Delegaci6n de Chile, agradecio las
atenciones y hospitalidad otorgadas par la Oelegacion de Bolivia.
Ambas Delegaciones determinaron que la Ill Reunion de este grupo de trabajo
Bolivia - Chile sabre el tema del Silala se celebrara a fines del primer semestre del
presente ano.
La presente Acta es suscrita en la ciudad de La Paz, Republica de Bolivia, a las
veinte dias del mes de enero del ano dos mil cinco.
POR LA DELEGACION DE LA
REPUBLICA DE BOLIVIA
POR LA DELEGACION DE LA
REPUBLICA DE CHILE
109
2. Define the parameters of the joint study and complement the existing
studies in each country, identifying the areas in which each activity will
be developed.
3. Build a joint database with the information available in both countries.
The constituted joint sub-commission will proceed as soon as possible, to agree the
final profile of the joint study, according to the ten aspects indicated in the meeting of
6 May 2004 and others that could be agreed. In this sense, both Delegations agreed to
hold a meeting within the first four months of 2005, in a city to be agreed upon.
Both Delegations may jointly request technical support from specialized international
organizations such as the United Nations International Atomic Energy Agency
(IAEA) and the Water Resources Program of UNESCO, among others, in order to
benefit, facilitate and complement the work of the joint sub-commission. The joint
studies to which the Parties arrive will serve as a basis for the agreements reached by
Bolivia and Chile.
The Bolivian Delegation expressed the importance of rational and sustainable
management of shared water resources, since these resources have a finite nature.
At the end of the meeting, the President of the Delegation of Chile thanked the
courtesies and hospitality given by the Delegation of Bolivia.
Both Delegations determined that the III Meeting of this Bolivia–Chile Working
Group on the Silala issue will be held at the end of the first semester of this year.
This Minutes is signed in the city of La Paz, Republic of Bolivia, on the twentieth day
of the month of January of the year two thousand and five.
[SIGNATURE] [SIGNATURE]
FOR THE DELEGATION OF THE FOR THE DELEGATION OF THE
REPUBLIC OF BOLIVIA REPUBLIC OF CHILE
110
REPUBLICA DE BOLIVIA
MINISTERIO DE RELACIONES
EXTERIORES Y CULTO
DELEGACION BOLIVIANA
William G. Torres Armas
Director de la Unidad de Analisis de Politica Exterior (UDAPEX)
Ernbajador Victor Rico Frontaura
Consul General de Bolivia
Consejero Isabel Cadima Paz
Directora de America
Doctor Fernando Urquidi
lngeniero Guimer Romero
Doctor Heman Vera
Tercer Secretario Yuri Arce
Encargado del Escritorio Chile
111
BOLIVIAN DELEGATION
William G. Torres Armas
Director of the Foreign Policy Analysis Unit (UDAPEX)
Ambassador Victor Rico Frontaura
Consul General of Bolivia
Advisor Isabel Cadima Paz
Director of America
Doctor Fernando Urquidi
Engineer Guimer Romero
Doctor Hernan Vera
Third Secretary Yuri Arce
Head of Chile’s Desk
112
REPUBLICA DE BOLIVIA
MINlSTERIO DE RELACJONES
EXTERIORES Y CULTO
DELEGACION CHILENA
Embajadora Maria Teresa Infante
Directora Nacional de Fronteras y Limites del Estado
Embajador Francisco Perez Walker
Consul General de Chile
Senor Humberto Pena
Director General de Aguas
Ministro Consejero Patricio Victoriano
Consul General Adjunto de Chile
Senor Anselmo Pommes
Director de Fronteras
Consejero Oscar Alcaman
Direccion de America del Sur def Ministerio de RR.EE.
Senor Arturo Heusser
Asesor del Servicio Nacional de Geo logia y Minerfa
Senor Julio Poblete
Jefe del Departamento de Asuntos Limitrofes
113
CHILEAN DELEGATION
Ambassador Maria Teresa Infante
National Director of State Borders and Limits
Ambassador Francisco Perez Walker
Consul General of Chile
Mr. Humberto Peña
General Water Director
Minister Counselor Patricio Victoriano
Acting Consul General of Chile
Mr. Anselmo Pommes
Director of Borders
Director Oscar Alcaman
South America Directorate of the Ministry of Foreign Affairs
Mr. Arthur Heusser
Advisor to the National Geology and Mining Service
Mr. Julio Poblete
Head of the Department of Border Affairs
114
115
Annex 6
Minutes of the XVIII Meeting of the Bolivia-Chile Political
Consultation Mechanism, 17 June 2008
(Original in Spanish, English translation)
116
ACT A DE LA XVIII REUNION DEL
MECANISMO DE CONSULTAS POLiTICAS
BOLIVIA- CHILE
En la ciudad de La Paz, Republica de Bolivia, el dia 17 de junio de 2008, se
celebro la XVIII Reunion del Mecanismo de Consultas PoHticas Bolivia - Chile, con
el prop6sito de realizar un analisis y seguimiento sabre los avances en los trece
temas de la agenda com(m arnplia y sin exclusiones, diseiiada por ambos paises.
La Delegaci6n de Bolivia estuvo presidida por el Embajador Hugo Fernandez
Ara.oz, Viceministro de Relaciones Exteriores y Cultos y la Delegaci6n de Chile
estuvo presidida por el Embajador Alberto van Klaveren Stork, Subsecretario de
Relaciones Exteriores.
Esta reunion fue precedida, el dia 16 de junio, por la VI Reunion del Grupo de
Trabajo para Asuntos Bilaterales, cuyas conclusiones fueron sometidas a
consideraci6n y aprobacion de los Jefes de Delegacion. La n6mina de las
Delegaciones de ambos paises se anexa a la presente Acta.
El Jefe de la Delegacion de Bolivia dio la mas cordial bienvenida a la Delegaci6n
de Chile, expres6 que se ha dinamizado la relaci6n a partir de la ultirna reunion de
este mecanismo, lo que muestra la vitalidad de las mismas, puntualizando que la
Agenda de los 13 Puntos gufa la relaci6n bilateral y que el avance de cada uno de
ellos permite el progreso del conjunto de la Agenda.
El Jefe de la Delegacion de Chile agradeci6 la bienvenida y serial6 que una de las
principales prioridades de la politica exterior de Chile consiste en fortalecer las
relaciones bilaterales con los pafses vecinos, especialmente con Bolivia por media
de una agenda amplia y sin exclusiones. Agreg6 que las actuales relaciones
bilaterales son fluidas y atraviesan por un muy buen momenta, percepci6n que es
compartida por los Gobiernos de Chile y Bolivia.
Con la finalidad de dar adecuado seguimiento al desarrollo de la Agenda de los 13
puntos, arnbas Delegaciones acordaron mantener una efectiva coordinaci6n con
ese prop6sito.
Habiendo aprobado la metodologia y agenda de la reunion, ambas Delegaciones
procedieron al desarrollo de la rnisma:
I. Desarrollo de la Confianza Mutlia.
Ambas delegaciones destacaron las numerosas actividades llevadas a cabo por
los gobiernos desde la ultima Reunion de este Mecanismo, y coincidieron en
continuar fomentando el desarrollo de encuentros de distintos sectores de la
sociedad civil de Bolivia y Chile, de tal modo de ir profundizando el desarrollo de la
confianza mutua que representa el pilar que sustenta el tratamiento de todos los
temas de la re!aci6n bilateral.
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MINUTES OF THE XVIII MEETING OF THE BOLIVIA-CHILE
POLITICAL CONSULTATION MECHANISM
The XVIII Meeting of the Bolivia-Chile Political Consultations Mechanism
was held in La Paz, Bolivia, on 17 June 2008, in order to analyze and monitor
the progress made on the thirteen points of the broad joint agenda without
exclusions designed by both countries.
The Bolivian Delegation was chaired by Ambassador Hugo Fernandez Araoz,
Vice-Minister of Foreign Affairs and Worship, and the Chilean Delegation was
chaired by Ambassador Alberto van Klaveren Stork, Undersecretary of Foreign
Affairs.
This meeting was preceded, on June 16th, by the VI Meeting of the Working
Group on Bilateral Affairs, whose conclusions were submitted to the Heads of
Delegation for their consideration and approval. A list of the Delegations of
both countries is attached to these Minutes.
The Head of the Bolivian Delegation warmly welcomed the Chilean Delegation,
stating that relations have grown closer since the last meeting of this mechanism,
which shows its vitality, and pointing out that the 13-Point Agenda guides the
bilateral relations and that the progress with each one of these items means that
progress can be made with the entire Agenda.
The Head of the Chilean Delegation was grateful for the welcome and said that
one of the main priorities of the Chilean foreign policy is to strengthen bilateral
relations with its neighboring countries, especially with Bolivia, by means of a
broad agenda without exclusions. He added that currently the bilateral relations
are fluid, and are going well—perception shared by the Governments of Chile
and Bolivia.
In order to properly monitor the progress of the 13-Point Agenda, both
Delegations agreed to maintain effective coordination for that purpose.
Having approved the methodology and the agenda for the meeting, both
Delegations proceeded to hold it:
I. Development of Mutual Trust
Both delegations emphasized the various activities that the two governments
have carried out since the last Meeting of this Mechanism, and agreed to
continue encouraging meetings of different sectors of the civil society from
Bolivia and Chile, in order to progressively deepen the mutual trust that is the
pillar that supports the treatment of all issues in the bilateral relationship.
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Entre las principales actividades realizadas en este marco se destacan:
Tres encuentros Presidenciales, tres de Cancilleres y cinco de otros Ministros de
Estado. Los Presidentes, Evo Morales y Michelle Bachelet, se reunieron en
Santiago, en noviembre de 2007, en ocasi6n de la Cumbre tberoamericana. En La
Paz, en diciembre del mismo ano, en ocasi6n de la suscripci6n de la "Declaraci6n
de La Paz", que impulsa el Corredor lnteroceanico Chile-Bolivia-Brasil, que ratifica
el compromiso con el proceso de integracion regional en el ambito de la
infraestructura fisica. En Lima, en ocasion de la V Cumbre de Jefes de Estado de
America Latina, el Caribe y la Uni6n Europea, realizada en mayo de 2008.
Los Cancilleres sostuvieron conversaciones, en Cartagena de lndias, en el marco
de la Reunion del Comite de Delegados de UNASUR, en enero de 2008; en Santo
Domingo, con ocasi6n de la Reunion del Grupo de Rio, en marzo de 2008 y, en
Medellin, durante la Asamblea General de la OEA, en junio de 2008.
Los Ministros de las Carteras de Defensa, Salud, Trabajo, Obras Publicas y la
Ministra de Cultura de Chile y el Viceministro de Culturas de Bolivia, tuvieron
ocasion de reunirse bilateralmente en diferentes oportunidades.
Con relaci6n al trabajo junto a la sociedad civil se destaco la visita a Santa Cruz y
La Paz, a invitaci6n del Gobierno de Bolivia, de los directores de los medios de
comunicaci6n y formadores de opinion de Chile, en marzo de 2008, quienes
tuvieron ocasi6n de reunirse con el Presidente y Vicepresidente de la Republica de
Bolivia, otras autoridades y grupos sociales. Asimismo, se tiene programada en la
segunda quincena de junio de 2008, la visita a Santiago de. un selecto grupo de
representantes de las organizaciones sociales de Bolivia. Tambien estan
planificados un Encuentro de los Rectores de Universidades y el Encuentro de
Mujeres Uderes de Chile y Bolivia, ambos en Santiago y en septiembre de 2008,
como asimismo, el segundo Encuentro de Directores de Medios y Formadores de
opinion, a realizarse en Santiago en octubre del afio en curso, a iniciativa del
Gobierno de Chile.
La intensidad de reuniones refleja el interes que existe en ambos gobiernos y en
las respectivas sociedades civiles, por enriquecer las relaciones bilaterales en los
distintos ambitos y es una muestra efectiva de la confianza mutua que se ha
alcanzado.
11. lntegraci6n Fronteriza.
• Comite de Frontera.
Ambas Delegaciones estimaron conveniente celebrar la IX Reunion de este
Comite, el mes de septiembre del afio en curso, en la ciudad de lquique. La
Delegaci6n chilena propuso, en principio, los dias 22 y 23 de ese mes.
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Most notable among the main activities in this context are the following:
Three Presidential meetings, three meetings of Foreign Ministers, and five
meetings of other State Ministers. Presidents Evo Morales and Michelle
Bachelet met in Santiago, in November 2007, on the occasion of the Ibero-
American Summit. In La Paz, in December that same year, on the occasion of
the signing of the “La Paz Declaration,” which promotes the Chile-Bolivia-
Brazil Interoceanic Corridor, which confirms the commitment to the process
of regional integration in the field of physical infrastructure. In Lima, on the
occasion of the 5th EU-CELAC Summit held in May 2008.
The Ministers of Foreign Affairs held talks in Cartagena de Indias, in the context
of the Meeting of the Council of Delegates of UNASUR, in January 2008; in
Santo Domingo, on the occasion of the Meeting of the Rio Group, in March
2008; and in Medellin, during the General Assembly of the OAS, in June 2008.
The Ministers of Defense, Health, Labor, Public Works, and Chile’s Minister
of Culture and Bolivia’s Vice-Minister of Cultures were able to hold bilateral
meetings on several opportunities.
As regards the work done alongside the civil society, most notable were the
visits to Santa Cruz and La Paz of media directors and opinion makers from
Chile, in March 2008, at the invitation of the Government of Bolivia; they had
an opportunity to meet with the President and Vice President of the Republic
of Bolivia, other authorities and social groups. Moreover, a visit to Santiago
has been scheduled for the second half of June 2008, by a select group of
representatives of social organizations from Bolivia. Plans have also been
made for a Meeting of University Rectors and a Meeting of Women Leaders
from Chile and Bolivia, both to be held in Santiago in September 2008, as well
as the second Meeting of Media Directors and Opinion Makers, to be held in
Santiago in October this year, at the initiative of the Government of Chile.
The very high number of meetings reflects the interest, on the part of both
governments and their respective civil societies, in enriching the bilateral
relationship in several fields, and is clear evidence of the mutual trust that has
been reached.
II. Border Integration
• Border Committee
The Delegations agreed to hold the IX Meeting of this Committee in the city of
Iquique this September. The Chilean Delegation proposed, in principle, 22 and
23 of that month.
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• Municipios y comunidades fronterizas.
Ambas Delegaciones tomaron conocimiento de los positivos resuttados del II
Encuentro entre Municipios Fronterizos de Bolivia y Chile, que tuvo lugar en Arica,
los dias 13 y 14 de marzo de 2008. En dicha ocasi6n se consideraron distintos
temas de interes, entre tos que destacan aquellos relativos a capacitaci6n en
diferentes niveles; apoyo a las iniciativas en el ambito de la salud; seguridad y
vigilancia para fronteras armoniosas, en cuyo ambito se propuso considerar la
posibilidad de implementar la Tarjeta Vecinal Fronteriza. Menci6n especial merece
el proyecto para la recuperacion, fomento y puesta en valor del patrimonio cultural
y natural aymara, que cuenta con financiamiento del BID, el que fue acordado el
26 de mayo de 2008.
Tambien se tomo debida nota del Acta del Encuentro de Alcaldes sobre Turismo
que se celebro en la ciudad de Potosi, el 27 de mayo pasado, habiendose
acordado ir encausando sus recomendaciones en las respectivas instancias del
Comite de Frontera.
• Reunion bilateral de autoridades aduaneras.
Ambas Delegaciones acordaron promover la pr6xima realizacion de la Ill Reunion
Bilateral entre las Aduanas de los dos paises.
• Taller sobre las peores formas de trabajo infantil.
Ambas Delegaciones coincidieron en la importancia de realizar el II Seminario
Taller, que se efectuara en la ciudad de lquique, tentativamente en la segunda
quincena de agosto de 2008.
• Desarrolto Fronterizo.
La Delegaci6n chilena se comprometi6 a proponer lugar y fecha para el II
Encuentro Salud sin Fronteras, dentro de las proximas dos semanas.
• Controles lntegrados de Frontera.
Las Delegaciones destacaron la celebraci6n de la V Reuni6n del Comite Tecnico
de Controles lntegrados de Frontera, que tuvo lugar en la ciudad de lquique, el 28
de mayo de 2008, y tomaron nota de los resultados de dicho encuentro.
Con la finalidad de preparar la implementaci6n de un control integrado de doble
cabecera en Pisiga • Colchane, acordaron en principio que a partir de la segunda
semana del mes de septiembre, se inicie bajo marcha blanca dicha modalidad de
control, cuyos resultados se conoceran en la IX Reunion del Comite de Frontera,
con miras a su implementaci6n definitiva. Hubo coincidencia entre los Jefes de las
Delegaciones en la importancia de que la inauguracion oficial de los Complejos
sea realizada conjuntamente por los Presidentes de Bolivia y Chile.
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• Border Municipalities and Communities
Both Delegations were informed of the positive results of the II Meeting of
the Bolivia-Chile Border Municipalities, held in Arica on 13-14 March 2008.
At said Meeting, various issues of interest were discussed, including, most
notably, those concerning training at different levels; support for health-related
initiatives; security and surveillance for peaceful borders, with a proposal, in
this context, to consider the possibility of implementing the Border Residents
Card. Special mention should be made of the project to recover, promote and
revamp the Aymara cultural and natural heritage, supported by IBD funding,
agreed on 26 May 2008.
The Delegations also acknowledged the Minutes of the Meeting of Mayors on
Tourism that was held in Potosi this past May 27th; an agreement was reached
to progressively implement their recommendations at the relevant levels of the
Border Committee.
• Bilateral Meeting of Customs Authorities
Both Delegations agreed to promote the upcoming III Bilateral Meeting
between the two countries’ Customs agencies.
• Workshop on the Worst Forms of Child Labor
Both Delegations concurred on the importance of holding the II Seminar-
Workshop, which will take place in the city of Iquique, tentatively in the second
half of August 2008.
• Border Development
The Chilean Delegation undertook to propose a date and a place for the 2nd
Health without Borders Meeting, within the coming two weeks.
• Integrated Border Controls
The Delegations noted the V Meeting of the Technical Commission on
Integrated Border Controls that was held in Iquique on 28 May 2008, and duly
noted the results of the meeting.
In order to prepare for the implementation of a joint Pisiga-Colchane dualmanager
control, they agreed that, in principle, a trial run will start in the second
week of September, the results of which will be revealed at the 9th Meeting of
the Border Committee, with a view to final implementation. The Heads of the
Delegations agreed on the importance of having the Complexes be officially
jointly inaugurated by the Presidents of Bolivia and Chile.
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Con relaci6n a la propuesta de Bolivia de realizar un ejercicio de control integrado
bajo la modalidad de cabecera (mica en Ollague, con una duraci6n de cuatro
semanas, la Delegaci6n chilena confirmara el periodo de duraci6n y la fecha de
realizaci6n.
En cuanto a Hito Cajones, la Delegaci6n boliviana reiter6 que se ha terminado el
diseno para la construcci6n de un centro integrado, teniendo previsto iniciar su
construcci6n dentro de 6 meses. Por su parte, Chile reiter6 que evalua la
posibilidad de trasladar sus instalaciones desde San Pedro de Atacama hasta un
punto mas cercano del paso.
Ill. Libre Transito
Ambas Delegaciones recogieron los acuerdos alcanzados en ocasi6n de la IX
Reunion del Grupo de Trabajo sabre Libre Transito, que se realiz6 en la ciudad de
la Paz, el 27 de mayo del 2008. Asimismo, coincidieron en la necesidad de
concretar la realizaci6n de las reuniones de los Comites Tecnicos Bilaterales de
los puertos de Arica y Antofagasta.
Tambien destacaron la importancia de las recomendaciones del Seminario sabre
Manipulaci6n, Almacenamiento y Transporte de Mercancias Peligrosas en el
Contexto de las Relaciones Bilaterales Bolivia - Chile, que tuvo lugar el 26 de
mayo de 2008, en la ciudad de la Paz. En este sentido, la Delegaci6n de Chile
inform6 que pr6ximamente presentara un cronograma de actividades para el
seguimiento de las recomendaciones arriba citadas, sin descartar la posibilidad de
realizar un segundo seminario.
• Sistema lntegrado de Transito (SIT).
Ambas Delegaciones coincidieron en la necesidad de continuar trabajando en la
revisi6n del Manual Operalivo del Sistema lntegrado de Transito y recomendaron
que la pr6xima reuni6n del grupo Ad-Hoc se lleve a cabo en agosto de 2008, en la
ciudad de La Paz.
• Habilitaci6n del Puerto de lquique.
La Delegaci6n de Bolivia inform6 que ha recibido oficialmente la nota verbal del
Gobierno de Chile sabre la habi1itaci6n del Puerto de lquique al Regimen de Libre
Transite, e indic6 que la misma esta siendo analizada y estudiada por las
instancias correspondientes de Bolivia y que se dara una respuesta
oportunamente.
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As regards Bolivia’s proposal for a joint single-manager control exercise in
Ollagüe, intended to extend for a period of four weeks, the Chilean Delegation
will confirm the duration period and the date of implementation.
As to the Cajones Marker, the Bolivian Delegation reiterated that the design
has been completed to build an integrated center, with construction set to begin
within 6 months. Moreover, Chile reiterated it is assessing the possibility of
moving its facilities from San Pedro de Atacama to a location closer to the
border crossing.
III. Free Transit
Both Delegations addressed the agreements reached on the occasion of the IX
Meeting of the Working Group on Free Transit, which was held in the city of
La Paz, on 27 May 2008. They also agreed on the need to hold meetings of the
Bilateral Technical Committees for the ports of Arica and Antofagasta.
They also emphasized the importance of the recommendations of the Seminar
on Handling, Storage and Transport of Dangerous Goods in the Context of
Bilateral Relations between Bolivia and Chile, which was held on 26 May 2008,
in the city of La Paz. Along these lines, the Chilean Delegation reported that it
will soon present a schedule of activities for monitoring the recommendations
cited above, although not discarding the possibility of holding a second seminar.
• Integrated Transit System (ITS).
Both Delegations agreed on the need to continue working on the revision of
the Operations Manual for the Integrated Transit System and recommended
that the next meeting of the Ad-Hoc Group be held in August 2008, in the city
of La Paz.
• Enabling of the Port of Iquique
The Bolivian Delegation reported that it had officially received the verbal note
from the Chilean Government regarding the enabling of the Port of Iquique
under the Free Transit Regime, and indicated that this note is being analyzed
and studied by the proper authorities in Bolivia and that an answer will be given
in due course.
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IV. lntegraci6n Flsica
• Grupo Tecnico sobre lnfraestructura (GTM).
Ambas Oelegaciones acordaron realizar la 111 Reunion del GTM en julio del
presente afio, en la ciudad de lquique, para intercambiar informaci6n, entre otras
materias, sabre los avances en la construcci6n del Corredor lnteroceanico definido
en la "Declaracion de La Paz", de diciembre de 2007. Asimismo, convinieron en
incluir los temas ferroviarios en dicha reunion.
La Delegacion boliviana informo que el cronograma acordado en la "Declaraci6n
de ta Paz", para ta construccion de los tramos Pararso-EI Tinto-San Jose de
Chiquitos, se encuentra en proceso de reprogramacion de obra, que preve una
ampliacion hasta el mes de noviembre de 2009.
• Reunion Bilateral de los Organismos Competentes de Aplicaci6n
del ATIT.
Ambas delegaciones tomaron nota del Acta de la VIII Reunion de tos Organismos
de Aplicaci6n del Convenio de Transporte Internacional Terrestre Bolivia - Chile,
que se reatizo en La Paz, et 28 y 29 de noviernbre de 2007.
La Delegaci6n de Chile confirmara et lugar y fecha para la realizaci6n de la IX
Reunion del A TIT.
• Ferrocarril Arica - La Paz.
La Delegacion boliviana realiz6 una recapitulaci6n de la informacion que disponra
desde ta ultima Reunion de este Mecanismo, en el que se reflejaba el anuncio de
la parte chilena de que la via se rehabilitaria el 2008.
La Delega'cion chilena informo que se aprob6 ta Oeclaraci6n de tmpacto Ambiental
y que se encuentra en proceso de elaboracion et proyecto de rehabilitaci6n que ha
incorporado las medidas de remediaci6n establecidas en dicha declaracion.
Agreg6 que en el proyecto se ha incluido ademas un mejoramiento sustancial det
estandar de la via, lo que ha generado un retraso en los plazas originales. Et
proyecto sera adjudicado en el segundo semestre de 2008 y las obras se
desarrotlaran durante el afio 2009.
La Detegaci6n boliviana expres6 su preocupaci6n por la reprogramacion y reiter6
la importancia que tiene et avance y conctusi6n de este proyecto en los nuevos
plazas sefialados.
La Delegaci6n chilena hizo presente que su Gobierno le esta dando ta maxima
priorfdad a este proyecto de rehabilitaci6n.
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IV. Physical Integration
• Technical Group on Infrastructure (TGI)
The Delegations agreed to hold the III Meeting of the TGI in July this year,
in the city of Iquique, to exchange information on, among other issues, the
progress made in the construction of the Interoceanic Corridor defined in the
“La Paz Declaration” of December 2007. In addition, they agreed to include
railway-related issues in the agenda for that meeting.
Both Bolivian Delegation reported that the schedule established in the “La Paz
Declaration” to build the Paraiso-El Tinto-San Jose de Chiquitos sections is in
the process of being reworked, and the works are now expected to extend to
November
2009.
• Bilateral Meeting of the Competent Enforcing Authorities of the ATIT
The Delegations duly noted the Minutes of the VIII Meeting of the Enforcement
Authorities of the Bolivia-Chile Agreement on International Ground Transport
(ATIT), which was held in La Paz on 28-29 November 2007.
The Chilean Delegation is to confirm the time and place for the IX ATIT
Meeting.
• Arica-La Paz Railway
The Bolivian Delegation summarized the information it has since the last
Meeting of this Mechanism, at which the Chilean Delegation announced that
the railway would be refurbished in 2008.
The Chilean Delegation reported that the Environmental Impact Declaration
had been approved and that the refurbishment plan is currently being drawn up,
as it has incorporated the remediation measures provided for by the declaration.
They added that the project has also included a substantial improvement to the
standard of the railway, which has led to a delay from the original deadlines.
The project will be awarded in the second half of 2008 and the works will be
implemented in 2009.
The Bolivian Delegation expressed its concern with the rescheduling and
reiterated how important the progress and completion of this project within the
new deadlines is.
The Chilean Delegation pointed out that their Government considers this
refurbishment project to be a top priority.
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V. Complementaci6n Econ6mica.
Ambas partes tomaron nota del Acta de la XIX Reuni6n de la Comisi6n
Administradora del ACE 22, que se celebr6 en La Paz, el 5 de junio de 2008, en la
cual sesionaron los comites tecnicos en las areas comercial, silvoagropecuaria,
turismo, aduanas, promoci6n comercial y cooperaci6n, asf como los subcomites
silvfcola, de normalizaci6n y medidas sanitarias y fitosanitarias. Cada una de estas
instancias defini6 su programa de trabajo para los pr6ximos meses.
Ambas Delegaciones coincidieron en la importancia que ha tenido el desarrollo del
Convenio CEPROBOL - PROCHILE, y se felicitaron en particular por el exito de
las Ferias de la Construcci6n de Bolivia que se han efectuado en Arica e lquique y
la que se inaugurara en Antofagasta el 26 de junio de 2008.
La Delegaci6n de Chile record6 que en la reunion de la Comisi6n Administradora
del ACE 22, Bolivia se comprometi6 a responder dentro de 15 dias la solicitud
chilena de restituir los anteriores niveles arancelarios a una lista de 34 productos.
Asimismo, record6 su compromiso a dar respuesta, tambfen en un plazo de 15
dfas, a la solicitud boliviana para que Chile apoye la participaci6n de Bolivia en
diversas instancias de promoci6n comercial que tendran lugar en Santiago durante
el afio 2009.
Ambas Delegaciones destacaron. la importancia que tienen, para el fortalecimiento
de la agenda econ6mica - comercial, las acciones y actividades de cooperaci6n
que se acuerden realizar. Ademas, resaltaron que el ambito econ6mico -
comercial constituye un componente importante del Plan de Trabajo que se
menciona en el punto VIII de la presente Acta.
La Delegaci6n de Chile transmiti6 el interes de la Junta de Aeronautica Civil de su
pafs por celebrar en Santiago, una reunion con su contraparte boliviana. La
delegaci6n chilena anunci6 que en las pr6ximos dlas se hara llegar una carta de
invitaci6n a dictia reunion .
La Delegaci6n de Chile inform6 que, en el marco del compromiso de su Gobierno
por dinamizar la agenda econ6mica - comercial con Bolivia, este ano participara
par primera vez en la Feria de Santa Cruz con un pabell6n propio.
VI. Terna Maritimo.
En la perspectiva de la profundizaci6n de\ dialogo sobre este tema, conforme a las
directrices de los respectivos Gobiernos y considerando la existencia de
importantes logros en la confianza mutua, se intercambiaron ideas y criterios sabre
formas especificas para abordar este tema y aproximaciones concretas en la
materia.
Analizadas las distintas opciones existentes, se profundiz6 en aquellas que
ofrecen mayor viabilidad a corto plazo. Para avanzar en este analisis, se
comprometieron a encomendar las debidos estudios tecnicos.
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V. Economic Complementation
Both parties took note of the Minutes of the XIX Meeting of the Administrative
Commission for ACE 22, held in La Paz on 5 June 2008, comprising meetings
of the technical commissions for trade, forestry and agriculture, tourism,
customs, trade promotion and cooperation, as well as the sub-commissions on
forestry, standardization and sanitary and phytosanitary measures. Each such
body defined its work schedule for the coming months.
Both Delegations agreed on the importance of the implementation of the
CEPROBOL – PROCHILE Agreement, and congratulated each other, in
particular, on the success of the Bolivian Construction Fairs held in Arica and
Iquique, and the one that will open in Antofagasta on 26 June 2008.
The Chilean Delegation mentioned the fact that, at the Administrative
Commission for ACE 22, Bolivia agreed to provide an answer to Chile’s request
to restore the previous tariff levels to a list of 34 products within 15 days. It also
mentioned its promise to have an answer, within 15 days as well, to Bolivia’s
request that Chile support Bolivia’s involvement in the various trade promotion
efforts to take place in Santiago in 2009.
Both Delegations highlighted the importance that the cooperation actions and
activities they may agree upon have in terms of strengthening the economictrade
agenda. Moreover, they noted that the economic-trade context is an
important component of the Work Plan mentioned in item VIII of these Minutes.
Chile’s Delegation conveyed the interest of Chile’s Civil Aviation Board
in holding a meeting with its Bolivian counterpart agency in Santiago. The
Chilean Delegation announced that a letter of invitation to the meeting will be
sent in the next few days.
The Chilean Delegation reported that, in the context of the Chilean Government’s
commitment to make the economic-trade agenda with Bolivia more dynamic,
this year it will be participating in the Santa Cruz Fair with its own sector for
the first time.
VI. Maritime Issue
With a view to deepening the dialogue on this topic, in accordance with the
guidelines from their respective Governments, and considering the existence of
important achievements in mutual trust, they exchanged ideas and criteria on
specific ways to address this topic and concrete approaches to the issue.
Having analyzed the various existing options, they then deepened those that are
more viable in the short term. To move ahead with this analysis, they undertook
to commission the appropriate technical studies.
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r0 ~l1
r /
~
Los Vicecancilleres reiteraron su conv1cc1on que mediante este proceso de
dialogo, con un enfoque realista y de futuro, podran alcanzarse los acuerdos
necesarios.
Los Vicecancilleres coincidieron en dar continuidad a este dialogo, para lo cual
consideraron necesario apoyarse en sus respectivos equipos internos.
VII. Silata y Recursos Hidricos.
En relaci6n a esta materia, las Delegaciones destacaron los acuerdos alcanzados
en la Ill Reunion del Grupo de Trabajo sobre el tema del Silala y que consign6 el
Acta suscrita e\ dia 10 de junio de 2008.
Despues de un amplio lntercambio de ideas, en el cual se constat6 la coincidencia
en darle a esta materia una dimension real, las Delegaciones acordaron queen los
pr6ximos 60 dias se intercambiaran esquemas con los contenidos para un
acuerdo basico inmediato, que tenga en cuenta el recurso hldrico en sus usos
existentes, los derechos de cada pals, y las formas y mecanismos para su
aprovechamiento de manera de generar beneficios econ6micos para Bolivia,
considerando la sostenibilidad del recurse. En este periodo se constituira una
Comisi6n Bilateral que estudiara los elementos antes indicados para ta conclusi6n
de dicho acuerdo antes de fin de ano.
En forma paralela se coordinaran las medidas para dar cumplimiento a lo
abordado en el Acta de la Ill Reunion, en lo relativo a los aspectos tecnicos.
VIII. lnstrumentos de lucha contra la pobreza.
Las Delegaciones constituyeron el Grupo de Trabajo de Cooperaci6n coordinado
por las respectivas Cancillerias, integrado por el Viceministerio de Inversion
Publica y Financiamiento Externo de Bolivia (VIPFE) y la Agencia de Cooperacl6n
Internacional de Chile (AGGI). Ambas Delegaciones se congratularon por la
suscripci6n entre ambas instituciones del Plan de Trabajo "Programa de
Cooperaci6n para el Fortalecimiento de Capacidades e lntercambio de
Experiencias 2008/2009", que se adjunta al presente Acta como Anexo II.
Ambas Delegaciones manifestaron su satisfacci6n por el significativo incremento
del trabajo de cooperaci6n experimentado durante los dos ultimas anos, esfuerzo
que se espera persista y que sea funcional a los objetivos de la Agenda de los 13
Puntos.
La Delegaci6n chilena anunci6 que para el ano 2009 habra un significativo
aumento del numero de becas de Magister, incrementando el numero de 21 a 40
becarios bolivianos, lo que fue agradecido por la Delegaci6n boliviana.
Destacaron asimismo la ampliaci6n de la cooperaci6n hacia la sociedad civil con el
apoyo del Programa de Voluntarios para Haiti. Se espera conformar el primer
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The Vice-Ministers reiterated their conviction that the necessary agreements
could be reached through this process of dialogue, with a realistic and futureoriented
approach.
The Vice-Ministers agreed to continue this dialogue, for which they deem it
necessary to rely on their respective internal teams.
VII. Silala and Water Resources
In relation to this matter, the Delegations highlighted the agreements reached in
the III Meeting of the Working Group on the Silala issue and that was recorded
in the Minutes signed on 10 June 2008.
After a broad exchange of ideas, in which an agreement was reached of giving
this subject a real dimension, the Delegations agreed that in the next 60 days,
the contents will be exchanged for an immediate basic agreement, that takes
into account the water resource in its existing uses, the rights of each country,
and the means and mechanisms for its use in order to generate economic
benefits for Bolivia, taking into account the sustainability of the resource.
During this period, a Bilateral Commission will be constituted in order to study
the aforementioned elements for the conclusion of said agreement before the
end of the year.
At the same time, measures will be coordinated in order to comply with the
provisions of the Minutes of the III Meeting, regarding the technical aspects.
VIII. Instruments to Fight Poverty
The Delegations set up the Cooperation Working Group coordinated by the
respective Ministries of Foreign Affairs, consisting of the Vice-Minister of
Public Investment and Foreign Financing of Bolivia (VIPFE) and Chile’s
International Cooperation Agency (AGCI). The Delegations exchanged
congratulations on the execution of the “2008/2009 Cooperation Program for
Strengthening Capacities and Sharing Experiences” Work Plan signed by both
institutions, attached as Annex II hereto.
Both Delegations expressed their satisfaction with the significant increase in
the amount of cooperation work during the past two years, which efforts they
expect to continue and be functional to the goals set in the 13-Point Agenda.
The Chilean Delegation announced a significant increase in the number of
scholarships for Master programs in 2009, with the number of Bolivian slots
rising from 21 to 40, which the Bolivian Delegation expressed its appreciation
for.
They also highlighted the expansion of cooperation to include civil society by
supporting the Volunteers for Haiti Program. The first team
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grupo de voluntarios bolivianos y chilenos a ese pals, para el segundo semestre
del 2008.
Por otra parte, ambas Delegaciones coincidieron en la importancia de suscribir un
Convenio de Cooperaci6n, entre las instituciones correspondientes, con el objeto
de fortalecer y facilitar la colaboraci6n en areas de interes mutuo.
Las Delegaciones propondran una fecha para coordinar una reunion de
seguimiento del mencionado Plan de Trabajo durante el segundo semestre del
presente afio.
IX. Seguridad y Defensa.
Ambas delegaciones constataron que ha continuado la dinarnica de visitas
institucionales de autoridades de los Ministerios de Defensa y de las Fuerzas
Armadas de los dos paises, lo cual constituye medidas concretas de transparencia
y de fomento de la confianza y la seguridad.
En ese contexto, destacaron la importancia de las visitas oficiales a Chile del
Ministro de Defensa de Bolivia, Sr. Walker San Miguel, los dias 5 y 6 de diciembre
de 2007 y el 14 de mayo de 2008, la ultima como un gesto de solidaridad ante la
catastrofe ocurrida en Chaiten.
Asimismo, resaltaron la relevancia de la visita oficial a Bolivia del Ministro de
Defensa Nacional de Chile, · Sr. Jose Goni, del 15 al 17 de junio de 2008, en la
cual se suscribi6 el "Memorandum de Entendimiento entre el Ministerio de
Defensa Nacional de la Republica de Chile y el Ministerio de Defensa Nacional de
la Republica de Bolivia sobre Cooperaci6n en Defensa".
• Desminado de Frontera
La Delegaci6n de Bolivia seria16 que ha manifestado permanentemente que, en el
marco de la confianza mutua que construyen ambos paises, la integraci6n
fronteriza requiere de mayor seguridad y cuidado de la vida humana asl como de
la vida silvestre que habita en la frontera comun.
La Delegaci6n de Chile entreg6 copia a la Delegaci6n de Bolivia de! ultimo lnforme
de Transparencia, presentado a Naciones .Unidas el 30 de abril de 2008, en
cumplimiento del articulo 7 de la Convenci6n de Ottawa sobre Prohibici6n de
Minas Antipers6nal y de la Memoria Anual de la Comisi6n Nacional de Desminado,
correspondiente al ario 2007. Asimismo, comunic6 que a fines de mayo de 2008
concluyeron los trabajos de desminado en Cancosa, iniciados en octubre de 2007.
Ademas, dio a conocer que con fecha 9 de junio de 2008 comenzaron las labores
de desminado en Chapiquif\a.
La Delegaci6n de Chile transmiti6 el deseo de la Comisi6n Nacional de Desminado
de hacer una reunion con su contraparte boliviana para abordar, especialmente, el
desminado fronterizo.
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group of Bolivian and Chilean volunteers would be created to that country, for
the second half of 2008.
On the other hand, both Delegations concurred on the importance of having the
relevant institutions sign a Cooperation Agreement with a view to strengthening
and facilitating collaboration in areas of mutual interest.
The Delegations will be proposing a date to arrange a follow-up meeting for the
aforementioned Work Plan in the second half of this year.
IX. Security and Defense
The Delegations verified that the institutional visits by authorities from both
countries’ Ministries of Defense and Armed Forces have continued, which
represents concrete transparency and trust and security promotion measures.
In this context, they noted the importance of the Bolivian Minister of Defense,
Mr. Walker San Miguel’s official visits to Chile on 5-6 December 2007, and 14
May 2008, the latter one as a demonstration of solidarity in the face of the
Chaiten disaster.
They further noted the importance of the Chilean Minister of National Defense,
Mr. Jose Goñi’s official visit to Bolivia on 15-17 June 2008, during which the
“Memorandum of Understanding between the Ministry of National Defense of
the Republic of Chile and the Ministry of National Defense of the Republic of
Bolivia on Defense Cooperation” was signed.
• Border Demining
The Bolivian Delegation pointed out that it has consistently expressed that, in
the context of the mutual trust both countries are in the process of building,
border integration calls for increased security and care for human life, as well
as the wild life along the common border.
The Chilean Delegation provided the Bolivian Delegation with a copy of
the latest Transparency Report, submitted to the United Nations on 30 April
2008, pursuant to Article 7 of the Ottawa Convention on the Prohibition of
Anti-Personnel Mines and the 2007 Annual Report of the National Demining
Commission. Moreover, it reported that the demining works in Cancosa, which
had begun in October 2007, were completed in late May 2008. It also informed
that demining works in Chapiquiña started on 9 June 2008.
The Chilean Delegation expressed the National Demining Commission’s
wishes to hold a meeting with its Bolivian counterpart agency to discuss, in
particular, the issue of border demining.
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Ambas delegaciones valoraron la rea1izaci6n de\ "I Curso Basico de Desminado
Humanitario", efectuado en el Centro de Desminado de la Escuela de lngenieros
Militares de\ Ejercito de Chile, del 24 de marzo al 3 de abril de 2008 y en el que
participaron 5 oficiales y 10 suboficiales de\ Ejercito de Bolivia.
• Proyecto de Convenio de Cooperaci6n entre Carabineros de Chile y
la Polic[a Nacional de Bolivia
Respecto de este proyecto de Convenio, ambas delegaciones observaron que el
texto esta terminado, raz6n par la cua\ coincidieron en la pertinencia de suscribirlo
pr6ximamente, conforme a lo acordado en la VIII Reuni6n del Comite de
Fronteras. Hubo acuerdo en inc\uir en dicho Convenio la figura del Oficial de
Enlace.
• Desastres Naturales
La Delegaci6n de Bolivia hizo entrega del proyecto de Convenio de Cooperaci6n
en Materia de Desastres Naturales y lo puso a consideraci6n de la De\egaci6n de
Chile.
Ambas Delegaciones recordaron que es necesario consultar sobre los cursos de
acci6n respecto del acuerdo de los Ministros de Defensa en cuanto a efectuar un
ejercicio sobre control de desastres naturales durante el ano 2008, conducido por
el Estado Mayor Conjunto de Bolivia y el Estado Mayor de la Defensa Nacional de
Chile.
La De\egaci6n de Bolivia agradeci6 a nombre de su Gobierno por la cooperaci6n
proporcionada por la Republica de Chile durante las inundaciones en el
Departamento del Beni que se produjeron durante los primeros meses del
presente ano.
Por su parte, la Delegaci6n de Chile tambien agradeci6 la muestra de solidaridad
de\ Ministro de Defensa de Bolivia al visitar la zona afectada por la erupci6n del
Volcan Chaiten.
• Tratamiento de otros temas en materia de seguridad y defensa
Ambas De\egaciones coincidieron en la necesidad de ampliar el punto relativo a
seguridad y defensa, abordando las coincidencias en estas materias en los foros
mu\ti\atera\es. Al respecto, la Oelegaci6n boliviana se comprometi6 a presentar
una agenda actualizada.
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Both Delegations recognized the value of the “1st Basic Course in Humanitarian
Demining,” which took place at the Demining Center of the School of Military
Engineers of the Chilean Army from 24 March to 3 April 2008, with 5 officers
and 10 non-commissions officers from the Bolivian Army in attendance.
• Draft Agreement on Cooperation between the Chilean Uniformed
Police [Carabineros] and the Bolivian National Police
As regards this draft Agreement, both Delegations noted that the draft is ready,
and therefore agreed it should be signed soon, as was agreed at the 8th Meeting
of the Frontier Committee. They agreed to include the Liaison Officer rank in
the Agreement.
• Natural Disasters
The Bolivian Delegation presented the draft Agreement for Cooperation on
Natural Disasters and submitted it to the consideration of the Chilean Delegation.
Both Delegations recalled that consultations are necessary regarding the course
of action to be taken in connection with the agreement by the Ministers of
Defense for a natural disaster monitoring exercise to be carried out in 2008,
run by the Joint Chiefs of Staff of Bolivia and Chile’s National Defense Chief
of Staff.
The Bolivian Delegation expressed the Bolivian Government’s appreciation
for the cooperation provided by the Republic of Chile during the floods in the
Department of Beni, in the early months of this year.
Moreover, the Chilean Delegation also expressed its appreciation for Bolivia’s
Minister of Defense’s show of solidarity by visiting the area affected by the
eruption of the Chaiten volcano.
• Discussion of Other Security and Defense Issues
The Delegations agreed on the need to expand the security and defense
discussion, addressing the shared viewpoints in these areas at multilateral fora.
In this regard, the Bolivian Delegation agreed to submit an updated agenda.
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X. Cooperacl6n para el control del trafico ilicito de drogas y de
productos qufmicos esenciales y precursores
Ambas delegaciones constataron los avances logrados en la "VII Reunion de la
Comisi6n Mixta sobre Drogas y T emas Conexos entre las Republicas de Bolivia y
Chile", celebrada en La Paz en septiembre de 2007, en la que se estab1eci6 un
mecanismo de seguimiento permanente en las Cancillerias de ambos palses. La
celebraci6n de la VIII Reunion de esta Comisi6n Mixta se realizara en Chile el afio
2009 y su convocatoria estara a cargo de las Cancillerias.
La Delegacion boliviana mencion6 que ambas Canciller(as vienen coordinando
para el pr6ximo afio la celebraci6n, preferentemente en una zona fronteriza, de un
Seminario sobre Cooperacion Judicial, Policial y Lavada de Actives.
Con relacion al Proyecto de "Convenio sobre lntercambio de lnformaci6n de
Antecedentes Penales por Delitos de Trafico llicito de Estupefacientes y
Sustancias Sicotropicas y Lavada de Dinero asociado a estos Delitos" que fue
presentada por la Delegaci6n de Chile en la VII Comixta antes mencionada, la
Oelegaci6n boliviana informo que esta preparando una contrapropuesta a ser
oficializada pr6ximamente.
XI. Educaci6n, Ciencia y Tecnologia.
Las Delegaciones resaltaron la reunion preparatoria para la Comixta de
Educaci6n, Ciencia y Tecnolog!a entre representantes de los Ministerios de
Educaci6n de ambos paises en la que se identificaron, entre otros, los siguientes
temas:
• Apoyo para desarrollar la segunda etapa del Portal Educabollvia.bo
• Encuentro de Academicos y Universidades
• Educaci6n intercultural
• Encuentro anual de historiadores
• Cooperaci6n chilena en escuelas de las ciudades de El Alto, Oruro y
Tarija
• Programa Escuelas sin Frontera
• Qhapaq Nan
• Ofrecimientos de cooperaci6n a nivel de experiencias en areas
educativas
La Delegacion boliviana confirmara la fecha de realizaci6n de dicha Comixta,
que se llevara a cabo en la ciudad de La Paz, en el curse del presente ano.
XII. Culturas.
Ambas Delegaciones convinieron que la constituci6n de la Comisi6n Mixta de
Culturas se realice durante el tercer trimestre del afio en curso en Santiago y que
posteriormente se firme en La Paz, el Memoranda de Entendimiento
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X. Cooperation for the Control of Illegal Trafficking of Drugs, Precursors
and Essential Chemicals
Both Delegations verified the progress made during the “VII Meeting of the
Mixed Bolivia-Chile Commission on Drugs and Related Issues” that took place
in La Paz in September 2007, at which a mechanism for permanent monitoring
at both countries’ Ministries of Foreign Affairs was established. The VIII
Meeting of said Mixed Commission will take place in Chile in 2009, to be
convened by said Ministries.
The Bolivian Delegation mentioned that both Ministries of Foreign Affairs have
been making arrangements for a Seminar on Judicial and Police Cooperation
and Money Laundering to be held next year, preferably in a border location.
As regards the draft “Agreement on the Exchange of Information on Criminal
Records for Trafficking of Narcotic Drugs and Psychotropic Substances
and Related Money Laundering Crimes” that was submitted by the Chilean
Delegation at the aforementioned VII Meeting of the Mixed Commission, the
Bolivian Delegation reported that it is preparing a counterproposal to be made
official in the near future.
XI. Education, Science and Technology
The Delegations highlighted the preparatory meeting for the Mixed Commission
on Education, Science and Technology between representatives of both
countries’ Ministries of Education, at which, among others, the following
issues were identified:
• Support for the second stage of the Educabolivia.bo website
• Meeting of Academia and Universities
• Intercultural education
• Annual meeting of historians
• Chilean cooperation in El Alto, Oruro and Tarija schools
• Schools without Borders Program
• Qhapaq Ñam
• Offering of cooperation concerning experiences in educational fields
The Bolivian Delegation will confirm the date for the meeting of the Mixed
Commission, which will take place this year in the city of La Paz.
XII. Cultures
Both Delegations agreed that the Mixed Commission on Cultures is to meet in
the third quarter of the current year in Santiago, then for the Inter-institutional
Memorandum of Understanding
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~
lnterinstitucional para un Programa de lntercambio Cultural entre las instancias
correspondientes de los Gobiemos de la Republica de Chile y de la Republica de
Bolivia para los anos 2008-2011, proyecto que esta siendo considerado por el
Viceministerio de Desarrollo de las Culturas de Bolivia.
La Delegaci6n chilena expuso sabre las actividades culturales realizadas durante
el primer semestre de 2008 y las que estan programadas para el resto del afio.
Ambas Delegaciones se congratularon por la intensa agenda que se ha
desarrollado.
En relaci6n al Proyecto de Convenio de Protecci6n y Restituci6n de Bienes del
Patrimonio Cultural, la Delegaci6n boliviana ofreci6 remitir pr6ximamente sus
comentarios.
XIII. otros Temas
• Contactos lnterparlamentarios
Ambas Delegaciones tomaron conocimiento de la programaci6n del II Encuentro
Oficial de las Comisiones de RREE de los Senados de Bolivia y Chile, que tendra
lugar el 8 de julio del presente afio en Valparafso.
• Convenio en materia de seguridad social
La Delegaci6n de Chile reiter6 la importancia de suscribir pr6ximamente este
Convenio que favorecera a un m1mero importante de bolivianos en Chile y de
chilenos en Bolivia y espera una respuesta respecto al texto propuesto.
La Oelegaci6n de Bolivia inform6 que se encuentra en tramite de aprobaci6n
congresal el Convenio lberoamericano de Seguridad Social y en ese marco poder
avanzar en un acuerdo bilateral con Chile sobre la materia.
• AADAA.
Ambas Delegaciones decidieron que los respectivos Directores Juridicos de las
Cancillerias se reunan pr6ximamente para dar continuidad a este tema y
presenten formulas alternativas para determinar una soluci6n definitiva a esta
materia.
• Visas a estudiantes chilenos en Bolivia
La Delegaci6n de Chile expres6 su preocupaci6n por el cobra de visas a
estudiantes chilenos par oficinas regionales del Servicio Nacional de Migraci6n de
Bolivia en los Departamentos de Cochabamba y Santa Cruz, lo que no se ajustaria
a la reciprocidad acordada en el Convenio Andres Bello.
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for a Cultural Exchange Program between the relevant authorities of the
Governments of the Republic of Chile and the Republic of Bolivia for 2008-
2011, which is under the consideration of Bolivia’s Office of the Vice-Minister
of Cultural Development, to be signed in La Paz.
The Chilean Delegation provided an account of the cultural activities carried
out in the first half of 2008, and those scheduled for the rest of the year.
Both Delegations exchanged congratulations on the busy agenda that has been
worked through.
As regards the Draft Agreement on the Protection and Restitution of Cultural
Heritage Assets, the Bolivian Delegation offered to provide its feedback shortly.
XIII. Other issues
• Inter-Parliamentary Contacts
Both Delegations noted that the II Official Meeting of the Bolivian and Chilean
Senate Commissions on Foreign Affairs has been scheduled to take place on
July 8th, this year, in Valparaíso.
• Social Security Agreement
The Chilean Delegation brought up, once again, the importance of signing an
Agreement in the near future that will favor a significant number of Bolivian
citizens in Chile and Chilean citizens in Bolivia, and is awaiting an answer on
the proposed draft.
The Bolivian Delegation informed that it is in the process of obtaining
congressional approval for the Ibero-American Convention on Social Security,
which will allow making progress towards a bilateral social security agreement
with Chile.
• AACW (Autonomous Administration of Customs Warehouses)
Both Delegations decided that the Directors of Legal Affairs of their respective
Ministries of Foreign Affairs will soon meet in order to continue to discuss
this issue and present alternative formulas to define a definitive solution in this
regard.
• Visas for Chilean Students in Bolivia
The Chilean Delegation expressed its concern over the fact that the regional
offices of Bolivia’s National Immigration Services in the Departments of
Cochabamba and Santa Cruz have been charging Chilean citizens for student
visas, which is not in line with the reciprocity agreed in the Andres Bello
Convention.
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La Delegaci6n de Bolivia se comprometi6 a hacer las consultas al Servicio
Nacional de Migraci6n para solucionar esta situaci6n.
• Convenio Marco de Cooperaci6n entre el Servicio Nacional de la
Mujer de Chile y el Vicemlnisterio de Genero y Asuntos
Generacionales de Bolivia
La Delegaci6n de Chile inform6 que el Servicio Nacional de la Mujer de Chile
(SERNAM) hizo entrega de la propuesta de Convenio al Viceministerio de Genero
y Asuntos Generacionales de Bolivia en enero de 2008 y que estaba a la espera
de una respuesta oficial. Asimismo, se comprometi6 a enviar el texto de dicho
Convenio a la Cancillerla boliviana.
Al termino del encuentro, las Oelegaciones acordaron que las pr6ximas reuniones
del Mecanismo de Consultas Pollticas y del Grupo de Trabajo sabre Asuntos
Bilaterales se realicen en Chile, en fecha a convenir por canales diplomaticos.
El Subsecretario de Relaciones Exteriores de Chile expres6 en nombre de su
Delegaci6n, los mas sinceros agradecimientos y aprecio por las atenciones
recibidas con ocasi6n de estas reuniones, de parte de la Cancilleria de Bolivia.
Suscrita en La Paz, a diecisiete dfas del mes de junio del afio 2008.
POR BOLIVIA PORCHILE
~~ Embajador Hugo Fer~fndez Araoz
Viceministro de Relaciones Exteriores y
Cultos
, . Em ajad r Alberto van Klaveren Stork.
· Subsecretario de Relaciones Exteriores
LA PRES!: ' ',:: fl~P~",JUCCIQN l:S C'J?!A FIB.
DEL 8" 1:" :: • •. , ! Af!=,:fl0\JC I.~ Y HARA
FE r· .. ,.,,., · ~ r1s ::iu :: 3ro EN
EL r- .s~ 1 e-:, "' rlorflVIL.
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139
The Bolivian Delegation agreed to contact the National Immigration Service to
resolve the issue.
• Framework Agreement for Cooperation between Chile’s National
Women’s Service and Bolivia’s Deputy Minister of Gender and Generational
Issues
The Chilean Delegation stated that Chile’s National Women’s Service
(SERNAM) submitted the draft Agreement to Bolivia’s Office of the Deputy
Minister of Gender and Generational Issues in January 2008, and was awaiting
an official reply. Moreover, it undertook to send the draft Agreement to the
Bolivian Ministry of Foreign Affairs.
As the meeting ended, the Delegations agreed that the coming meetings of the
Political Consultations Mechanism and the Working Group on Bilateral Affairs
will be held in Chile, on dates to be agreed upon via diplomatic channels.
The Undersecretary of Foreign Affairs of Chile expressed on behalf of his
Delegation the sincerest thanks and appreciation for the attentions received
on the occasion of these meetings, on behalf of the Bolivian Foreign Ministry.
Subscribed in La Paz, on the seventeenth day of the month of June of the year
2008.
Done in La Paz, on 17 June 2008.
Stamp:
THIS REPRODUCTION IS A TRUE COPY
OF THE ORIGINAL OF ITS REFERENCE AND WILL BE
IN ACCORDANCE WITH THE PROVISIONS
OF ARTICLE 1311 OF THE CIVIL CODE.
La Paz, 23 June 2008
[Signature]
Stamp: Dr. Patricia Alina Mendoza Garcia
Head of the Legalization Office
Ministry of Foreign Affairs and Worship
12
FOR BOLIVIA
[Signature]
Ambassador Hugo Fernandez Araoz
Vice-Minister of Foreign Affairs and Worship
FOR CHILE
[Signature]
Ambassador Alberto van Klaveren Stork
Undersecretary of Foreign Affairs
140
ANEXO I
DELEGACION BOLIVIANA
Embajador Hugo Fernandez
Viceministro de Relaciones Exteriores y Cultos
Embajador Freddy Bersatti
Consul General de Bolivia en Santiago de Chile
Embajador Jean Paul Guevara
Director General de Asuntos Bilaterales y Cultos
Embajador Edgar Pinto
Direcci6n General de Asuntos Multilaterales
M.C. Maria Estela Mendoza
Jefe de Unidad de America
P.S. Frolian Castillo
Jefe de Unidad de Asuntos Especiales
T.S. Gabriela Orosco
Jefe de Unidad de Gesti6n de Proyectos y Cooperaci6n Internacional
Viceministerio de Relaciones Econ6micas y Comercio Exterior
S.S. Franz Orozco
Responsable UDAPEX
S.S. Arturo de la Riva
Funcionario UDAPEX
S.S. Yuri Arce
Funcionario, Unidad de America
T.S. Paola Soux
Responsable Escritorio Chile, Unidad de America
Claudia Benitez
Funcionaria
Viceministerio de Inversion Publica y Financiamiento Externo
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DELEGACION CHILENA
Embajador Alberto van Klaveren
Subsecretario de Relaciones Exteriores
Embajador Jorge Montero
Director de America del Sur
Embajador Roberto Ibarra
Consul General de Chile en La Paz
Embajadora Maria Teresa Infante
Directora Nacional de Fronteras y Limites del Estado
Sra. Maria Cristina Lazo
Directora Ejecutiva de la Agencia de Cooperaci6n Internacional (AGCI)
Sr. Anselmo Pommes
Director de Fronteras
M.C. Juan Pablo Crisostomo
Consul General Adjunto de Chile en La Paz
M.C.E. Enrique Soler
Director Oficina Cornercial de Chile en La Paz
C. Jaime Bascunan
Encargado Unidad de Bolivia, Diramesur
Sr. Alejandro Manriquez
Agregado Cultural de Chile en Bolivia
Sr. Sebastian Herreros
Jefe del Departamento de America Latina de la
Direcci6n de Asuntos Econ6micos Bilaterales
P.S. Rodrigo Hume
Jefe del Departamento de Desarme de DIPESP
Sr. Eugenio P6ssel
Encargado Escritorio Bolivia, AGCI
P.S. Rodrigo Olsen
Jefe de Gabinete del Sr. Subsecretario
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S.S. Jose Miguel Concha
Encargado Cooperaci6n Consulado de Chile en La Paz
T.S. Fernando Morales
Unidad Bolivia, Diramesur
Javier Fernandez
Asesor de Prensa Subsecretario
143
Annex 7
Minutes of the IV Meeting of the Bolivia-Chile Working Group
on the Silala Issue, 14 November 2008
(Original in Spanish, English translation)
144
Acta de la IV Reunion del Grupo de Trabajo Bolivia - Chile
sobre el Terna del Silala
En la ciudad de Santa Cruz de Sierra, Bolivia, el dia 14 de noviembre de 2008, se
reunieron las delegaciones de Bolivia y Chile, presididas por el Embajador Hugo
Fernar,dez Araoz, Viceministro de Relaciones Exteriores y Cultos de Bolivia, y :a
Embaj;1dora Marfa Teresa Infante, Directora Nacional de Fronteras y Limites del
Estado del Ministerio de Relaciones Exteriores de Chile, con el objeto de continuar
el tratamiento del tema relative a las aguas del Silala (Siloli).
La n6r,-,;na de las delegaciones de ambos paises figura come anexo de la presente
Acta.
Despues de aprobar la agenda y el programa de trabajo de la reunion, los jefes de
las delegaciones se refiriero:1 a la forma come podrian implementarse los
acuerdos alcanzados en la Ill Reunion de este Grupo de Trabajo, coincidiendo en
que :,e debe trabajar para que los enfoques tecnicos sean los mismos y asi liegar
a resuitados aceptables par& 2,mbas partes, que sirvan de base para un acuerdo
preiirnirar a corto plazo y su posterior perfeccionamiento en otro definitive.
1.- Respecto a los estudios tecnicos a realizar hubo coincidencia en lo
sig,1ie11te:
1. lmplementaci6n de una red de estaciones hidrometeorol6gicas
La implementaci6n de una red de estaciones de medici6n de variables
hidrometeorol6gicas para obtener registros de precipitaci6n (lfquida y nival),
temperatui-a del aire y otras variables, segun el siguiente detalle:
Estacion meteorologica en el sector de cruce de frontera para registrar
precipitaci6n (liquida y nival), te,~peratura del aire y viento (velocidad y
direcci6n).
E.stacion hidrometrica en el sector de cruce de frontera que registre
caudales. En el !ado chileno, inmediatamente pr6ximo al cruce del limite
internacional, existe una estaci6n de la Direcci6n Ge'.1 eral de Aguas de
Chiie, DGA, que puede actuar come fuente corroborativa de la estacion que
Ee situara en el sector de cruce de frontera.
Estacion hidrometrica en el cruce def camino proximo a los bofedales
orientales (Bolivia).
Estacion meteorologica en la divisoria de aguas en el extrema este.
145
MINUTES OF THE IV MEETING OF THE BOLIVIA-CHILE
WORKING GROUP ON THE SILALA ISSUE
In the city of Santa Cruz de la Sierra, Bolivia, on 14 November 2008, the
Delegations of Bolivia and Chile met, presided by Ambassador Hugo Fernandez
Araoz, Vice-Minister of Foreign Affairs of Bolivia, and Ambassador Maria
Teresa Infante, National Director of State Borders and Limits of the Ministry
of Foreign Affairs of Chile, with the aim of continuing addressing the issue
related to the waters of the Silala (Siloli).
The list of the Delegations of both countries is annexed to this Minutes.
After approving the agenda and the work program of the meeting, the Heads
of the Delegations referred to the way in which the agreements reached in the
III Meeting of this Working Group could be implemented, agreeing that work
must be done so that the technical approaches are the same and thus reach
results acceptable to both Parties, which serve as the basis for a preliminary
agreement in the short term and its subsequent improvement into a final one.
I. Regarding the technical studies to be carried out, there was an agreement
in the following:
1. Implementation of a network of hydro-meteorological stations
The implementation of a network of hydro-meteorological variables measuring
stations in order to obtain records of precipitation (liquid and snow), air
temperature and other variables, according to the following detail:
Meteorological station in the border crossing area to record precipitation
(liquid and snow), air temperature and wind (velocity and direction).
Hydrometric station in the border crossing sector that record flows. On the
Chilean side, immediately next to the crossing of the international boundary,
there is a station of the General Directorate of Water of Chile (DGA for its
acronym in Spanish) that can act as a corroborative source of the station that
will be located in the border crossing sector.
Hydrometric station at the crossing of the road near the Orientales bofedals
(Bolivia). (Bofedals: High altitude wetlands)
Meteorological station in the watershed divide at the east end.
1
146
I r---,..._
~
i 1'
Estacion meteorol6gica en una ladera del volcan lnacaliri.
Estacion meteorol6gica en la zona de bofedales (vertiente oriental) que
registre precipitaci6n (lfquida y nival), temperatura del aire, velocidad del
viento, radiaci6n solar y humedad.
De las seis estaciones propuestas, Ires estan en el cruce de frontera y son
binaci0nales, dos estan ubicadas en territorio boliviano y la ultima se situara en la
ladera del volcan lnacaliri, en una localizaci6n a determinar. Adicionalmente, Chile
tiene en su territorio una estaci6n hidrometrica, pr6xima a la frontern. El
emplazamiento de las seis estaciones propuestas se definira luego de una visita
conjunta a terreno.
Dada la ubicaci6n remota de la red de estaciones y la necesidad de que ambos
paises cuenten con informaci6n continua, simultanea y en tiempo real, las
estaciones tendran transmisi6n satelital, de modo que ambos paises puedan
monitorear la informaci6n y el funcionamiento general de las estaciones y sus
sensores.
2. Responsabilidad de la ejecuci6n
Por la parte chi lena, la ejecuci6n del proyecto estara a cargo de la DGA; por la
parte boliviana la ejecuci6n sera de! Servicio Nacional de Meteorologia e
Hidrologia, SENAMHI. Estas instituciones designaran a sus respectivos
coordinadores.
La propiedad de las estaciones ubicadas sabre la linea de frontera sera binacional;
consecuentemente sus costos de adquisici6n e implementaci6n seran
compartidos.
La definici6n de las equipos, el numero de visitas conjuntas anuales, la operaci6n
del sistema, etc., sera realizada conjuntamente por las instituciones antes
indicadas.
Cada instituci6n asumira sus propios costos operativos.
3. Periodo de Monitoreo
Se define un periodo de monitoreo conjunto de cuatro ciclos hidrol6gicos anuales
que permiia determinar el balance hfdrico, el comportamiento hidrometrico, la
dataci6n de las aguas, los flujos superficiales, la influencia de las obras sabre el
caudal entre otros, utilizando una metodolog fa cientfficamente validada y
concordada.
147
Meteorological station on a slope of the Inacaliri volcano.
Meteorological station in the area of bofedales (eastern spring) that records
precipitation (liquid and snow), air temperature, wind speed, solar radiation
and humidity.
Of the six stations proposed, three are at the border crossing and are binational,
two are located in Bolivian territory and the last one will be located on the slope
of the Inacaliri volcano, in a location to be determined. Additionally, Chile has
a hygrometric station in its territory, close to the border. The location of the six
proposed stations will be defined after a joint field visit.
Given the remote location of the network of stations and the need for both
countries to have continuous, simultaneous and real-time information, the
stations will have satellite transmission, so that both countries can monitor the
information and the general operation of the stations and their sensors.
2. Implementation responsibility
For the Chilean part, the implementation of the project will be in charge of
the DGA; for the Bolivian part, the implementation will be the responsibility
of the National Service of Meteorology and Hydrology, SENAMHI. These
institutions will appoint their respective coordinators.
The property of the stations located on the border line will be binational;
consequently, their acquisition and implementation costs will be shared.
The definition of the teams, the number of annual joint visits, the operation of
the system, etc., will be carried out jointly by the aforementioned institutions.
Each institution will assume its own operating expenses.
3. Monitoring Period
A period of joint monitoring of four annual hydrological cycles is defined to
determine the water balance, hydrometric behavior, water dating, surface flows,
the influence of the works on the flow, among others, using a scientifically
validated and agreed upon methodology.
2
148
l~I procesamiento, archivo y acceso a los datos quedara a cargo de cada
organismo y su analisis se efectuara utilizando modelos y metodologias acordadas
conjuntamente.
4. Actividades adicionales
Programa de monitoreo de la calidad y daiaci6n del agua, con toma de muestras
dos veces al ano, en invierno Uulio) y verano (enero), en los sectores de bofedales
yen el cruce de frontera.
Recopilaci6n y sistematizaci6n de los antecedentes meteorol6gicos e hidrol6gicos.
Complementaci6n de los trabajos cartograficos del area del Si!ala, mediante el
apoyo te:rrestre a las fotografias aereas tomadas en conjunto en 2001, adquisici6n
de imagenes satelitales, elaboraci6n de modelos digitales de terrene y etras.
5. lnformes
Cenjuntamente se elaboraran informes semestrales y un informe final al cabe de
los cuatro aiios con les resultados de los estudios. Este informe final constituira la
base de un acuerde definitive sobre los porcentajes de las aguas de libre
disponibilidad de cada pais.
II.- Respecto a los acuerdos preliminary definitivo:
Las delegaciones propusieron la celebraci6n por parte de ambos Estados de un
acuerde provisiona l, relative al aprovechamiento de las aguas, que servira de base
para uno dsfinitive.
Para llegar al acuerdo preliminar, las partes realizaran en el certo plazo
mediciones en el cruce de frontera, con el fin de establecer el caudal sobre el cual
se determinaran los porcentajes de las aguas de libre disponibilidad
correspondientes a cada parte.
Las aguas que resulten de libre disponibilidad de Bolivia y que no fueren utilizadas
en ese pais, podran ser puestas a disposici6n para su uso en Chile, para lo cual
se debera acordar un mecanismo que permita la constituci6n de derechos de
aprovechamiente en la frontera, asi como el valor que correspondiere por su uso
exclusivo. Bolivia no afectara la naturaleza y la continuidad de dichas aguas. En el
acuerdo se debera establecer un procedimiento de seluci6n de contreversias.
Con estos elementos del acuerdo preliminary los datos tecnicos emanados de los
estudies conjuntos, se procedera a elaborar un acuerdo definitivo.
3
149
The processing, filing and access to the data will be the responsibility of each
organism and its analysis will be carried out using jointly agreed models and
methodologies.
4. Additional activities
Program for quality monitoring and water dating, with sample taking twice a
year, in winter (July) and summer (January), in the bofedales sectors and at the
border crossing.
Collection and systematization of meteorological and hydrological history.
Complementation of cartographic works in the Silala area, through ground
support to the aerial photographs jointly taken in 2001, acquisition of satellite
images, development of digital terrain models and others.
5. Reports
Jointly, semi-annual reports and a final report will be prepared after four years
with the results of the studies. This final report will constitute the basis of a
definitive agreement regarding the percentages of freely available waters in
each country.
II. Regarding the preliminary and final agreements:
The Delegations proposed the conclusion of a provisional agreement by both
States, regarding the use of waters, which will serve as the basis for a definitive
agreement.
In order to reach the preliminary agreement, the Parties will carry out
measurements in the short term at the border crossing, in order to establish the
flow rate over which the percentages of the freely available waters corresponding
to each Party will be determined.
The waters that are freely available in Bolivia and that were not used in that
country, may be made available for use in Chile, for which a mechanism must
be agreed upon that allows the constitution of exploitation rights in the border,
as well as the value that corresponds for its exclusive use. Bolivia will not affect
the nature and continuity of said waters. In the agreement, a dispute resolution
procedure must be established.
With the elements of the preliminary agreement and the technical data emerging
from the joint studies, a final agreement will be elaborated.
3
150
Finalmente, ambas delegaciones convinieron que la V Reunion de este Grupo de
Trabajo se efectue en Chile, en la ul!ima semana de enero de 2009. En dicha
oportunidad, los equipos tecnicos expondran los resultados de sus trabajos
preliminares sabre el caudal de las aguas de! Silala en el cruce de frontera, a fin
de avanzar en la elaboraci6n de! acuerdo preliminar, teniendo en cuenta las
propuestas aportadas por ambas delegaciones sobre los otros aspectos arriba
mencionados.
La del1,gaci6n de Chile agradeci6 las especiales atenciones recibidas de parte de
la delegaci6n de Bolivia.
~~ Embajador Hugo Fernandez Araoz
Por la Delegaci6n de Bolivia
,I v!w /W~ '-"-' ,.
Embajadora Maria~i
Por la Delegaci6n de Chile
LA PRESENTE REPRODUCCION ES COPIA R!L
DEL ORIGINAL DE SU REFERENCIA Y HARA
FE DE CONFORM1DAD A LO DISPUESTO EN
EL ARTICULO 1311 DEL GODIGO CML
La Paz, .. .,_--44-mc,_wQ.,___.....,,._ ____,~=..1-
151
Finally, both Delegations agreed that the V Meeting of this Working Group be
held in Chile, in the last week of January 2009. On said occasion, the technical
teams will present the results of their preliminary work regarding the flow of
Silala waters at the border crossing, in order to move forward in the preparation
of the preliminary agreement, taking into account the proposals made by both
Delegations regarding the other aforementioned aspects.
The Delegation of Chile thanked the special attention received from the
Delegation of Bolivia.
Stamp:
THIS REPRODUCTION IS A TRUE COPY
OF THE ORIGINAL OF ITS REFERENCE AND WILL BE
IN ACCORDANCE WITH THE PROVISIONS
OF ARTICLE 1311 OF THE CIVIL CODE.
La Paz, 4 December 2008
[Signature]
Stamp: Dr. Patricia Alina Mendoza Garcia
Head of the Legalization Office
Ministry of Foreign Affairs and Worship
[Signature]
Ambassador Hugo Fernandez Araoz
For the Delegation of Bolivia
[Signature]
Ambassador Maria Teresa Infante Caffi
For the Delegation of Chile
152
~
V
DELEGACION BOLIVIANA
Emb. Hugo Fernandez Araoz
Viceministro de Relaciones Exteriores y Cultos.
Jefe de Delegaci6n
Sr. Rene Orellana
Ministro de Aguas
Sr. Juan Carlos Al urralde
Asesor de! Ministro de Relaciones Exteriores y Cultos
M.C. Estela Mendoza
Jefe de Unidad de America
S.S. Artu ro De la Riva
Funcionario de la Unidad de: Analisis de Politi ca Exterior (UDAPEX)
T.S. Paola Soux
Escritorio de Chile
Unidad de America
T.S. Gabriela Morales
Direcci 6n General de Asuntos Juridicos
Ing. Carlos Diaz
Director Nacional
Servicio Nacional de Meteorologia Hidrologia (SENAMHI)
Ing. Rafael Cortez Y.
Coordinador de Proyectos de Aguas Subterraneas
Servicio Nacional de Geologfa y Tecnico de Minas (SERGEOTECMIN)
Capitan de Corbeta DIM. Guillermo Rafael Linares Ch.
Representante de! Servicio Nacional de Hidrografia Naval
153
BOLIVIAN DELEGATION
Amb. Hugo Fernandez Araoz
Vice-Minister of Foreign Relations and Worship
Head of the Delegation
Mr. Rene Orellana
Minister of Waters
Mr. Juan Carlos Alurralde
Adviser to the Minister of Foreign Affairs and Worship
C.M. Estela Mendoza
Head of Unit of America
S.S. Arturo de la Riva
Official of the Foreign Policy Analysis Unit (UDAPEX)
T.S. Paola Soux
Chile Desk
Unit of America
T.S. Gabriela Morales
General Directorate of Legal Affairs
Eng. Carlos Diaz
National Director
National Meteorology and Hydrology Service (SENAMHI)
Eng. Rafael Cortez Y.
Coordinator of Groundwater Projects
National Service of Geology and Mining Technician (SERGEOTECMIN)
Corvette Captain DIM. Guillermo Rafael Linares Ch.
Representative of the National Service of Naval Hydrography
154
DELEGAC!ON CHILENA
Emb. Marfa Teresa Infante
Di recto: a Nacional de Fronteras y Umites del Estado
Ministerio de Relaciones Exteriores
Jefa de De!egaci6n
Emb. Roberto Ibarra
Consul General de Chile en La Paz, Bolivia
Sr. Rodrigo Weisner
Director General de Aguas
Ministerio de Obras Publicas
Sr. Anselmo Pommes
Director de Fronteras
Ministerio de Relaciones Exteriores
M.C. Frank Sinclair
Consul General de Chile en Santa Cruz, Bolivia
C. Jaime Bascunan
Jefe Unidad Bolivia
Direcci6n America del Sur
Ministerio de Relaciones Exteriores
Sr. Alejandro Ahumada
Direcci6n de Fronteras y Lfmites
Ministerio de Relaciones Exteriores
155
CHILEAN DELEGATION
Amb. Maria Teresa Infante
National Director of State Borders and Limits
Ministry of Foreign Affairs
Head of Delegation
Amb. Roberto Ibarra
Consul General of Chile in La Paz, Bolivia
Mr. Rodrigo Weisner
General Director of Waters
Ministry of Public Works
Mr. Anselmo Pommes
Director of Borders
Ministry of Foreign Affairs
M.C. Frank Sinclair
Consul General of Chile in Santa Cruz, Bolivia
C. Jaime Bascuñan
Head of Bolivia Unit
Director South America
Ministry of Foreign Affairs
Mr. Alejandro Ahumada
Directorate of Borders and Limits
Ministry of Foreign Affairs
156
157
Annex 8
Initial Agreement [Silala or Siloli], Agreed Draft, 28 July 2009
(Original in Spanish, English translation)
158
Borrador de version final (28 de julio 2009)
ACUERDO INICIAL (SILALA O SILOLI]
El Gobierno de la Republica de Chile y el Gobierno del Estado Plurinacional de Bolivia, en adelante
"las Partes",
CONSIDERANDO
Que los Ministerios de Relaciones Exteriores de la Republica de Chile y del Estado Plurinacional de
Bolivia constituyeron en 2004 un Grupo de Trabajo Bolivia - Chile sabre el tema del Silala, que
plasm6 sus resultados en las actas suscritas el 6 de mayo de 2004, el 20 de enero de 2005, el 10 de
junio de 2008 y el 14 de noviembre de 2008;
Que el tema del Sil ala o Silo!i fue incluido en el punto Vil de la Agenda bilateral de 13 puntos
adoptada ;;or ambas Partes en julio de 2006 y que desde esa fecha, e!las se han esforzado en
proponer formulas destinadas a superar :as diferencias surgidas en torno al sistema hidrico del Silala
o Siloli, y las caracteristicc::s de sus aguas;
Que los estudios realizados hasta el presente en forma individual, por cada una de las Partes, han
ar.ortado suficiente informaci6n para establecer el presente Acuerdo inicial que servira de base para
un nuevo Acuerdo de largo plazo, que se concluira teniendo en consideraci6n los resultados de los
estudios tecnicos contemplados en el presente Acuerdo, la cont:nuaci6n de los trabajos conjuntos
inicia.dos en el ario 2000, las aprovechamientos existentes y el uso sustentable de las aguas del
Silala;
Que ei presente Acuerdo no se refiere a otros temas relatives al Silala o Siloli que a cada una de las
Partes interese abordar al memento de negociar el nuevo Acuerdo de largo plaza;
Que el ambiente de mutua confianza que se ha desarrollado entre ambos paises ha permitido
acercar las voluntades para profundizar las entendimientos que los ;iueblos anhelan, formulando un
Acuerdo de mutuo beneficio sabre este punto de la agenda bilateral.
159
Final version draft (28 July 2009)
THE INITIAL AGREEMENT [SILALA OR SILOLI]
The Government of the Republic of Chile and the Government of the
Plurinational State of Bolivia, hereinafter “the Parties”,
CONSIDERING
That the Ministries of Foreign Affairs of the Republic of Chile and the
Plurinational State of Bolivia created a Bolivia-Chile Working Group on the
Silala issue in 2004 and recorded the results attained in the minutes signed on 6
May 2004, 20 January 2005, 10 June 2008, and 14 November 2008;
That the Silala, or Siloli issue was included in Point VII of the Bilateral Agenda
of 13 Points, adopted by both Parties in July 2006, and that since that date, they
have made efforts to propose formulas intended to overcome their differences
regarding the Silala, or Siloli hydrologic system and the characteristics of its
waters;
That the studies carried out to date by each of the parties individually have
provided sufficient information to reach this initial Agreement, which shall
serve as a basis for a new long-term Agreement that will be concluded taking
into consideration the results of the technical studies referred to herein, the
continuation of the joint work started in 2000, and the present utilization and
sustainable use of the waters of Silala.
That the present Agreement does not address other issues that each of the
parties might have an interest in addressing when negotiating the new longterm
Agreement regarding the Silala or Siloli.
That the atmosphere of mutual trust that has been developed between the two
countries has helped bring together their will to deepen the understandings that
both their peoples long for, formulating a mutually beneficial Agreement on
this point of the bilateral agenda.
1
160
Barradar de version final (28 de julia 2009)
ACUERDAN
ASPECTOS GENERALES
.\ rticulo 1
Est2blecer un Acuerdo bilateral para la preservaci6n, sostenibilidad, uso y aprovechamiento del
sistema hidrico del Silala o Silo!i para beneficio de ambos paises.
Articulo 2
El presente Acuerdo ir,\ cial considera el volumen de agua del sistema hfdrico del Silala a Silali que
fluye superficialmente a traves de la frontera desde el Estado Plurinacional de Bolivia hacia la
Republica de Chile. Considera, asimismo, que del volumen total de aguas superficiales que
actualme :i!e fluyen a traves de la frontera, un porcentaje corresponde a Bolivia y es de su libre
disponibi:idad, y que las estudias cientfficos serviran de base a las decisiones que se adoptaren en el
futuro a este respecto, de acuerdo a lo que establece el articulo 6.
Articula 3
Par el presente Acuerda se establece que las aguas de libre disponibilidad de Bolivia y captadas en
su pais podran ser car.ducidas para ser aprovechadas en Chile. En tal caso, el titular publico
boliviano de la autorizaci6n para el atorgamiento del uso de dichas aguas sera compensada por las
persanas juridicas de derecho publica o privado que se constituyan en aprovechatarias de dichas
aguas.
P::ira el otorgamiento del uso de dichas aguas C:e libre disponibilidad, el titui2r publico boliviano
considerara el derec',o preferente de las persanas juridicas de derecha publica a privado que
actualmente estuvieren hacienda uso de dichas aguas en Chile. Este derecho preferente se ejercera
por un espacio de sesen'.a dias a partir de la camunicaci6n por vfa oficial de la ;mplementaci6r. de
esta parte del Acuerdo.
Las persanas jurfdicas antes individualizadas deberan desarrollar las accianes que correspondieren
en Chile, en caso de que esas aguas fueren 3 ser uti!izadas en este pais, p:.,diendo Bolivia caducar
la autorizaci6n otorgada si no se concretaren esos prop6sitos en el plazo que hubiese fijado.
161
Final version draft (28 July 2009)
Have agreed as follows:
GENERAL ASPECTS
Article 1
To conclude a bilateral Agreement for the preservation, sustainability, use, and
exploitation of the Silala, or Siloli hydrologic system to the benefit of both
countries.
Article 2
This initial Agreement takes into consideration the volume of water of the Silala,
or Siloli hydrologic system that flows on the surface across the border, from the
Plurinational State of Bolivia to the Republic of Chile. This Agreement also
takes into consideration the fact that, of the total volume of surface water that
currently flows across the border, a percentage corresponds and shall be freely
available to Bolivia, and that scientific studies will inform the decisions that
might be adopted in the future in this regard, as per the stipulations of article 6.
Article 3
The present Agreement hereby establishes that the waters that are freely
available to Bolivia and abstracted in that country may be driven to be exploited
in Chile. In such case, the Bolivian public holder of the authorization to award
the use of these waters shall be compensated by the public or private legal
entities established as users of these waters.
To award the use of these freely available waters, the Bolivian public holder
shall take into consideration the right of first refusal of public or private legal
entities that were currently making use of such water in Chile. This right of first
refusal shall be exercised during a period of sixty days from the implementation
of this part of the Agreement via official channels of communication.
In case these waters were to be used in Chile, the legal entities previously
individualized shall take the actions that are applicable in that country; Bolivia,
nevertheless, shall be able to declare that the authorization granted has expired
if the said actions are not taken during the established period.
2
162
B,x rador de version final (28 de julio 2009)
Articulo 4
Considerando la fragilidad de! ecosistema de! Silala o Si!oli, par el presente Acuerdo las Partes se
comprometen a mantener las condiciones actuales de caudel y calidad de! agua que fluye a !raves
de la frontera, ya cuidar que cualquier obra que emprendan a futuro individual a conjuntamente no
a\'ecte dicho caudal y calidad .
Articulo 5
Par este Acuerdo las Partes se comprometen a efectuar conjuntamente estudios complementaries
sobre el sistema hidrico del Silala (Siloli), para lograr un mayor conocimiento sabre su
funcionamiento y naturaleza.
Articulo 6
Las Partes establecen, de conformidad con el Articulo 2, que del volumen total del agua del Silala o
Si Ioli, que fluye a traves de la fron tara (100%), el 50% corresponde, inicialmente, al Estado
Plurinacional de Bolivia, es de su libre disponibilidad y lo podra .. :i!izar en su territorio o autorizar su
captaci6n para su use par terceros, incluyendo su conduction a Chile. Este porcentaje podra ser
incrementado a favor de Bolivia, en funci6n de las resul'.ados de las estudios conjuntos que se lleven
a cabo en el marco del presente Acuerdo.
Tan pronto sea su;;crito el presente Acuerdo las Partes se comprometen a instaiar la estaci6n
hidrometrica mencionada en el Articulo 8, letra b), la cual registrara los volumenes de agua en el
cruce de frontera, que serviran para su imPlementaci6n.
ASPECTOS TECNICOS
Articulo 7
A partir de! presente Acuerdo inicial, ias Partes implementaran en la zona una red de estaciones
hidrometeorol6gicas que permitan obtener dates y realizar estudios conjuntos con vistas a la
suscripci6n de un nuevo Acuerdo de largo plaza.
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163
Final version draft (28 July 2009)
Article 4
Considering the fragility of the Silala or Siloli ecosystem, by this Agreement,
the Parties undertake to maintain the current flow and water quality conditions
of the water flowing across the border, and to ensure that any future work
undertaken individually or jointly will not affect said flow and quality.
Article 5
By this Agreement, the parties undertake to jointly perform complimentary
studies on the Silala (Siloli) hydrologic system in order to achieve a better
understanding of its functioning and nature.
Article 6
The Parties hereby agree, in accordance with Article 2, that the out total
water volume of the Silala, or Siloli that flows across the border (100%), 50%
corresponds, initially, to the Plurinational State of Bolivia, is freely available
to it and shall be used within its territory, or authorized to be abstracted for the
use of third parties, including its conveyance to Chile. This percentage may be
increased in Bolivia’s favor based on the results of joint studies to be carried
out under this Agreement.
As soon as this Agreement is signed, the parties undertake to install the
hydrometric station referred to in Article 8, b), which will record the volume
of water crossing the border; volume which will be used for the Agreement’s
implementation.
TECHNICAL ASPECTS
Article 7
After this initial Agreement is signed, the parties shall implement a network
of hydrometeorological stations in the area to collect data and perform joint
studies with a view to signing a new long term Agreement.
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Articulo 8
Con el proposito de establecer el porcentaje de aguas de iibre disponibilidad de cada pafs y avanzar
en !a comprf;!nsi6n del sistema hidrico, se acuerda imp!ementar una red de estaciones de medicion
de caudales y variables hidrometeorol6gicas para obtener registros de precipitaci6n (lfquida y nival),
temperatura del aire y otras variables, segun el siguiente detalle:
a Estacion meteorol6gica en el sector de cruce de frontera.
b. Estacion hidrometr!ca en el sector de cruce de frontera.
c. Estacion hidrometrica en el cruce del camino proximo a los bofedales orientales en
territorio de Bolivia.
d. Estacion meteorologica en la divisoria de aguas en el extremo Este del sistema.
e. Estacion meteoro logica en la ladera boliviana del volcan lnacaliri.
f. Estacion reteorologica en la zona de bofedales de la vertiente oriental.
De las seis estaciones propuestas, dos (a y b) se encontraran en el cruce de frontera, y seriln
binacionales, cuatro (c, d, e y f) estaran ubicadas en territorio boliviano.
Ademas, formara parte de la red la estaci6n de la Direcci6n General de Aguas de Chile, DGA,
ubicada en el lado chileno, pr6xima al cruce del If mite internacional.
Adicionalmente, las Partes se comprometen a intercambiar datos provenientes de otras estaciones
proximas al area de investigac'6n.
Dada la ubicacion remota de la red de estaciones y la necesidad de que ambos paises cuenten con
informaci6n continua, simultanea y en tiempo reai, las estaciones tendran transmisi6n sa t~ lital, de
modo que ambas Partes mon:toreen la informacion y el funcionamiento general de las estaciones.
Articulo 9
Las Partes definiran un periodo de monitoreo conjunto de cuatro ciC:os hidrol6gicos anuales que
permitan determinar el balance hidrico, el comportamiento hidrometrico, la dataci6n de las aguas, los
fiujos superficiales y subterraneos, y la influencia de las obras sobre el caudal, entre otros, utilizando
una metodologia cientfficamente valida y concordada.
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Article 8
In order to establish the percentage of water freely available to each country and
make progress in understanding the water system, the parties agree to implement a
network of stations to monitor the flow and hydrometeorological variables in order to
record precipitation (rain and snow), air temperature and other variables, as detailed
below:
a. A meteorological station at the boundary crossing.
b. A hydrometric station at the border crossing.
c. A hydrometric station at the junction of the road next to the Orientales
Wetlands (known as the South Wetlands in Bolivia) in Bolivian territory.
d. A meteorological station in the watershed at the east end of the system.
e. A meteorological station on the Bolivian slopes of the Inacaliri Volcano.
f. A meteorological station in the area of the wetlands found on the east
spring.
Of the six proposed stations, two (a and b) will be located on the border crossing and
will be binational, and four (c, d, e and f) will be located inside Bolivian territory.
In addition, the said network will form part of Chilean General Directorate of Water
network, located on the Chilean side, near the international border crossing.
Additionally, the Parties agree to exchange data from other stations near the study
area.
Given the remoteness of the network of stations and the need for both countries to
have continuous, simultaneous, and real-time information, the stations will be set up
with satellite transmission, so that both Parties can monitor the information and the
overall functioning of the stations.
Article 9
The Parties shall define a joint monitoring period of four annual hydrological cycles
to determine the water balance, hydrometric behavior, age of the waters, surface and
groundwater flows, and influence of waterworks on the flow, among other parameters,
using scientifically valid and agreed upon methodology.
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La reco:ecci6n, archive y procesamiento de los datos, quedara a cargo de la Direcci6n General de
Aguas (DGA) en Chiley del Servicio Nacional de Meteorologia e Hidrolog ia (SENAMHI) en Bolivia.
Articulo 10
Por el presente Acuerdo inicial, se establece un programa de moni!oreo para determinar la calidad y
la dataci6n del agua, con toma de muestras dos veces al ario, en invierno Uulio) y verano (enero), en
las sectores de bofedales y en el cruce de frontera.
Se establece, asimismo, que se complementaran los trabajos cartograficos del area del Sila!a o Silo!i,
mediante trabajos de terreno de apoyo tecnica a las fotagrafias aeraas tor.adas en conjunto el aria
2001, para elaborar una cartografia de detalle, y se adquiriran imagenes satelitales, ademas de
elaborarse modelos digilales de terrena.
Articulo 11
Las Partes elaboraran informes semestraies y un informe final al caba de cuatro arios, con las
resultadas de las estudios. Este informe final constituini la base para el nuevo Acuerdo de largo
plaza que establecera los porcentajes de libre disponibilidad de cada pais.
ASPECTOS INSTITUCIONALES
Articulo 12
El Estado Plurinacional de Bolivia a traves del M!nisterio de Medio Ambiente y Agua designara a la
Prefectura del Departamento de Potosi a a otra persona juridica de derecho publico que actuara
como el sujeto detentor de la autarizaci6n de uso de las aguas de libre disponibilidad boliviana del
Silala o Siloli.
Bajo el marco del presente Acuerdo inicial, el seguimiento y operaci6n tecnica del uso y
aprovechamiento del agua, por Bolivia, estara a cargo del sujeto cetentor arriba mencionado; por
Chile, estara a cargo de la Direcci6n General de Aguas del Ministerio de Obras Publicas.
Las Partes se informaran mutuamente sabre cualquier modificaci6n que establezcan respect□ del
regimen antes indicado.
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Data collection, storage and processing shall be the responsibility of the General
Water Directorate (DGA) in Chile and the National Service of Meteorology
and Hydrology (SENAMHI) in Bolivia.
Article 10
Under this initial agreement, a monitoring program shall be established to
determine the quality and the age of the water, taking samples twice a year, in
winter (July) and summer (January), in the wetland area and the border crossing.
It is also herewith agreed that cartographic work in the Silala or Siloli area will
be complemented through field work to provide technical support for the aerial
photographs taken jointly in 2001 in order to develop a detailed cartography;
also, satellite imagery shall be acquired and a digital terrain model developed.
Article 11
The Parties shall produce semi-annual reports and a final report after four years
with the results of the studies. This final report will form the basis for the new
long term Agreement that will establish the percentage of water freely available
to each country.
INSTITUCIONAL ASPECTS
Article 12
The Plurinational State of Bolivia, through the Ministry of Environment and
Water, will appoint the Prefecture of the Department of Potosi or a different
public legal entity as the subject entitled to authorize the use of the water of the
Silala or Siloli that is freely available to Bolivia.
Under the framework of this initial Agreement, the monitoring and technical
operation of water use and utilization will be the responsibility of the
aforementioned subject, for Bolivia, and the General Water Directorate,
Ministry of Public Works, for Chile.
The Parties shall inform each other of any changes regarding the regime
established above.
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Articulo 13
El Ministerio de Medic Ambiente y Agua determinara el valor por metro cubico que percibira el Estado
Plurinacional de Bolivia a titulo de compensaci6n en funci6n del vclumen transferido, el que sera
acordado directamente con la persona juridica de derecho publico o privado interesada. Asimismo,
determinara la periodicidad con que percibira dicho valor y las garantias para 2segurar la
compensaci6n.
Articulo 14
Para la determinaci6n de la compensaci6n el Ministerio de Media Ambien~e y Agv:,. podra tener en
cuenta, entre otros, el valor promedio efectivamente pagado par metro cubico de aguas crudas en la
II Region de Chile.
Articulo 15
De conformidad con el presente Acuerdo, el Gobierno de Bciivia, declara que la persona _!uridica, de
derecho publico o privado, que haya side autorizada por el Ministerio de Medic Ambiente y Agua para
el uso en territorio chileno de las aguas de/ Si/ala o Siloli de su libre disponibilidad, podra
aprovechar/as sin ninguna restricci6n o discriminaci6n.
El Gobierno de Chi!e declara que no se opondra a la aplicaci6n de medicias que conforme al"
ordenamientc juridico boliviano y al p;-esente Acuerdo, se apll~uen al aprovechatario que no cumpla
las obligaciones adquiridas con la persona juridica de derecho pub/ice designada par el Ministerio de
Media Ambiente y Agua, en virtud def presente Acuerdo.
Las diferencias que pudiesen su rgir entre una persona juridica y el Estado Plurinacional de Bolivia en
el marco de las Articulos 3 y 6 relatives a la autorizaci6n, y su cJmplimiento o ejecuci6n, seran
resueltas segun las norm as aplicables en dicho Estado y las que establec ere la autorizaci6n para el
aprovechamiento correspondiente, siendo competentes para estos efectos las instancias
jurisdiccionales internas de/ Estado Plurinacional de Bolivia.
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Article 13
The Ministry of Environment and Water shall determine the value per cubic
meter to be allocated to the Plurinational State of Bolivia in compensation,
depending on the volume transferred, which shall be negotiated directly with
the relevant public or private legal entity. The Ministry shall also determine the
payment frequency and guarantees to ensure compensation.
Article 14
To determine the compensation due, the Ministry of Environment and Water
may take into account, inter alia, the average price currently paid per cubic
meter of untreated water in Chile’s Region II.
Article 15
In accordance with this Agreement, the Government of Bolivia hereby declares
that the public or private legal entity authorized by the Ministry of Environment
and Water to have the unencumbered right to use the waters of Silala or Siloli
in Chilean territory, may use these waters without restriction or discrimination.
The Government of Chile declares that it will not oppose to the application of
measures which, under Bolivian law and this Agreement, shall be applicable to
users that do not meet the obligations undertaken with the public legal entity
appointed by the Ministry of Environment and Water under this Agreement.
The differences that may arise between a legal entity and the Plurinational
State of Bolivia under Articles 3 and 6 regarding authorization, compliance
or enforcement, shall be resolved under the provisions applicable in that State
and those by which authorization for appropriate use was established; the
internal jurisdictional instances of the Plurinational State of Bolivia shall thus
be regarded competent for this purpose.
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SOLUCl6N DE DIFERENCIAS
Articulo 16
En caso de que en la aplicaci6n o interpretaci6n de este Acuerdo surgiere una diferencia,
contingencia o asunto que req u:era la atenci6n conjunta de las Partes, cualquiera de eilas podra
convocar al Grupo de Trabajo Bolivia-Chile sobre el tema del Siiala, creado por las Cancil:erias de
ambos Estados en 2004, para resolverla o dar!e una respuesta apropiada.
En los trabajos tecnicos a que se refieren los articulos 7 a 11, las Partes se esforzaran en cooperar
activamente, asi como en alcanzar resultados que sirvan de referencia para futuros acuerdos. En
caso de que, a pesar de los esfuerzos desplegados, no fuere posible ponerse de acuerdo sobre los
volumenes de agua de libre disponibilidad, entre otras ma\erias, las Partes pondran en ejecuci6n
mecanismos que permitan superar esas diferencias, con el apoyo de expertos si fuere necesario.
Sin perjuicio de ello, las Partes, de comun acuerdo podran solicitar en tod,J memento la asistencia
de un organismo tecnico o cientiiico especializado y de renombre internacional, a fin de que aporte
elementos que conduzcan a un arreglo entre las Partes.
Si no pudiere llegarse a un acuerdo a !raves de estos procedimientos respecto de la aplioci6n o
interpretaci6n del presente Acuerdo, cualquiera de las Partes podra soliciiar que se constituya una
Comisi6n de Conciliaci6n de !res miembros, para someter la diferencia a su conocimiento y
recomendaci6n.
En el plazo de trein!a dias despues de recibida la solicitud, cada Parle designara un integrante de la
Comisi6n de Conciliaci6n. El tercero, que la presid ira, sera designado de comun acuerdo y no podra
ser nacional de ninguna de las Partes. En caso de desacuerdo sobre la pe:·sona a designar o si una
de las Partes no designare en dicho plazo al miembro de la Comlsi6n que le corresponde, cualquiera
de las Partes podra solicitar a la maxima autoridad de los siguientes organismos o programas
internacionales segun sus normas fundamentales constitutivas, que lo designe, segun el siguiente
orden sucesivo. En la Organizaci6n de las Naciones Unidas para la Ee xaci6n, la Ciencia y la
Cultura, UNESCO, el Director Ejecutivo; en la Organizaci6n Meteorol6gica Mundial, OMM, el
Secretario General; en el Programa de las Naciones Unidas para el Medio Ambiente, PNUMA, el
Director Ejecutivo; en la Organizaci6n Internacional de Energia At6mica, OIEA, el Director Genera!; o
en el Programa de las Naciones Unidas para el Desarrollo, PNUD, el Administrador. No sera
considerado un org anismo o programa cuya
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DISPUTES SETTLEMENT
Article 16
If, any differences, contingencies or matters that require the Parties’ joint
attention arise in the application or interpretation of this Agreement, either
Party may convene the Bolivia-Chile Silala Working Group, created by the
Foreign Ministries of both States in 2004 to settle or provide a proper response.
In the completion of the technical works referred to in Articles 7 to 11, the
Parties shall endeavor to actively cooperate and achieve results that serve as
reference for future agreements. If, despite all efforts, it is not possible to agree
on the volume of freely available water, among other matters, the Parties shall
implement mechanisms to overcome these differences, with the support of
experts where necessary.
Notwithstanding the above, the Parties may, by mutual agreement and at
any time, request the assistance of an internationally recognized technical
or scientific expert, in order to provide them with information that leads to a
settlement between the Parties.
If it is not possible to reach an agreement regarding the application or
interpretation of this Agreement through these procedures, either party may
request that a three-member Settlement Commission be established to apply its
knowledge and recommendations to the dispute.
Within thirty days after receiving the request, each party shall appoint a member
for the Settlement Commission. The third member, who shall preside the
commission, shall be appointed by mutual agreement and cannot be a national
of either Party. In case of disagreement on the appointed person or if a Party
fails to nominate a member to the Commission within that period, either party
may request the highest authority of the following agencies or programs, based
on their fundamental constitutional rules, to appoint the member in question, in
the following order: The Executive Director of the United Nations Educational,
Scientific and Cultural Organization (UNESCO); the Secretary-General of
the World Meteorological Organization (WMO); the Executive Director of
the United Nations Environment Program (UNEP); the Director General of
the International Atomic Energy Agency (IAEA); or the Administrator of the
United Nations Development Program (UNDP). An agency or program whose
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maxima autoridad sea nacional de una de las Partes, o cuando dicha persona haya trabajado al
servicio de una de el:as.
En caso de que a pesar de la aplicaci6n del procedimiento anteriormente mencionado no se llegare a
entendimiento en algu;i aspecto especifico, las Partes podran someterlo al arbitraje.
En el nuevo Acuerdo de largo plazo se establecera un mecanismo de soluci6n de controversias.
VIGENCIA
Articulo 17
Este Acuerdo inicial tendra una vigencia de cuatro anos, y dara lug::ir a ur, nuevo Acuerdo una vez
concluidos los estudios pertine:~~es. Si al cabo de los cuatrn anos no ;;udiera establecerse el Acuerdo
de largo plazo, se prorrogara por periodos anuales.
E! nuevo Acuerdo de largo plazo tendra en cuenta los actos de autorizaci6n que se hubiesen
adoptado durante la vigencia del presente Acuerdo inicial.
El presente Acuerdo entrara en vigor treinla dias despues de recibida la ultima Nota por la cual las
Partes se comuniquen reciprocamente el cumplimiento de los requisites internos correspondientes.
Sin perjuicio de lo anterior, el segundc parrafo de! Articulo 6 entrara en vigor al momento de su
suscripci6n.
Despues de transcurridos cuatro anos, el presente Acuerdo podra ser denunciado por cualquiera de
las Partes, mediante una notificaci6n escrita a la otra Parte, con seis meses de anticipaci6n. La
denuncia cobrara vigor a partir de! cumplimientc de dicho plazo.
Suscrito en ...
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Final version draft (28 July 2009)
maximum authority is a Party national, or a person that has worked in the
service of one of them, shall not be taken into consideration.
If, despite the application of the abovementioned procedure, it is not possible to
reach an agreement on some specific aspect, the Parties may submit the matter
to arbitration.
The new long term Agreement shall establish a dispute settlement mechanism.
ENTRY INTO FORCE
Article 17
This initial Agreement will have a validity of four years and will lead to a new
Agreement upon the completion of relevant studies. If the long-term Agreement
cannot be reached after four years, the initial Agreement’s validity shall be
extended on an annual basis.
The new long-term Agreement shall take into account authorization acts that
may have been adopted while this Agreement was valid.
This Agreement shall enter into force thirty days after receipt of the last Note
by which the Parties notify each other of compliance of the relevant internal
requirements. This notwithstanding, the second paragraph of Article 6 shall
enter into force upon its signing.
Four years after its entry into force, this Agreement may be terminated by
either party, by written notice to the other party, six months in advance. The
termination will come into effect following said period.
Signed at ...
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175
Annex 9
Initial Agreement [Silala or Siloli], Agreed Draft, Santiago,
13 November 2009
(Original in Spanish, English translation)
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llorrador acordado el 13 de noviembre de 2009, en Santiago.
ACUERDO INICIAL (SIIAlA O SILOLI)
El Gobierno de la Republica de Chile y el Gobierno del Estado Plurinacional de Dolivia, en adelante
"las Partes",
CONS!DERANDO
Que los Ministerios de Relaciones Exteriores de la Republica de Chile y del Estado Plurinacional de
Bolivia constituyeron en 2004 un Grupo de Trabajo Bolivia - Chile sabre el tema del Sflala, que plasm6
sus resultados en las actas suscritas el 6 de mayo de 2004, el 20 de enero de 2005, el 10 de junio de
2008 y el 14 de noviembre de 2008;
Que el tema del Silala o Siloli fue incluido en el punto VII de la Agenda bilateral de 13 puntos
adoptada por ambas Partes en julio de 2006 y que desde esa fecha, ellas se han esfonado en
proponer f6rmulas destinadas a superar las diferencias surgidas en torno al sistema hfdrico del Silala
o Si Ioli, y las caracteristicas de sus aguas;
Que los estudios conjuntos realizados previamente no avanzaron hacia su conclusion respecto de la
naturaleza de las aguas y las Partes consideran necesario continuar su realizaci6n conjunta;
Que los estudios realiiados hasta el presente en forma individual, por cada una de las Partes, han
aportado suficiente informaci6n para establecer el presente acuerdo inicial que servira de base para
un nuevo acuerdo de largo plazo, y que se concluira teniendo en consideracion los resultados de los
estudios tecnicos contemplados en el presente acuerdo, la continuaci6n de los trabajos conjuntos
iniciados en el ai'io 2000, los aprovechamientos existentes y el uso sustentable de las aguas;
Que cl presente acuerdo no se refiere a otros temas relativos al SUala o Si loli Que a cada una de las
Partes interese abordar en forma previa o al momento de negociar el nuevo Acuerdo de largo plazo;
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INITIAL AGREEMENT [SILALA OR SILOLI]
The Government of the Republic of Chile and the Government of the Plurinational
State of Bolivia, hereinafter “the Parties”,
CONSIDERING
That the Ministries of Foreign Affairs of the Republic of Chile and the Plurinational
State of Bolivia created a Bolivia-Chile Working Group on the Silala
issue in 2004 and recorded the results attained in the minutes signed on 6 May
2004, 20 January 2005, 10 June 2008, and 14 November 2008;
That the Silala, or Siloli issue was included in point VII of the Bilateral Agenda
of 13 Points, adopted by both Parties in July 2006, and that since that date, they
have made efforts to propose formulas intended to overcome their differences
regarding the Silala, or Siloli hydrologic system and the characteristics of its
waters;
That the joint studies carried out previously did not move forward towards their
conclusion regarding the nature of the waters and that the Parties consider it
necessary to continue their joint implementation;
That the studies carried out to date by each of the Parties individually have provided
sufficient information to reach this initial agreement, which shall serve as
a basis for a new long term Agreement that will be concluded taking into consideration
the results of the technical studies referred to herein, the continuation
of the joint work started in 2000, and the present utilization and sustainable use
of the waters of Silala;
That the present Agreement does not address other issues that each of the Parties
might have an interest in addressing when negotiating the new long-term
Agreement regarding the Silala, or Siloli;
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Oorr~dor acordado el l3 de noviembre de 2009, en Santiago.
Que el ambiente de mutua confianza que se ha desarrollado entre ambos paises ha permitido acem1r
las voluntades para profundizar Jos entendimientos que los pueblos anhel;in, formulando un acuerdo
de mutuo beneficio sobre este punto de la agenda bilateral.
ACUER0AN
ASPECTOS GENERALES
Articulo 1
El presente acuerdo lnicial establece el marco para trabajar conjuntamente con miras a avanzar en la
convergencia de tos diferentes ountos de vista que han surgldo entre Chile y Bolivia sobre las aguas
del Sllala, considerando que:
a) Para Bol ivia las aguas del Sllala son de su total propiedad, provlenen de decenas de
manantiales ubicados en su territorio, y las obras de captaci6n y conducci6n e:<lstentes son las
que dan origen al actual escurrimlento superficial.
b) Para Chile las aguas del Silala escurren naturalmente por la frontera y constituyen un curse de
agua sucesivo internacional, al cual se aplican los criterios sobre los usos equitativos y
razonables, segun el cJerecho internacional, donde Bolivia es Estado de curso Superior y Chile
de curse inferior.
Articulo 2
El Acuerdo lnicial tendra como prop6sitos, los siguientes:
1. Estabiecer un acuerdo bilateral para la preservaci6n, sostenibilidad, uso y aprovechamiento del
sistema hidrico del Silala o Siloli para beneficio de ambos paises.
2. Realitar los estudios y mediciones que permitan determinar la naturaleza, el balance hidrico, el
comportamiento hidrometrico, la dataci6n de las aguas, los flujos superficiales y subterraneos,
y la influencia de las obras civiles sobre el caudal, entre otros, utiliza ndo una metodologia
cientificamente valida y concordada, que sirva de base al establecimiento definitive def
porcentaje de las aguas de fibre disposlci6n de cada pa fs.
3. Establecer un procedimiento mediante el cual el Estado Plurinacional de Bolivia autorice,
conforme al articulo 3, que las aguas de su fibre disponibilidad, captadas en su pa is, puedan ser
cond ucidas a Chile y aprovechadas recibiendo una compensaci6n.
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That the atmosphere of mutual trust that has been developed between the two
countries has helped bring together their will to deepen the understandings that
both their peoples long for, formulating a mutually beneficial Agreement on
this point of the bilateral agenda.
HEREBY AGREE
GENERAL ASPECTS
Article 1
This initial agreement establishes the framework to work together with a view
to moving forward in the convergence of the different points of view that have
emerged between Chile and Bolivia over the Silala waters, considering that:
a) To Bolivia, the Silala waters are of its complete property and come from
dozens of springs located within its territory; and the existing abstraction
and canalization works are responsible for giving rise to the current
surface runoff.
b) To Chile, the Silala waters flow naturally across the border and constitute
a successive international watercourse, to which the criteria on equitable
and reasonable uses are to be applied, under International Law, situation in
which Bolivia is an upstream State and Chile the downstream one.
Article 2
The initial Agreement shall have the following purposes:
1. To establish a bilateral agreement for the preservation, sustainability, use
and exploitation of the Silala or Siloli water system for the benefit of both
countries.
2. To carry out studies and measurements to determine the nature, water
balance, hydrometric behavior, water dating, surface and groundwater
flows, and the influence of civil works on the flow, among others, using
a scientifically valid and agreed methodology that serves as the basis for
the definitive establishment of the percentage of freely available waters for
each country.
3. To establish a procedure by which the Plurinational State of Bolivia au
thorizes, according to Article 3, that the freely available waters, abstracted
in its country, be transported and used in Chile, within the framework of
compensation.
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Sorr~dor acordado el 13 de 11oviembre de 2009, en Sa11tiago.
Articulo 3
Por el presente acuerdo se establece que las aguas de libre disponibilidad de Bolivia y captadas en su
pais pod ran ser conducidas para ser aprovechadas en Chile. En ta I caso, el titular publico boliviano de
la autorizacion para el otorgamiento de/ uso de dichas aguas sera compensado por las personas
juridicas de derecho publico o privado que se constituyan en aprovechatarias de dichas aguas.
Para el otorgamiento del uso de dichas aguas de libre disponibilidad, cl titular publico boliviano
considerara el derecho preference de las personas juridicas de derecho publir.o o privado que
actualrnente estuvieren haciendo use de dichas aguas en Chile. Este derecho preferente se ejercera
por un espacio de sesenta dias a partir de la corn1mlcacicin per via oficial de la irnplernentaci6n de esta
parte de/ Acuerdo.
Las personas juridicas antes individualizadas deberiin desarrollar las acciones que corrcspondieren en
Chile, en caso de que esas aguas fueren a ser utilizadas en este pais, pudiendo Bolivia caducar la
autorizacion etorgada si nose concretaren esos prepositos en el plazo que hubiese fijado.
Articulo 4
Considerando la fragilidad del ecosistema del Silala o Silo!i, per el presente Acuerdo las Partes se
comprometen a mantener las condiciones de caudal y calidad del agua que dependan de las partes, y
a cuidar que cualquier obra que emprendan a future individual o conjuntamente no afecte dicho
caudal y calidad.
Artfcule 5
Por este Acuerdo las Partes se comprometen a efectuor conjuntamente estudios complementaries
sabre el sistema hidrlco del Silala (Siloli), para fograr un mayor conecimiento sobre su funcionamiento
y naturaleza.
Articulo 6
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Draft agreed to on 13 November 2009, in Santiago
Article 3
By this agreement, it is established that the freely available waters of Bolivia
and abstracted in that country may be canalized to be used in Chile. In such
case, the Bolivian public holder of the authorization to award the use of said
waters will be compensated by the public or private law legal entities that are
established as beneficiaries of said waters.
To grant the use of said freely available waters, the Bolivian public holder will
consider the preferential right of the public or private law legal entities that
are currently making use of said waters in Chile. This preferential right will
be exercised for a period of sixty days from the official communication of the
implementation of this part of the Agreement.
The legal entities, previously individualized, must develop the corresponding
actions in Chile, in case these waters are to be used in this country, and Bolivia
may expire the authorization granted if these purposes are not fulfilled within
the term that had been established.
Article 4
Considering the fragility of the Silala or Siloli ecosystem, by this agreement
the Parties undertake to maintain the conditions and quality of the water for
which either of the Parties is responsible, and ensure that any work undertaken
individually or jointly does not affect said flow and its quality.
Article 5
Through this agreement, the Parties undertake to jointly carry out complementary
studies on the Silala (Siloli) water system, in order to achieve a better
understanding of its behavior and nature.
Article 6
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Borrador acordado el 13 de noviembre de 2009, en Santiago
Teniendo en cuenta lo sefialado en el articulo primero del presente acuerdo, las Partes establecen,
coma hipotesis de trabajo y mientras se realicen las estudios indicados er. el artfculo 2.2., que del
volumen total del agua del Silala o Siloli, que atraviesa superficialmente la frontera, el SO%
corresponde, inicialmente, al Estado Plurinacional de Bolivia, es de su libre disponibilidad y lo podra
utilizar en su territorio o autorizar su captaci6n para su uso por terceros, in::luyendo su conducci6n a
Chile. Este porcentaje podra ser incrementado a favor de Bolivia, en funci6n de los resultados de los
estudios conjuntos que se lleven a cabo en el marco del presente Acuerdo.
Tan pronto sea suscrito el presente Acuerdo las Partes se comprometen a inst2lar la estacion
hidrometrica mencionada en el Artfculo 8, letra b), la cual registrara las volumenes de agua en el
cruce de frontera.
ASPECTOS TECNICOS
Articulo 7
A partir del presente Acuerdo inicial, las Partes implementaran en la zona una red de estaciones
hidrometeorol.6gicas que permitan obtener dates y realizar estudios conjuntos con vistas a la
suscripci6n de un nuevo acuerdo de largo plarn.
Articulo 8
Con el prop6sito de establecer el porcentaje de aguas de libre disponibflidad de cada pais y avanzar
en la comprension del sistema hidrico, se acuerda implementar una red de estaciones de medici6n de
caudales y variables hidrometeorologicas para obtener registros de precipitaci6n (lfquida y nival),
temperatura del a ire y otras variables, segun el slguiente detalle:
a. Estacion meteorologica en el sector de cruce de frontera.
b. Estacion hidrometrica en el sector de cruce de frontera.
c. Estaci6n hidrometrica en el cruce del camino pr6ximo a las bofedales orientales en territorio
de Bolivia.
d. Estacion meteorol6gica en la divisoria de aguas en el extrema Este def sistema.
e. Estacion meteoro16gica en la ladera boliviana del volcan lnacaliri.
f. Estacion meteoro16gica en la zona de bofedales de la vertiente oriental.
4
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Draft agreed to on 13 November 2009, in Santiago
Taking into account the provisions of the first article of this agreement, the
Parties hereby establish, as a working hypothesis and while carrying out the
studies indicated in Article 2.2, that of the total water volume of the Silala or
Siloli that crosses the border on the surface, 50% corresponds, initially, to the
Plurinational State of Bolivia, is freely available to it and may be used in its
territory or authorized to be abstracted for the use of third Parties, including
its conveyance to Chile. This percentage may be increased in favor of Bolivia,
depending on the results of the joint studies carried out within the framework
of this Agreement.
As soon as this agreement is signed, the Parties undertake to install the hydrometric
station mentioned in Article 8, sub-paragraph b), which will record the
volumes of water at the border crossing.
TECHNICAL ASPECTS
Article 7
Based on this initial agreement, the Parties will set up a network of hydrometeorological
stations in the area in order to obtain data and carry out joint
studies with a view to signing a new long term agreement.
Article 8
In order to determine the percentage of freely available water in each country
and move forward in the understanding of the water system, the Parties hereby
agree to implement a network of flow measurement stations and hydro-meteorological
variables in order to obtain records of precipitation (rain and snow),
air temperature and other variables, in accordance with the following detail:
a. A meteorological station at the border crossing.
b. A hydrometric station at the border crossing.
c. A hydrometric station at the junction of the road next
to the Orientales Wetlands in Bolivian territory.
d. A meteorological station in the watershed at the eastern end of
the system.
e. A meteorological station on the Bolivian slopes of the
Inacaliri Volcano.
f. A meteorological station in the area of the wetlands found on
the eastern spring.
4
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Borrador acordado el 13 de noviembre de 2009, en Santiago.
De las seis est-aciones propuestas, dos (a y b) se encontraran en el cruce de front!:)ra, y seran
binacionales, cuatro (c, d, e y f) estaran ubicadas en territorio boliviano y seran de propiedad de!
Estado Plurinacional de Bolivia.
Ademas, formara parte de la red la estaci6n de la Direcci6n General de Ag:.ias de Chile, DGA, ubicada
en el !ado chileno, pr6xima al cruce del limite internacional.
Adicionalmente, las Partes se comprometen a intercambiar datos provenientes de otras estaciones
pr6ximas al area de !nvestigaci6n.
Dada la ubicaci6n remota de la red de estaciones y la necesidad de que ambos pa1ses cuenten con
informaci6n continua, simultanea y en tiempo real, las estaciones tendran transmisi6n satelital, de
modo que ambas Partes monitoreen la informaci6n y el funcionamiento general de las est9ciones.
Articulo 9
Las Partes definiran un periodo de monitoreo conjunto de cuatro cidos hidrol6gicos anuales que
permitan determinar el balance hidrico, el comportamiento hidrometrico, la dataci6n de las aguas, los
flujos superficiales y subterraneos, y la infiuencia de las obras sobre el caudal, entre otros, utilizando
una metodologia cientfficamente valida y concordada.
La recolecci6n, archivo y procesamiento de las datos, quedara a cargo de la Direcci6n General de
Aguas (DGA) en Chile y d~I Servicio Nacionai de Meteorologfa e Hidrologfa (SENAMHI) en Bolivia.
Artfculo 10
Por el presente Acuerdo inicial, se establece un programa de monitoreo para determinar la calidad y
la dataci6n del agua, con toma de mLiestras dos veces al aiio, en invierno (ulio) y verano (enero), en
las sectores de bofedales y en el cruce de frontera.
Se establece, asimismo, que se complementaran los trabajos cartograficos del a;ea def Silala o Siloli,
mediante trabajos de terreno de apoyo tecnico a las fotografias aereas tomadas en conjunto el aiio
2001, para elaborar una cartografia de detalle, y se adquiriran imagenes satelitales, ademas de
elaborarse modelos digitales de terreno.
Articufo 11
185
Draft agreed to on 13 November 2009, in Santiago
Of the six proposed stations, two (a and b) shall be located at the border crossing
and shall be binational, and four (c, d, e and f) shall be located in Bolivian
territory and shall be property of the Plurinational State of Bolivia.
In addition, the said network will form part of the Chilean General Directorate
of Water [DGA, for its Spanish acronyms] network, located on the Chilean
side, near the international border crossing.
Additionally, the parties agree to exchange data from other stations near the
area studied.
Given the remoteness of the network of stations and the need for both countries
to have continuous, simultaneous, and real-time information, the stations
will be set up with satellite transmission, so that both parties can monitor the
information and the overall functioning of the stations.
Article 9
The Parties shall define a joint monitoring period of four annual hydrological
cycles to determine the water balance, hydrometric behavior, age of the waters,
surface and groundwater flows, and influence of the works on the flow, among
others, using scientifically valid and agreed upon methodology.
Data collection, storage, and processing shall be the responsibility of the General
Directorate of Water (DGA) in Chile and the National Service of Meteorology
and Hydrology (SENAMHI) in Bolivia.
Article 10
Under this initial Agreement, a monitoring program shall be established to
determine the quality and the age of the water, taking samples twice a year, in
winter (July) and summer (January), in the wetland area and the border crossing.
It is also herewith agreed that cartographic work in the Silala or Siloli area will
be complemented through field works to provide technical support for the aerial
photographs taken jointly in 2001 in order to develop a detailed cartography;
also, satellite imagery shall be acquired and a digital terrain model developed.
Article 11
5
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Borrador acordado el 13 de noviembre de 2009, en Santiago.
Las Partes elaboraran informes semestrales y un informe final al cabo de cuatro afios, con los
resultados de los estudios. Este informe final constituira la base para el nuevo Acuerdo de largo plaza
que establecera los porcentajes de libre disponibilidad de cada pafs.
ASPECTOS INSTITUCIONALES
Artkulo 12
El Estado Plurinacional de Bolivia a traves del Ministerio de Medic Ambiente y Agua designara a la
Prefectura del Departamento de Potosi o a otra persona jurfdica de derecho publico que actuara
como el sujeto detentor de la autorizaci6n de uso de las aguas de libre disponibilidad boliviana del
Sil ala o Siloli.
Bajo el marco del presente Acuerdo inicial, el seguimiento y oper2ci6n tecnica de! uso y
aprovechamiento def agua, por Bolivia, estara a cargo def sujeto detento~ arriba mencionado; por
Chile, estara a cargo de la Direcci6n General de Aguas del Ministerio de Obras Publicas.
Las Partes se informaran mutuamente sobre cualquier modificacion que establezcan respecto de!
regimen antes indicado.
Artfculo 13
El Ministerio de Medio Ambiente y Agua determinara el valor por metro cubico que percibira el
Estado Piurinacional de Bolivia a titulo de compensaci6n en funci6n def volumen transferido, el que
~era acordado directamente con la persona jurfdica de derecho publico o privado interesada.
Asimismo, determinara la periodicldad con que percibira dicho valor y las garantfas para asegurar la
compensaci6n.
Artfculo 14
Para la determinaci6n de la compensaci6n el Ministerio de Medic Ambiente y Agua podra tener en
cuenta, entre otros, el valor promedio efectivamente pagado por metro cubico de aguas crudas en la
11 Region de Chile.
187
Draft agreed to on 13 November 2009, in Santiago
The Parties shall produce semi-annual reports and a final report after four years
with the results of the studies. This final report will form the basis for the new
long-term Agreement that will establish the percentage of water freely available
to each country.
INSTITUTIONAL ASPECTS
Article 12
The Plurinational State of Bolivia, through the Ministry of Environment and
Water, will appoint the Prefecture of the Department of Potosi or a different
public legal entity as the subject entitled to authorize the use of the water of the
Silala or Siloli that is freely available to Bolivia.
Under the framework of this initial Agreement, the monitoring and technical
operation of water use and utilization will be the responsibility of the
aforementioned subject, for Bolivia, and the General Directorate of Water of
the Ministry of Public Works, for Chile.
The Parties shall inform each other of any changes regarding the regime
established above.
Article 13
The Ministry of Environment and Water shall determine the value per cubic
meter to be allocated to the Plurinational State of Bolivia in compensation,
depending on the volume transferred, which shall be negotiated directly with
the relevant public or private legal entity. The Ministry shall also determine the
payment frequency and guarantees to ensure compensation.
Article 14
To determine the compensation due, the Ministry of Environment and Water
may take into account, inter alia, the average price currently paid per cubic
meter of untreated water in Chile’s Region II.
6
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Borrador acordado el 13 de noviembre de 2009, en Sar;'.iago.
Artfculo 15
De conformidad con el presente Acuerdo, el Gobierno de Bolivia, declara que la persona juridica, de
derecho publico o privado, que haya sido autorizada por el Ministerio de Media Ambiente y Agua
para el uso en territorio chileno de las aguas del Silala o Siloli de Sll l:bre disponibilidad, podra
aprovecharlas sin ninguna restricci6n, o discriminaci6n.
El Gobierno de Chile declara que no se opondra a la aplicacion de medidas que conforme al
ordenamiento jurfdico boliviano y al presente Acuerdo, se apliquen al aprovechatario que no cumpla
las obligaciones adquiridas con la persona juddica de derecho publico designada por el Ministerio de
Medic Ambiente y Agua, en virtud del presente Acuerdo.
Las diferencias que pudiesen surgir entre una persona juridica y el Estado Plurinacional de Bolivia en
el marco de los Artfculos 3 y 6 relativos a la autorizaci6n, y su cumplimiento o ejecuci6n, seran
resueltas segun las normas aplicables en dicho Estado y las que estableciere la autorizacion para el
aprovechamiento correspondiente, siendo competentes para estos efectos las instancias
jurisdiccionales internas de/ Estado Plurinacional de Bolivia.
SOLUC/6N DE DIFERENCIAS
Artfculo 16
En caso de queen la aplicacion o interpretacion de este Acuerdo surgiere una diferencia, contingencia
o asunto que requiera la atenck·-1 conjunta de la Partes, cualquiera de el/as podra convocar al Grupo
de Trabajo Bolivia-Chile sabre el tema de/ Si/ala, creado por las Cancillerfas de ambos Estados en
2004, para resolver/a o darle una respuesta apropiada.
En los trabajos tecnicos a que se refieren los articulos 7 a 11, las Partes se esforzaran en cooperar
activamente, as[ como en alcanzar resultados que sirvan de referenda para futuros acuerdos. En caso
de que, a pesar de los esfuerzos desplegados, no fuere posible ponerse de acuerdo sobre los
volumenes de agua de libre disponibilidad, entre otras materias, las Partes pondran en ejecucion
mecanismos que permitan superar esas diferencias, con el apoyo de expertos si fuere necesario.
Sin perju icio de ello, las Partes, de cornun acuerdo podran solicitar en todo momenta la asistencia de
un organismo tecnico o cientifico especializado y de renombre internacio1al, a fin de que aporte
elementos que conduzcan a un arreglo entre las Partes.
Si no pudie,e 1/egarse a un acuerdo a traves de estos procedimientos respecto de la aplicacion o
interpretaci6n de/ presente Arnerdo, cualquiera de las P;;rtes podra solicitar que se constituya una
7
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Draft agreed to on 13 November 2009, in Santiago
Article 15
In accordance with this Agreement, the Government of Bolivia hereby declares
that the public or private legal entity authorized by the Ministry of Environment
and Water to have the unencumbered right to use the waters of Silala or Siloli
in Chilean territory, may use these waters without restriction or discrimination.
The Government of Chile declares that it will not oppose to the application of
measures which, under Bolivian law and this Agreement, shall be applicable to
users that do not meet the obligations undertaken with the public legal entity
appointed by the Ministry of Environment and Water under this Agreement.
The differences that may arise between a legal entity and the Plurinational
State of Bolivia under Articles 3 and 6 regarding authorization, compliance or
enforcement, shall be resolved under the provisions applicable in that State and
those by which authorization for the corresponding use was established; the
internal jurisdictional instances of the Plurinational State of Bolivia shall thus
be regarded competent for this purpose.
DISPUTE SETTLEMENT
Article 16
If, any differences, contingencies or matters that require the Parties’ joint
attention arise in the application or interpretation of this Agreement, either
Party may convene the Bolivia-Chile Silala Working Group, created by the
Foreign Ministries of both States in 2004 to settle them or provide a proper
response.
In the completion of the technical works referred to in Articles 7 to 11, the
Parties shall endeavor to actively cooperate and achieve results that serve as
reference for future agreements. If, despite all efforts, it is not possible to agree
on the volume of freely available water, among other matters, the Parties shall
implement mechanisms to overcome these differences, with the support of
experts where necessary.
Notwithstanding above, the Parties may, by mutual agreement and at any time,
request the assistance of an internationally recognized technical or scientific
organ, in order to provide them with information that leads to a settlement.
If it is not possible to reach an agreement regarding the application or
interpretation of this Agreement through these procedures, either party may
request that a three-member
7
190
Borrador acordado el 13 de noviembre de 2009, en Santi~go.
Comisi6n de Conciliaci6n de tres miembros, para someter la diferencia a su conocimiento y
recomendaci6n.
En el plazo de treinta dias despues de recibida la solicitud, cada Parte de~ignara un integrante de la
Comisi6n de Conciliaci6n. El tercero, que la presidira, sera designado de comun acuerdo y no podra
ser nacional de ninguna de las Partes. En caso de desacuerdo sabre la persona a designar o si una de
las Partes no designare en dicho plazo al miembro de la Comisi6n que le corresponde, cualquiera de
las Partes podra solicitar a la maxima autoridad de las siguientes organismos o programas
internacionales segun sus normas fundamentales constitutivas, que lo designe, segun el siguiente
orden sucesivo. En la Organizaci6n de las Naciones Unidas para la Educacion, la Ciencia y la Cultura,
UNESCO, el Director Ejecutivo; en la OrganizaC:6n Meteorol6gica Mundial, OMM, el Secretario
General; en el Programa de las Naciones Unidas para el Media Ambiente, PNUMA, el Director
Ejecutivo; en la Organizaci6n lr.ternaciona! de Energia At6mica, OIEA, el Director General; o en el
Programa de las Naciones Unidas p~ra el Desarrollo, PNUD, el Administrador. No sera considerado un
organismo o programa cuya maxima autoridad sea nacional de una de las Partes, o cuando dicha
persona haya trabajado al servicio de una de ellas.
En case de que a pesar de la aplicaci6n del procedimiento anteriormente mencionado nose llegare a
entendimiento en algun aspecto especifico, las Partes podran somete;lo al arbitraje.
En el nuevo Acuerdo de largo plazo se establecera un mecanismo de soluci6n de controversias.
VIGENCIA
Artfculo 17
Este Acuerdo inicial tcndra una vigencia de cuatro aiios, y dara lugar a un nuevo Acuerdo una vez
concluidos los estudios pertinentes. Si al cabo de las cuatro afios no pudiera establecerse el Acuerdo
de largo plazo, las Partes de mutuo acuerdo, podran prorrogarlo per periodcs anuales.
El nuevo Acuerdo de largo plazo tendra en cuenta los actos de autorizaci6n que se hubiesen adoptado
du rante la vigencia del presente Acuerdo inicial.
El presente Acuerdo entrara en vigor treinta ciias despues de recibida la 1Hima Neta per Ja cual las
Partes se comuniquen redprocamente el cumplimiento de los requisites irternos correspondientes.
Sin perjuicio de lo anterior, el segundo parrafo del Articulo 6 entrara en vigor al momenta de su
suscripci6n.
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Draft agreed to on 13 November 2009, in Santiago
Conciliation Commission be established to apply its knowledge and
recommendations to the dispute.
Within thirty days after receiving the request, each party shall appoint a member
for the Conciliation Commission. The third member, who will preside the
commission, shall be appointed by mutual agreement and cannot be a national
of either Party. In case of disagreement on the appointed person or if a Party
fails to nominate a member to the Commission within that period, either party
may request the highest authority of the following agencies or programs, based
on their fundamental constitutional rules, to appoint the member in question, in
the following order: The Executive Director of the United Nations Educational,
Scientific and Cultural Organization (UNESCO); the Secretary-General of
the World Meteorological Organization (WMO); the Executive Director of
the United Nations Environment Program (UNEP); the Director General of
the International Atomic Energy Agency (IAEA); or the Administrator of the
United Nations Development Program (UNDP). An agency or program whose
maximum authority is a Party national, or a person that has worked in the
service of one of them, shall not be taken into consideration.
If, despite the application of the abovementioned procedure, it is not possible to
reach an agreement on some specific aspect, the Parties may submit the matter
to arbitration.
The new long-term Agreement shall establish a dispute settlement mechanism.
VALIDITY
Article 17
This initial Agreement will have a validity of four years and will lead to a new
Agreement upon the completion of relevant studies. If the long-term Agreement
cannot be reached after four years, the initial Agreement’s validity shall be
extended on an annual basis.
The new long-term Agreement shall take into account authorization acts that
may have been adopted while this initial Agreement was valid.
This Agreement shall enter into force thirty days after receipt of the last Note
by which the Parties notify each other of compliance of the relevant internal
requirements. This notwithstanding, the second paragraph of Article 6 shall
enter into force upon its signing.
8
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Borrador acordado el 13 de noviembre de 2009, en Santiago.
Despues de transcurridos cuatro aiios, el presente Acuerdo podra ser denunciado por cualquiera de
las Partes, mediante una notificaci6n escrita a la otra Parte, con seis meses de anticipaci6n. La
denuncia cobrara vigor a partir del cumplimiento de dicho plazo.
Suscrito en .....
9
193
Draft agreed to on 13 November 2009, in Santiago
Four years after its entry into force, this Agreement may be terminated by either
Party, by written notice to the other Party, six months in advance. The termination
will come into effect following said period.
Signed at ...
9
194
195
Annex 10
Minutes of the First Part of the VIII Meeting of the Bolivia-Chile
Working Group on the Silala Issue, October 2010 (unsigned)
(Original in Spanish, English translation)
196
ACTA DE LA PRIMERA PARTE DE LA VIII REUNl6N DEL GRUPO DE
TRABAJO BOLIVIA-CHILE SOBRE EL TEMA SILALA
En la ciudad de La Paz, a los treinta dlas del mes de sepliembre y primero de
octubre de 2010, sesion6 en su prlmera parte la VIII Reuni6n del Grupo de Trabajo
Bolivia - Chile sobre el tema Silala.
La Delegaci6n de Bolivia fue presidida por el Sr. Rogel Mattos, Director General de
Limites, Fronteras y Aguas lnternacionales del Ministerio de Relaciones Exteriores
de Bolivia. La Delegaci6n de Chile, por su parte, fue presidida por el Sr. Anselmo
Pommes, Director Nacional de Fronteras y Limites del Estado, del Ministerio de
Relaciones Exteriores. La n6mina de las respectivas delegaciones se adjunta a la
presente Acta como Anexo 1.
Ambas delegaciones destacaron la importancia de la Reuni6n, que responde a un
compromiso asumido por ambos palses con ocasi6n de la XXII Reuni6n del
Mecanismo de Consultas Pollticas, efectuada en La Paz, el 14 de julio de 2010, en
cuyo punto VII del Acta de dicha Reuni6n se senala que el "Grupo de Trabajo
sobre la tematica del Silala, se reuna nuevamente con el objetivo de conocer,
analizar y responder todas las propuestas surgidas a ralz del proceso de
socializaci6n del Acuerdo lnicial".
Las Delegaciones efectuaron una lectura completa del texto borrador del Acuerdo
lnicial, al que se le incluyeron las complementaclones sugerldas por la Delegaci6n
de Bolivia, y que son basicamente las siguientes:
1. La compensaci6n econ6mica por el uso de las aguas realizado por Chile
(Artlculo 1: inciso a).
2. La conducci6n por parte de Bolivia de las aguas de su libre disponibilidad
(Artlculo 3).
3. La elaboraci6n del contrato respectivo en Bolivia bajo el marco de la
legislaci6n vigente (Artlculo 3).
4. La introducci6n de un plazo para las actividades contempladas en el primer
parrafo del Artlculo 8.
5. La definici6n del punto de partida para el periodo de monitoreo conjunto al
que se refiere el Artlculo 9.
6. La referencia a la finalizaci6n de los estudios tecnicos ademas de
considerar los cuatro anos en la clausula de vigencia (Artlculo 17).
En relaci6n a las modificaciones planteadas por la Delegaci6n Boliviana, la
Delegaci6n de Chile dio respuesta a las mismas de la siguiente forrna:
• Respecto a la modificaci6n referida al parrafo primero del Artlculo 3, la
Delegaci6n chilena no coincidi6 con el senlido y redacci6n propuesta. De tal
forrna, esta Delegaci6n qued6 de estudiarla, para dar respuesta a la misma
en la continuaci6n de la presente Reuni6n.
197
MINUTES OF THE FIRST PART OF THE VIII MEETING OF THE
BOLIVIA-CHILE WORKING GROUP ON THE SILALA ISSUE
In the city of La Paz, on the 30th day of September and the first of October
2010, the VIII Meeting of the Bolivia-Chile Working Group on the Silala issue
met in its first part.
The Delegation of Bolivia was chaired by Mr. Rogel Mattos, General Director
of Borders, Boundaries and International Waters of the Ministry of Foreign
Affairs of Bolivia. The Delegation of Chile, for its part, was chaired by Mr.
Anselmo Pommes, National Director of State Borders and Boundaries of the
Ministry of Foreign Affairs. The list of the respective delegations is attached to
this Minutes as Annex 1.
Both delegations highlighted the importance of the Meeting, which responds to
a commitment assumed by both countries on the occasion of the XXII Meeting
of the Political Consultation Mechanism, held in La Paz, on 14 July 2010, in
which point VII of the Minutes of said Meeting it is indicated that the “Working
Group on the Silala issue, meets again with the objective of knowing, analyzing
and answering all the proposals arising from the process of socialization of the
Initial Agreement.”
The Delegations made a complete reading of the draft text of the Initial
Agreement, to which the complements suggested by the Delegation of Bolivia
were included, and which are basically the following:
1. The economic compensation for the use of the waters made by Chile
(Article 1, paragraph a).
2. The channeling by Bolivia of the free available waters (Article 3).
3. The elaboration of the respective contract in Bolivia under the
framework of the current legislation (Article 3).
4. The introduction of a deadline for the activities referred to in the first
paragraph of Article 8.
5. The definition of the starting point for the joint monitoring period
referred to in Article 9.
6. The reference to the completion of the technical studies in addition to
considering the four years in the validity clause (Article 17).
In relation to the modifications proposed by the Bolivian Delegation, the
Delegation of Chile responded to them as follows:
- Regarding the amendment referred to the first paragraph of Article 3, the
Chilean Delegation did not agree with the proposed meaning and wording.
In this way, this Delegation was supposed to study it, in order to respond to
it in the continuation of this Meeting.
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198
Respecto de las demas modificaciones propuestas por la Delegaci6n de
Bolivia, la Delegaci6n de Chile manifest6 su conformidad con las mismas,
quedando incorporadas al texto borrador del Acuerdo lnicial. Respecto de la
modificaci6n planteada en el numeral 1 del parrafo anterior, cabe sel'lalar
que esta constituye una precisi6n de la postura de Bolivia, por lo que la
Delegaci6n de Chile de igual forma complement6 su posici6n, contenida en
la letra b) del Artfculo 1 del Acuerdo lnicial.
Como reflejo del proceso de consulta interna, la Delegaci6n boliviana propuso la
inclusi6n de un Artfculo transitorio referido al monto y la forma de erogaci6n por
parte de Chile respecto del uso pasado de las aguas del Silala ("deuda hist6rica'),
que dirla lo siguiente:
"Artlculo Transitorio.- En la XXIII Reunion de/ Mecanismo de Consultas
Politicos Bolivia - Chile se definird el monto y la forma de erogacion por parte de
la Republlca de Chile respecto de/ uso pasado de las aguas de/ Si/ala".
Respecto a la modificaci6n consistente en la incorporaci6n del Artlculo Transitorio,
la Delegaci6n de Chile manifest6 su disconformidad con la misma y con su
incorporaci6n en el texto borrador del Acuerdo lnicial, atendido a que la finalidad
perseguida con la suscripci6n del citado Acuerdo es buscar una soluci6n al tema
del Silala o Siloli.
Como argumento para la inclusi6n del Artlculo transitcrio y en concordancia con el
Artlculo 1, incise a), del texto borrador del Acuerdo lnicial, la Delegaci6n boliviana
expuso los fundamentos por los cuales considera que Chile tiene una deuda
hist6rica por el uso pasado de las aguas del S lala. Los fundamentos presentados
se refieren a la constataci6n del cambio del objeto de uso de la concesi6n que
estaba destinada originalmente al uso del agua por locomotoras a vapor, debido a
que a partir de los anos 50s las locomotoras de vapor dejaron de ser utilizadas y
estas aguas pasaron a ser destinadas a otros usos no autorizados por la autoridad
boliviana competente.
Asimismo, la Delegaci6n boliviana expuso que se realizaron obras de
infraestructura en el area de los manantiales del Silala en su territorio que
incrementaron el caudal para otros usos sin autorizaci6n boliviana.
Adicionalmente, la Delegaci6n boliviana senal6 que Chile regulariz6 derechos de
agua bajo el mandate de su C6digo de Aguas de 1981, sin considerar los
derechos bolivianos existentes sobre las aguas del Silala.
De igual manera, enfatiz6 que la concesi6n fue revocada el al'lo de 1997
notificandose a las empresas respectivas en el territorio chileno. Se explic6 que el
Gobierno boliviano licit6 las aguas del Silala estableciendose una nueva concesion
el ano 2000 a la empresa DUCTEC SRL, la que emiti6 las facturas respectivas por
el uso de las aguas del Silala a las empresas usuarias correspondientes,
199
Regarding the other amendments proposed by the Delegation of Bolivia, the
Delegation of Chile expressed its agreement with them, being incorporated
into the draft text of the Initial Agreement. Regarding the modification proposed
in paragraph 1 of the previous paragraph, it should be noted that this
constitutes a clarification of the position of Bolivia, reason why the Delegation
of Chile also complemented its position, contained in letter b) of Article
1 of the Initial Agreement.
As a reflection of the internal consultation process, the Bolivian Delegation
proposed the inclusion of a transitory article referring to the amount and form
of expenditure by Chile regarding the past use of the Silala waters (“historical
debt”), which would read as follows:
“Transitory Article – At the XXIII Meeting of the Bolivia-Chile Political
Consultation Mechanism, the amount and manner of expenditure by the Republic
of Chile regarding the past use of Silala waters will be defined.”
Regarding the amendment consisting of the incorporation of the Transitory Article,
the Chilean Delegation expressed its disagreement with it and its incorporation
in the draft text of the Initial Agreement, given that the purpose pursued
with the signing of the aforementioned Agreement is to seek a solution to the
issue of Silala or Siloli.
As an argument for the inclusion of the Transitory Article and in accordance
with Article 1, paragraph a), of the draft text of the Initial Agreement, the Bolivian
Delegation explained the reasons why it considers that Chile has a historical
debt for the past use of the waters from Silala. The fundaments presented
refer to the verification of the change of object of use of the concession that was
originally intended for the use of water by steam locomotives, because from the
50s steam locomotives stopped being used and these waters were destined to
other uses not authorized by the competent Bolivian authority.
Likewise, the Bolivian Delegation explained that infrastructure works were
carried out in the area of the Silala springs in its territory that increased the
flow for other uses without Bolivian authorization.
In addition, the Bolivian Delegation pointed out that Chile regularized water
rights under the mandate of its Water Code of 1981, without considering the
existing Bolivian rights over the Silala waters.
Similarly, it was emphasized that the concession was revoked in 1997, notifying
the respective companies in the Chilean territory. It was explained that the
Bolivian Government tendered the Silala waters, establishing a new concession
in 2000 to the Company DUCTEC SRL, which issued the respective invoices
for the use of the Silala waters to the corresponding user companies,
2
200
recibiendo como respuesta la negativa de pago por instrucclones de la Cancillerla
chilena.
Por lo tanto la Delegaci6n boliviana senat6 que existen obligaciones por parte de
Chile respecto del uso de las aguas bolivianas del Sllala usadas en el pasado y
que estas deberlan ser compensadas econ6micamente ('deuda hist6rica").
La Delegaci6n chilena reiter6 su posici6n que esta contenida en el Artlculo 1 letra
b) del borrador de Acuerdo lnlclal respecto del 6llala o 611011. Par lo mlsmo, no
procede discutlr ni hacerse cargo de 10s planteamlentos y elementos expuestos
por la Delegaci6n de Bolivia, citados en los parrafos precedentes.
En esta perspectiva, y respecto del primer planteamiento de Bolivia, la Delegaci6n
de Chile expuso que no procede pronunciarse respecto de eventuates deudas que
pudieren existir con el Estado de Bolivia por uso de aguas del Silala o Siloli. En
consecuencia, la Delegaci6n de Chile se opuso a la inclusi6n de la clausula
transitoria sobre deuda hist6rica en el texto borrador de Acuerdo lnicial.
La Delegaci6n boliviana, frente a la negativa de la Delegaci6n chilena, senal6
entonces que Bolivia se reserva el derecho de utilizaci6n de las aguas de libre
disponibilidad bolivianas usandolas en su territorio o reconstituyendo las
condiciones naturales del area de los manantiales del Silala.
La Delegaci6n chilena consider6 que este planteamiento no se condice con los
prop6sitos que han llevado a la redacci6n actual del texto borrador de Acuerdo
lnicial.
Se adjunta como Anexo 2 la versi6n del texto borrador de Acuerdo lnicial del 1° de
octubre de 2010.
Como resultado del desarrollo de esta Reuni6n, ambas delegaciones, en orden a
continuar perfeccionando el referido texto borrador del Acuerdo lnicial, acordaron
efectuar la segunda parte de esta Reuni6n del Grupo de Trabajo sobre el Terna
Silala, a la brevedad posible, antes de la realizaci6n de la XXIII Reuni6n del
Mecanismo de Consultas Pollticas Bolivia Chile, sugiriendo la Delegaci6n
boliviana que esta se realice en el curso de los pr6ximos quince dlas.
Se convino que en la continuaci6n de esta Reuni6n participe tambien una
comisi6n tecnica compuesta por el Servicio Nacional de Meteorologla e Hidrologia
de Bolivia (SENAMHI) y la Direcci6n General de Aguas de Chile (DGA), para
avanzar en la definici6n de las cuestiones referidas a las especificaciones tecnicas
y metodol6gicas para la instalaci6n de las estaciones de monitoreo a que se hace
referencia en el Articulo 8 del texto borrador del Acuerdo lnicial. Para estos
efectos, la Delegaci6n boliviana entreg6 un borrador de cronograma con plazos y
fechas tentativas para la instalaci6n de las citadas estaciones, cuyo texto se
adjunta como Anexo 3 de la presente Acta.
D. Rogel Mattos
Por la Delegaci6n de Bolivia
D. Anselmo Pommes
Por la Delegaci6n de Chile
201
receiving as a response the refusal to pay for instructions from the Chilean
Foreign Ministry.
Therefore, the Bolivian Delegation indicated that there are obligations on the
part of Chile regarding the use of Bolivian waters of Silala used in the past and
that these should be economically compensated (“historical debt”).
The Chilean Delegation reiterated its position that is contained in Article 1
letter b) of the draft Initial Agreement regarding the Silala or Siloli. For this
reason, there is no need to discuss or acknowledge the proposals and elements
presented by the Delegation of Bolivia, cited in the preceding paragraphs.
In this perspective, and with respect to the first approach of Bolivia, the Delegation
of Chile stated that there is no need to rule on any debts that may exist
with the State of Bolivia for the use of Silala or Siloli waters. Accordingly, the
Delegation of Chile opposed the inclusion of the transitional clause on historical
debt in the draft text of the Initial Agreement.
The Bolivian Delegation, faced with the refusal of the Chilean Delegation, indicated
that Bolivia reserves the right to use Bolivian free-available waters by
using them in its territory or by reconstituting the natural conditions of the area
of the Silala springs.
The Chilean Delegation considered that this approach does not match the purposes
that have led to the current drafting of the initial draft of the Initial Agreement.
Attached as Annex 2 is the draft text of the Initial Agreement of 1 October
2010.
As a result of the development of this Meeting, both delegations –in order to
continue improving the draft text of the Initial Agreement– agreed to carry out
the second part of this Meeting of the Working Group on the Silala Issue, as
soon as possible, before the realization of the XXIII Meeting of the Bolivia-
Chile Political Consultation Mechanism, suggesting the Bolivian Delegation
that this be done during the next fifteen days.
It was agreed that in the continuation of this Meeting a technical commission
composed of the National Service of Meteorology and Hydrology of Bolivia
(SENAMHI) and the General Directorate of Water of Chile (DGA) should also
participate, in order to move forward in the definition of the issues referred to
the technical and methodological specifications for the installation of the monitoring
stations referred to in Article 8 of the draft text of the Initial Agreement.
For these purposes, the Bolivian Delegation submitted a draft schedule with
timelines and tentative dates for the installation of the aforementioned stations,
the text of which is attached as Annex 3 to this Minutes.
3
D. Rogel Mattos
For the Delegation of Bolivia
D. Anselmo Pommes
For the Delegation of Chile
202
Sin perjuicio de lo tratado respecto al tema de Silala y con relaci6n a los recursos
hfdricos compartidos Bolivia-Chile, las Delegaciones concordaron en la
importancia que para ambos parses representa avanzar en la identificaci6n e
inventario de dichos recursos.
Para eflo, la Delegaci6n de Chile sugiri6 proponer al Mecanismo de Consultas
Polfticas Bolivia-Chile la creaci6n de un Grupo de Trabajo, definiendo su nombre
en forma tentativa como "Grupo de Trabajo de Recursos Hfdricos Compartidos
Chile - Bolivia", con el objeto de hacer un inventario, avanzar en su conocimiento y
evaluaci6n y en una adecuada gesti6n de los mismos, en forma equitativa,
racional y sustentable, con pleno respeto a la naturaleza jurfdica de esos recursos.
Al respecto, la Delegaci6n boliviana mencion6 que considerara esta sugerencia y
se pronunciara durante la continuaci6n de la presente reuni6n.
A su vez la Delegaci6n boliviana solicit6 que respecto al rfo Lauca, se instalen
estaciones hidrometricas conjuntas en un plazo de ciento veinte dias.
Sobre el particular, la Delegaci6n chilena indic6 que considerara esta solicitud y
respondera durante la continuaci6n de la presente reuni6n.
La Delegaci6n de Chile agradeci6 las especiales atenciones recibidas de parte de
la Delegaci6n de Bolivia.
D. Rogel Mattos
Por la Delegaci6n de Bolivia
D. Anselmo Pommes
Por la Delegaci6n de Chile
203
Without prejudice to what was discussed regarding the Silala issue and in
relation to Bolivian-Chilean shared water resources, the Delegations agreed
on the importance for both countries to move forward in the identification
and inventory of these resources.
To this end, the Chilean Delegation suggested proposing to the Bolivia-
Chile Political Consultation Mechanism the creation of a Working Group,
tentatively defining its name as the “Chile-Bolivia Shared Water Resources
Working Group”, in order to make an inventory, move forward in their
knowledge and evaluation and in an adequate management of them, in an
equitable, rational and sustainable manner, with full respect for the legal
nature of those resources.
In this regard, the Bolivian Delegation mentioned that it will consider this
suggestion and will pronounce itself during the continuation of this meeting.
In turn, the Bolivian Delegation requested that, in relation to the Lauca River,
joint hydrometric stations be installed within a period of one hundred and
twenty days.
In this regard, the Chilean Delegation indicated that it will consider this request
and will respond during the continuation of this meeting.
The Delegation of Chile thanked the special attentions received from the
Delegation of Bolivia.
4
D. Rogel Mattos
For the Delegation of Bolivia
D. Anselmo Pommes
For the Delegation of Chile
204
ANEXO 1
VIII Reuni6n del Grupo de Trabajo Bolivia- Chile sobre el Tema Silala
30 de septiembre, 1° de octubre de 2010
DELEGACION DE CHILE
1. Anselmo Pommes
Director Nacional de Fronteras y Limites del Estado Subrogante
DIFROL - Ministerio de Relaciones Exteriores
2. Jorge Canelas
C6nsul General de Chile en Bolivia
3. Matias Desmadryl
Director General de Aguas - Ministerio de Obras Publicas
4. Eleodoro Pempelfort
C6nsul de Chile en La Paz
5. Carlos Ciappa P.
Direcci6n General de Aguas - Ministerio de Obras Publicas
6. Alejandro Ahumada
Direcci6n Nacional de Fronteras y Limites
DIFROL - Ministerio de Relaciones Exteriores
7. T.S. Pablo Selame
Escritorio Bolivia - DIRAMESUR
Ministerio de Relaciones Exteriores
205
ANNEX 1
VIII Meeting of the Bolivia-Chile Working Group on the Silala Issue
30 September, 1st October 2010
DELEGATION OF CHILE
1. Anselmo Pommes
Acting National Director of State Borders and Boundaries
DIFROL - Ministry of Foreign Affairs
2. Jorge Canelas
Consul General of Chile in Bolivia
3. Matias Desmadryl
General Director of Waters - Ministry of Public Works
4 Eleodoro Pempelfort
Consul of Chile in La Paz
5. Carlos Ciappa P.
General Directorate of Water - Ministry of Public Works
6. Alejandro Ahumada
National Directorate of Borders and Limits
DIFROL - Ministry of Foreign Affairs
7. T.S. Pablo Selame
Desk of Bolivia - DIRAMESUR
Ministry of Foreign Affairs
206
DELEGACION DE BOLIVIA
1. Rogel Mattos
Director General de Limites, Fronteras y Aguas lnternacionales
2. MC. Guadalupe Palomeque de la Cruz
Directora General de Relaciones Bilaterales a.i.
3. Juan Carlos Alurralde
Asesor del Ministro de Relaciones Exteriores
4. C. Mayra Montero
Jefe de la Unidad de Aguas lnternacionales
5. PS. Zandra Rodriguez
Funcionaria de la Unidad de America
6. Andres Vargas Zurita
Funcionario de la Unidad de America
7. Aquil es Arce
Director de Cuencas y Recursos Naturales, Viceministerio de Aguas
8. Luis Noriega
Director del Area de Hidrologia - SENAMHI
9. Jorge Bellot
Funcionario de SERGEOTECMIN
OBSERVADORES
Celestino Condori
Presiden Comite Civico Potosinista - CONCIPO
Daniel Berna
Honorable Alcalde de San Pablo de los Lipez
207
DELEGATION OF BOLIVIA
1. Rogel Mattos
General Director of Boundaries, Borders and International Waters
2. MC. Guadalupe Palomeque de la Cruz
Acting Director General of Bilateral Relations
3. Juan Carlos Alurralde
Adviser to the Minister of Foreign Affairs
4. C. Mayra Montero
Head of the International Waters Unit
5. PS. Zandra Rodriguez
Officer of the America Unit
6. Andres Vargas Zurita
Officer of the America Unit
7. Aquiles Arce
Director of Watersheds and Natural Resources, Vice-Ministry of
Waters
8. Luis Noriega
Director of the Hydrology Area – SENAMHI
9. Jorge Bellot
SERGEOTECMIN Official
OBSERVERS
Celestino Condori
President of the Civic Committee of Potosi - CONCIPO
Daniel Berna
Honorable Mayor of San Pablo de Los Lipez
208
209
Bolivia – Chile Diplomatic Correspondence
(Annexes 11 - 12)
210
211
Annex 11
Note Nº VRE-DGRB-UAM-018880/2011 from the Ministry of
Foreign Affairs of Bolivia to the General Consulate of Chile in
La Paz, 29 August 2011
(Original in Spanish, English translation)
212
ESTADO PLUR.INACIONAL DE BOLIVIA
MINISTERIO DE RELACIONES EXTERIORES
VRE-DGRB-UAM-018880/2011
EL MINISTERIO DE RELACIONES EXTERIORES - Direcci6n General de
Asuntos Consulares, saluda muy atentamente al Honorable Consulado General
de Chile y tiene a bien proponer realizar la segunda parte de la VII Reuni6n del
Grupo de Trabajo Bolivia - Chile sobre el Terna Silala pa ra el dla 12 de
septiembre de 2011, en la ciudad de La Paz, en forma previa a la XII Reunion del
Grupo de Trabajo sabre Libre Transito Bolivia - Chile del dia 13 de septiembre del
ano en curse, en atenci6n a la conversaci6n sostenida entre el Vicemin istro de
Relaclones Exteriores, Embajador Juan Carlos Alurralde y el Director General de
Palses Limitrofes en Asuntos Regionales, Embajador Pedro Suckel, el dia 11 de
agosto del alio en curse.
EL MINISTERIO DE RELACIONES EXTERIORES - Direcci6n General de
Asuntos Consulares, hace propicla la oportunidad para re iterar al Honorable
Consulado General de Chile las seguridades de su mas alta y distlnguida
consideraci6n.
Al Honorable
CONSULADO GENERAL DE CHILE
Presente.-
La Paz, 2 9 AGQ 2011
213
PLURINATIONAL STATE OF BOLIVIA
MINISTRY OF FOREIGN AFFAIRS
VRE-DGRB-UAM-018880/2011
THE MINISTRY OF FOREIGN AFFAIRS – General Directorate of
Consular Affairs, attentively greets the Honorable Consulate General of Chile
and wishes to propose to hold the second part of the VII Meeting of the Bolivia–
Chile Working Group on the Silala Issue for 12 September 2011, in the city of
La Paz, prior to the XII Meeting of the Working Group on Free Transit Bolivia–
Chile of September 13th of the current year, in response to the conversation
held between the Vice-Minister of Foreign Affairs, Ambassador Juan Carlos
Alurralde and the General Director of Border Countries in Regional Affairs,
Ambassador Pedro Suckel, on August 11th of this year.
THE MINISTRY OF FOREIGN AFFAIRS – Directorate General for
Consular Affairs, avails itself of the opportunity to reiterate to the Honorable
Consulate General of Chile the assurances of its highest and most distinguished
consideration.
La Paz, 29 August 2011
Stamp: MINISTRY OF FOREIGN AFFAIRS VICE-MINISTRY OF
FOREIGN AFFAIRS
To the Honorable
CONSULATE GENERAL OF CHILE
Hand Delivered.-
214
215
Annex 12
Note Nº VRE-DGRB-UAM-009901/2012 from the Ministry of
Foreign Affairs of Bolivia to the General Consulate of Chile in
La Paz, 24 May 2012
(Original in Spanish, English translation)
216
EST ADO PLURINACIONAL DE BOLIVIA
MINJSTERJO DE RELACIONES EXTERJORES
VRE-DGRB-UAM-009901 /2012
EL MINISTERIO DE RELACIONES EXTERIORES - Direcci6n General de
Asuntos Consulares, saluda muy atentamente al Honorable Consulado Gene~[ de
la Republica de Chile y tiene a bien hacer referencia a su Nota Verbal N° 199/39
rnediante la c,ual observa la informaci6n difundida por la prensa entorno al anunci~
efectuado por el Gobernador de Potosi, sef\or Felix Gonzalez, sobre la
construcci6n de una planta piscfcola en el naciente de los manantiales del Silala,
?omo el primero de tres proyectos de aprovechamiento de estas aguas, que
incluira ademas, la construcci6n de una represa y una planta embotelladora de
agua mineral para el 2013.
Al respecto, el Ministerio de Relaciones Exteriores reitera firrnemente y de manera
fehaciente que las aguas del Silala son nacimientos o brotes naturales de aguas
subterraneas que se originan y proceden de un acuffero o dep6sito subterraneo de
formaciones geol6gicas que fluyen a la superficie de modo natural, debida a la
erosi6n . de las rocas volcanicas y que afloran como rnanantiales o vertientes
dentro del territorio boliviano que no generan un cause, ni un curso natural, nl un
sistema que integre el agua a un cause de las riberas para formar un rio de curso
sucesivo.
En consecuencia, lo que la Republica de Chile denomina "rio Internacional" es en
sf, resultado del producto humano de canalizaci6n artificial de aguas, que de
manera natural, no hubiera podido ocurrir; motive par el cual, las vertientes del
Silala no pueden ser consideradas como rio internacional.
En este sentido, el Ministerio de Relaciones Exteriores reitera la posici6n def
G.obiemo de Bolivia manifestada en la "VIII Reunion de! Grupo de Trabajo Bolivia -
Chile sabre el tema del Silala", sin Acta suscrita, que se llev6 a cabo en la ciudad
de La Paz del 30 de septiembre al 1° de octubre de 2010, sobre la existencia de
obligaciones por parte de Chile respecto del uso de las aguas bolivianas de! Silala
en el pasado y que estas deberian ser compensadas econ6micamente ("Deuda
Hist6rica"), debido al cambio de! objeto de uso de la concesi6n que estaba
destinada originalmente al use del agua par locomotoras a vapor, las cuales
dejaron de ser utilizadas a partir de los aiios 50s, y de esta forma, pasando estas
aguas a ser destinadas a otros uses no autorizados por la autoridad boliviana
cornpetente.
Al Honorable
CONSULADO GENERAL DE LA
REPUBLICA DE CHILE
Presente.-
Calle Junin Esq. bgavi La Paz - Bolivia ·
Telefonos (591-2) 2408330 -2406884 -2408900-24091 J4 J?ax No. (591-2) 2408642 Email: [email protected]
217
PLURINATIONAL STATE OF BOLIVIA
MINISTRY OF FOREIGN AFFAIRS
VRE-DGRB-UAM-009901/2012
THE MINISTRY OF FOREIGN AFFAIRS – General Directorate of Consular
Affairs, very attentively greets the Honorable Consulate General of the Republic
of Chile and kindly refers to its Verbal Note Nº 199/39, through which it observes
the information disseminated by the press about the announcement made by the
Governor of Potosi, Mr. Felix Gonzalez, regarding the construction of a fish
farm in the source of the Silala water-springs, as the first of three projects for
the use of these waters, which will also include the construction of a dam and a
bottling plant for mineral water for 2013.
In this regard, the Ministry of Foreign Affairs firmly and irrefutably reiterates
that the Silala waters are natural groundwater springs that originate and come
from an aquifer or underground reservoir of geological formations that flow
to the surface in a natural way, due to the erosion of volcanic rocks and that
emerge as springs or streams within the Bolivian territory that do not generate a
channel, nor a natural course, nor a system that integrates the water to a channel
of the riverbanks to form a river of successive course.
Consequently, what the Republic of Chile denominates “international river” is
in itself, result of the human product of artificial canalization of waters, which
in a natural way it could not have happened; for this reason, the Silala water
springs cannot be considered as an international river.
In this sense, the Ministry of Foreign Affairs reiterates the position of the
Bolivian Government expressed at the “VIII Meeting of the Working Group
Bolivia–Chile on the Silala issue,” without a signed Act, which took place in
the city of La Paz from 30 September to 1 October 2010, on the existence of
obligations by Chile regarding the use of Bolivian waters of Silala in the past
and that these should be economically compensated (“Historical Debt”), due to
the change of the object of use of the concession that was originally destined
to the use of water by steam locomotives, which stopped being used in the 50s,
and in this way, passing these waters to be destined to other uses not authorized
by the competent Bolivian authority.
To the Honorable
CONSULATE GENERAL
OF THE REPUBLIC OF CHILE
Hand Delivered.-
Junin Street, Ingavi Corner. La Paz – Bolivia
Phones: (591-2) 2408330 – 2406884 - 2408900 - 2409114 Fax Nº (591-2) 2408642 Email: [email protected]
218
' ESTADO PLUl\lNACIONALPB BOUVIA
MINISTERJO DE RU.ACIONES 2XTERlORtS
Por tanto, se insta a la Republica de Chile a seguir avanzando en un
entendimiento comun para que el Grupo de Trabajo sobre la tematica de! Silala se
reuna nuevamente con el objetivo de conocer, analizar y responder, todas las
propuestas surgidas a raiz de! proceso de socializaci6n del Acuerdo lnicial, tal
como fue acordado en la ·xxu Reunion del Mecanismo de Consultas Politicas
Bolivia - Chile", celebrado en la ciudad de La Paz, de! 12 al 14 de junio de 2010.
De igual forma, tomando en cuenta que hasta la fecha no se hizo efectiva ninguna
visita de campo al terreno, se invita una vez mas al Gobiemo de Chile, a realizar
una "Visita Conjunta" a dicha regi6n, previa elaboraci6n de una Agenda Tecnica
que considere las temporadas de estiaje, tal como fue manifestado por la
delegaci6n de Bolivia en la reunion sostenida entre autoridades gubernamentales
de ambos paises el 13 de septiembre de 2011.
Finalmente, el Ministerio de Relaciones Exteriores en concordancia de la cultura
de dialogo que caracteriza al Estado Plurinacional de Bolivia manifiesta su
predisposici6n de continuar explorando las instancias necesarias que conduzcan a
un entendimiento comun para seguir avanzando en el tratamiento de! tema.
EL MINISTERIO DE RELACIONES EXTERIORES - Direcci6n General de
Asuntos Consulares, hace propicia la oportunidad para reiterar al Honorable
Consulado General de la Republica de Chile las seguridades de su mas alta y
distinguida consideraci6n.
La Paz, 2 4 MAYa 2012
Calle Iwiin Esq. lngavi La Paz- Bolivia .
Telefonos (591-2) 2408330-2406884. 2408900 •2409114 Fax No. (591'2) 2408642 Email: [email protected]
219
PLURINATIONAL STATE OF BOLIVIA
MINISTRY OF FOREIGN AFFAIRS
Therefore, the Republic of Chile is urged to continue moving forward in a common
understanding so that the Working Group on the Silala issue meets again
with the objective of knowing, analyzing and responding, all the proposals arising
from the process of socialization of the Initial Agreement, as agreed in the
“XXII Meeting of the Political Consultation Mechanism Bolivia–Chile,” held
in the city of La Paz, from 12 to 14 June 2010.
In the same way, taking into account that no field visits have been carried out to
date, the Government of Chile is once again invited to carry out a “Joint Visit”
to that region, after drawing up a Technical Agenda that takes into account the
dry seasons, as it was manifested by the Delegation of Bolivia in the meeting
held between governmental authorities of both countries on 13 September 2011.
Finally, the Ministry of Foreign Affairs in accordance with the culture of dialogue
that characterizes the Plurinational State of Bolivia expresses its willingness
to continue exploring the necessary instances that lead to a common
understanding to continue moving forward in the treatment of the matter.
THE MINISTRY OF FOREIGN AFFAIRS – Directorate General of Consular
Affairs, on this occasion reiterates to the Honorable Consulate General of the
Republic of Chile the assurances of its highest and distinguished consideration.
La Paz, 24 May 2012
Stamp: MINISTRY OF FOREIGN AFFAIRS VICE-MINISTRY OF
FOREIGN AFFAIRS
Junin Street, Ingavi Corner. La Paz – Bolivia
Phones: (591-2) 2408330 – 2406884 - 2408900 - 2409114 Fax Nº (591-2) 2408642 Email: [email protected]
220
221
Bolivian Official Documents
(Annex 13)
222
223
Annex 13
Bolivian Supreme Decree N° 24660, 20 June 1997
(Original in Spanish, English translation)
224
G A C E T A 0 F I C I A L D E B O L I V I A
DECRETO SUPREMO N° 24660
GONZALO SANCHEZ DE LOZADA
PRESIDENTE CONSTITUCIONAL DE LA
REPUBLICA
CONSIDERANDO:
Que el Prefecto del Departamento de Potosi, ha revocado y anulado,
mediante Resoluci6n Administrativa 7 I /97 de I 4 de mayo de 1997, la concesi6n sobre
uso y aprovechamiento de aguas de las vertientes del "Silala" (Siloli), que la
mencionada prefectura otorg6 a la compafiia "The Antofagasta (Chili), and Bolivia
Railway Company Limited", exclusivamente para alimentaci6n de sus locomotoras a
fuerza de vapor, mediante proveido prefectural de 21 de septiembre de 1908, elevado
a rango de escritura publica bajo el No. 48/ 1.908, y otorgada ante el Notario de
Hacienda de Potosi, e inscrita en el departamento de Derechos Reales, bajo la partida
3, foja 3 vuelta del libro segundo de hipotecas de la Provincia Sud Lipez, en fecha 28
de octubre de 1908;
Que la Resoluci6n Prefectural, se justifica plenamente con la desaparici6n
del objeto, la causa y la finalidad de la concesi6n temporal del uso de las aguas, por
factores sobrevinientes decisivos, tales como la conversion tecnol6gica de las
locomotoras de la empresa concesionaria, eliminando su necesidad de agua, para la
fuerza de vapor que -antes las impulsaba, a lo que debe aiiadirse la inexistencia de la
propia concesionaria como persona colectiva en actividad en el territorio boliviano;
Que se ha evidenciado el aprovechamiento indebido de dichas aguas por
terceras personas ajenas a la concesi6n de su uso, con perjuicio para los intereses del
Estado yen clara infracci6n de los articulos 136 y 137 de la Constituci6n Politica del
Estado;
Que corresponde al Poder Ejecutivo cumplir y hacer cumplir las
resoluciones de organismos estatales como las prefecturas, en una correcta exegesis
<lei articulo 96 numeral 12 de la Constituci6n Politica del Estado.
EN CONSEJO DE MINISTROS
DECRETA:
ARTICULO UNICO.- Elevase a rango de Decreto Supremo la
Resoluci6n Administrativa 71/97 de 14 de mayo de 1997, dictada por el senor
Prefecto del Departamento de Potosi.
- 2 -
225
O FFICIAL G AZETTE O F B OLIVIA
SUPREME DECREE Nº 24660
GONZALO SANCHEZ DE LOZADA
CONSTITUTIONAL PRESIDENT OF THE REPUBLIC
CONSIDERING:
That the Prefect of the Department of Potosi has revoked and annulled,
through Administrative Resolution Nº 71/97 of 14 May 1997, the concession on
the use and exploitation of waters from the “Silala” (Siloli) water-springs; that
the aforementioned Prefecture granted to the Antofagasta (Chili) and Bolivia
Railway Company Limited, exclusively for powering its locomotives by steam
power, through prefectural provision of 21 September 1908, raised to the rank
of public deed under Nº 48/1.908, and granted before the Finance Notary of
Potosi, and registered in the Department of Property Law, under heading 3,
page 3 of the second book of mortgages of the South Lipez Province, dated 28
October 1908;
That the Prefectural Resolution is fully justified with the disappearance of
the object, cause and purpose of the temporary concession for the use of waters,
by decisive supervening factors, such as the technological conversion of the
locomotives of the concessionaire company, eliminating their need for water,
for the steam power that previously propel them, to which must be added the
non-existence of the concessionaire itself as an active corporate in Bolivian
territory;
That there has been evidence of the improper use of said waters by third
Parties outside the granting of their use, with prejudice to the interests of
the State and in clear violation of Articles 136 and 137 of the State Political
Constitution;
That it corresponds to the Executive Power to comply with and enforce the
resolutions of State agencies such as the Prefectures, in a correct non-existence
of Article 96 numeral 12 of the State Political Constitution.
THE CABINET
DECREES:
SINGLE ARTICLE.- Raise to the rank of Supreme Decree the
Administrative Resolution 71/97 of 14 May 1997, issued by the Prefect of the
Department of Potosi.
2
226
NR 2008 GA CE TA OF IC I AL D E B O L I V I A
Los seiiores Ministros de Estado en los Despachos de Relaciones
Exteriores y Culto, Gobiemo y de la Presidencia quedan encargados de la ejecucion y
cumplimiento del presente Decreto Supremo.
Es dado en el Palacio de Gobierno de la ciudad de La Paz, a los veinte de
junio de mil novecientos noventa y siete aiios.
FDO. GONZALO SANCHEZ DE LOZADA, Antonio Aranibar Quiroga, Victor
Hugo Canelas Zannier, Alfonso Erwin Kreidler Guillaux, Jose Guillermo Justiniano
Sandoval, Rene Oswaldo Blattmann Bauer, Fernando Candia Castillo, Franklin Anaya
Vasquez, Moises Jarmusz Levy, Jorge Espana Smith, MINISTRO SUPLENTE DE
TRABAJO, Mauricio Antezana Villegas, Alfonso Revollo Thenier, Jaime Villalobos
Sanjines.
DECRETO PRESIDENCIAL N° 24661
GONZALO SANCHEZ DE LOZADA
PRESIDENTE CONSTITUCIONAL DE LA
REPUBLICA
CONSIDERANDO:
Que el Dr. Antonio Aranibar Quiroga, Ministro de Relaciones Exteriores y
Culto, debe ausentarse del pais a la ciudad de Quito-Ecuador, para asistir a la Reunion
de Cancilleres del X Consejo Presidencial Andino, la misma que se realizara del 24 al
26 de junio de I 997.
Que de conformidad a lo dispuesto por el articulo 12 de la Ley 1493 de 17
de septiembre de 1993, es necesario designar al Ministro suplente para la continuidad
administrativa del mencionado Despacho de Estado.
DECRETA:
ARTICULO UNICO.- Designase Ministro suplente de Relaciones
Exteriores y Culto, al Emb. EDUARDO TRIGO O'CONNOR D'ARLACH,
Secretario General Nacional, mientras dure la ausencia del titular.
Es dado en el Palacio de Gobierno de la ciudad de La Paz, a los veinte
dias del mes de junio de mil novecientos noventa y siete aiios.
FDO. GONZALO SANCHEZ DE LOZADA, Fdo. Jose Guillermo Justiniano
Sandoval.
- 3 -
227
N° 2008 OFFICIAL GAZETTE OF BOLIVIA
The Ministers of State in the Offices of Foreign Affairs and Worship,
Government and Presidency are in charge of the implementation and fulfillment
of this Supreme Decree.
It is given in the Government Palace of the city of La Paz on the twentieth
day of June of one thousand nine hundred and ninety seven years.
Signed by GONZALO SANCHEZ DE LOZADA. Antonio Aranibar
Quiroga, Victor Hugo Canelas Zannier. Alfonso Erwin Kreidler Guillaux, Jose
Guillermo Justiniano Sandoval, Rene Oswaldo Blattman Bauer, Fernando
Candia Castillo, Franklin Anaya Vasquez, Moises Jarmusz Levy. Jorge España
Smith, ACTING MINISTER OF LABOR, Mauricio Antezana Villegas.
Alfonso Revollo Thenier, Jaime Villalobos Sanjines.
[...]
3
228
229
Press Articles
(Annexes 14 - 16)
230
231
Annex 14
El Diario, “The Silala is not a matter of discussion” for Chile,
La Paz, 28 May 1996
(Original in Spanish, English translation)
232
The concession was renewed, according to the Chilean Vice-Chancellor
The Silala “is not a matter of discussion” for Chile
Concesi6n fue renovada. mun Vicecanciller chileno
El Silala "no es on tema de discusi6n" para Chile
!l.'>. t1C1iilc.cl J)®l<mliorddolviodcllfoSil~1yb111illnciOnlk• ~ IUI 11'11('1 un l!0DIO - rlGdrinno boliviano y U cmpttSa
,a,'lffllmq,,,~6 .. ,lt.lij,,o pmniso d<lap,,rt<tUnpolO!iN.
""""''" ti ,,c,m.,cillrr\-tulrnoMmft fcnmdn.
s.,l"n cl Jipl.ir.ill,-o ·<:"-~ tludil) ttrrrint I 11111 Clffi .. l tomj)(n•
ixi&I por tl ll!Od< mls.k 100 ,t,osd< •1"1dukt••tl pmni!o<Oft b
,mp«sa h«td.'I> d< lo! primc!OI d<tt<hos «didoi • la -Tot
~-Bol~ian Rlil•.,.-. fuc ttoovai!o ksalmrncc.
F<mi.,Jcz 1bori!.\ tl 1tm1tn iomu mlusi11 ton EL DIARIO y pudO
:k.lvtn:nt q~ lt ~b ! l:s:>l.) p"1 la ClffilWiibd d< hact,lo, pudtO
1••~lcn 11>1nOit)6~, p:nu,,10docum!oorigirwde<OC1CCSi6n
•. ,llS \ ffl lffitN.
·o,,;,.,,;s-i:n:n:, r< un ~ ltnu de OfflpttSll y <OftCtSi6n de 1g11>1•
rc11M11'1)., Lr l<X'I II Gco:ttrio bo!iYi2no o al uiburlll <Oftlptltnlt dcl
lu11111 t11l bitno M, l1 «lO<t!idftde ,iua. Nors un ttma pollli<o".
En r,:ncip:o. dest,,6 ~" sr l~bitn p(Oducido un dcs•lo dcl cautc
,11,1,1.m l de lo! =.twos o st hub'.tr, p:,pcu>do un uso ikg,1d cl
"HI) UIII <Olffli6:i dd '!"• <OOkrid, ltJ~11•n1t por cl ~
bol,-,.,. cn 141 lf""L 190i, 1 l1 Bolivian Railw,y Comp1ny, quc ha
lido asadc p0llttl0mltntt por b! rmptt11S qat hall lon\ldo ti nombft
lnl<f .. dc l1 BolilWI lwl-1)' . 1<IJ!6.
F<:nl.-.cc, :>:;6 la posibiiid>d de 'l"' cl pmnil<l no futra ttnovado.
ins la ~i6o le b p:imo cmprw qur Jo¢ cl bcnrr~io.
~ Yi<t,111(11!,r 111011:6 U., d0a:==:o y ky6. I ttqattimicft10 de C!IC
diltio ~JUOOS pln>fos: •q,,c la Cltllllltl de~ y <Oftli.
guitn1e ldminiwxi6n quc rue en las vcnitnlCS del •im dcnominad>
Silall.rxb1tn1e1cn larompttnsi6ndelnnr6nquc rione la p!O'lint~dc
Sud Lipe, dc t11t 11<pwment0, lo oror,a cl prerecto <Jon Renl Calvo
AtW en su <anct<1 de suporint<nd<n" d< hacienda del dcpwmcnro
en fav«de la Coolpo'lb Cl,ikna Bolivian COffll)Olly limiuda".
Apg6 q11e cl mismo documeMIO rue SUStriio en b cN'dad de 1'01osl.
cl ll!ode 190S.
•Sc hizo la <Ol'l((li6n de ,iuas. la rompallla fC1T11<arikr.1 IOd:lvla
>dminiw., el ,iUJ. ""' pw del asua <Iii dcslinada. stJlln la misma
~-alcoosumommano", 10S1uvo.
HISTORIA DE SUCESIO~ES
Scpn F<m!ndcz. la conc,si6n tu\'O la virlud de IOfflll en u1ili1.1blcs
bl •:u.squc sc pcnllan •sin bcnrr~io pora nad~·.
·Yo no soy ll<nicocn asuas ni cs mi r,ma. pen, sl le pucdo dc<ir lo
si:uitnt, • .,, hly ""'CUCS1i6n enrrt una cn,prcsa. uno conccsi6n de
,aua de una cmprcsa translcrida 1ot1hn.111t , suc,sivas tmpr,ill quc
hln comprado los paarimonios de cmpr,us anttriotts, OIO!Jadas ltJ•I• ! ':.i::. cl gobicmo boliviano y cxplorldas l<t'ln los tbminoi dcl
Mis ujanre .On, cl V,cccancillcr tte1k6QU1 cl ca,o, pora tl gobicmo
de Cl,ik. ·no cs un rem1 de diS<USi6n",
·vo k cstoy dando una cxplkx i6n <Oftt<di6 II COl!CSpoMOI de <SIC
moMino-, porquc ul1Cd ~gunta: pen, cstc es "" - cnuc una
cmpinayclgobicmobohvianosobctw~de1JU&!".
"BOFEDALES"
Oesdc cl punro de vilta thikno. Fcmlftdcz dio una descripci6n de la
Concesion fue renovada. se~un Vicecanci/ler chileno
zona del no Silala 1. sus vtftitn!C$:
·Sc mu de an n)On quc earn (las i.-uas) y QUI no ritncn OIIO uso sl
no ie cwliun _si no, st pltrdcn en bofcd,Jcs. No vivt nadit, no lo
uriliu nadit, ,su hc<hl la cootesl6n . .", dip sin lk: ar a coovt nrcr
iobcecljuMir~arivo.
Mis adcllnic rciter6 que cl problcma de uno Cl'<Mual compcnsad6n
pot ti USOccnltnariode Ill ,;uas. cstudior!t ll)n pot la Canrillcria boli·
viw. sc reduce a 11111 oegotoaci6n <Oft la 9Cfllll tmptt!> quc dcl,nra cl
IUpUCSIOpmDilo.
·No hly mls.La cmp!t$111,ti usodel Cjtttkio kitrimo de S<lldctt•
chos dOnd< ~ ,1 gobkmo boliviano", ldvini6.
Dip QUI la SUCCSOr.1 de ta ,mJtua tmJ)tt$1 rcmwiaria sr dcnomina
•fcrrocaril de Alltol,iasu I La Paz. o ,1,0 asr. Es una cmptt!> pri,
,·Illa, ttmarc6 sin menriolllr a la compa/111 CNz Bl«~ quc foe la quc
dio los pcnnisos poraquc sus ~ incut1ionltan en 1, rronrer,
l>olivian,, en lo! alttdcdo<cs dcl SiLlla. pm limpi,r los canalcl de
desvixi6n.
Rcspttto de las obns civik1 <OftSINidas tt<kntc men1, y 9uc consolidan
cl ikgal dorninlo chikno de las aguas pora abasltt1m~nto de 11
pol>lati6n civil y no par, las Jocomocoru, el diplomll lco s6lo at,n6 •
dc<ir.
·Yo no rcngo lllda quc l'CI <Oft ti rema. csta cmpresa. Clllndo 101116 la
~dcl ap. loqoc hizofl>Cqoccnm depctdtnecn bolodaltS
SC hkic!on sendcros de picdn plll quc cl a,aa corrim dew mancn
ndsO!Jllli:>da.~dehact...cholicmpo".
El Silala "no es un tema de discusi6n" para Chile
233
For Chile, the problem for the Silala River
diversion and the illegal use of its waters is a
matter between the Bolivian Government and
the railroad company that inherited an old
permit from the Potosi prefecture, argued the
Chilean Vice-Chancellor Mariano Fernandez.
According to the diplomat, who avoided
referring to an eventual compensation for the
use of more than 100 years of fresh water,
the permit with which the company inherited
the first rights granted to “The Antofagasta–
Bolivian Railway,” was renewed legally.
Fernandez addressed the issue exclusively with
EL DIARIO and it could be noticed that he had
prepared himself for the eventuality of doing it,
since paper in hand he read an alleged original
document of concession of the springs.
“It is definitely a problem of companies and
water concessions, he noted. It is up to the
Bolivian Government or the competent court
to determine if it is okay or not, the water
concession. It is not a political issue.” In
principle, he ruled out that an illegal use of
water had been perpetrated.
“There is a concession of water, legally conferred
by the Bolivian Government in its time, 1908, to
the Bolivian Railway Company, which has been
subsequently used by companies that have taken
the previous name of the Bolivian Railway ,”
he said.
Fernandez denied the possibility that the permit
was not renewed, after the disappearance of the
first company that achieved the benefit.
The Vice-Chancellor showed a document and
read some paragraphs at the request of this
newspaper: “that the writing of concessions and
P3t~ Chil , d ~ (kl no Sil~a y la ulilla:IOn lk•
,: ~ u. quas . el ~erM bol~lano y la cmpmn r~ \'311'11 · pnm1so de la prercaura p.11oslna,
el, Mm Ftmindez.
cl J ~ ttfcrirsc a una cvcn1ual compcn• ~ioo pore . wsde agu2 duke .. cl ptnndOCOll b
e ·rneroi dercchos ccdidos a b 1bc
, fuc rcnovado ~galMc,
F mlusiv2 c n EL OIARIO y pudo
pm 13 C\'Cnlual~ de hrtrlo, puCSIO
, unto dc,:umtn(o ori;itlll de c«ffl~n
•,'
· ,. cnu de em~ y COIICC$i6n t ogim•
re . bo!ivi3no o ml lribu~ com~tlllc dcl
I i6n dusua. No cs un 1cma pollliro~.
En r,:r,:i hu ~ra proo ido un de vlo del c~
113lural J hu : ~ ~~undo un USO llcg I del
aiui
k11lmen1 p« cl gobicmo
Railway Company, que ~
tmpms quc han 10mm cl nombrc
I ,St !6,
Fe . de q cl permi~ no f ira rtno,•ado,
. · i6n c b ~mera cmprcs3 quc logr6 cl bcncr~io.
~I ~~mcillcr •~UA~ l le)'6i a ~micn1odc cst.c
dwio ~gunos pmfos: -~ b ~ntuta de ~ y COI\SI•
234
consequent administration that was on the water
springs called Silala, existing in the understanding
of the canton that has the province of South
Lipez of this department, is granted by the Prefect
Mr. Rene Calvo Arana in his capacity as Superintendent
of Treasury of the department in favor
of the Chilean company ‘Bolivian Railway Company
Limited.’”
He added that said document had been entered
into in Potosi city, in 1908.
“The water concession was made, the railroad
company still manages the water, part of the water
is destined, according to the same concession, for
human consumption,” he said.
HISTORY OF SUCCESSIONS
According to Fernandez, the concession had the
virtue of making use of the waters that were lost
“without benefit for anyone.”
“I am not a water technician nor is my subject,
but I can tell you the following, here is a question
between a company, a water concession of a company
legally transferred to successive companies
that have purchased the assets of previous companies,
granted legally by the Bolivian Government
and exploited according to the terms of the
agreement.”
Even more emphatic, the Vice-Chancellor stressed
that the case, for the Government of Chile, “is not
a matter of discussion.”
“I am giving an explanation –granted to the correspondent
of this newspaper– because you ask: but
this is a topic between a company and the Bolivian
Government about a water concession.”
“BOFEDALS”
From the Chilean point of view, Fernandez gave a
description of the
gu~mc mln~oi ~ rue en las \tnicn~ dcl agUl dcminada
Silal , e~ 1en1es en lrnxn11ttn i6n del can16n quc lknc ~ ~incl1 de
Sud LI~ Ile tttc •mcn10, lo 0101'11 cl p-cfCCIO don Rcrt Calvo
Arw en SU Meler de supcnnicndcnlc de ht:~004 (kl dcpanamen10
en favor deb COO!paftla Chilcna B~ivbn CMi~1 limlw!a",
Agreg6 quc cl ml mo ~umcnnlo rue susaiio en 13 ciudad do Polo~1
cl 31',) de 1008,
"Sc hiro ~ COl'l(C i6n de aguas, la (Mlpahl3 f cnu3tllCIQ 1odavla
adminiSlta cl oi~ una pane dcl asua c.ui deslinada. se1~n 11 mi~
conccsi6n, al •mo mmano", SOS1uvo,
HISiORIA DE SUCESIOXES
Sc~n Fem~ I~ conccsidn 1uvo ~ vinud de 1m en u1iliz:bks
bs ;uas quc f.c l)erdl~" in bcncr(io ~ nad~",
·Yo no soy 1knico en ag~ ni cs mi 1cma. pcro sl le ~ dccit ~
siguicn1c, ac, hay una CUC$1i6n cn1re un.2 cmprcsa, una CM;esi6n de
agua de una cm~ 1rwfmd1 kgalMlt ~ s«esivas emprcsas que
han mp,ado los palrimonlos de cm~ an1~. 01cq• kgal•
men1c ~ cl gobffl boliviano y explffld sun los lmninos (kl
CooYCnlO'',
M4s 1a~1c ~n. cl Viccm,:illcr r«alc6 quc ~I caso, 1)3111 el ,oo~mo
de Chile, ·no cs un 1cm3 de dlscu ~n··.
"Yo ~ c~oy dando u~ cxplkxidn con«dl6 al co,m~onsal de cs1e
tNMino-, potqllC uslCd ~1unia: ~ C$1C cs un lfflll Cftltt UM
cm~ y cl gob~ bohviano sobro w ~ de ,gua.,~.
'10FEDALEr'
~ cl punlO de visu chi~noi ~ d~ Un3 ~idi, de ~
235
area of the Silala River and its springs:
“It is a ravine from which waters that would
be useless if they were not canalized fall... and
that have no other use if not canalized... if not,
they are lost in bofedals. Nobody lives there,
nobody uses it, the concession is made...”, he
said without convincing about the justification.
Later he reiterated that the issue of an eventual
compensation for the centennial use of the
waters –still studied by the Bolivian Foreign
Ministry– is reduced to a negotiation with the
current company that holds the alleged permit.
“There’s no more. The company will make use
of the legitimate exercise of its rights where it
corresponds to the Bolivian Government,” he
warned.
He said that the successor of the old railway
company is called “Railroad from Antofagasta
to La Paz or something like that.” It is a private
company, he noted without mentioning the
company Cruz Blanca, which was the one that
gave the permits for its workers to venture into
the Bolivian border, in the vicinity of Silala, in
order to clean the diversion canals.
Regarding the civil works recently built and that
consolidate the illegal Chilean dominion of the
waters to supply the civil population and not for
the locomotives, the diplomat only managed to
say:
“I have nothing to do with the subject, this
company, when it took the water concession,
what was done is to prevent these waters from
being lost into wetlands by building rock-canals
for the water to run in a more organized fshion.
These paths date back long ago.”
%4fta del no Si~~ r, SUS ven~nltt
11Se 1ra14 de un ca~ que cacn (las 1gu1 ) y quc no 1~ncn oiro u o sl
no sc c1n1liun ... sl noi sc pltrdcn en oorcd3fos. No vivo ~~le, no ~
u1iliu n~~. c~4 heeh1 la CMCosl6n .. .''. dip In l~iar I convcnetr
sobre cl ~~lnca1lvo,
M~ llel&n~ rci1~r6 quc el pw~ma ~ una oven1ual comptnsac~
~el USOCtMCl!Pdc las ,uas. CSludilaalln p« la Canclllerfa boo·
Viana, SC. a UN ncgociacl6n ~ la t:IU41 Cffllffll quc dc1enia cl
SUPJC$!0 perm~
"No hay mt u cmpresa hri uso dcl c~rck~ ~gl1imo de ~ trc•
chos dondc ~ :I gob~mo bolivianoi'i advlni6,
Di~ quc la~ de I~ an1~u.1 cm~sa (crroviria sc denomiiu
"Fefl'C(aril de An1of ogas1a a La P1~ o olgo if\ Es una emprc~ ~·
vad2, ~•6 ~n mcncion3r a la compaftla Cruz Blw-a, que (uc ~ que
dio loi pcrmisos para quc sus ttabajadorci incursionw en Im (ron~~
bolivlana, en I alrtdcdort dcl Silnla, para limpinr los ~wks de
dewir,:ioo,
Rcspcc10 de las ooras cM~ con~lnlld rc<kn1cmen1c y quc coruo,
lidan el l~gal domin~ cMkno de las guas pam abas1«1mlen10 de 11
~laci~ civil y no para las locOIIIOloras, cl diplom!llto s61o 11ln6 a
d«ir.
KYo no 1cngo ~ quc vcr con cl 1cma. csia em~rc", cuando lom6 la
~ti agua. ~~ hizo file~ en vci de perdenc en bofcdalc$
sc h~icronSCftdctosdc pim pan quc cl ~uamde una -,a
nwcqaiim Oal&ftdc ~ mucho1iemPo1
,
236
237
Annex 15
El Mercurio, “Clarification from the Chilean Chancellery: There
is no conflict with Bolivia over the Silala River”, Santiago,
17 May 1997
(Original in Spanish, English translation)
238
BlbUoteca del Congreso Naclonal
EL MERCURIO
P6gino ~ ---F-e--cha_;. t ~10-\9·~-7- •I ~I Ublcacl6n del recorle _ - -----
Cotumno
PRECISO CANCILLERIA CHILENA:
No Hay ConfJicto con
Bolivia por Rio Silala
Mariano Fernandez explic6 que decisi6n boliviana
de poner fin a una concesi6n de aguas
de ese curso a una empresa chilena es un tema
que corresponde resolver segun las normas
de los contratos internacionales.
El coblerno ehileno prccfa6
nnocbe qu.e no ex-lste nJ~un.a con•
t.roYen.ia c-on el «oblerno de BolivJa
ce.apecto dcl uso de las ac,uas
cl.el rlo SUala que abastecen a po•
blaclone.s del norte de nueatro
fc~~ ! ~e~~~~:!,';! d~ 1:i:'r::.!~6 :r~:
dT~uli~!:ren::~~'!~.-!•,.;!~~ debe
UC tt;:• i::.:~~~~~6~:~.!:i!f ~~
iota.sf decidi6 poner t~rmlno • la
conet!!sf6n tle o~as q,uc 30 cntrega ::t1: ~!1e;::r~~:r'i,1~: 'it,'igro:
eosta.
SegUn precls6 el Minisll"O subroc:
anle de Relocionos Exterlores.
Mariano l-.... ern4ndez. csto es un
~ontrato de dcrccho privado lnlcr-
~;1i:;'d~ ro::: ,}: :;::::~a:~=~•c has
En ese scntldo. agrcg:6 corros•
ponde • la Comp11Afa dt:1 FerrocorrH
Antofacosla-Rolivia cntrar en
contacto c.on qulen otore6 la con•
cc•l6n p•r• ver de qu~ manera .se
slaue adelanto en esc.e punto .
.. Por ahorA yo tcugo quc dccir
(lue no cxlste controver.5,la ontre
cl aoblcrno botlvinno y cl chllcno
en est.a rnntorla. El c6nsul ,::eneral
d~o•r C hile en Lo Poz.. embnJador Os• Fuentes. ha tcnldo ~ootacto n:r.<.,T~i:f:r c+Jl~~c;r:,~~~rc!::
tact.cs squlrAn el fune.s P•-ro pre•
ci•ar exactamente la situacl6n
que ha ocur-rldo en la zone••.
Doslac6 ')UC cs important• en
todo coso tener en c-uonto quc cl
rfo SUala es un cur&o internacional
de acu a QIM: se rigo por la• leyes
inte.rnocionalca sobre osta motcda.
de tat mAncro que sl no sc
olterara cl discurrir ru:aturel cJc los
os,uns de un pats n Olro ••esto no
~r:°c::t;~rpr:i:~3~se qu~~a t'!~~~x..,:,~_;
rc:cularsc de acucrdo a las lcycs ...
SegLln l-"'ern4ndoz~ si pcrsisticron
dircrcncins de opinidn Que PU•
dfcran en ol£'1n n,omento poruirr>
ar cJ ttuJO nutu1·nt <le ngun. porllcularn,
e:nle n Jos rfo.s Sun Pedro y
Loa en Chile "me fmagino QUO OtiUmaren,
os ncccsArlo con cl go--,
biorno bollvlano discutir alc-Gn tipo
de tts:,imen de ocua mU prcclso
con el objolo de evltar altarac:
loocs de cunlqulcr cor6ctcr"'.
cla ~0s~~~.~~~ v7>~9«:~ ;!~,!:d•ago~:;
La Pat. las outorldndcs bollvJo.nos
Anularon un contreto quc porrnttfa
abastecer do •.-..• do un surcno ~:s ~ ~r.:..·.': rnr:;;~•1.:;--,,':'''"~•nto
d1::"1f:~~c~•:t:1:e.:1d~,!'t'i:c-:.'~r;
concesi611 do los ns:n•• del rfo Sllaln.
que crnn uliliz.ndos pu1·u cl
nbastcchnicnto do las pohlocloncs
~.~rfo0 ~'!:'"!f:-aS::iu~C:~cc:,,rc.i~tc;:
mairon la$ autoridades rcgionmles.
cl1·•o'f1n~r:~r3!d ~~.fi'l!~'ke1~s'!r~~=
eiOn. Oac»T Manz.ano,. dljo que la
re.solucl6n "dcbc ser rarrendada
por unn comunicacidn ol'icial de la
!C:::atn2c.. U•l crf• de La raz a ID de San• Chilo " la CnlA)'Or) breve-
Monz.nno nnot6 quc In dccisi6n
sc dcbJ6 n quc no hny .. motivaaciones
y raz.oncs para quc •e ma.ntCJna:~
la menclooada conccai6n,. otorgadn
hace 89 at\os a la cmpresa fcn-
oviaria The Aotofoa:asta and Bolivian
R:aHway Compony. quc on Ja
actualldad ya no ex1st.o••.
Las aa:uos dol Sllala son reoolectada.
a en un reservorlo de .edi-
=~gt:::;\~~Jo ~:S:'e':-rf::..rn!.u~i/!n~
para lncrcsar a los slstomas de
ngua pot.able que oba•to.cen a alf:
s°:~t~~~f!!'t!ilvf:n::_ucrdo a
El rlo Siloli. conocldo como Silula
en nucslro _pol•. pcnctra a
Chilo dcsdc Bolivu, a ◄ liil6nu:?tros
nl sur dcl cerro Jn11ct1liri -ubiCJtdO
a unos 300 kil61netros al no!"'
Cslo de Antofacasln. aobre la
~~:n~4;_';,~ {lt~~:~~0 f.1:s~1fic::;
cc>mo nnucntc cJel rfo lnncaltrl. al
cunl •urtu cou un c.:uud•I total de
2.50 lttros flor sea.undo.
.Jaime Andrade. ccrentc de
A$Unloa Pdblico.s de Codclco--Chuqulcamala.
rec:onoc:16 que las
oduccloncs de •cu• do la cmpreaa
con.sldernn ol caudal dol ln.ace1liri. :~~~'I::: :::::!i6 ~'t:,~!.~'J~~:!r~e=
que so consumca crandcs canlldodes
do Uqutdo. en un ranco de una
tonclodai de snlncral por una de
ag:ua.
En tanlo. en In En.1prosa de
Servicios Sonilarios de Antoragnsln
S .A ~ <E••an>, de:11oat!moron un
cl'cclo ncicativo sobrc cl sumlnlsl\•o
que onlror.o.n n lo 1>oblocl6n clc Ins
ri'it'!;,l~ ~,:;tp=~~ "~:~1::::,:cc~~
~•~-;.•:;n -i:::h1d~ 1:o& n~l1!~•~~.~-is.quo
239
National Congress Library
El Mercurio [newspaper]
Date: 17 May 1997
Page: 20
Column: 5
Location of the clipping
Clarification from the Chilean Chancellery:
There is no conflict with Bolivia
over the Silala River
Mariano Fernandez explained that the Bolivian decision to end
a water concession of that watercourse in favor of a Chilean
company is a subject that must be resolved according to the
rules of international contracts.
I Blblloteco del Congreso Naclonol
EL MERCURIO
fecho l 7 M~O \991
P6gino ~
Columno £ /. i ( '., · 1 1\'V
Ublcocl6n del recorla ~-----··-··------ - ----· ·-·-- -
PRECISO CANCILLERIA CHILENA:
No Hay Conflicto con
Bolivia por Rio Silala
Mariano Fernandez explic6 que dedsi6n boliviana
de poner fin a una concesi6n de aguas
de ese curso a una empresa chilena es un tema
que corresponde resolver segun las normas
de los contratos internacionales.
240
The Chilean Government said last night
that there is no controversy with the Government
of Bolivia regarding the use of the Silala River
waters that supply the northern populations of
our country and said that the issue is subject to
a contract of International Private Law, which
should be discussed in those terms.
This declaration arose after the
Provincial Prefecture of Potosi decided to put
an end to the water concession that was granted
almost a century ago to the Antofagasta Railway
Company.
According to the acting Minister of Foreign
Affairs, Mariano Fernandez, this is a contract of
International Private Law and therefore follows
the rules of all contracts.
In that sense –he added– it is up to the
Antofagasta-Bolivia Railway Company
to get in touch with the one who granted the
concession to see how it is going to be from this
point forward.
“For now I have to say that there is no
controversy between the Bolivian Government
and the Chilean Government in this matter. The
Consul General of Chile in La Paz, Ambassador
Oscar Fuentes, has had contact today (yesterday)
with the Bolivian Vice-Chancellor Victor Trigo,
and these contacts will continue on Monday to
precisely specify the situation that has taken
place in the area.”
He stressed that it is important in any
case to take into account that the Silala River is
an international water course that is governed by
international laws on this matter, in such a way
that if the natural water flow from one country
to another is not altered, “this will not be more
than a discrepancy between private Parties that
will have to be regulated according to law.”
According to Fernandez, if differences
of opinion persist that could at some point
disturb the natural water flow, particularly to the
San Pedro and Loa rivers in Chile “I imagine
that we will consider it necessary with the
Bolivian Government to discuss some type of
more precise water regime in order to avoid
alterations of any kind.”
According to a version of the Associated
Press dated in La Paz, it was reported today that
Bolivian authorities annulled a contract that
allowed to supply water from a southern river in
this country to several towns in Chile.
Regional authorities informed that the
Prefecture of the Department of Potosi annulled
the concession contract for the waters of the
Silala River, which were used to supply the
populations of Antofagasta, Calama and the
Atacama Desert in Chile.
El goblerno chileno prccfs6
cmoche qu. no exlste ni~n• con'
6-o¥enia ecm e.l ~blerno de BolivJa
re.apecto dcl uso de las acuas
del rfo Sllala que abastecen a poblaclones
del norte de nuestro
pals y precls6 que cl tema e11t6 auJclo
a un conlrato do derecllo prlvodo
internaclon'!l, cl quc debe
disc1iUr5 en e sos terml~.
Esta dcclaraci6n surgl6 Juego
quc I ■ PreCectura Provuii:ial de
Polos( decidi6 s>on~r t6rmlno a la
coneesi6n \le a.cues ~uc sc ntrega
desde bace cosl un saglo o to CompeMa
del Fcrrocorril de Anlofi~ensta.
Segun precls6 cl Min.islro subrocante
de Relocionos Exterlores.
Mariano Fern6nde:z. esto es un
4!0ntrato de dcrccho privado lnternc0cional
y por lo tanlo siauc h,s
re~lns de todos los contratos.
En ese scntldo. agrcg6 corres•
ponde a la CompAftfa del Fercocnrril
Antof•~••la-Bolivia entrar en
contaeto con qulen otore6 la con•
ccsl6n para ver de qu~ ma~ra se
slaue adelante on est.a punto .
.. Por ahorn yo tcngo quc decir
que no exlste controversla entre
el goblcrno boliviano y el chllono
en cstc0 mnlorl . El c6nsul ,i:eneral
do Chile en La Paz. embaJ dor Oscar
Fuentes. ha tcnido contado
hoy {ayer) con cl vlcecanclll r bollviano,
Victor Trigo. y cstos contactos
seguir6n el lunes para prccisar
exactamente la situacl6n
que ha ocurrldo en la z.ona".
Desl4c6 que es important• n
todo caso tener en cuento quc cl
rfo Silala es un curso internacional
do acu a que so rigc por las le•
~• interncacionales sobre osta motcrh
». de tal manero que sl no sc
allerara el discurrir natural de las
aguas de un pats n otro "esto no
pasa o ser m6s guc una discrcpancla
cntrc privodos que lcndr4 quc
rcgularse de acucrdo a las lcycs··.
Seglln l-'ern6nde%, si pcrsislieran
difercncins de opint6n Que PU·
tlicran en olclln momento porturr>
or cJ IIUJO natural de ngu • p rucularmontc
n los rios San Pedro y
Loa en Chile "me lmagino quo e~llmaremos
nccesnrlo con cl co.
bierno bollvlano discutir ••con tipo
de re.:imen de agua mu prcclso
eon el objoto de evltar alt rac:
loocs de cunlqulcr carActcr".
So~tln una vcrsl6n de la agoucla
Associated Press fechado on
La Pa~ las outorldndcs bollvlanas
nnule.ron un contralO que ~rmltla
abestecer do ..-.i• do un surcfto
rfo de ~ oafs r, ,..~rl~"' 1W1bl11cl onas
en Ch lie. se nfonno boy.
La r,roCcctura del deportA.monto
de I ol0$1 oout6 al cont.rnto 'de
conc:esi6Q tlo las agues del rlo S1-
lnln. quc crnn ulilizndos pnrn cl
;,baslccimiunto de las poblocloncs
do Antofa~sct.a. Calnma y cl dcsicrto
de Alac ma en Chile. lnro r m;
uon la:5 utorld des region lcs.
241
The Prefect of Potosi, the main political
authority of that region, Oscar Manzano, said
that the resolution “should be endorsed by
an official communication from the Foreign
Ministry of La Paz to the Foreign Ministry of
Santiago de Chile as soon as possible.”
Manzano noted that the decision was
made because there are no “motives and reasons
why the aforementioned concession, granted
89 years ago to the Antofagasta and Bolivian
Railway Company Limited, which currently no
longer exists, should be maintained.”
According to the Bolivian authorities, the
Silala waters are abstracted in a sedimentation
reservoir and pass through a pipeline to another
reservoir located in Chilean territory to enter
the drinking water systems that supply some
populations.
The Siloli River, known as Silala in our
country, enters Chile from Bolivia 4 kilometers
south of the Inacaliri Hill –located about 300
kilometers northeast of Antofagasta, on the
border– and then flows for about 5 kilometers
until it reaches the Inacaliri River, which has a
total flow of 250 liters per second.
Jaime Andrade, Public Affairs Manager
of Codelco-Chuquicamata, acknowledged that
the water conveyances of the company consider
the flow of the Inacaliri [River], although he
estimated that the possible effects would be
minimal, because large amounts of liquid are
consumed, in a range of one ton of mineral per
one of water.
Meanwhile, in the Sanitary Services
Company of Antofagasta S.A. (Essan), they
dismissed a negative effect on the supply
delivered to the population of the four main
cities of the II Region that are Antofagasta,
Calama, Tocopilla and Mejillones, which total
more than 400 thousand people.
El prcrcx:to de Pototf la princlpol
auloridad politico de csa reei6n,
Oacur Man-zano. dlJo que la
resolucl6n -dcbc sor rcf'rendada
por unn comuniCACfdn olicial de la
C;,nclllcrfa de La Paz a l de Santiago
a Cbllo a la <mayor> brevedad".
Manznno anot6 quc In decisi6n
so debl6 n quc no hny "molivaciones
y rnz.oncs para que se raantena::
i J monclooada conccaidn. otorgad~
ha~ 8'9 aftos a la empre.sa ferrovlaria
flle Aotor. aasta and BoJivlon
Railway Compo~. que on la
actualldsacJ ya no existo •
Las aauos dol Sllala son re-oolectodu
en un reservorlo de sedlm-
0ntacl6n "" pas.an por tube-ria o
otro ublcado en terrltorlo cbilorw
para ln&resar a l0$ slstomas de
ogu potable que boatec n a aleuu
s poblaciones do •~uerdo o
has autorJdades b<>l\vlannt.
El rlo Siloli, conocldo como Sllala
en nucslro pals, p netr~ a
Chilo dcsdc Bolivu, a 4 kil6nictros
I sur dcl cerro lnaculiri -ubicpdo
a uno:s 300 kildmetros al no?"
C.Slc do Anlofi gasln, sobre la
rront ro- y posteriormcmlo corre
unos S kil6metros host. 1{cg:1r
como onucnlc <lei rfo lnnc lirl. al
cunl surtc cou un c:uudal total de
250 lllroa por &ca.•.mdo .
.Jahno Andrade. c rcntc do
A untoa NbUcos de Codclco-Chuqulcamola,
reconoc16 qu~ las
aducclonas de •cu• do I empreaa
con.slderon cl caudal dol lnaccalirl,
aunque cslfm6 quo los evcnhmles
efcctos sorlnn mfnlmoa, debido a
que so consurnen erandcs canlidades
do lfquldo, en un ranco do una
toncl d do 1nineral por una de
agua.
En tonto. en lo Empro5a de
Servicios Sanitarios do Antofagruito
S .A. <Esson>. deso•timaron un
cfccto ncarativo sobrc ol sumlnlstro
c_aue cnlro~on n lo poblocl6n de Ins
cuntro prJncipalcs ciuoJadcs de la
If He~l6n quc son Anlot ~a. Calam:
a. Tocup Ila 'Y McJilloncs. quo
suman ru ·de~ mil pcrsonas.
242
243
Annex 16
La Razón, “Everything will be done after signing
the initial agreement”, La Paz, 30 August 2009
(Original in Spanish, English translation)
244
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245
INTERVIEW
“Everything will
be done after signing
the initial agreement”
David Choquehuanca, the Foreign Minister of the
Republic, defends the progress made in the negotiations
with Chile. He believes these are the basis to
solve the dispute over the Silala
E TREV STA
••Todo se hara
luego de la firma
del acuerdo inicial""
DAVID CHOQ 'EH ~ A I an illerd laR publi a
dtifi. nd I avan d la. n o ia ion on 'hile., er. que
on lab para r. olv r I d[fi. rendo obr l ilala.
246
DIPLOMACY
The Minister of Foreign Affairs has gained
experience in the world of diplomacy. This
dialogue regarding the Silala agreement shows
an authority that is determined to sign the
agreement, but also disagrees when talking
about deadlines to do so.
What is the result of the consultation with
social sectors of the Quetena region about
the Silala pre-agreement from the Foreign
Ministry’s point of view?
There is a positive and constructive reaction
to the process of socialization of the initial
agreement. Once they know about it, they
tell us: “Go ahead, we are here to defend
the agreement.” They tell us that Chile has
been allowed to take the water for more
than 100 years without paying a single cent.
I have participated in the Second National
Water Meeting, in which sectors from all
departments participate, and there I was able
to explain about the initial agreement and they
have manifested to carry it forward, I have
also been with the Regional Workers Central
(COR for its acronym in Spanish) of El Alto;
all, practically all, have supported the work
that the Government has done regarding the
Silala. After August 3rd, when we presented
the document, we received a resolution vote
so that we could sign this initial agreement. I
have been to Omasuyos and there is a positive
response and some were surprised because
we explained the initial agreement and also
because the Chancellor has never come to
explain things to them. There is no small
print, there is no secret clause, and I told them
that if they approve it, we will sign the same
document.
From the point of view of the State Political
Constitution and with binding criteria,
whose opinion is valid? Is the opinion of the
people of Quetena or that of the Bolivian
people valid?
The opinion of the Bolivian people as a whole.
The opinions of social sectors, institutions,
experts, the opinion of all
El Ministro de Relaciones Exteriores
ha adquirido experiencia
en el mundo de la diplomacia. Este
d.ialogo sobre el acuerdo del
Silala muestra a una autoridad
decidida a firrnar el acuerdo. pero
tam bien discrepa al hablar de
plazas para hacerlo.
~ Cual es. desde el punto de vista
de la Cancillerfa. el resultado
de la consulta que hizo con
sectores sociales de la regi6n
del Quetena sobre el preacuerdo
del Silala?
Hay una reacci6n positiva y constructiva
al proceso de socializaci6n
del acuerdo inicial. Una vez
que lo conocen. nos dicen: "Metanlo,
estamos para defender el
acu erdo" Nos dicen que se ha
permitido que Chile se lleve el
agua por n1as de 100 aiios sin pagar
un solo centavo. I-le partic i pado
de! Segundo Encuentro
Nacional del Agua, en el que participan
sectores de todos los departamentos,
y allf pude explicar
sabre e l acuerdo inicial y s e han
manifestado para que se lleve
adelante, tambien he estado con
la COR de El AJto; todos. practicamente
todos, h a n respaldado
el trabajo que e l Gobie rno h a h echo
sabre el Silala. Despues d e l
3 de agosto, cuando presentamos
el documento, nos llega un voto
resolutive para que llevemos la
firma de este acuerdo inicial. He
estado en Omasuyos y hay una
respuesta positiva y algunos sorpren9-
idos porque les explicamos
el acHerdo inicial y, ademas, porqNe
nunca antes el Canciller llegaba
para explicarles. No hay
le'lr:ra chica, no hay clausula secreta.
yo les dije que si lo aprueban,
vamos a firmar el mismo
documento.
;.Desde el punto de vista de la
CPE y con criterio vincu.lante,
la opinion de qu.ien es valedera?
;.La opinion de los
pueblos de Qu.etena o la
del pueblo boliviano?
La opini6n del pueblo boliviano
en su conjunto.
La de los sectores sociales,
las instituciones,
los expertos. la
opinion de todos
247
is important. This morning (on
Wednesday 26th) I was asked, what
will happen if the Senate does not
accept the pre-agreement? And I
researchers, because this
initial agreement establishes
that in four years, we will
work together in a long-term
agreement, so
“Now, we are going to make this agreement and
tomorrow we are going to deal with the historical
debt and for this we need studies”
told them it’s not about the Senate
not wanting it, it’s about the people
wanting it.
And how and when do we reach
the conclusion?
There are resolutions that reach the
Chancellery. The civil society is
organized, the social movements, the
Central Bolivian Workers (COB for
its acronym in Spanish), the National
Council of Ayllus and Markas
of the Qollasuyo (CONAMAQ
for its acronym in Spanish), the
factory workers, the miners, the
sectors that have made history in
this country, they are the ones who
decide what direction this country
is going to take. It is important
to gather the contribution of the
Bolivia. In these four years, all
Bolivians will have the opportunity
to construct the long-term
agreement.
What will be the immediate
and direct impact of the initial
agreement on Silala?
Fresh incomes for Bolivia, which
may allow the development of
south-eastern Potosi. If one goes to
the place, one does not understand
how the people have been able to
survive. This income can help us
to work little by little on programs
in order to improve the condition
of the inhabitants. In addition we
would be establishing sovereignty.
How are they going to establish
sovereignty in Quetena?
Making the waters ours. Today,
Chile does not pay a single
cent. By making Chile respect
our sovereignty. If we sign this
agreement, we will carry out joint
studies, which will allow us to
prove that we have springs.
that Chile pays 100 percent of
the waters that belong to
es importante. Esta maftana (la
d eJ m ier c ole s 26) me preguntaban.
q u e va a pasa.r s i el Senad.o
n o acept a el preac uerdo y yo les
gadores . porque este acuerdo iniciaJ
estable c e que en c uatro afios .
trabajaremos c onjuntamente e n
un acuerdo de largo plazo. para
'9 '9 Ahora. vamos a hacer este acuerdo ~'
manana ·vamos a tratar la deuda historica y
para esto igual necesitamos cstudios ~ ~
decl a que no se trata d e q ue e l
Senad o no lo quiera. se b ·ata d e
que e l pue blo lo quie r a.
<,Y c6mo y cu3.ndo llega a la
conclusi6n?
Hay resolucion es q u e llegan
a la Can c ill e ri a . La s o c iedad
c ivil est.a o rganizad a..
los m o'\·imientos soci a les.
la C OB. C ona maq,
los fa b riles. los miner
os. los sectores que
h a n h ech o historia en
este p ais. e llos s o n los
que decid en que ru.mbo
va a to m ar e ste pa{s.
Es irnpor tante recoger
el apor t e d e los inque
C hile p ague e l 10 0 p o r cien to
d e las aguas q ue p e r ten ecen a
Bolivia. En estos c uatro a.nos. todos
los bolivianos tendr3.n la
oportu..nidc:1.d de construir el
a c uerdo de largo plaza.
i. Cua.J sera el impacto in.med.iato
y direct:o del acuerdo inicial
sobre el Silala?
lngreso s fresco s para Bolivia. que
pue d e n p e rm.itir e l des arrollo del
s udeste potosino. S i uno v a a al
luga r. uno no e ntie nde c6mo es
que los compa fl e ros han pod.ido
s obre vivir. Esto s i.ngreso s p o d.ra n
a yuda r a q u e poco a poc o tra b a j
e m os e n pro gra m as p a r a m e j or
a r l a condic i6n d e los
p o bl a d o res. Ade n1.is est ariarnas
sentando s obe ranfa.
;.C6mo van a se.ntar sobeT'an.
ia en las Quetenas?
Hac ienda que las c1.guas
sean nuestras. Hoy. Chile
n o paga un s olo c e ntavo.
al hacer que Chile respete
nuestra soberania. S 1 fir rnamos
este conve njo. va•
m.os a lle var estudios de
nanera c onju.nta, que nos
permitir.in d e mos trar
que
248
When you talk about establishing
sovereignty, are you talking about bringing
development to Quetena?
I am talking about establishing a legal
framework to force Chile not to make arbitrary
use of the waters, as the Senators said during
the report.
How will the fresh money that comes in for
the exploitation of water be administered?
The Constitution says that the Government
will distribute [the resources] equitably in
the regions with less development, but my
grandfather says that the first thing that must
be done is that the piglets are born, then we
sell them. So, first, let’s solve this, then we will
discuss the distribution.
So, let’s talk about piglets. The initial
agreement does not establish with precision
that Chile must pay for 50 percent of the
waters, why does Article 6 not clearly state
that Chile must pay for that 50 percent?
Article 6 says that 50 percent is freely
available and the other 50 percent is subject
to studies. And it also says that this percentage
can be increased in favor of Bolivia, once
the studies are finished. So, while the longterm
agreement is being constructed, we will
work on all the precisions with well-founded
information. We need information, we do not
know how many liters pass to Chile per day.
This is the first step so that in four years Chile
can compensate us.
This agreement speaks of 50 percent, but
does not clearly state that it will pay for that
50 percent, why?
Chile is willing to do it, once the agreement
is signed, we give it 60 days. They will have
a preferential term, those who today use
the water without paying a single cent. The
Ministry of Water will make them regularize
or adapt to the agreement. If they do not, we
can dispose of the water. Don’t forget that
water is a more important natural resource
than hydrocarbons.
Please clarify this, that agreement does not
accurately establishes the payment.
Chile will have to compensate for the water
and has 60 days to decide, because there may
be other companies that have an interest in
exploiting the waters.
Who are those who must
.;_Cuando habla de se"Dta:r sobe.-.....:
U:a.. est.a h.ab1-ndo de Uevar
desa.rr<>ll<> a I .as ~ete11lla.s?
Estc>y hablando de est:ablecer u:a
marco ju.ridico para. ob li.g,ar a que
Chile no haga u.so a.rbitrario de
las a.guas. como decfaAL los senadores
durante el informe .
.;_Co.mo sera aclrn.iii:i.strado el
di.n.ero fresco que en:t:re por la
ex:plo~i_on del a.giia?
La Cor1stituci&n c:Uce que el Gobierno
distribuira. equitativarnente
en las regiones con menos
desarrollo. pero mi abu.elo clice
qu.e lo p.rimero qu.e hay que hacer
es que los cha.nchitos n...a.zcan.
luego los vendemos. Entonces.
primero. resolvamos esto. tuego
se ver.i la d..istrib'l...l.ci6n.
Ent<>IJ.ces.,. va.ya.rnos a los cha..nch.
it:;os- El a.c:'-.ierd.o .u:iicia.l no esta.
blece co:n precis"J.on. que
Chile debe pa.gar por el 50 por
cient:o de las a.guas . .;__por que
el a.rticulo 6 Ill<> establece con
claridad qu.e Chile debe pa.gar
por ese 50 por ciento?
El articulo 6 dic e que el SO por
ciento e s de libre disponibilidad
y e l otro SO poi:- ciento e sta sujeto
a estu.clios. Y dice tarnbien que
e se porcentaje podr.i ser i n c rernentado
en ta.var d e Bolivia.. un.a
v e z que terminen los estu.di.os.
Ent:onc e s . OUentra.s se constru.ye
el a c u e rdo de largo plaza. varnos
a trabajar e n todas las precision
e s con in.formaci6n fi.i.nda da.
Nec esita.mos inforrnaci.6n. no sabemos
c u ci.ntos lit:ro s pasa n a
Chile por dfa. E s te es el pnro-e r
paso para que en c uatro aTlos
Chile pue da compens ar.
Este acuerdo habla del SO por
cient:o, per<> no establece con
claridad que va a pagar por ese
50 por cien.to .. ;,.por que?
Chile siesta dispuest:o a hacetlo.
u.na ve.z fi.rmad._o el acuerdo. n.osotros
le <larnos 60 dias de plazo.
Ellos van a ten.er un. plazo preterencia.
l. los que hoy u.san el agua
sin pagar un solo centavo. El :rv1i nisterio
del Agua hara. que se regularicen
o adecuen al
acuerdo_ Si no lo hace-n.
podemos disponer de
ella. no olvides qu.e el
a.gua es el recurso nah..1.ral
mas icnportant:e que
los hidroca.rbl...l..rOs.
a.cl&reme- ese
a.cuerdo 11<> dispone con
precision eJ pago.
Chile va. a. t.ener q-u..e co~
pensar por las agu.as y
tienen 60 d..fas para decidi,:;
porque puede haber
otra.s emprP.sas qu.e
tenge.n IDteres en e _~plotar
las aguas.
J.Que e& lo q'I.Jle
deben ,ananl- .::,
249
manifest in these 60 days?
Those who are using [the water], i.e. Codelco
or Luksic. They must do it and they will have
to pay. They have that term. The Ministry of
Water will establish contracts, agreements,
on how they will pay. We are going to have
to ask for guarantees and [establish] how they
are going to pay. There will be a process of
agreement for the payment of each month
and rules on what will happen if they do not
comply [with the payment].
In Chile, there are sectors that believe that
the initial agreement establishes that each
country can freely dispose of 50 percent of
the waters. That is to say that Chile would
pay only for the additional part besides that
50 percent...
The agreement clearly says that 100 percent
of the waters, 50 percent is freely available in
Bolivia and that in the other 50 percent we will
listen to scientific research. They are willing to
compensate for 50% of the Silala waters.
How do we get to the amount of 17 thousand
dollars?
There is not an exact amount. When this
agreement was being worked on, the cubic
meter was at 0.65 dollars today, it is at 2.2
dollars in Chile. Then, the Ministry of Water
will take that price as a reference. The longer
we take to sign this agreement, the more we
lose.
In Chile, the agreement was expected to be
signed on August 10th.
Possibly, us too. In this issue there has been a
process of participation, we can even say that
we ask for authorization for dialogue, we have
spoken with different social organizations,
most of them from Potosi. That’s why, in
Quetena, the [social] organizations knew the
initial agreement and they gave us the green
light, they told us to go ahead.
In Quetena, they have asked –don’t forget
Chancellor– to include the historical debt in
this agreement.
They also reflect our concern. We are not going
to renounce the historical debt, ever, but we
have separated it, just as we have established
the 13 points on the agenda to deal separately
with the enabling of ports, the commercial
issue and the maritime issue. If we are going to
try to address all the issues [at once], we will
not reach an agreement, many years would
have to pass by, maybe more than 100 years.
Now, we are going to make this agreement
and tomorrow we are going to deal with the
historical debt and for this we need studies.
~ fcstarseen estos 60 c:lf-7
Los que csta.:n u.snndo. es de Jr
Codel o o Lu.ksic. E llos deben hacerlo
y van u t:ener que pa.gar_ n
l'ICn ese plazo. El M.in..isterio del
Agua va a stablecer cootratos.
ncue rdos. sobre c6mo van a pagnr.
Vamos u tener que pedir boletas
de garant.fas y c6mo van a
pagar. Habra un pr<.:>ceso de
acu c rdo paru pago de sada m es
y norm as sobre qutf> es lo que p a,..
sarasi nocumplen.
En Chile, hoy sect.ores que ereen
quc cl ocuerdo i.nicial estahlecc
quc coda pais puede
disponcr librement:e del 50 por
cicnto de Joa aguas. Es deci-.que
Chile pa.garfa solo por la
parte ndicional a.I 50 por ciento
...
El ocuerdo cUce clanto. que <lei
JOO por ciento de Ja.s aguas_ 50
por cienlo es de libre dispo:nibilidnd
de Bolivia y que en el otro
50 por c iento varnos a escuchar
uno invest:igaci6n cien ifi a. Estan
dispuest:os a compensar por
el 50% de las aguas del Silala.
;,C6mo se Uega a lu ci.fra. de 17
mUd61nres?
No hay una c ifra e.xa cla. Cua.ndo
seeslaba Lrabajando e ste a cue r do.
el metro cubico est.aha e n 0 .65
d61ures hoy esta en 2.2 d61a.res e n
C hile. Entonces. e l Ministerio <lei
Agua va a tomar aque l precio co-mo
referenciaJ. M.ienLras mas tarde
fir.memos este a c uerdo.
perdemos mas.
En Chile. se csperaba. que el
ucuerdo se O .rme el i Ode agosto.
I>osiblemente. nosotros tambien.
E.n esle tema ha h~"l..bido un proceso
de part.icipaci6n. incluso podemos
decir qu e p e dimos
a utorizaci6n para e l d.ialogo. hemos
h ablado con <liferentes organjzaciones
socia.les.. ]a mayorfa
de e llas potosinas. Por esow en
Quetenaw las orga.n Jzaciones conocfan
e l acuerdo iniciaJ y nos
hnn d.icho. meta.nle. adela.nLe .
En Quctenu.. Jes ha.n ped.ldo. no
lo olvide Conciller. que se in cl.
uya In deudu b.iRLOrica. en e81:e
acuerdo.
E.llos tnmbien reilejRn nuestro.
preocupaci6n. No va.rr:ios a renunciar.
jnn'"lO.s. u la d eudo. h..ist:6-
rica. pero hemos .sepurado. a.sf
coma hemo.s est.abl e cido Jo s 1 3
P-Untos en ta agenda para t:ralar
Por s epara.do la h .abiliLaci6n d e
los pue- rto::;, e l Le ma (;Q rne r c iu.l. e l
leri"la. ma..1-fti n"lo_ S i va.--nos a t..rat-~LJ.~
d e o. b ord a x Ludo.s Los Lt::::l n O..S . no
Vl:uTl oo.u. H ega,- H 1tn n c u r e.lo. t.e n drfa
n . qu~ p .._~ ~ .r rnu ·h us tt-ilo~~ L1:-tJ
Ve--..t rnb,_6c.J · 100uf\v 8. Ju .. ,ru. v cv
rnos ~ h act"r t:sLu acu erU.o y muOa.
nc:t vu n1 , ..1s a Lr>..1. L~1. •~ I ll. d udu
hiHlor icc.1- y p uru csLu iguc.11 n .. L .
s iLu,.111u~ ~ s lu<l.iu.s.
250
;,En la n egocla.cl6n se ha h a blo.
do de la deuda hjst6rica?
Se ha hablado. pcro no esta e n el
acu.erdo y varnos trabajar .sobre
ello en es«>s cuatro BJ\os.
Canciller, no lo olvide eJ acuerdo
inicial estabJece clarainen te
quc los cuatro ru'losson para
establecer la dif'erencia del 50
porc ient.o~
Nosotros queremos resolver en
cuatro a nos c l djferendo del Silala.
tene1nos que demoslra.r que
son ma.nanliaJes~ No es sOlo para
que pai:,,ue po rel rcstante 50 por
cicnto.
Entonces, la deuda his l6rica
sera nbordnda en e l futuro. no
este n.cucrdo.
Si el pueblo boliviano csta de
acu4,;rdo con este acuerdo. ma·
"o.na mismo instn.lamos unn co•
misi6n 1>-•ra la deuda hist6ricu.
Todo scra despucs d e la firm a. la
finna cs po.rn iniciJS d proccso,
fi.rmamos y colocare,nos los 1uecU<
los de agua. pant sabt?r Clu.'ll
exucla1ncnle us cl opoclc de 1as
lluv,os. Pura lu medlcl6n de lt1
le1npemtlU-'d. V\IOlOS. .(\ COI\Sliluir
cquipos de t,.,b .. jo puru :;aber<le
~rue e"tamos I mbla.n<.lo lo dd munanti-
1.lt y fonnu:1"C1nos \,:'ornhi6.n
PW"tt 1 .. d,rnda hisl6ricu.
C6mo va a re,,olver la cuestt6n
lnterna., ahora.. ElMAS p(de ln cluir
el teo:na trl IAorico en el actual
acue·rdo.
El le1na de la deuda hist.6rica tiene
que estar resueito en el acuerdo
de largo pla.zo.
El 13 dlciembre se realizanui
l as elecciones presidenclales
uun.blin en Chile. Y por lo que
se sabe es probabl&que eJ vencedor
no sea un politico a.fin aJ
preatdente Morales. corno lo es
ahora la presidenta BacbeJet.
;,No cs conven iente para el Gobierno
finnar ahora el acuerdo?
;_No es oportuno abora?
No vamos a politizar ni electoralizar
el h~1na Vcren1.os c6mo vu n\1\durn.
ndo. c6mo avunza el proceso
de socializaci6n. El a<.uerdo de! Silala
no estA sujeto n la cuesli6o
elcctorol. no hay desesperaci6n.
En Chile se habl6 del 10 de
ogosto co,no phu.o.
No hLtbo 10 clc ago.,10. no tencn1os
pJo.:.t.u. Ahuru. ~laro. yo n,ismo
clt.•seub •. 1 <[Ut! ~sle nc-u..:!rdo
Jcbfn slt"r fir11n.1.Jo t""n t,go slo.
1nlenlco.s mtb. Jttn\v~n,os. 1ni.'i.s
le c:01\, i.:-nc ti Chili: .. Lo:-- quc r,o
qui"-·r~u qu-..-. &J 6L u,c cl ucu'-'rdo.
<11..1iert.·n qu.....- Chil4! sig~'- bcn'-.. llc;
Un<los,11.::. E.n cl acuerdv <lic.."t que
Ulla vez te:rrn1nados los estudJott
dice que se incrernentanl. el por
centaje a favor de Bolivia y eso lo
demostraremos~
;_Cuando sabra que tiene fir m..
ar el acue-rdo?
Necesito la 1nanifcst,c1c-16n de l~
maeslros ru.r-..Jes.. de las a.mas de
casa. de es:tudiantes. pero hasta
ahora no he C:'.'ncont rado rechazo.
l..o import ante es que este tem.t
es parle de la ..genda nac,onal.
has ta los ninos hablan del tema.
los profesorcs ordenan tr.J.baJOS
de invesliga.c-i.<'.',n. fo<lo el ,uun<.lo
habla. sobre d S1lal.,. muches de
nosoLrOs no sabian·1os de ~-te t:ema.
Loque nos" ha lo!(l"'«do ha-
~El acuerdo de largo
plazo no serci para l 00
atios ni para -JO ai1os.
Tenemos que tomar prevision
es par.t coostruir
un <lique o para in<lustrializarcl
a.gua. No nos
vamos a amarrar ~
cer. una pol.itica de Estu.do. ahom
sf se esta construyendo,
;.Sob.-., la politica de. &t.ad;o.
existc docUDJentaci6n para de-
n,ostrar que cl Sllnlo e. un man_
antia! boli..-i.a.no?
Hay var,os cstu<llos que r\OS permitien,
n negocia.r. p,,ro los ~tudios
c ,enulicv-s 4u" hare.rn= no,,
perm.itlr-.u, Je.n,o,,t..-ar a l,1, ,:omu
ni<..l(h.l !uternacl<,1u\J que '$On
ugurus bol ►via.,rns. El c.;tudio l>.,
hax--:.. ,m ba:s.l al J.CU<l'roo.
'Poe la c onsulto quc h,. hc,cho.
,1b11 eocoul.nHlo w.gu.,, .. critlco
251
Has the historical debt been
discussed in the negotiation?
It has been discussed, but it is
not in the agreement and we are
going to work on it in these four
years.
Chancellor, do not forget that
the initial agreement clearly
states that the four years are to
establish the difference of the
50 percent.
We want to resolve the Silala
dispute in four years, we have to
prove that they are springs. It’s
not just for [Chile] to pay for the
remaining 50 percent.
Then, the historical debt
will be addressed in the future,
not in this agreement.
If the Bolivian people agree with
this agreement, tomorrow we
would constitute a commission
[to address] the historical debt.
Everything will be after the
signature, the signature is to start
the process, we will sign [the
agreement] and we will include
the water measurements, in
order to know exactly what the
contribution of the rains is. In
order to measure the temperature,
we will set up work teams in
order to know if these are springs
we are talking about, and then we
will constitute a commission [to
address] the historical debt.
Now, how will you solve the
internal question? The MAS
(Movement Towards Socialism
– Governmental Party) asks to
include the historical topic in the
current agreement.
The issue of historical debt has to be
resolved in the long-term agreement.
On December 13th the presidential
elections will also take place in
Chile. And as far as is known,
it is likely that the winner is not
a politician akin to President
Morales, as President Bachelet is
now. Is it not convenient for the
Government to sign the agreement
now? Is it not appropriate [to sign
it] now?
We are not going to politicize or
electoralize the issue. We will see
how it progresses, how the process
of socialization moves forward. The
Silala agreement is not an electoral
issue, there is no desperation.
In Chile, it was discussed that the
deadline was August 10th.
There was no deadline of August
10th, we do not have a deadline.
Now, of course, I myself wished that
this agreement be signed in August;
the longer we delay, the more it
benefits Chile. Those who do not
want the agreement to be signed,
want Chile to continue benefiting.
In the agreement
it says that once the studies are
finished, the percentage in favor
of Bolivia will increase and we
will demonstrate that.
When will you know you have
to sign the agreement?
I need the manifestation of the
rural teachers, of the housewives,
of students, but until now I
have not found rejection. The
important thing is that this issue
is part of the national agenda,
even children talk about the
subject, teachers order research
[on this issue]. Everyone talks
about the Silala, many of us did
not know about this topic. What
has not been
achieved [in the past], a State
policy, is now being built.
Regarding the State policy, is
there documentation to prove
that the Silala is a Bolivian
spring?
There are several studies that
allowed us to negotiate, but the
scientific studies that we will
carry out will allow us to prove
to the international community
that they are Bolivian waters.
The study will be based on the
agreement.
Regarding the consultation you
have done, have you found any
criticism
“The long-term
agreement will not
be for 100 years
or for 40 years.
We have to take
precautions to
build a dam or
to industrialize
the water. We’re
not going to tie
ourselves up”
252
that leads you to modify the agreement,
before signing it?
They asked us to make them pay 80%, and
that they should pay with interests. They have
expressed their concerns, but we will treat them
when we address the long-term agreement. We
have raised the issue of the historical debt to
the Chileans, but they have told us that studies
are needed. If we include the historical debt,
we will cause a delay.
What ensures that this agreement will be
honored by the Chileans?
It’s just that we’re serious, they did not even sit
down at the negotiating table before. Because
senators in the past let 100 years pass by.
You know that if this agreement is not
signed, there is no progress in the Agenda
of the 13 Points?
No, that is not true. There is progress at every
point, we are working on this. In addition,
there are no conditions in any of the 13 points.
Each one has its own dynamics.
Do you believe that this agreement must be
signed before December?
It depends on the people. Even the Senators
representing the MAS [Governmental
Political Party] have manifested on this issue,
they have asked for a referendum. We do not
oppose. The State Political Constitution the
mechanism, at this moment I cannot say, there
are several reactions.
The agreement states that the waters can be
canalized?
In the town of Quetena, a farmer said that in
four years, Chileans will drill wells. And the
agreement says that drilling is not to be done,
for the sustainability of Silala. Nothing is to be
touched. If it signs the agreement, Chile does
not touch anything, neither [drilling of] wells
nor new canals, in the following four years,
but also afterwards.
The agreement states that Bolivia can freely
dispose of 50 percent of the waters?
The long-term agreement will not be for
100 years or for 40 years. At this moment,
we are not in conditions to build a dam or to
industrialize the water, but Bolivia already
gives added value to natural resources, [soon]
we are going to have money. Our international
reserves went up, we already have money,
when we are in conditions we will take
measures. We’re not going to tie ourselves up
in the long-term agreement. When we are in
conditions, we can determine what we will do
with our waters. We have to take precautions,
as long as we do not have other possibilities to
exploit our waters, Chile has to compensate.
que le lleve a modi.fi.car e l
acuerdo. ant.E"'s. de firmarJor!'
Nos p ·idieron que pa~utc...---n el so•.-.;;,.
y que paguen c on lntereses. l tan
expr esa.do sus preocupacion-e-c;.
p ero l a.s- varno.s a tratar <.:. u.a:n<lc,
vayan,o~ aJ acuerdo <le larg<·., plazo.
A los chJ.leno5 les hen,0$. planteado
e l terna de l a deuda
hls tOrica. pero nL)S ha.n dic hc.> que
se neces iLan esludius. Sl inc1Lri mo
·s lo de ta deuda bistoric.::a. vamos
a d e morarn·os.
Que a.segura que este a.cuerdo
ser3. acatado por los chilenos.
Es que sornos s erios nosotros.
antes ni siquiera se s ent.a.con en
la mesa de negociaciones. Porque
los s en adores de ahora dejaron
pnsar 100 ano-s.
Usted sabe que si no se firm.a
este acuerdo,, no se avan-z.a en
la agenda 1 3_
No. no es cierto. Hav avances en
cada punto. esLatT10; trabajando.
adema-S no hav condicionarnlentos
en ningu.no d; los 13 pu.ntos. Cada
uno tiene s u propiadin::irrtlc-a.
<,. l .Jsted cree que est.e a..cuerdo
debe ser firrna:do ant.es de d.iciembre?
Depende del puebk, . lncluso los
sen adores de-J i\.L~S se ha.n mar~ifestado.
han pedido referendum.
No c1os oponernos. La CPE esta.b
.lece e l mec anls.n-10. en este 1nomento
no pu.edo decir. hay v-aria.s
n?acc-lones.
El acuerdo establece que las
aguas podran ser conducidasEn
la poblacion de Quetena.. un
can'"lpesino decfa que en cuatro
afi.os. los ch.ilenos van a perforar
pozos. Y el acuerdo dice que no
se hacen perforaciones. por Ja
sostenibilidad de! Silala. Nose
toca nada. Si firma el acuerdo,.
Chile no toe-a na.da. ni pozos ni
nuevos canales. en ~stos cuatro
aiios. pero tan1bi€"n despues.
El acuerdo establece que Bolivia
_puede d.isponer Libremente
del 50 por ciento de las agu.as_
El acuerdo de largo pla.zo no ser.i
para l 00 anos I ii pn.ra 40 arlos. En
este rnomento. no est.amos en
condici.ones para le"\.-'a.ntar un cli que
o para industrializar el agua.
pero Bolivia ya da valor agregado
a los recursos naturales. va van1os
a ten er pla ta. Nuest.ras reservas
internacion.;.Ues subieron.
ya tene1nos platita. cuando esten10.
s e n condlciunes vamos a tornar
n1edidas. No nos vamos u
arnari-ar er1 el acuerdo de largo
plazo. Cuando esrc-tnos en cond
i c i ones. _μodetn u s Lletermin.ar
qu~ cs lo que hdcen1.os con nuestrGts
d.guas Tenernus '---lue tornar
previsi on~:::.. n1ienlreis no t e ngarnos
otras posibil idades para
aprovechar nuestras :::tguas Chile
tiene que compensar.
253
Technical Documents
(Annex 17)
254
255
Annex 17
Danish Hydraulic Institute (DHI), Study of the Flows in the
Silala Wetlands and Springs System, 2018
(Original in English)
256
257
Contract CDP-I No 01/2018, Study of
the Flows in the Silala Wetlands and
Springs System
Product No. 2 - 2018
Final Report
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Source: DIREMAR, 2017
Plurinational State of Bolivia, Ministry of Foreign Affairs, DIREMAR
July 16, 2018
258
I Approved by
X
This report has been prepared under the DHI Business Management System
certified by Bureau Veritas to comply with ISO 9001 (Quality Management)
Claus Skotner
Executive Director
259
Contract CDP-I No 01/2018, Study of
the Flows in the Silala Wetlands and
Springs System
Final Report
Prepared for
Project manager
Quality supervisor
Plurinational State of Bolivia, Ministry of Foreign
Affairs, DIREMAR
Roar Askrer Jensen
Dr. Michael Brian Butts
Source: DIREMAR, 2017
Authors Roar A. Jensen, Torsten V. Jacobsen, Michael M. Gabora, Ms Birgitte v. Christierson ,
Project number 11820137
Approval date 16July2018
Revision 3
Classification Confidential
DHI • Agern Alie 5 • • DK-2970 H0rsholm • Denmark
Telephone: +45 4516 9200 • Telefax: +45 4516 9292 • [email protected] • www.dhigroup.com
260
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CONTENTS
Executive Summary ............. ................................................................................................ 1
1 Introduction ........................................................................................................ 5
1.1 The project ........................................................................................................................... 5
1.1.1 Objectives ............................................................................................................................ 5
1.2 About this report ................................................................................................................... 5
1.3 Study approach and methodology ....................................................................................... 6
2 The system and the area .................................................................................... 9
2.1 The wetlands ........................................................................................................................ 9
2.2 The Silala Area ................................................................................................................... 10
2.2.1 The Silala catchment ......................................................................................................... 1 O
2.3 Historical descriptions of the Silala Spring System ............................................................ 11
2.4 Processes through which the canalization may have affected the cross-border flows ..... 11
3 Climate .............................................................................................................. 13
3.1 Approach to the climate analyses ...................................................................................... 13
3.2 Precipitation ....................................................................................................................... 13
3.3 Temperature ....................................................................................................................... 14
3.4 Potential Evaporation ......................................................................................................... 14
4 Surface waters .................................................................................................. 15
4.1 The canal system ............................................................................................................... 15
4.1.1 Excavations ........................................................................................................................ 17
4.1.2 Main canal .......................................................................................................................... 17
4.1.3 Later manmade changes ................................................................................................... 17
4.2 The observed flow distribution and the temporal flow variation ......................................... 18
5 Soil Analyses and hydraulic characteristics of the wetlands ....................... 25
6 Upland water balance, contributing areas and sources ................................ 25
7 Hydrogeology and groundwater ..................................................................... 27
7.1 Field surveys, objectives and main results ........................................................................ 27
7.2 Conceptual Hydrogeological Model (HCM) ....................................................................... 30
7.3 Groundwater over the international border ........................................................................ 35
8 Integrated surface water - groundwater modelling ........................................ 37
8.1 Rationale and objective ...................................................................................................... 37
8.2 Establishment of the integrated surface water - groundwater model ................................ 37
8.2.1 Implementation of the conceptual models ......................................................................... 37
8.2.2 Model calibration and performance .................................................................................... 38
9 Assessment of the natural flows ..................................................................... 39
9.1 Flows in the natural wetlands without the canalization ...................................................... 39
10 Conclusions ...................................................................................................... 41
11 References ........................................................................................................ 43
Glossary ........................................................................................................................... 44
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FIGURES
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
Figure 17
Figure 18
TABLES
Table 1
Location of the Silala Springs System .... .... .. .. .... ... ..... ... .... ........... .... .. ...... ... ..... ... .... ............ 5
Approximate extent of the Silala Near Field. (Mulligan & Eckstein, 2011 ) .. ........ ................ 7
Approximate extents of the Silala Far Field.. . ...... ... .... .... ... .... 7
Vegetation in and above the southern Silala wetland. Source: OHi Field visit Feb. 2018 .. 9
The hydrological catchment used as a basis for the recharge assessments and water
balances of this study ...... ........ .... ........... .... .. .. ....... ........ ............... .... .. ......... ........ .............. 11
Map showing the details of parts of the manmade drainage network in the Northern
wetland ... .... ....... .... .... ....... .. .. .. ...... .... .... ... .... .. .. ........ .... ........... .... ... .... .... ....... .. ... .... ... .... .... .. 16
Main drain canal, Northern wetland . Source: OIREMAR 2017 ..... .... ........... ........ ............ .. 16
Photo of an excavated section and vertical peat profile at the edge of an undisturbed
wetland patch in the Northern Wetland. Source: OHi Field visit February 2017 . .. ............ 17
Canal modification diverting canal flow to wetland subsystem. OHi , 2017 . ..... ... .. .. .... .... .. 18
Mapping of flows and net inflows based on simultaneous mean canal flow measurements
(in I/s, and percent of the flow at confluence point (the most reliable assessment point) .20
Southern canal profile (S-1 to C-5) comparing canal elevations and observed groundwater
and spring levels with observed discharge (average of 10 campaigns) ...... ........ ... ........... 21
Northern canal profile (S-18 to C-6) comparing canal elevations and observed
groundwater and spring levels with observed discharge (average of 10 campaigns) ....... 22
Principal canal from the confluence to the international border (C7 - S21) comparing
canal elevations and observed groundwater and spring levels with observed discharge
(average of 10 campaigns) ... ... .... ........... .... .. .. .... ... ..... ... .... ........... .... .. ...... ... ..... ... ... .. ......... 23
Modelled water content over time in a sandy soil column above the Silala wetlands. The
colours show the content in the soil from light blue (dry soil) to dark blue (saturated soil)
from the surface to the depth of 4 meters for the period 1969-2016 . ... ....... .. ... ........... .... .. 27
Borehole locations and groundwater level contours in the Silala Near field , interpolated
form Piezometer wells spring elevations and wetland excavations for soil sampling. N.B.
the contouring away from the wetlands and the boreholes are uncertain ... ..... ... .. .. .... .... .. 29
14C concentrations (fat black numbers) and stiff diagrams of water chemistry from Silala
water sampling locations indicating spring water in the Northern Wetland and spring water
from the Chilean right bank being significantly different than deeper ground water from the
fault zone and spring water from the Southern Wetland ....... .... ... .... .... .... .... .... ... .. ...... .... .. 31
A) Delineation of hydrogeologic units (HGUs) in the Silala area. B) Silala site imagery
overlaid by delineated HGUs ... .... ........... ..... .......... ........ ............... .... ........... ........ .............. 33
Hydrogeologic Framework Model rendered in 3D. The Silala Fault (HGU7) is highlighted
in red . Remaining units are displayed with transparency for easier viewing of modelled
subsurface . ... .... .... .... ....... .. .. .... .... .... .... ... .... .. .. .... ... .. ... ... ........ .... ....... .... .... .... .... ... .. ...... .... .. 34
Hydrogeologic Units ......... ........ .... .... ... .... .... .. .. ............... .... ........... .... ........ ... ........ ... ........... 32
263
ANNEXES
Annex A.
Annex B.
Annex C.
Annex D.
Annex E.
Annex F.
Annex G.
Annex H.
Annex I.
The Silala catchment
Climate analysis
Surface waters
Soil analyses
Water balances
Hydrogeology
Integrated surface water/ groundwater modelling
Natural flow scenarios
Questionnaire put by the Plurinational State of Bolivia to OHi
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Executive Summary
Background
OHi (the Consultant) has been contracted by the Government of the Pluri-national State of
Bolivia (Directorate: DIREMAR) to execute the independent technical study: "Flow Analysis of
the Silala Springs, Canal and Wetland System". The present report constitutes the final
deliverable of the study.
The Silala springs and wetlands are located In the Bolivian Potosi Province 4-5 km from the
border to Chile. The springs are fed by groundwater which in the natural state discharged into
wetlands. In the early 20th century the Antofagasta-Bolivia Railway Company introduced a
drainage network which today leads the water through manmade canals to a water intake on the
Chilean side of the border. At present an ongoing dispute between Chile and Bolivia about the
status and use of the Silala's waters has been brought for the International Court in The Hague.
Objective
The main objective of this technical study is to quantify the surface and subsurface flows of the
Silala Wetland and Spring System , under current (modified) conditions as well as in their natural
state, i.e. without the manmade canal and drainage network.
Approach
Surface flows can be measured directly while quantification of groundwater flows (often referred
to as the hidden component of the water cycle) is more complex as it has to be derived from
interpretation of geological (surface) maps and information on hydrogeological properties from
boreholes and indicative geophysical methods.
To establish sufficient data for the flow quantification intensive data collection has been
undertaken. The data collection included : surface flow monitoring , geological mapping;
hydrogeological drilling and testing and analyses of top soils.
Although the groundwater discharge through the Silala Springs system originates from a larger
upstream area, the quantification of the present flows as well as the impacts of the man made
canals can be confined to a much smaller area. This 'Near Field' area comprises only a few
square kilometres in the Silala Valley from the international border to just upstream the Silala
Northern and Southern Wetlands. The data collection as well as the technical analyses has
therefore focused on this 'Near Field ' area.
Historical information on flows and climate prior to the introduction of the canals is insufficient for
proper quantification of the pre-canal flows . Therefore the approach adopted in this study has
been:
to perform a comprehensive analysis of the present (modified) flow system resulting in
a trustworthy conceptual model of it including an understanding of its key hydrological
and hydrogeological drivers and how these processes have been influenced by the
canalization;
to implement this conceptual system understanding in a mathematical model of the
system and subsequently
to use the measurements and the conceptual and mathematical models to quantify the
present flows and finally
Remove the canals in the mathematical model and apply it to quantify flows without the
canals.
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2
To supplement the analyses assessments of infiltration and recharge rates to the aquifers under
the present climatic conditions have also been made.
Major Findings
The findings on the present surface flows in the system:
1. Despite independent continuous and simultaneous flow measurements on the Chilean
and Bolivian side of the border, the actual canal flow at the border remains uncertain .
Based on the records the cross-border surface flow is 160 -210 1/s.
2 . The flow records both in Bolivia and in Chile have a large and constant base flow
fraction indicating that the flow mainly originates from groundw ater. The lack of clear
seasonality in the records also confirms that surface runoff is not an important source.
3. Simultaneous propeller flow measurements carried out under this study have rather
consistently recorded around 160 1/s at the border during May-Sept 2017. These
measurements show that Northern and Southern w etlands contribute to around 40%
and 60% of the confluence flow, respectively.
4 . Inflows from identifiable springs in the Northern and Southern wetland have been found
to account for roughly 60 % of the total canal flow at the confluence of the Northern and
Southern canals, while diffuse groundw ater inflows account for the remaining 40 %.
The findings on the present groundw ater flows in the system :
5. The observed groundw ater levels in the many boreholes established in the Silala "Near
Field" and above show a clear flow direction of the groundw ater from East to West.
Together with the evidence from boreholes of a pervious and w ater holding aquifer this
proves the presence of cross border groundw ater flow into Chile.
6 . While considerable uncertainty remains around the magnitude of the cross border
groundwater flow the hydraulic gradients, ignimbrite aquifer thickness and hydraulic
conductivity indicate that the flux is considerable , i.e. comparable to the present surface
flow
7 . The model results of the Near Field suggest the present cross border groundwater flows
over a 450m wide section around the ravine to be in the order of 100 I/s.
8 . Water sample analysis indicate a w ater age of up to 1,000 years and 11 ,000 years in
the Northern and Southern w etlands, respectively, suggesting relatively long
groundwater residence times in the aquifers and different recharge sources.
9 . The model results confirm a coupled groundw ater - surface w ater system w ithin the
Silala Near Field area e xtending across the border.
Our analyses show that in a situation w ithout the manmade canals:
10. Without canals, both surface w ater and groundw ater w ill cross the border. A reduction in
surface flow of 30-40 % is estimated compared to current conditions . The estimate
includes the effect in the Silala Near Field area hereunder the increased
evapotranspiration and infiltration losses from the confluence to the border.
11 . W ithout the canals, more w ater crosses the border as groundw ater. The groundw ater
flow through a 450 m wide cross section at the border increases by 7-11 % from the
present situation.
267
12. The evapotranspiration increases by 20-30 % by removing the canals and restoring
wetlands. This, however, corresponds to a reduction of only 2-3 I/s in the combined
cross border groundwater and surface water flow.
13. In a situation without the canals, it is not possible that all surface water discharged from
the wetlands infiltrate from the confluence point to the border. The best estimate (based
on detailed simulations) is that 8-12% of the flow may be lost to subsurface flow. At
maximum 25 % may be lost.
14. The canals have changed the amount of discharge from the Silala springs but not the
direction of natural outflow from the Silala wetlands. Also, in a situation without the
canals, the discharge direction is towards Chile.
Other Contributions
DHls approach has been guided by meeting the project objectives and assessing the effects of
removing the canal and drainage network.
In the process a number of separate, yet substantial, analysis have been carried out and
documented in the Final Report annexes. Apart from supporting the project conclusions, each
annex represent a deliverable contributing to the description and an updated understanding of
the climate and hydrological and hydrogeological characterization of the Silala wetlands.
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1
1.1
1.1.1
Introduction
The project
Through contract no. CDP-I N° 001 /2017 of 7 February 2017, the Office for the Protection of
Silala Springs, Diresilala, contracted OHi for the realisation of the first part of this technical study
of the flows of the Silala Wetland and Springs System.
Diresilala was subsequently integrated into DIREMAR, the Strategic Office for the Maritime
Vindication, Silala and International Water Resources. DIREMAR signed new contracts with OHi
(Contract Nos. CDP-I 15/201 ?and CDP-I 01 /2018) for the execution of the remaining part of the
study. The present report constitutes the final deliverable of the technical study of the flows of
the Silala Wetland and Springs System.
The Silala Springs are located at altitudes
from 4300 to 4400 m above sea level in the
arid western part of the Potosi Department of
Bolivia, a few kilometres from the border with
Chile (see Figure 1 ). The Silala Springs
System is fed by groundwater from sources
further inside Bolivia and constitutes the only
flowing surface water resource on the
Bolivian side of the border within a distance
of 20 kilometres.
The Silala Springs System in Bolivia is today
a modified flow system in which a fine
network of pipes and stone lined canals
drains the Silala wetlands and conveys the
water efficiently from the large number of
individual springs in the Northern and
Southern wetlands in Bolivia to a water intake
on the Chilean side of the international border
around 4 km downstream (see Figure 2).
Objectives
Figure 1 Location of the Silala Springs System
The project objective is to carry out a technical study of the flows of the Silala Wetland and
Spring System, quantifying the surface and subsurface flows , both in their current condition and
in their natural state, i.e. flows without the manmade canal and drainage network. The
canalization was introduced by the Antofagasta Railway Company in the early 20th century to
control the flow from the Silala Springs and use it to supply the steam locomotives on the
Antofagasta-Bolivia Railway. The objective concerns and can be confined to a 'near field ' area in
the Silala Valley from the Bolivian-Chilean border to just upstream the Silala Northern and
Southern wetlands located in Bolivia , approximately 3.5 km upstream of the border.
1.2 About this report
This report documents and concludes the study. This main part of the report summarizes the
technical analyses and conclusions which are described in more details in the annexes A-G ,
each referring to one of the technical sections of the main report.
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The report is structured as follows :
Section 1:
Section 2:
Section 3:
Section 4:
Section 5:
Section 6:
Section 7:
Section 8:
Section 9:
Section 10:
Section 11:
(this section): Provides an introduction and context to the overall study.
Describes the Silala Springs System, the hydrological area in which it is located.
It also includes a summary of previous work relevant to understanding the
hydrology and hydrogeology of the Silala area.
Contains our analyses of the most relevant climate components namely the
precipitation, temperature and potential evaporation of the Silala area.
Presents the available information and our analyses of the present surface
water flows of the Silala Springs and wetlands.
Includes the analyses and hydraulic characteristics of the wetlands and the top
soils of the upstream area.
Contains our estimates of aquifer recharge and upland water balance under the
present climate conditions and accounting for the soil types of the area.
Gives our conceptual hydrogeological understanding of the Silala Area as built
from earlier studies and from the extensive hydrogeological field data collection
program.
Describes the establishment and calibration of the integrated numerical surface
water - groundwater model established in accordance with the conceptual
understanding of the system (Section 4 and 7).
Presents the results of the modelled scenarios of the flow conditions of the
Silala Springs System in natural conditions under the present climate but without
the canalization.
Summarizes the conclusions and recommendations of the study.
Is the list of references.
1.3 Study approach and methodology
6
The canal system was established in the early 20th century by the Antofagasta-Bolivia Railway
Company (FCAB) to provide water for the steam locomotives and has until recently been
maintained by the company to keep it free of weeds and siltation.
In its current state, the main canal of the modified system carries a flow at the border of 160-210
I/s. It is the objective of this study to establish the rate of cross-border flow (if any) in a natural
Silala system without the canals.
Very little information is available on the local climate and hydrology prior to the introduction of
these canals and since climate can vary over time scales of decades, it is not possible to
recreate exactly the original hydrological conditions before the canalization. Hence, the
approach taken in this study is to analyse the present modified system in detail, establish a
model capable of reflecting the factors through which the canalization has impacted the natural
system and simulate the system under the present climate conditions but in its natural state
without the canals.
Although the groundwater discharge through the Silala Springs originates from a larger
upstream catchment, the relevant impacts of the introduced modifications are confined to and
described through processes inside a 'Near Field' area in the Silala Valley from the international
border to just upstream the Silala Northern and Southern wetlands (see Figure 2).
271
'
' ' '
Figure 2
Figure 3
N A
'
' '
FCAB ;_
intake
North Cana l
Principal Canal
0 1.5km
Approximate extent of the Silala Near Field. (Mulligan & Eckstein, 2011 ).
Approximate extents of the Silala Far Field.
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Furthermore, it was not possible within the scope and time of this project to collect and process
sufficient hydrogeological information to conduct a comprehensive analysis and determine the
exact extent and flow conditions in the full upstream catchment supplying groundwater to the
Spring. This larger catchment is referred to here as the Far Field, Figure 3. The approach
adopted for this study has therefore been to concentrate the data collection program as well as
the technical analyses on the Silala Near Field .
To improve the basis for the technical analyses, an intensive data collection program in the
Silala Near Field was executed in parallel with the technical analyses. This data collection
program included: surface geological mapping; surface flow monitoring, hydrogeological drilling
and testing, soil sampling in the wetlands and geophysical transect monitoring. Its output data
forms, together with previously collected information, the basis for the technical analyses of this
study.
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The system and the area
Silala belongs to the high altitude Altiplano, a dry puna mountain zone in the transition to arid
Atacama Desert climate. The topography and geology of the Altiplano are dominated by
volcanoes and thick deposits of a pyroclastic density currents (lgnimbrites) (SERGEOMIN,
2003). Due to both climate and altitude, the vegetation is characterised by sparse and scattered
grasses on the plains and volcano slopes. In valleys or low-lying depression areas , wetlands fed
by mainly groundwater are found (Figure 4).
2.1 The wetlands
The Silala Springs System is an example of a type of high Andean wetlands described as
cushion bogs (bofedales) with peat layers formed by Distichia cushions growing within 1-5 cm of
the ground surface.
The wetlands are vulnerable and rely on a long-term steady and reliable water supply to
maintain suitable hydrological conditions and with time build peat layers of organic deposits. In
Silala, the extent of both the Northern and Southern Wetlands is controlled by the topography
and groundwater discharges through springs.
Figure 4 Vegetation in and above the southern Silala wetland . Source: OHi Field visit Feb. 2018
The Silala Springs have been declared an area to be protected through the RAMSAR
convention. The Convention's mission is the "conservation and wise use of all wetlands through
local and national actions and international cooperation, as a contribution towards achieving
sustainable development throughout the world ". In line with the Convention, the Bolivian
Government wants to restore the Silala Springs and Wetlands to its natural state. In addition ,
Silala is part of the Eduardo Abaroa Andean Fauna National Reserve .
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2.2 The Silala Area
2.2 .1
10
Silala has a desert climate with low precipitation, low temperatures but high potential
evaporation. Outside the wetlands the vegetation is very sparse and top soils are coarse and
sandy (Figure 4 ), originating from weathered or glacier eroded lava and ignimbrite formations.
The base rock formation consists of ignimbrite layers with a general inclination towards West
and the valley in which the Silala springs, wetlands and canals are located has been identified
as major faults in the lgnimbrites (SERGEOMIN, 2001 ).
As further described in Annex Fon hydrogeology, the lgnimbrites are porous and fractured and
have been found to have significant hydraulic conductivities. In some areas, the ignimbrites are
found directly under the top soils, while in other parts of the area, they are superimposed by
layers of lavas which have been deposited during later eruptions.
The potential groundwater heads, as found in the piezometer wells established by DIREMAR as
part of this study, indicate a groundwater flow from higher eastern grounds towards the Silala
Springs and further on towards the international border (Annex F).
The Silala catchment
Silala is a groundwater fed system where contributions from superficial catchment runoff are
small in comparison to the stationary or slowly varying groundwater flow contribution (see
Section 4).
The Chilean memorial (Alcayaga, 2017) has delineated a strictly topographical catchment for
Silala upstream of the lnacaliri Police Station. Of this catchment, 59.1 km2 contribute to the
discharge at the international border. The recharge from rainfall over this (59.1 km2 )
topographical catchment cannot, in itself, explain the observed cross-border flows (see Section
6). The hydrological catchment supplying groundwater to the Silala springs is therefore much
larger.
This study has identified the likely hydrological catchment of 234.2 km2 draining to the Silala
springs through known groundwater faults and aquifers. This hydrological catchment has been
used for the recharge and water balance assessments presented in this report. It was found that
the recharge to the aquifers in this catchment can sustain a discharge in the same order of
magnitude as the estimated cross border surface water and groundwater flows .
However, the estimates both of the transborder groundwater flows and of the catchment climate
are uncertain and the exact extension of the real hydrological catchment (the Far Field) remains
unknown, but the identified 234.2 km2 catchment (shown in Figure 5 ) provides sufficient
recharge to explain a substantial part of the cross-border flow.
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---- Geological faults
---- Road
Figure 5
International border
Silala canal
The hydrological catchment used as a basis for the recharge assessments and water
balances of this study.
2.3 Historical descriptions of the Silala Spring System
During the construction of the railway line to Bolivia in 1909-1910, the Antofagasta and Bolivia
Railway Company built a water pipeline from Silala to San Pedro in Chile to supply the steam
locomotives.
In 1922, R. H. Fox, chief engineer for water works at the Antofagasta Bolivia Railway company,
published an article on the water supply to the railway line (Fox, 1922) and described the water
intake at Silala as "a small dam across the stream which has a daily flow (with very slight
variation) of 11 ,300 m3/day" (corresponding to 131 I/s). This is somewhat less than the current
flow range of 160-210 I/s (see Section 4).
In 1928, the present detailed canalization was introduced. This fine masked network of pipes
and rock lined canals was designed to drain the wetlands and convey the flows efficiently from
the many identified springs at the banks or inside the wetlands to the pipeline intake close to the
international Bolivian-Chilean border.
2.4 Processes through which the canalization may have affected the
cross-border flows
The impacts of manmade interventions on the wetlands are clearly visible in the field and on
aerial photos and satellite images provided by DIREMAR. The drainage and canalization work
and more recent local decommissioning or modifications of some sections of the canals are all
visible (Annex C).
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The processes through which the canalization has affected the flow are:
• Increase of discharge emerging from springs and diffuse sources due to lowering
of the hydraulic head loss by removal of peat or constraining rock cover.
Most of the upstream ends of the drainage network constructed within both the Northern
and Southern wetlands, originate in an identifiable spring. At these spring discharge
points, the soil and any underlying layers of coarser material or rocks have been
completely removed. This enhances the spring flow rates by reducing the resistance to
the emerging groundwater. Under natural conditions, less water would emerge on the
surface while more would be retained underground. The direct connection from the
spring to the drainage canal system conveys water more effectively out of the wetland
system , reducing the amount of water retained in the wetland further compared to the
natural situation .
• Decrease in actual evapotranspiration due to drainage and drying of wetlands.
Both the retention of water and the evapotranspiration processes within the wetland
soils have been short circuited . The drainage canals cut through most of the wetlands
not only efficiently conveying water from the springs but also lowering water levels along
these canals. The effect of lowering water tables and soil water contents along canals is
that the availability of water for the wetland vegetation is further reduced and
evapotranspiration within the wetland decreased. The lower water levels will also reduce
the overall area of the wetland retaining water, which will increase the downstream flow
rates. Under natural conditions, the water would be travelling more slowly through the
wetlands both above and below ground.
• Infiltration of surface water reduced in reaches with groundwater tables lower
than the terrain level.
Although the canal lining is pervious, it may still reduce the water's contact to the
surrounding soils, as compared to a free flowing natural channel, and reduce the
seepage out of the canal. However, an even larger effect comes from the concentration
of flow in a narrow canal cross section as compared to a natural situation with a
broader flow area with higher infiltration to the underlying aquifers.
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Climate
This section summarizes our best estimates of relevant climate parameters used in the
catchment water balance studies described in Section 6 and in the detailed integrated
groundwater I surface water studies of the Si/ala Nearfield (Section 8). Technical details on our
climate analyses methodology and results are given in Annex B to this report.
3.1 Approach to the climate analyses.
Silala has a desert climate with highly variable precipitation from year to year. This means that
the recharge to the aquifers may be dominated by the precipitation in a few rare wet years. Both
an assessment of the average recharge and detailed flow analyses of the Silala Springs system
therefore require consistent and reliable data, over many years, for local precipitation, potential
evaporation and temperature.
The density of climate stations in the area is low and the harsh climate conditions in combination
with the remote location of Silala reduce the accuracy of some records. Since the most relevant
climate parameters (precipitation, potential evaporation and temperature) all vary significantly
with location in mountainous areas, it is nevertheless important to make use of measured data
within the area of interest.
Climate time series have been compiled for the hydrological catchment (Figure 5) by combining
local ground based observations with the terrain information of the catchment. Where local
ground observations have been found insufficient to represent the catchment area as a whole,
satellite observations of the area have been used to supplement the ground data. This
combination of ground based and remote sensing observations of the local area is considered
the most reliable estimate for the Silala catchment compared to correlating with observations
over long distances or importing data from other areas with different characteristics.
3.2 Precipitation
Precipitation is the single most important parameter in hydrological analyses and particularly in
mountainous areas such as the Silala area, it varies significantly within short distances.
Furthermore, the density of observation stations is often low in such remote areas, which further
challenges the precipitation assessments.
The precipitation in the Silala catchment is mainly caused by convective activity in a north-east
south-westerly direction with most of the precipitation occurring during the austral summer
months, between December and March, and little precipitation during the winter months, from
April until September.
In Silala, the two local stations are located at the military camp in the Southern Wetland and at
the water intake on the Chilean side of the border, respectively. Unfortunately, both stations
have record lengths that are too short to describe the interannual climate variation in the area.
A combination of ground station data from lnacaliri (5 km downstream of the border) and
satellite based remote sensing data (CHIRPS) is considered the best estimate of long-term
catchment rainfall and has been used in these analyses. The derived average catchment rainfall
using this approach is 125 mm/year for 1969-2017. The inter-annual variation in precipitation is
very high , ranging from close to 0 mm/year rainfall in 2009/2010 to over 300 mm/year in 1997
and 1999.
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Snow has been recorded and observed in the Silala catchment during the austral winter months
but is not captured in the weather station data or in the precipitation satellite data. Precipitation
based on station data, such as the ones used by this study, is therefore likely to underestimate
the actual precipitation, although it has not been possible to quantify the bias.
3.3 Temperature
Precipitation recorded as rain at stations at lower elevations fall as snow at higher
elevations.Temperature records are used to calculate the formation and melting of snow in the
catchment, at higher altitudes.
Temperature records for Silala for 1969-2010 have been constructed by repeating station data
from Laguna Colorada and Silala. The annual average temperature for Silala is 2 .2 °C with
maximum and minimum daily temperatures between +19.6 °C and -19.6 °C.
3.4 Potential Evaporation
14
Strong winds and high radiation from the atmosphere result in a high potential for evaporation in
the Silala catchment. The potential evapotranspiration (Eta) is representative of the evaporating
power of the atmosphere at a specific location and time and only depends on local climatic
variables. It is important for the analyses of the recharge rates to aquifers and for the calculation
of the wetland water losses through evapotranspiration , both in their present and in their natural
state.
Actual evapotranspiration , on the other hand, is the amount of water that is actually evaporated
from the soil and transpired by the plants. It is controlled by water availability and is therefore
usually smaller than the potential evapotranspiration .
As precipitation events in the Silala basin are intermittent, actual evapotranspiration from most
of the basin is only close to the potential rate for short periods of time just after rainfall. However,
in the healthy parts of the wetlands, where water is readily available most of the year, actual
evapotranspiration will be close to Eta.
Potential evapotranspiration records (EtO) have been calculated using weather station data for
three weather stations: Silala, Laguna Colorada and Sol de Manana. The resulting series has an
annual potential evapotranspiration rate of 1472 mm/year ranging from around 2-2.5 mm/day in
the austral winter months to 5-5.5 mm/day in the summer.
The compiled potential evapotranspiration series for Silala has been compared with daily
records from the seven closest stations in Chile and found to be within the range given by these
stations.
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Surface waters
The surface water flows in the present system is described in this section. The spatial and
temporal flow variation is analysed and a conceptual understanding of the system established
and described. This understanding describes the processes affecting the surface flows at the
border under current conditions. It also describes how the canalization has changed the
hydrological/hydrogeological system and thus the impact on natural flows. This is essential to
the development of a numerical model (which is described in Section 8 and 9).
The section also presents the outcome of analyses of the historical and recently surveyed flow
data. The present flows at the border as well as the inflows and possible flow losses to and from
the various sub parts of the system are quantified.
The actual detailed analyses of the present surface flows in the system is included in Annex C.
4.1 The canal system
Dense manmade drainage networks are in function in both the Southern and Northern wetlands.
The drainage canals have been dug as 2nd order and 3rd order branches that collect water
directly from the individual springs and drain these efficiently into the main canals which convey
water to the border (Figure 6). The soil cover, typically in the depth range of 0 .2 - 1.0 m, has
been removed along the drainage canals down to the underlying bedrock and drainage canals
depths vary significantly across the wetland areas. The drainage canals cut through most of the
wetlands and apart from collecting spring water, they act as drains for water from within the
wetland soils, which lowers the water table in the peat soils. Evidence of this is seen in the
subsidence of the peat.
Without these canals more water would be retained over a longer period , both above and below
the surface in a natural wetland system. The effect of lowering water tables and soil water
contents along canals imply reduced availability of water for the wetland vegetation , creating
corridors for invasive dryland grasses (Figure 7).
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Figure 6 Map showing the details of parts of the manmade drainage network in the Northern wetland.
Figure 7 Main drain canal , Northern wetland. Source: DIREMAR 2017.
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4.1.3
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Excavations
Excavations are clearly visible not only at the springs and along drainage and main canals but
also across large parts of the wetland areas. In the Northern wetland, drainage pipes linking up
with the open canal drainage network are found. They have been installed by first excavating
trenches. After laying down the pipes, they have been covered by soil leaving large parts of the
wetland disturbed and dug through (Figure 8). Only smaller coherent patches of undisturbed
soils and wetland vegetation are found in both wetlands. Especially in the Northern wetland,
peat soils have been turned and peat in varying stages of decomposition is visible.
As a result of lowering the water table (because the spring water has now been diverted from
the wetland through these pipes and these excavations), peat layers are exposed to aerobic
conditions. This leads to a gradual degradation of the organic material. Subsidence can be
observed as an impact of this drainage and peat degradation.
In contrast to these excavated areas, undisturbed wetlands develop an undulating surface with a
continuous vegetation cover and open water visible at the surface.
Figure 8 Photo of an excavated section and vertical peat profile at the edge of an undisturbed wetland
patch in the Northern Wetland. Source: OHi Field visit February 2017.
Main canal
The Southern and the Northern main canals are also manmade and cut through the mid-section
of the wetlands collecting water from the second and third order drainage network. They have
been constructed in straight line sections with an approximately uniform slope (Figure 6). The
main canals act as collectors for the surface drainage networks but also as local drains for the
areas close to the channel. The main canal is lined by rocks for stability and to reduce
resistance to flow. In most places, the canal bed sits directly on the underlying permeable base
rock surface and as a result of the pervious canal lining, seepage in and out of the canal occurs
along its entire length.
Later manmade changes
In recent years, the canal network has been changed and modified in sections of the Silala
Wetland and Spring System. In parts of the Southern wetland, the canal and drains have been
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removed, filled in or blocked. This is visible as sections of the canal without any rock lining,
rocks being piled up across the canal and drains, creating upstream water level rises and
diversions to wetland sub-systems. The changes appear to be partial attempts at wetland
restoration (Figure 9).
Figure 9 Canal modification diverting canal flow to wetland subsystem. DHI, 2017.
4.2 The observed flow distribution and the temporal flow variation
18
Continuous flow measurements for the Silala canal are available from two permanent gauging
stations located lose to the international border in Bolivia and in Chile, respectively. These data
have been supplemented by new measurements carried out by SENAMHI during 2017 of which
the data from May to September 2017 have been available for this study. The field program
includes simultaneous micro-propeller flow measurements (21 locations), spring flow
measurements (20-33 springs) and continuous water level recordings behind weirs (six
locations) which are converted to flows .
The long-term time series from the Bolivian and Chilean permanent flumes show mean flow
rates around 160 I/s - 21 0 I/s, with the series from Chile generally showing flows 15-25 I/s lower
than the Bolivian ones. The temporal variations in flow at both locations are generally not
mutually correlated or correlated with seasons, climate or direct runoff events.
The flow data analysis in the two permanent flumes clearly shows that the flows are dominated
by groundwater discharges which are relatively constant in time. The temporal variation
observed in the two series are site-specific and cannot be explained by responses in
neighbouring measurement locations or any climate or runoff events
Despite independent continuous and simultaneous flow measurements on the Chilean and
Bolivian side of the border, the actual canal flow at the border remains uncertain (160 -210 I/s).
The distributed flow measurements have been used to calculate the spatial distribution of
inflows over the canal system as presented in Figure 10. These measurements show that
Northern and Southern wetlands contribute around 40% and 60% of the flow, respectively, and
that a significant part of the flow in the Southern canal enters along the upper reaches of the
southern ravine upstream of the confluence.
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A vertical profile along the Southern canal is shown in Figure 11 . The figure compares observed
flows and canal levels with observed groundwater levels from (boreholes and spring levels). It is
noted that the groundwater levels are higher than the bottom of the canal in the reaches with
high flow increases. Similar profiles for the Northern and the Principal canals are shown in
Figure 12 and Figure 13 respectively.
Inflows from identifiable springs in both the Northern and Southern wetland have been found to
account for roughly 60 % of the total canal flow at the confluence between the Northern and
Southern canals while diffuse inflows account for the remaining 40 %.
Smaller periodic daily flow variations have been detected at all of the seven continuous gauging
sites during the winter of 2017. They cannot have been caused by wetland evaporation since
this is highest at midday and would tend to reduce the flows at this time of the day. The flow
variations may be from the freezing/melting of the water in the wetlands.
The flow measurements have provided valuable information regarding the spatial distribution of
inflows and allowed a breakdown of water balances by reach. Although considerable flows
(approximately 95 I/s) enter through the springs at the Northern and Southern wetlands, a large
groundwater inflow contribution has been identified along the Southern Canal between C3-C5,
especially along the upper reaches of the ravine, coinciding with a locally steep drop in
topography and canal levels.
The different continuous flow measurements around C5-C7 just upstream the border revealed
inconsistencies between the flow records and have not contributed to narrowing the canal flow
range.
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Figure 10
20
157 1/s, 102%
59 1/s
Legend
0 Coitinuous Ftow Stallons
e S1mu1taneou!i. Flow St&IICl'IS
- WbllZonu
COOR0ENADAS_OJOS_AGUAS
(::J Canal Inflow
~
38 1/s GE]
~
37 1/s v
25 % 24 %
Mapping of flows and net inflows based on simultaneous mean canal flow measurements (in 1/s, and percent of the flow at confluence point (the
most reliable assessment point)
18 %
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4420
4400
4380
"!
rt!
E
-;:;- 4360
-0~ rt! >
~
LU
4320
4300
Figure 11
2800 2600
I
I◄
I
~
Groundwater to canal
discharge zone
2400 2200 2000
Profile A - Southern canal
1800
SP-26
\
SP-27
1600
SP-22
SP-25
SP-28
1400 1200
S-7
I
1000
Canal chainage from upstream (m)
Calicata Punto 18 l Barreno Punto 13
DS-13 ----------. t P-!0 S~ l3
C-3
800
DS-12
DS-11-1
Barrena Punta 16
Barrena Punta 14
S-6 S-5
600 400
j SP-3
SP-4
S-1
200
- canal bed elevation • Observed groundwater or spring level ----·Groundwater level - Discharge
Southern canal profile (S-1 to C-5) comparing canal elevations and observed groundwater and spring levels with observed discharge (average
of 10 campaigns)
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140
120
100
.;;-
80 :::::-
(I)
~
60 rt! .c
u
.!!!
Cl
40
20
0
0
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22
Profile B - Northern canal
4400
4390 Barrena punto lb
4380 Barrena punto g , Barrena punto 8
-;-4370
"?
ro 4360
E
;; 4350
0
-~ 4340 ~ C-6
> Q)
T .. ':."~'.")1LV''~:' L ~il~l r d ----- -
---------------------
SP-42
UJ 4330
4320
4310
4300
700 600 500 400 300 200 100
Canal chainage from upstrem end of canal (m)
- canal bed elevation _ .. . Observed groundwater and spring levels --Observed Discharge
Figure 12 Northern canal profile (S-18 to C-6) comparing canal elevations and observed groundwater and spring levels with observed discharge
(average of 10 campaigns)
160
140
120
100 ~
Q)
80 tl.O ... ro
..uc
V, 60 ci
40
20
0
0
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Profile C - Principal canal
180
4390
160
4370
140
=- 4350 120
"!
ro ~
,S 4330
C
0 ·.;:::;
100 -;
DSf37 e!>
ro
80 .c
u
~ 4310
QJ -------;;;,-"'· V'l
ci
w 60
4290
4270 '\.S:,, ... \ :,7:,;······· DS-32
40
20
4250 ~-.------------,----------,---------,---------r---------r---------+ 0
2940
Figure 13
3540 3440 3340 3240 3140 3040
Canal chainage from confluence (m)
- surface elevation • Groundwater level - .. -. Groundwater levels (shallow) • Groundwater level (deep) --Discharge
Principal canal from the confluence to the international border (C7 - S21) comparing canal elevations and observed groundwater and spring
levels with observed discharge (average of 10 campaigns).
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5
6
Soil Analyses and hydraulic characteristics of the wetlands
A soil survey including a field survey, soil profile description, soil sampling and analysis has
been undertaken by DIREMAR during 2017 and used by this study for the development of a
conceptual understanding of the Silala wetlands and springs area and for further development of
an integrated numerical surface water - groundwater model of the Silala wetlands:
Hand auger boreholes and trial pits were established in the wetland area and have mainly been
used for observing the water table but have also provided soil samples for assessing soil
properties. Diamond drilled boreholes have been established in the wetland area and borehole
lithologies have been used for constructing geological profiles below the canal bed .
Soil properties have been assessed using pedo-transfer functions based on soil samples for
both the Far Field area and the wetland area. Annex D to this report gives a brief summary of
the soil data used and the soil profiles within the two wetlands. More comprehensive
descriptions of the further analyses of the data are given in Annex E (on water balances) and
Annex G (on the integrated surface water - groundwater model).
Upland water balance, contributing areas and sources
The scope of this study does not concern the origin of the water discharging through the Si/ala
Springs System, which is not possible to determine due to lack of detailed hydrogeological
information from the full hydrological catchment (the Far Field). Nevertheless, to better
understand the hydrological processes driving the system, this section quantifies probable rates
of infiltration recharge to the aquifers under the present climatic conditions, roughly assesses
possible groundwater travel times to the springs and discusses the possible influence of fossil
water and transbasin flows as further detailed in Annex E.
Based on a water balance, the origin of groundwater discharging the springs is discussed, i.e.
whether this is a result of recharge from rainfall under current climatic conditions or there is a
contribution from fossil groundwater formed under an earlier climate era.
Although important information is lacking such as the real extent of the contributing catchment
(the Far Field) and the exact transborder groundwater flow, it is still possible to draw some
conclusions on the possible sources and catchment areas , as described in detail in Annex E
The water balance and possible storage capacities of two catchments, referred to here as
Catchment A and Catchment B, have been analysed:
Catchment A is the upper part (59.1 km2) of the strictly topographical catchment (delineated by
(Alcayaga, 2017)) that discharges to the Silala canal upstream of the international border. It
includes the Near field as a sub-catchment. The larger hydrological Catchment B (234.2 km2)
includes Catchment A as a sub-catchment and an additional area (the 'Road Catchment')
draining sub-superficially to the Silala Springs. Catchment B is considered hydrologically
representative for the recharge conditions of the Far Field. The two catchments are illustrated in
Figure 5.
Detailed distributed simulations of the rainfall-evaporation-infiltration processes in the two
catchments have been undertaken and have resulted in long term average aquifer recharge
rates (from infiltrated rain water) of 21 mm/y for Catchment A and 24 mm/y for Catchment B,
respectively. Significant recharge takes place in a few wet years only.
The maximum active storage capacity of the aquifers of the two catchments have been roughly
assessed and compared to the required storage volume of a system discharging solely fossil
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26
water or a mix of recharged and fossil water over a period of 5000 years corresponding to an
approximate average water age from isotope analyses.
It was found that Catchment A (Alcayaga, 2017) is only capable of maintaining a discharge of
34-84 I/s, based on recharged water which is significantly less than the observed surface water
across the border (160-210 I/s). Furthermore, this catchment does not have sufficient active
groundwater storage capacity to sustain the remaining part of the observed surface discharge
over the assumed discharge period from fossil water. This suggests that the area contributing
water to the Silala Springs must be significantly larger than that of Catchment A.
The hydrological catchment, Catchment B, can sustain a flow of 151-374I/s from recharged
water which is in the same order of magnitude as the observed surface water (160-210 I/s) and
estimated cross border groundwater flow in the order of (100-230 I/s) (Annex F and Annex H).
Overall, the analysis indicates that a large proportion of the water feeding the wetland is from
recharge from rainfall and snow melt in the hydrological catchment.
However, the estimates (particularly of the cross border groundwater flows and the catchment
climate) are uncertain and the possibility remains of the real contributing area (the Far Field)
being different to the assumed hydrological catchment or of other sources also contributing to
the Silala springs.
More specifically the water balance studies have established that:
• Despite the lack of vegetation, a large part of the precipitation (70--85%) of the
precipitation falling outside the wetlands evaporates,
• The aquifer recharge is complex and takes place as a consequence of a few larger
precipitation events. It also varies significantly from year to year (Figure 14).
Hydrological simulations with a daily or finer temporal resolution and covering many
years are necessary to capture this recharge pattern.
• The largest recharge rates are found at high altitudes around the top of the volcanoes
where a larger fraction of the precipitation falls as snow, which also reduces the
evaporation loss at these altitudes.
Exploratory groundwater simulations of Catchment B show long residence times for the water in
the aquifers , although shorter than those indicated by the Isotope analyses. These simulations
have not been able to capture the difference in water age in the two wetlands.
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Modelled water content over time in a sandy soil column above the Silala wetlands. The
colours show the content in the soil from light blue (dry soil) to dark blue (saturated soil) from
the surface to the depth of 4 meters for the period 1969-2016.
Hydrogeology and groundwater
This section summarizes the findings of our hydrogeo/ogica/ analyses combining the previous
geological and hydrogeological mapping; the results of the extensive hydrogeological
characterisation program executed during 2017; the available hydro-chemical data and the
knowledge on the surface water flows in the system. Our findings are compiled in a so called
Hydrogeological Conceptual Model comprising a three-dimensional interpretation of the
hydrogeo/ogica/ conditions in the Si/ala Near field ,i.e. the dominant water bearing fractures and
formations along with their hydrogeo/ogica/ characteristics such as water levels, hydraulic
conductivity and water holding capacity. The conceptual model forms the basis of the
groundwater component of the integrated numerical model which is being used to determine
surface water flows in a natural situation without the manmade canals.
In this section, we also present coarse assessment of the possible groundwater flow across the
international border. More detailed technical description of our analyses and findings are given
in Annex F.
7.1 Field surveys, objectives and main results
An extensive hydrogeological characterisation program in the Silala Near Field was executed by
DIRE MAR during the second half of 2017. The purpose of this program was to provide important
insights into the hydrogeology of the site including groundwater levels, hydraulic properties,
horizontal and vertical groundwater flow patterns.
The results of the program have together with existing geological , hydrogeological and hydrochemical
data been used to develop a Hydrogeological Conceptual Model (HCM) for the Silala
Near Field. The HCM provides the foundation for understanding the Silala hydrogeology and the
Silala Near Field groundwater flow component of the integrated hydrological model.
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28
In porous media such as soil or weathered rock, groundwater flows in voids between grains or
fragments, while in more compact rock formations , the flow takes place in fractures and faults.
Hydrogeological formations with a highly developed and interconnected pattern of fractures
react equivalently to a porous media.
Gradients in the groundwater water levels in both artesian and unconfined aquifers determine
the direction of groundwater flow. Together with the hydraulic properties of the aquifers
(conductivities and depths), they determine the local groundwater flow rates. Since both the
groundwater levels and the hydraulic properties of the formations vary with the location and
depth, it is never possible to obtain a complete picture of the groundwater conditions but
approximations can be interpolated from point information (boreholes) and supplemented by
geophysical measurements (e .g. electro resistivity measurements, which have been used in
Silala).
Thirty-five piezometer boreholes with depths varying from 5m to 142m have been established
for groundwater level monitoring, water sampling for laboratory analysis (see Figure 15). To
estimate hydraulic conductivities of the aquifers 89 in-situ permeability tests were carried out in
the thirty-five boreholes. Additionally, pumping tests, that provide hydraulic properties integrated
over a larger area and therefore provide results more representative of the larger aquifer
system, have been performed in the upstream end of the Southern wetland in borehole DS-4P.
An interpolated map of the groundwater levels in the Silala Near field (Figure 15) show gradients
towards the wetlands, levels close to the terrain inside the wetlands and general gradient along
the wetlands in the same directions as the bottoms of the ravines. Thus, the groundwater flow
direction is towards Chile.
The difference in groundwater levels from the uppermost borehole to the Southern wetland and
from the Southern wetland to the international border are 70 m and 120 m respectively. It is
therefore not conceivable that the canalization with its rather limited excavation depth should
have changed the direction of the groundwater flow.
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...,
A
Figure 15
1
Kilometers
D~
Spring
Piezometers (Groundwater Elevation. masl)
--- December 2017 Water Levels
- - --- International Border
Borehole locations and groundwater level contours in the Silala Near field , interpolated form Piezometer wells spring elevations and wetland
excavations for soil sampling. N.B. the contouring away from the wetlands and the boreholes are uncertain.
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7.2 Conceptual Hydrogeological Model (HCM)
30
The data from hydrogeological characterisation program (the boreholes and electro resistivity
transects) has been combined with previous Bolivian data (surface geological mapping, water
quality, surface water flow rates) and borehole data and pumping test results from the Chilean
side of the border (Arcadis 2017). The combined data have been used to develop the HCM of
the Silala Near Field and to a lesser extent the Silala Far Field areas.
The conclusions of the combined data analyses regarding the conceptual groundwater flow
system of the Silala Near Field include:
Groundwater discharge is the principal source of water to the Silala spring system .
Dominant sources of groundwater to the springs are:
• Northeast trending structures including several large faults. These fault
zones are brecciated and have elevated hydraulic conductivity relative
to the surrounding materials and are interpreted to be transmitting
groundwater over large distances (i.e. Silala Far Field or beyond);
• A network of small apertures, northwest trending fractures act as
conduits transmitting groundwater along strike;
Pumping tests completed in the Southern Wetland indicate a transmissive ignimbrite
aquifer with large-scale hydraulic conductivity estimated to be about 18 m/d and locally
higher conductivity within the Silala Fault Zone (up to 54 m/d). These are higher than
the 6.5 m/d estimated from the pumping tests in Chile near the border;
Hydraulic test data indicate that:
• Fractures in the ignimbrites are well connected over a large scale, and
appear to control the flow characteristics of the aquifer.
• The aquifers approximate a porous media;
Groundwater head measurements indicate that groundwater is discharging to the
Southern and Northern wetlands (gaining) but much further downstream the
groundwater may be hydraulically disconnected from the Silala Canal at the ChileanBolivian
border (disconnected losing stream);
The hydrochemistry and age of the groundwater discharging into the Northern wetlands
is significantly different from that of the Southern wetland (Figure 16). Water in the
southern wetland was found to be considerably older than water in the northern
wetland . Isotope analyses indicate the average age to be up to 1,000 years in the
Northern and 11 ,000 years in the Southern wetland , respectively. Although such
analyses may over-estimate the real water age (see Annex F), the age of the spring
water is indeed very old. A likely interpretation of the difference in water chemistry and
age is that this older water is derived from flow within the Silala Fault zone from a subregional
to regional flow regime (i.e. the Silala Far Field), while the younger water in the
Northern wetland is more likely to be derived from localised flow closer to the Silala
Near Field . Hydrochemistry data also suggests that Laguna Khara (itself) is not a
significant contributor to the groundwater discharge to the Silala Spring System.
295
Na+K
ca r: M,
3 2
KEY I - 3 r'---, WWW- .._ < C .......
N
' ............
' A o■c■oo::.,2,■s-o■-s==o::i.1■s-•1 '
" ~ -metens
' · ... , .... -,_ 1..-.-,lu~ ~ '--
,, ·,, ,
i
! ; ,_
·,\ ...
-\
\\
D ~
-" - 1 0 I
Laguna Khara
Fi'■, ,,-17kmtotheNW
. 1(1]
\ Red Plots: Springs
\,. __________ .......... Green Plots: Groundwater
Blue Plots: Silala River
Percent Modem carbon
Figure 16 14C concentrations (fat black numbers) and stiff diagrams of water chemistry from Silala water sampling locations indicating spring water in the
Northern Wetland and spring water from the Chilean right bank being significantly different than deeper ground water from the fault zone and
spring water from the Southern Wetland.
The expert in WATER ENVIRONMENTS 31
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The geological formations have been classified according to their hydrogeological
characteristics which have resulted in 8 hydrogeological units (HGUs) (Table 1 and Figure 17).
These 8 HGUs constitute the building blocks of the Conceptual Hydrogeological model, as
illustrated in Figure 18.
Table 1 Hydrogeologic Units
Hydrogeologic Unit Basic Lithology Approximate Thickness
(m)
HGU1 Colluvial deposits 1 to 10 m
HGU2 Glacial deposits, sandy loams 1 to 10 m
HGU3 Weathered lava flows 1 to 30 m
HGU4 Felsic volcanic sequences Up to 600 m
HGU6 Upper lgnimbrite deposits with a high degree of welding Up to 150 m
HGU5 lgnimbrite deposits with a low degree of welding 10to120m
HGU6 Lower lgnimbrite deposits with a high degree of welding
Up to 300 m; assumed to be
300 m in the model
HGU7
Fault zones believed important for groundwater 50 to 100 m wide, depth to
flow base of ignimbrite (assumed)
HGU8 Volcanic neck of Silala Chico
650 to 760 m diameter; depth
to base of ignimbrite
297
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A B
N N A --·-- .... M._ ....... - "'"' - K;U2 - K;Ul - "'"' - "'"' - K;UO - K;U7 A --·-- .... M._ ....... "'"' "'"' ><lU3 >«Ju• "'"' ><lUO ..,.,,
Figure 17 A) Delineation of hydrogeologic units (HG Us) in the Silala area. B) Silala site imagery overlaid by delineated HGUs.
The expert in WATER ENVIRONMENTS 33
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Figure 18
34
' ~~
-0~
..
Hydrogeologic Framework Model rendered in 3D. The Silala Fault (HGU7) is highlighted in red . Remaining units are displayed with transparency for easier
viewing of modelled subsurface.
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7 .3 Groundwater over the international border
There is considerable evidence to suggest that there is significant groundwater flow across the
international border. The Chilean pumping tests confirm that permeable and saturated ignimbrite
exists at the border to a depth of at least 117 m below ground surface. Furthermore, gradients in
the groundwater levels both on the Bolivian and Chilean side of the border indicate groundwater
flows from Bolivia to Chile.
While uncertainty remains around the exact value of transboundary groundwater flow into Chile,
the hydraulic gradients, ignimbrite aquifer thickness and hydraulic conductivity indicate that the
flux may be in the same order of magnitude as the observed surface flow.
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8 Integrated surface water - groundwater modelling
This section gives a brief overview of the numerical integrated surface water- groundwater model
of the Si/ala Near Field developed for this study and its performance. A full technical
documentation of the model establishment and its calibration is given in Annex G to this report.
8.1 Rationale and objective
8.2
8.2.1
An integrated hydrological modelling tool of the Silala Near Field area has been developed and
used in scenario analysis with the objective to assess the differences between flow conditions in
the present canalized situation and scenarios where the canals are removed. As explained in
section 2.3 above, the processes through which the canals have affected the surface water flows
are all related with surface water - groundwater interactions. An integrated numerical surface
water - groundwater model is therefore needed to quantify these impacts.
Establishment of the integrated surface water - groundwater model
Implementation of the conceptual models
The total model area of the Silala Near Field is 2.7 km2 and the main elements of the model has
been established in accordance with the conceptual models described in the previous sections.
All canals are represented in the hydrodynamic one-dimensional model in terms of cross
sections and levels as surveyed in the field . Canal modifications as observed in the field has
been included.
Flow and water ponding on terrain is described in the two-dimensional overland flow component
in a 1 0 m by 1 0 m grid of the whole Near Field. The terrain levels of the overland flow model
have been interpolated from the detailed drone survey of the area.
The unsaturated zone model calculates the evapotranspiration from the wetlands and all upland
areas and has been established using standard parameters for the soil types found in the
wetlands during the soil survey. This model uses the same grid resolution as the overland flow
model.
The 3-D hydrogeological model developed from geological maps, geophysical transects and
borehole data (Appendix F) is implemented in the numerical groundwater model. The
hydrogeological units and their spatial extents defined in the hydrogeological model are
represented . The numerical groundwater model applies three layers. The top layer has varying
thickness and hydrogeological properties as it incorporates all surficial lense deposits (HGU 1 -
HGU 4). The second layer includes the upper Silala ignimbrite (HGU 5) and the third layer
represents the deep ignimbrite layer (HGU 6). The fault line (HGU 7) defined from the surface to
a depth of 400 m cuts across the layers and introduces a high permeable flow zone along the
canals. The same horizontal grid resolution of 10 m by 10 m as in the above models is used.
The boundary conditions to the model is Climate (precipitation , potential evaporation and
temperature), ground water levels (as determined by the field observations) along the upper
groundwater boundaries and constant groundwater gradient along the lower boundary.
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8.2.2 Model calibration and performance
38
Model parameters have been adjusted iteratively in a calibration process to demonstrate that the
model qualitatively describes the Silala Near Field hydrology in accordance with conceptual
understanding and that the model results produced quantitatively matches the measured values.
It has been found that the overall results of the integrated model reproduce the important
characteristics from the field observations in terms of:
• Significant groundwater inflows to the Silala Near Field area through the high permeable
fault zone and upper Silala ignimbrite
• Overall groundwater flow towards the low-lying wetlands, the canals and the deep cut
ravine sections.
• Groundwater feeding surface water by discharges to the springs, canal and drainage
network
• Upstream gaining canal reaches versus the downstream neutral or loosing reach from
the confluence to the border.
• Outflow of the Silala Near Field area as combined canal and groundwater flow at the
border
The calibration against field data show that:
• The model simulates groundwater discharge to the canal system in terms of measured
mean canal flow (C1-C7) reasonably well, i.e. 0 -18 % deviation.
• The largest relative difference is found at upstream southern canal (C1-C3). From C4 to
the downstream confluence and border area including the northern branch (C6), the
model performs well with differences to the observations which are within the canal flow
measurements uncertainty.
• The calibrated model water balance shows groundwater flow across the downstream
model boundary in the order of 106 I/s compared to surface water flow of 150 I/s. The
few groundwater observations in the cross section are from the ravine and insufficient to
fully verify the model simulated flow. The width of the downstream model boundary is
450 m (with the ravine in the centre). For comparison, the rough hand calculation in
Annex F assessed 230 I/s (or more), but over a much larger cross section and using
less information.
• Evapotranspiration mainly occurs in the wetlands and along the canal riparian corridor.
Due to the restricted total area the total ET losses correspond to only 10 I/s under
current conditions.
In summary:
The numerical model is developed from the conceptual understanding and the field data
collected . The calibrated model is able to simulate the canal flows (C1-C7) reaching
approximately 150 I/s at the border.
The model results suggest a considerable groundwater flow component but it cannot be
confirmed by measurements and is therefore more uncertain than surface water flows.
However, the model results confirm a coupled groundwater - surface water system within
the Silala Near Field area extending across the border.
The calibrated model is in reasonable agreement with the current conditions and therefore
a sound basis for estimating the impacts of the canals.
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Assessment of the natural flows
To address the main objective of this project, the following baseline and scenario models have
been run:
1) Baseline model. Represents the current (2018) Silala Near Field area with the canal and
drainage network. The surface water canal model includes both reaches which are more or
less unchanged compared to the original canal construction but also reaches where the
canal has been removed or blocked. The baseline scenario is used as a reference to
estimate the magnitude of changes .
2) No canal scenario. The entire canal and drainage network included in the baseline model
is removed. Surface water flow is not restricted to the narrow canal cross sections and the
direction of flow is largely controlled by the surface topographical slope.
3) Wetland restoration scenario. By removing the canal and drainage network, the basis is
created for restoration of the degraded wetlands and riparian corridors. The scenario
considers the resurfacing and long-term peat accumulation in wetlands.
9.1 Flows in the natural wetlands without the canalization
According to the integrated model scenario results removing the canals and restoring wetlands
will affect both groundwater and surface water and both inflows and outflows of the Silala Near
Field area.
1. The simulated surface water flow at the downstream model boundary (located at the
Bolivian-Chilean border) reduces by 31-40 % relative to the present situation.
2. The simulated groundwater flow at the downstream model boundary (located at the
Bolivian-Chilean border) increases by 7-11 % relative to the present canalized situation
3. The total model boundary inflow at the upstream model boundary decreases by
10-15 %.
4. The evapotranspiration increases by 20-30 % by removing the canals and restoring
wetlands. This increase amounts to 2-3 I/s in the situation without the canals and is
included in the cross-border flow changes mentioned under point 1 and 2
5. For the confluence to border section, a maximum of 25 % of surface water may be lost
to subsurface flows. Infiltration loss in this section is included in the cross-border flow
changes mentioned under point 1 and 2.
6. All of the scenario results and local model analysis suggest that both surface water flow
and groundwater flow should be expected at the border.
The flow impact percentages describe the model results ranges but not the uncertainty on model
results. Model predictive uncertainty depends on a number of factors and uncertainty sources,
e.g. limitations in input data, model structure, parametrisation and measurement errors. A strictly
quantitative uncertainty analysis is not feasible and has not been attempted but model
uncertainty should not be ignored in the interpretation of results.
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10 Conclusions
The findings on the present surface flows in the system:
1. Despite independent continuous and simultaneous flow measurements on the Chilean
and Bolivian side of the border, the actual canal flow at the border remains uncertain.
Based on the records the cross-border surface flow is 160 -210 I/s.
2. The flow records both in Bolivia and in Chile have a large and constant base flow
fraction indicating that the flow mainly originates from groundwater. In the Bolivian
records , this base flow fraction is around 160 I/s. The lack of clear seasonality in the
records also confirms that surface runoff is not an important source.
3. Simultaneous propeller flow measurements carried out under this study have rather
consistently recorded around 160 I/s at the border during May-Sept 2017. These
measurements show that Northern and Southern wetlands contribute to around 40%
and 60% of the confluence flow, respectively.
4. Inflows from identifiable springs in the Northern and Southern wetland have been found
to account for roughly 60 % of the total canal flow at the confluence of the Northern and
Southern canals while diffuse groundwater inflows account for the remaining 40 %.
The findings on the present groundwater flows in the system:
5. The observed groundwater levels in the many boreholes established in the Silala "Near
Field" and above show a clear flow direction of the groundwater from East to West.
Together with the evidence from boreholes of a pervious and water holding aquifer, this
proves the presence of cross border groundwater flow into Chile.
6. While considerable uncertainty remains around the magnitude of the cross border
groundwater flow the hydraulic gradients, ignimbrite aquifer thickness and hydraulic
conductivity indicate that the flux is considerable, i.e. comparable to the present surface
flow
7. The model results of the Near Field suggest the present cross border groundwater flows
over a 450m wide section around the ravine to be in the order of 100 I/s.
8. Water sample analysis indicate a water age of up to 1,000 years and 11 ,000 years in
the Northern and Southern wetlands, respectively, suggesting relatively long
groundwater residence times in the aquifers and different recharge sources.
9. The model results confirm a coupled groundwater - surface water system within the
Silala Near Field area extending across the border.
Our analyses show that in a situation without the manmade canals:
10. Without the canals, both surface water and groundwater will cross the border. A
reduction in surface flow of 30-40 % is estimated compared to current conditions. The
estimate includes the effect in the Silala Near Field area hereunder the increased
evapotranspiration and infiltration losses from the confluence to the border.
11. Without the canals, more water crosses the border as groundwater. The groundwater
flow through a 450 m wide cross section at the border increases by 7-11 % from the
present situation
12. The evapotranspiration increases by 20-30 % by removing the canals and restoring
wetlands. This, however, corresponds to a reduction of only 2-3 I/s in the combined
cross border groundwater and surface water flow.
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13. In a situation without the canals, it is not possible that all surface water discharged from
the wetlands infiltrate from the confluence point to the border. The best estimate (based
on detailed simulations) is that 8-12% of the flow may be lost to subsurface flow. At
maximum 25 % may be lost.
14. The canals have changed the amount of discharge from the Silala Springs but not the
direction of natural outflow from the Silala wetlands. Also, in a situation without the
canals, the discharge direction is towards Chile.
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11 References
Alcayaga, H., 2017. CHARACTERIZATION OF THE DRAINAGE PATTERNS AND RIVER
NETWORK OF THE SILALA RIVER AND PRELIMINARY ASSESSMENT, s.l. : Universidad
Diego Portales.
Arcadis, 2017. Detailed Hydrogeological Study of the Silala River. International Court of Justice
Dispute over the status and use of the waters of Silala (Chile vs.Bolivia), s.l.: Memorial of the
Republic of Chile, Volume IV, Annex 2.
Chile, M. o. t. R. o. , 2017. Volume I, Memorial and experts report,, s.l.: International Court of
Justice.
COFADENA, 2017. Proyecto Geofisico 28 Lineas Tomograficas Zona Silala, La Paz, Bolivia:
Corporacion de las Fuerzas Armadas para el Desarrollo Nacional (COFADENA).
Fox, R. H. , 1922. Engineering hydraulic works to capture and analyse the water of the Siloli
Plains. s.l. :South African Journal of Science. Vol. 19, p: 120-131 .Ministerio de Energias, 2017.
Analisis Fisico Quimico de Aguas, La Paz, Bolivia: INSTITUTO BOLIVIANO DE CIENCIA Y
TECNOLOGIA NUCLEAR CENTRO DE INVESTIGACIONES Y APLICACIONES NUCLEARES
UNIDAD DE ANALISIS Y CALI DAD AMBIENT AL.
Mulligan, B. & Eckstein, G., 2011 . The Silala/Siloli Watershed: Dispute over the Vulnerable
Basin in South America. Water Resources Development Vol 27, no 3., 27(no.3).
SERGEOMIN, 2001 . Studies of Hydrographic Catchments, Catchment of the Silala Springs,
Catchment 20. s.l. :DEpartment of Potosi.
SERGEOMIN, 2003. Studies of Hydrographic Catchments, Catchment of the Silala Springs,
Catchment 20. s.l.:DEpartment of Potosi.
SERGEOMIN, 2., 2001 . Mapa no 2 Geologia, Hidrologia y hidrogeologia de los manantiales del
Silala. s.l. :SERGEOMIN.
SERGEOTECMIN, 2004. lnvestigaciones en los Manantiales del Silala - Presentacion Silala
FISICO-QUIMICO ISOTOPOS, La Paz: Internal investigation report., s.l.: s.n.
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Glossary
Term
Aquifer
Austral summer
Basin
Catchment
Confined aquifer
Depression, terrain
depression or sink
Desert climate
Digital elevation model
(DEM)
Discharge
El Nino
Meaning/Definition
Geological formation capable of storing, transmitting and yielding
exploitable quantities of water.
Summer period in the Southern Hemisphere.
Area having a common outlet for its surface runoff.
The whole of the land and water surface contributing to the discharge at
particular stream cross section. This means that any cross section of a
stream will have a unique catchment of its own. (Wilson, 1978).
Confined aquifers are aquifers that are overlain by a confining layer,
often made up of clay or other geological formations with low
permeability.
A depression (or sink) is a low point in the terrain surrounded by higher
ground in all directions. If the soil is impervious, the depression collects
rain water from a local catchment. Surface water or groundwater inflows
will accumulate in the depression until:
- the water level reaches the nearest terrain threshold and runs off or
- the evaporation from the depression is equal to its combined surface
water groundwater inflows. However, a depression may also drain subsuperficially
to lower lying areas through pervious soils, geological
faults or groundwater aquifers.
Desert climate (in the Koppen climate classification BWh and BWk,
sometimes also BWn), also known as an arid climate, is a climate in
which precipitation is too low to sustain any vegetation at all, or at most
a very scanty shrub and does not meet the criteria to be classified as a
polar climate.
Data files holding terrain levels often organised in a quadratic grid with
a certain cell size (e.g. 30m by 30 m). They are very convenient tools
for and often used as standard tools in Geographic Information
Systems (GIS) for delineation of topographical catchment and for many
other purposes.
Volume of water flowing per unit time, for example through a river
cross-section or from a spring or a well.
El Nino is the warm phase of the El Nino Southern Oscillation
(commonly called ENSO) and is associated with a band of warm ocean
water that develops in the central and east-central equatorial Pacific
(between approximately the International Date Line and 120°W),
including off the Pacific coast of South America. El Nino Southern
Oscillation refers to the cycle of warm and cold temperatures, as
measured by sea surface temperature (SST) of the tropical central and
eastern Pacific Ocean. El Nino is accompanied by high air pressure in
the western Pacific and low air pressure in the eastern Pacific. The cool
phase of ENSO is called "La Nina" with SST in the eastern Pacific
below average and air pressures high in the eastern and low in western
Pacific. The ENSO cycle, both El Nino and La Nina, causes global
changes of both temperatures and rainfall.
309
Evapotranspiration
Food and Agriculture
Organization of the
United Nations (FAO)
Fossil Water
Geographic
Information System
(GIS)
Groundwater
Hydrogeological
Conceptual Model
(HCM)
Hydrogeological
Framework Model
(HGFM)
Hydrological
catchment
Combination of evaporation from free water and soil surfaces and
transpiration of water from plant surfaces to the atmosphere.
Specialised agency of the United Nations that leads international efforts
to defeat hunger. FAO is also a source of knowledge and information,
and helps developing countries in transition modernise and improve
agriculture, forestry and fisheries practices, ensuring good nutrition and
food security for a 11.
While all definitions of fossil water agrees that it is old water stored in
aquifers or glaciers for thousands or millions of years, they do not
strictly agree if the waters are non renewable (Definition 1) or if they
have "just" infiltrated many years ago (Definition 2). In this report,
definition 1 has been used.
Definition 1: Oxford living Dictionary
(https://en.oxforddictionaries.com/definition/fossil_water): Fossil water is
water that has been contained in an aquifer, glacier etc. for a very long
period of time (thousands or millions of years) and hence is not
renewable.
Definition 2: UNESCO defines fossil groundwater as water that
infiltrated usually millennia ago and often under climatic conditions
different from the present, and that has been stored underground since
that time.
A geographic information system (GIS) is a system designed to
capture, store, manipulate, analyse, manage, and present spatial or
geographic data.
Subsurface water occupying the saturated zone (i.e. where the pore
spaces (or open fractures) of a porous medium are full of water).
The conceptual understanding of the individual components in a
hydrologic system (i.e. groundwater, surface water, and recharge) and
the processes involved between each component.
A three-dimensional geologic model that defines the spatial extent of
stratigraphic and structural features. The development of the HGFM
incorporates topographic, geologic, geophysical, and hydrogeologic
datasets.
The hydrological catchment is the total area contributing to the
discharge at a certain point. The hydrological catchment includes all the
surface water from rainfall runoff, snowmelt, and nearby streams that
run downslope towards a shared outlet, as well as the groundwater
underneath the earth's surface. Since groundwater may cross the
topographical divides a hydrological catchment to a point may be larger
than the corresponding topographical catchment as indicated in the
The expert in WATER ENVIRONMENTS 45
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Infiltration
Penman-Monteith
Recharge
Reference
evapotranspiration
(Eto)
Remote sensing
Satellite
Sensitivity analysis
Spatial variation
Spring
Princi le sketch below.
// topogrophicol
waler d1v1de
surfoc
catchment
A
runof
Hydrological catchment B
The movement of water from the surface of the land into the
subsurface.
Method for estimating reference evapotranspiration (Eta) from
meteorological data. It is a method with strong likelihood of correctly
predicting ETo in a wide range of locations and climates and has
provision for application in data-short situations.
Contribution of water to an aquifer by infiltration.
The evapotranspiration per area unit under local climate conditions from
a hypothetical grass reference crop with an assumed crop height of
0.12 m, a fixed surface resistance of 70 s m-1 and an albedo of 0.23.
The reference surface closely resembles an extensive surface of green,
well-watered grass of uniform height, actively growing and completely
shading the ground. A good approximation to the maximum
evapotranspiration that under a certain climate can evaporate from an
area unit covered by an ever-wet short green vegetation (e.g. a
wetland)
Acquisition of information about an object or phenomenon without
making physical contact with the object and thus in contrast to on-site
observation. In current usage, the term "remote sensing" generally
refers to the use of satellite- or aircraft-based sensor technologies to
detect and classify objects on Earth, including on the surface and in the
atmosphere and oceans, based on propagated signals (e.g.
electromagnetic radiation).
Artificial body placed in orbit round the earth or another planet in order
to collect information or for communication.
Sensitivity analysis is the study of how the uncertainty in the output of a
mathematical model or system (numerical or otherwise) can be
apportioned to different sources of uncertainty in its inputs.
When a quantity that is measured at different spatial locations exhibits
values that differ across the locations.
A spring is a place where groundwater emerges naturally from the rock
or soil. The forcing of the spring to the surface can be the result of a
confined aquifer in which the recharge area of the spring water table
rests at a higher elevation than that of the outlet. Spring water forced to
311
Topographical
catchment
Weather station
Wetland
Conceptual model
Numerical model
D~
the surface by elevated sources are artesian wells. Non-artesian
springs may simply flow from a higher elevation through the earth to a
lower elevation and exit in the form of a spring, using the ground like a
drainage pipe. Still other springs are the result of pressure from an
underground source in the earth, in the form of volcanic activity. The
result can be water at elevated temperature such as a hot spring.
A catchment delineated strictly by topographical divides of the terrain.
The topographical catchment includes all the surface water from rainfall
runoff, snowmelt, and nearby streams that run downslope towards a
shared outlet. This is the correct catchment if all discharge is surface
flow (i.e. no groundwater). The topographical catchment is often a good
approximation to the catchment, particularly for larger catchments.
A facility, either on land or sea, with instruments and equipment for
measuring atmospheric conditions to provide information for weather
forecasts and to study the weather and climate.
A wetland is a land area that is saturated with water, either permanently
or seasonally, such that it takes on the characteristics of a distinct
ecosystem. The primary factor that distinguishes wetlands from other
land forms or water bodies is the characteristic vegetation of aquatic
plants, adapted to the unique hydric soil. Wetlands play a number of
roles in the environment, principally water purification, flood control,
carbon sink and shoreline stability.
Representation and simplification of a real life, physical system e.g. a
hydrological system by means of overall, key processes governing flow
A model solving governing equations of e.g. flow. Typically a computer
program simulating state variables such as flow and water levels in time
and space
The expert in WATER ENVIRONMENTS 47
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313
Danish Hydraulic Institute (DHI), Study of the Flows in the
Silala Wetlands and Springs System, 2018
Annex A: The Silala Catchment
(Original in English)
314
315
Contract CDP-I No 01/2018, Study of
the Flows in the Silala Wetlands and
Springs System
Product No. 2 - 2018 Final Report
Annex A : The Silala Catchment
o L
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Plurinational State of Bolivia, Ministry of Foreign Affairs, Diremar
July 16, 2018
DHI • Agern Alie 5 • • DK-2970 H0rsholm • Denmark
Telephone: +45 4516 9200 • Telefax: +45 4516 9292 • [email protected] • www.dhigroup.com
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CONTENTS
Glossary ...................................................................................................................................... 3
1 Introduction ................................................................................................................. 6
2 Location of the Silala Springs System and the area in general ........... .................... 6
2.1 The Altiplano area and its wetlands ... ..... .... .... ....... ... ..... ..... .... ...... ..... .... ..... ...... ............. ..... ..... ...... 6
2.2 The Silala area .... ..... .. ... .. ... .. ... .. .... ..... ..... .... ... .. ....... .... .. .. ... ... .. ... ....... .. .. ..... ....... ....... ................ .... .. 8
3 Digital elevation models of the Silala catchment ...................................................... 9
4 The topographical catchment of the Silala Springs ................................................ 10
5 The hydrological catchment of the Silala Springs .................................................. 12
6 References ................................................................................................................. 13
FIGURES
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
TABLES
Table 1
Table 2
Location of the Silala Springs .. .. ....... .. ...... .. .... .. .. .. .. ... .... ........ .... ..... .. ... .. .... .... .. ... .. .... .... .. ... .. .... ...... 6
The Near field and far field of the Silala springs system .. ... .......... ... ....... ..... ..... ............. ..... ..... .. .... 7
Approximate extent of the Silala near field . (Mulligan, et al. , 2011 ) . .... .. .. ... .. ... .. .. ... .. ... .. ... .. ... ..... .. 7
Vegetation in and above the southern Silala wetland .... ..... ....... ... ............. .......... ............... ...... ..... 8
Soils in Silala's hydrological catchment (the Far Field) .... ..... ......... .. .... ..... ..... .......... .......... ..... .. .... 9
Topographical data used in the surface model. The coloured area was interpolated from 1
m contour lines received from DIREMAR (IGM, 2016). The remaining area is based on
topographical raster information from the drone flight (IGM, 2016). The man-made
drainage canals are shown as blue lines .. .. ..... ... .. .. ... .... .... ... .. ... ..... ... .. .. ... .. ... .. ... .. .... .... ..... ...... .... 10
Silala topographical catchment insufficient to maintain the flow at the springs . ... ....... .... ... .. ....... 11
The hydrological catchment of the Silala Springs .. ....... ..... .... ... ... ..... ..... ..... .......... ... ... .. ...... .. .. ..... 12
Areas of various sub catchments that contributing to the Silala springs .. .... .... ...... ..... ....... ... .... .. 11
Comparison between the topographical catchments for Silala at the lnacaliri police station
(Chile) as delineated in this study and by (Alcayaga, 2017), respectively .. .... .. ..... ... ...... .... .. ..... .. 11
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DOCUMENTATION OF THE STUDY
Main Report Containing the summary and conclusions
Technical Annexes:
Annex A.
Annex B.
Annex C.
Annex D.
Annex E.
Annex F.
Annex G.
Annex H.
Annex I.
2
The Silala catchment (this annex)
Climate analysis
Surface waters
Soil analyses
Water balances
Hydrogeology
Integrated surface water - groundwater modelling
Natural flow scenarios
Questionnaire put by the Plurinational State of Bolivia to OHi
319
Glossary
Term
Aquifer
Austral summer
Basin
Catchment
Confined aquifer
Depression, terrain
depression or sink
Desert climate
Digital elevation model
(DEM)
Discharge
El Nino
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Meaning/Definition
Geological formation capable of storing, transmitting and yielding
exploitable quantities of water.
Summer period in the Southern Hemisphere.
Area having a common outlet for its surface runoff.
The whole of the land and water surface contributing to the discharge at
particular stream cross section. This means that any cross section of a
stream will have a unique catchment of its own. (Wilson, 1978).
Confined aquifers are aquifers that are overlain by a confining layer,
often made up of clay or other geological formations with low
permeability.
A depression (or sink) is a low point in the terrain surrounded by higher
ground in all directions. If the soil is impervious, the depression collects
rain water from a local catchment. Surface water or groundwater inflows
will accumulate in the depression until:
- the water level reaches the nearest terrain threshold and runs off or
- the evaporation from the depression is equal to its combined surface
water groundwater inflows. However, a depression may also drain subsuperficially
to lower lying areas through pervious soils, geological
faults or groundwater aquifers.
Desert climate (in the Koppen climate classification BWh and BWk,
sometimes also BWn), also known as an arid climate, is a climate in
which precipitation is too low to sustain any vegetation at all, or at most
a very scanty shrub and does not meet the criteria to be classified as a
polar climate.
Data files holding terrain levels often organised in a quadratic grid with
a certain cell size (e.g. 30m by 30 m). They are very convenient tools
for and often used as standard tools in Geographic Information
Systems (GIS) for delineation of topographical catchment and for many
other purposes.
Volume of water flowing per unit time, for example through a river
cross-section or from a spring or a well.
El Nino is the warm phase of the El Nino Southern Oscillation
(commonly called ENSO) and is associated with a band of warm ocean
water that develops in the central and east-central equatorial Pacific
(between approximately the International Date Line and 120°W),
including off the Pacific coast of South America. El Nino Southern
Oscillation refers to the cycle of warm and cold temperatures, as
measured by sea surface temperature (SST) of the tropical central and
eastern Pacific Ocean. El Nino is accompanied by high air pressure in
the western Pacific and low air pressure in the eastern Pacific. The cool
phase of ENSO is called "La Nina" with SST in the eastern Pacific
below average and air pressures high in the eastern and low in western
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4
Evapotranspiration
Food and Agriculture
Organization of the
United Nations (FAQ)
Geographic
Information System
{GIS)
Groundwater
Hydrogeological
Conceptual Model
(HCM)
Hydrogeological
Framework Model
(HGFM)
Hydrological
catchment
Infiltration
Penman-Monteith
Pacific. The ENSO cycle, both El Nino and La Nina, causes global
changes of both temperatures and rainfall.
Combination of evaporation from free water and soil surfaces and
transpiration of water from plant surfaces to the atmosphere.
Specialized agency of the United Nations that leads international efforts
to defeat hunger. FAO is also a source of knowledge and information ,
and helps developing countries in transition modernize and improve
agriculture, forestry and fisheries practices, ensuring good nutrition and
food security for all.
A geographic information system (GIS) is a system designed to
capture, store, manipulate, analyse, manage, and present spatial or
geographic data.
Subsurface water occupying the saturated zone (i.e. where the pore
spaces (or open fractures) of a porous medium are full of water).
The conceptual understanding of the individual components in a
hydrologic system (i.e. groundwater, surface water, and recharge) and
the processes involved between each component.
A three-dimensional geologic model that defines the spatial extent of
stratigraphic and structural features. The development of the HGFM
incorporates topographic, geologic, geophysical, and hydrogeologic
datasets.
The hydrological catchment is the total area contributing to the
discharge at a certain point. The hydrological catchment includes all the
surface water from rainfall runoff, snowmelt, and nearby streams that
run downslope towards a shared outlet, as well as the groundwater
underneath the earth's surface. Since groundwater may cross the
topographical divides a hydrological catchment to a point may be larger
than the corresponding topographical catchment as indicated in the
Princi le sketch below.
// lopographical
water divide
surfac
calchmenl
A
runof
I rain I calchmenl
B
Hydrological catchment B
The movement of water from the surface of the land into the
subsurface.
Method for estimating reference evapotranspiration (Eto) from
meteorological data. It is a method with strong likelihood of correctly
predicting ETo in a wide range of locations and climates and has
provision for application in data-short situations.
321
Recharge
Reference
evapotranspiration
(Eta)
Remote sensing
Satellite
Sensitivity analysis
Spatial variation
Spring
Topographical
catchment
Weather station
Wetland
Contribution of water to an aquifer by infiltration.
The evapotranspiration per area unit under local climate conditions from
a hypothetical grass reference crop with an assumed crop height of
0.12 m, a fixed surface resistance of 70 s m-1 and an albedo of 0.23.
The reference surface closely resembles an extensive surface of green,
well-watered grass of uniform height, actively growing and completely
shading the ground. A good approximation to the maximum
evapotranspiration that under a certain climate can evaporate from an
area unit covered by an ever-wet short green vegetation (e.g. a
wetland)
Acquisition of information about an object or phenomenon without
making physical contact with the object and thus in contrast to on-site
observation. In current usage, the term "remote sensing" generally
refers to the use of satellite- or aircraft-based sensor technologies to
detect and classify objects on Earth, including on the surface and in the
atmosphere and oceans, based on propagated signals (e.g.
electromagnetic radiation).
Artificial body placed in orbit round the earth or another planet in order
to collect information or for communication.
Sensitivity analysis is the study of how the uncertainty in the output of a
mathematical model or system (numerical or otherwise) can be
apportioned to different sources of uncertainty in its inputs.
When a quantity that is measured at different spatial locations exhibits
values that differ across the locations.
A spring is a place where groundwater emerges naturally from the rock
or soil. The forcing of the spring to the surface can be the result of a
confined aquifer in which the recharge area of the spring water table
rests at a higher elevation than that of the outlet. Spring water forced to
the surface by elevated sources are artesian wells. Non-artesian
springs may simply flow from a higher elevation through the earth to a
lower elevation and exit in the form of a spring , using the ground like a
drainage pipe. Still other springs are the result of pressure from an
underground source in the earth, in the form of volcanic activity. The
result can be water at elevated temperature such as a hot spring.
A catchment delineated strictly by topographical divides of the terrain.
The topographical catchment includes all the surface water from rainfall
runoff, snowmelt, and nearby streams that run downslope towards a
shared outlet. This is the correct catchment if all discharge is surface
flow (i.e. no groundwater). The topographical catchment is often a good
approximation to the catchment, particularly for larger catchments.
A facility, either on land or sea, with instruments and equipment for
measuring atmospheric conditions to provide information for weather
forecasts and to study the weather and climate.
A wetland is a land area that is saturated with water, either permanently
or seasonally, such that it takes on the characteristics of a distinct
ecosystem. The primary factor that distinguishes wetlands from other
land forms or water bodies is the characteristic vegetation of aquatic
plants, adapted to the unique hydric soil. Wetlands play a number of
roles in the environment, principally water purification, flood control,
carbon sink and shoreline stability.
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1 Introduction
This annex to DH rs final report of the Study of the Flows in the Si/ala Wetlands and Springs
System describes the location of the springs and gives a broad introduction to the geographical
area in which they are located.
The main objective of this study, namely the quantification of the cross-border groundwater and
surface flows at present and in a natural situation, can be confined to a study of the Near Field
area close to the springs. However, OHi was asked to perform infiltration and water balance
analyses based on the available data to assess the various theories on the origin of the spring
water.
Therefore, this annex also discusses the possible extent of the hydrological catchment, the Far
Field that may contribute to the discharge through the wetlands and springs. A possible
hydrological catchment representative for the climate and infiltration in the area is delineated
and has been used as a basis for the analyses of recharge and possible origin of the waters, as
presented in Annex E and Annex F.
2 Location of the Silala Springs System and the area in
general
The Silala Springs are located in the arid
western part of the Potosi Department of
Bolivia, a few kilometres from the border with
Chile at altitudes of 4300-4400 m above sea
level (see Figure 1 ).
The Silala Springs are fed almost entirely by
groundwater that originates from an unknown
Far Field area (Figure 2) as further described
below. Figure 3 shows the Near Field of the
Silala Springs where the discharge from the
upper springs in the northern and southern
wetlands are collected by a network of
manmade canals. The flow of water is
westward and the canals join into a principal
branch that crosses the Chilean-Bolivian
border about 4 km downstream of the
Northern wetland at an elevation 150 m lower
than the upper springs.
2.1 The Altiplano area and its wetlands
Figure 1 Location of the Silala Springs.
Silala belongs to the high altitude Altiplano, a dry puna mountain zone in the transition to arid
Atacama Desert climate. The topography and geology of the Altiplano are dominated by
volcanoes and thick deposits of a pyroclastic density currents (lgnimbrites) (SERGEOMIN,
2003). Due to both climate and altitude, the vegetation is characterised by sparse and scattered
grasses on the plains and volcano slopes. In valleys or low-lying depression areas, wetlands fed
by mainly groundwater are found (Figure 4).
323
Figure 2 The Near field and far field of the Silala springs system.
' '
' ' '
N A
' ' ' '
FCAB ;_
intake
1\'orth Cana l
Principal Canal
0 1.5 km
Figure 3 Approximate extent of the Silala Near field. (Mulligan , et al., 2011 ).
D ~
The Silala Springs System is an example of a type of high Andean wetlands described as
cushion bogs (bofedales) with peat layers formed by Distichia cushions growing within 1-5 cm of
the ground surface. Distichia is the dominant native species of the Andes wetlands at elevations
between 3500 and 5000 m. Despite low growth rates, it creates peat layers up to several meters
deep (G.Skrzypek, 2011 ). The Distichia wetland areas are comprised of micro-topographic
variations of pools and lawns with a high water storage capacity. Due to the water retention
properties, pools are generated by bofedale wetland vegetation in the region , even on sloping
ground and without creation of any natural stream or narrowly confined flow features.
The wetlands are vulnerable and rely on a long-term steady and reliable water supply to
maintain suitable hydrological conditions and with time build peat layers of organic deposits. In
Silala and other bofedales in the Potosi region , groundwater provides this steady water supply.
In Silala, the extent of both the Northern and Southern Wetlands is controlled by the topography
and groundwater discharges through springs.
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Figure 4 Vegetation in and above the Southern Silala wetland.
The Silala Springs have been declared an area to be protected through the RAMSAR
convention. The Convention's mission is the "conservation and wise use of all wetlands through
local and national actions and international cooperation, as a contribution towards achieving
sustainable development throughout the world". In line with the Convention, the Bolivian
Government wants to restore the Silala Springs and Wetlands to its natural state.
2.2 The Silala area
8
Silala has a desert climate with low precipitation, low temperatures but high potential
evaporation . Outside the wetlands the vegetation is very sparse and top soils are coarse and
sandy (Figure 5), originating from weathered or glacier eroded lava and ignimbrite formations.
The base rock formation consists of ignimbrite layers presumably deposited through several
eruptions around 8 million years ago. The ignimbrite layers have a general inclination towards
West, and the valleys in which the Silala springs, wetlands and canals are located have been
identified as major fault lines in the ignimbrites (SERGEOMIN, 2003). One of these major fault
lines continue upstream of the Southern wetland in direction ESE - WNW. Further away from the
wetlands, perpendicular faults to this in direction NNW -SSE have been identified
(SERGEOMIN, 2003).
As further described in Annex F, the lgnimbrites are porous, fractured and have been found to
have significant hydraulic conductivities both in the main fault zones and in their fractured
matrix. In some areas, the ignimbrites are found directly under the top soils, while in other parts
of the area, they are superimposed by layers of lavas which have been deposited during later
eruptions.
The potential ground water heads as found in the piezometer wells, established by DIREMAR as
part of this study, indicate a groundwater flow from higher eastern grounds towards the Silala
Springs and further on towards the international border (Annex F).
325
Figure 5 Soils in Silala 's hydrological catchment (the Far Field).
3 Digital elevation models of the Silala catchment
Digital elevation models (DEMs) are state of the art tools for delineation of topographical
catchments and have, in the absence of detailed topographic surveys of specific borehole
elevations, also been used to determine terrain and groundwater levels at the boreholes,
exploration pits and at the various springs.
Three different OEM's have been used for the Silala area:
1. NASA's SRTM model generated from a space shuttle radar mission has a horizontal
resolution of approximately 30 m (NASA, 2017). This model is used by this project for
analyses of the Far Field area. This DEM constitutes the background image of Figure 6.
2. A high resolution Digital Elevation Model (DEM) acquired by DIREMAR based on
measurements taken during a drone flight in the last half of 2016 (IGM, 2016). This DEM,
which covers the whole Near Field area except the downstream 350 meters close to the
border, has a resolutions of 5 cm (horizontally) and 2 cm (vertically). The DEM, illustrated in
grey scale in Figure 6, has been used for analyses and modelling of the Silala Near Field
and for levelling of the hydrogeological field survey results.
3. The DEM used by (Alcayaga, 2017) to delineates a topographical catchment for the Silala
for a location close to the lnacaliri Police station around 4 km downstream of where the
Silala canal crosses the international border with Chile. This DEM has a horizontal
resolution of 5 m.
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Figure 6 Topographical data used in the surface model. The coloured area was interpolated from 1 m
contour lines received from DIREMAR (IGM, 2016). The remaining area is based on
topographical raster information from the drone flight (IGM, 2016). The man-made drainage
canals are shown as blue lines.
4 The topographical catchment of the Silala Springs
10
A topographical catchment is the area from which superficial runoff runs downhill and
discharges into a point. The inflows to the Silala Springs are, however, dominated by
groundwater flows and superficial runoff both in the catchment area and to the wetlands is
negligible. Furthermore, there are geological indications of faults and water bearing ignimbrites
crossing the topographical water divides (SERGEOMIN, 2003) as shown in Figure 7.
The topographical catchment for the point where the Silala canal crosses the Chilean-Bolivian
border has been delineated using NASA's SRTM 30 m Digital Elevation Model (DEM). The
topographical catchment is shown in Figure 7 and has an area of 59.1 km2 (Table 1 ).
As reported in Annex E, water balance analyses has shown that the area of the topographical
catchment is insufficient to sustain the measured cross border flows , and this catchment is
therefore of less importance than the hydrological catchment, which is described in the following
section.
The topographical catchment is described here for reference and for comparison with the
analyses presented in the Chilean memorandum (Alcayaga, 2017) on catchment delineation.
Topographical catchments to the Silala may be delineated for any point on the canal. (Alcayaga,
2017) has delineated a topographical catchment for the lnacaliri Police station located at the
canal around 5 km downstream of the international border ( Figure 7). The Alcayaga catchment
has been prepared from another DEM, but its area deviates only slightly from the area of the
one delineated in this study (see Table 2). The deviances are insignificant considering the
uncertainties related to the determination of the hydrological catchment in general (see Section
5 below).
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faults
International border
Figure 7 Silala topographical catchment insufficient to maintain the flow at the springs.
Table 1 Areas of various sub catchments that contributing to the Silala springs.
Name of catchment or sub catchment Area {in km2)
Near Field (sub catchment) 2.7
Topographical from the border less nearfield (sub catchment) 56.4
Topographical from the border incl. nearfield (sub catchment) 59.1
Road catchment (sub catchment) 175.1
Hydrological catchment 234.2
Table 2 Comparison between the topographical catchments for Silala at the lnacaliri police station
{Chile) as delineated in this study and by {Alcayaga, 2017), respectively.
Assessment DHI Alcayaga Difference*
Unit km2 km2 %
Total area from the lnacaliri Police station 99.4 95.5 -3.9
Sub area in Bolivia** 69.1 69.0 -0 .1
Sub area in Chile 30.3 26.5 -12.5
Catchment upstream of the border*** 59.2 - -
* Difference = (Alcayaga-DHl)/DHl*100 .. Includes areas discharging to reaches of the canal downstream the border. These areas are no part of ***
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5 The hydrological catchment of the Silala Springs
12
The hydrological catchment of the Silala Springs (the Far Field area) is the full area contributing
to the discharge through the springs and canals on the Bolivian territory. This catchment is
larger than the previously discussed topographical catchment and relevant for water balance
estimates or the Silala Springs and to assess possible origins of the flows .
Upstream of the topographical catchment to the Silala Springs an area of 175.1 km2 along the
road between Tayka del Desierto and Laguna Colorada drains topographically towards minor
depressions very close to the upstream boundary of Silala's topographical catchment.
Geological mapping (SERGEOMIN, 2003) has identified a major fracture zone crossing the
topographical divide of the Silala topographical catchment. The hydrogeological field exploration
as executed by Diremar in 2017 has found this fracture zone as well as the regional ignimbrite
layers to have significant hydraulic conductivity and hydraulic gradients towards the Silala
Springs (see Annex F). The fractures and ignimbrites will drain the "road catchment" area subsuperficially
to the Silala and form a combined hydrological catchment as shown in Figure 8 with
a total area of 234.2 km2 (231 .5 km2 excluding the Near Field).
The hydrological catchment delineated in Figure 8 is assumed to be hydrologically
representative for the precipitation, evaporation , soil types and infiltration rates of the Far Field
and has been used for the water balance assessments (Annex E). Although it may not represent
the exact extension of the Far Field, it has been found capable of generating water in an order of
magnitude similar to the observed and modelled cross border flows .
---- Geological faults
Figure 8
- Road
International border
Sllala canal
Hydrological catchment.
The hydrological catchment of the Silala Springs.
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6 References
Alcayaga H.S. "Characterization of the drainage patterns and river network of the Silala river
and preliminary assessment" [Report]. - [s.l.] : Universidad Diego Portales, 2017.
E.M.Wilson "Engineering Hydrology" [Book]. - Stanford : TheMacmillan Press LTD., 1978.
G.Skrzypek Z. Engel, T.Chuman, L. Sefrna, 2011 "Distichia peat - A new stable isotope
paleoclimate proxy for the" [Book]. - [s.l.] : Earth and Planetary Science Letters vol 307, 298-
308, 2011 .
IGM Technical Report "Georeferenced Topographic Survey - Silala water sources" [Report]. -
[s.l.]: IGM, 2016.
Mulligan B.M. and Eckstein G.E. "The Silala/Siloli Watershed: Dispute over the Vulnerable
Basin in South America" [Journal] // Water Resources Development Vol 27, no 3 .. - [s.l.] : Water
Resources Development Vol 27, no 3., 2011. - no.3 : Vol. 27.
NASA "NASA Shuttle Radar Topography Mission (SRTM) Version 3.0 Global 1 arc second"
[Book]. - [s.l.] : https://earthdata.nasa.gov/nasa-shuttle-radar-topography-mission-srtm-v…-
3-0-global-1-arc-second-data-released-over-asia-and-australia, 2017.
SERGEOMIN, "Study of the Geology, Hydrology, Hydrogeology and Environment of the Silala
Water-Springs Area, June 2000 - 2001 , Final edition June 2003 [Report]. - [s.l.] : Department of
Potosi, 2003.
Wilson E.M. "Engineering Hydrology" [Book]. - Stanford : TheMacmillan Press LTD., 1978.
330
331
Danish Hydraulic Institute (DHI), Study of the Flows in the
Silala Wetlands and Springs System, 2018
Annex B: Climate Analysis
(Original in English)
332
333
Contract CDP-I No 01/2018, Study of
the Flows in the Silala Wetlands and
Springs System
Product No. 2 - 2018 Final Report
Annex B : Climate Analysis
Plurinational State of Bolivia, Ministry of Foreign Affairs, Diremar
July 16, 2018
• Agern Alie 5 • • DK-2970 H0rsholm • Denmark
Telephone: +45 4516 9200 • Telefax: +45 4516 9292 • [email protected] • www.dhigroup.com
334
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CONTENTS
Glossary ..................................................................................................................... 4
1 Introduction ................................................................................................ 7
2 Precipitation ................................................................................................ 7
2.1 Annual average rainfall .. ..... ..... ..... .. ...... ...... ....... ...... ... ... ..... ... .. ... ....... .. ...... .... ....... ..... .. 9
2 .2 Annual and seasonal variation ... ...... .. ... ...... .... ..... .... ....... .... .. ...... ... .... ... .. ........ ..... .. .... 10
2.3 Snow formation ... .. ........ .... .. ..... ... ...... ..... ... ... ....... ..... ... .... .... .... .... ...... .. ... .. ... ... ...... .. .... 11
2.4 Spatial distribution of rainfall .... ......... ..... ........ ...... .... ....... .... ... .. ... ........ ... ...... .. ....... ..... 14
2 .5 Catchment rainfall ......... .... .. ... ... ... ..... ..... ......... .... ..... ...... .. ... ... .. ... ... ... .. ..... .... .. ...... .. .... 17
3 Evapotranspiration ..... ............................................................................... 17
3.1 Annual average reference evapotranspiration .. .... .. .......... .. .. ..... .. ... ...... ............... ...... 18
3.2 Spatial variation of reference evapotranspiration ... ........ ... .. .... .. .. ...... ... ......... ... ... ...... 19
3.3 Catchment reference evapotranspiration ..... .... .. ..... ........ .... .. ..... .. ... ...... .... ..... ...... ...... 19
4 Temperature ............................................................................................... 20
4 .1 Annual average temperature and spatial variation ........ .. ..... ..... ....... .. .... .. ... ... .... ....... 21
4 .2 Catchment temperature .. .. ........... ................ ... ......... ....... .............. .. ... ... .... ....... .... ... ... 21
5 Summary .................................................................................................... 22
6 References ................................................................................................. 23
FIGURES
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
2
Locations of weather stations with rainfall data in Bolivia and Chile (Senamhi stations
in green) .... ... .... ... .......... ........ .......... .. ...... .. .. ..... ... ................. .... ... ...... .. ... ............. ........ . 8
Annual precipitation at lnacaliri, Silala, Linzor and Laguna Colorada .. ................. ... ... 9
Annual precipitation at the I nacaliri and Silala gauges ... .. ... ... ... ...... .. .. .... .... ... .... ....... 10
Monthly average precipitation at the lnacaliri (1969-2016) and Silala gauges (2001-
2016) . ... ...... ... .... ...... .... .. ...... .... ... ... .. .. ... .. .... .. ....... .... ... .. .. .... ... .. .......... .. .. .... .. ... ...... .. .... 11
MODIS satellite snow cover in the Silala catchment in June 2013 .... ..... ...... ... .. ... .... 12
Comparison of satellite snow cover {blue) to the north of the wetland on the ridge
with rainfall daily recorded at lnacaliri (red) . ..... ...... .... .... .. ... ...... .. .... .. ... .. ... .. ... ... .. ...... 13
Mean annual precipitation gradients for the stations located in the Second Region ,
Chile taken from Munoz et al. , 2017 . .... ...... ... .. ... .. ... ... ... ................ ... ... ... ... .. .. ... ...... ... 15
Regional annual average precipitation as a function of altitude based on CHIRPS
data from 1981-2017 compared with station data at Silala, Linzor, Ollague and
Laguna Colorada and precipitation-elevation relationship derived by Munoz et al.,
2017 .. ... .... ... .. ... .. ... .. .. .. ......... ... .. ... .. ...... .. ... ... ... .... ..... .... ... .... ... .. .... ....... ... ... ... .. .... .. .. .... 15
Contours of annual average precipitation over the Silala topographic catchment
based on CHIRPS data from 1981-2017 and NASA 30 m DEM . ... .... ..... ...... ..... ....... 16
Terrain elevation {shaded) and rain-gauged annual mean rainfall over the central
Andes and adjacent lowlands taken from Garraud et. a/. , 2003 .. ... .... ....... .... ... .. ....... 16
FAO reference Eta for Silala, Laguna Colorada and Sol de Manana (30 day moving
averages) compared with the range (min to max daily values) of 7 nearby Stations
from DGA Chile ... ......... ....... ...... ... ... .. .. ...... ...... .... .................. .......... .... ... ................. ... 18
Regional annual reference Eta as a function of altitude . ... ... .... ...... ... .. ...... ... ... ... ..... ... 19
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Figure 13 Average daily reference Eta for stations Silala, Laguna Colorada and Sol de Manana
including 15 day- moving averages. An average value for each day of the year has
been calculated for each station for the periods in Table 2 ........ ................... ............ 20
Figure 14 Annual mean temperature gradient as a function of altitude ... ... ... .... ... .... ..... .. ....... ... 21
TABLES
Table 1
Table 2
Table 3
Overview of weather stations with rainfall in Bolivia and Chile ... .. ... .. .. .. .. ...... .. ..... .. .. ... 8
Overview of weather stations in Bolivia used for reference evapotranspiration (Eta)
estimation and Eta provided for stations in Chile ..... .. ...... ...... .. ... .. .. ... ....... ..... .. ...... .... 17
Overview of weather stations in Bolivia and Chile with temperature data ......... ........ 20
DOCUMENTATION OF THE STUDY
Main Report Containing the summary and conclusions
Technical Annexes:
Annex A.
Annex B.
Annex C.
Annex D.
Annex E.
Annex F.
Annex G.
Annex H.
Annex I.
The Silala catchment
Climate analysis {this annex)
Surface waters
Soil Analyses
Water balances
Hydrogeology
Integrated surface water - groundwater modelling
Natural flow scenarios
Questionnaire put by the Plurinational State of Bolivia to DHI
337
4
Glossary
Term
Aquifer
Austral summer
Basin
Catchment
Confined aquifer
Depression, terrain
depression or sink
Desert climate
Digital elevation model
(DEM)
Discharge
El Nino
Meaning/Definition
Geological formation capable of storing, transmitting and yielding
exploitable quantities of water.
Summer period in the Southern Hemisphere.
Area having a common outlet for its surface runoff.
The whole of the land and water surface contributing to the discharge at
particular stream cross section. This means that any cross section of a
stream will have a unique catchment of its own. (Wilson, 1978).
Confined aquifers are aquifers that are overlain by a confining layer,
often made up of clay or other geological formations with low
permeability.
A depression (or sink) is a low point in the terrain surrounded by higher
ground in all directions. If the soil is impervious, the depression collects
rain water from a local catchment. Surface water or groundwater inflows
will accumulate in the depression until:
- the water level reaches the nearest terrain threshold and runs off or
- the evaporation from the depression is equal to its combined surface
water groundwater inflows. However, a depression may also drain subsuperficially
to lower lying areas through pervious soils, geological
faults or groundwater aquifers.
Desert climate (in the Koppen climate classification BWh and BWk,
sometimes also BWn), also known as an arid climate, is a climate in
which precipitation is too low to sustain any vegetation at all, or at most
a very scanty shrub and does not meet the criteria to be classified as a
polar climate.
Data files holding terrain levels often organised in a quadratic grid with
a certain cell size (e .g. 30m by 30 m). They are very convenient tools
for and often used as standard tools in Geographic Information
Systems (GIS) for delineation of topographical catchment and for many
other purposes.
Volume of water flowing per unit time, for example through a river
cross-section or from a spring or a well.
El Nino is the warm phase of the El Nino Southern Oscillation
(commonly called ENSO) and is associated with a band of warm ocean
water that develops in the central and east-central equatorial Pacific
(between approximately the International Date Line and 120°W),
including off the Pacific coast of South America. El Nino Southern
Oscillation refers to the cycle of warm and cold temperatures, as
measured by sea surface temperature (SST) of the tropical central and
eastern Pacific Ocean. El Nino is accompanied by high air pressure in
the western Pacific and low air pressure in the eastern Pacific. The cool
phase of ENSO is called "La Nina" with SST in the eastern Pacific
below average and air pressures high in the eastern and low in western
Pacific. The ENSO cycle, both El Nino and La Nina, causes global
changes of both temperatures and rainfall.
338
Evapotranspiration
Food and Agriculture
Organization of the
United Nations (FAO)
Geographic
Information System
(GIS)
Groundwater
Hydrogeological
Conceptual Model
(HCM)
Hydrogeological
Framework Model
(HGFM)
Hydrological
catchment
Infiltration
Penman-Monteith
Recharge
D~
Combination of evaporation from free water and soil surfaces and
transpiration of water from plant surfaces to the atmosphere.
Specialized agency of the United Nations that leads international efforts
to defeat hunger. FAO is also a source of knowledge and information,
and helps developing countries in transition modernize and improve
agriculture, forestry and fisheries practices, ensuring good nutrition and
food security for all.
A geographic information system (GIS) is a system designed to
capture, store, manipulate, analyse, manage, and present spatial or
geographic data.
Subsurface water occupying the saturated zone (i.e. where the pore
spaces (or open fractures) of a porous medium are full of water).
The conceptual understanding of the individual components in a
hydrologic system (i.e. groundwater, surface water, and recharge) and
the processes involved between each component.
A three-dimensional geologic model that defines the spatial extent of
stratigraphic and structural features. The development of the HGFM
incorporates topographic, geologic, geophysical, and hydrogeologic
datasets.
The hydrological catchment is the total area contributing to the
discharge at a certain point. The hydrological catchment includes all the
surface water from rainfall runoff, snowmelt, and nearby streams that
run downslope towards a shared outlet, as well as the groundwater
underneath the earth's surface. Since groundwater may cross the
topographical divides a hydrological catchment to a point may be larger
than the corresponding topographical catchment as indicated in the
Princi le sketch below.
// topographical
waler divide
catchment
A
surfac
runoff
I rain I colchmenl
B
Topographical catchment B
Hydrological catchment B
The movement of water from the surface of the land into the
subsurface.
Method for estimating reference evapotranspiration (Et0) from
meteorological data. It is a method with strong likelihood of correctly
predicting ETo in a wide range of locations and climates and has
provision for application in data-short situations.
Contribution of water to an aquifer by infiltration.
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6
Reference
evapotranspiration
(Eto)
Remote sensing
Satellite
Sensitivity analysis
Spatial variation
Spring
Topographical
catchment
Weather station
Wetland
The evapotranspiration per area unit under local climate conditions from
a hypothetical grass reference crop with an assumed crop height of
0.12 m, a fixed surface resistance of 70 s m·1 and an albedo of 0.23.
The reference surface closely resembles an extensive surface of green,
well-watered grass of uniform height, actively growing and completely
shading the ground. A good approximation to the maximum
evapotranspiration that under a certain climate can evaporate from an
area unit covered by an ever-wet short green vegetation (e.g. a
wetland)
Acquisition of information about an object or phenomenon without
making physical contact with the object and thus in contrast to on-site
observation. In current usage, the term "remote sensing" generally
refers to the use of satellite- or aircraft-based sensor technologies to
detect and classify objects on Earth, including on the surface and in the
atmosphere and oceans, based on propagated signals (e.g.
electromagnetic radiation).
Artificial body placed in orbit round the earth or another planet in order
to collect information or for communication.
Sensitivity analysis is the study of how the uncertainty in the output of a
mathematical model or system (numerical or otherwise) can be
apportioned to different sources of uncertainty in its inputs.
When a quantity that is measured at different spatial locations exhibits
values that differ across the locations.
A spring is a place where groundwater emerges naturally from the rock
or soil. The forcing of the spring to the surface can be the result of a
confined aquifer in which the recharge area of the spring water table
rests at a higher elevation than that of the outlet. Spring water forced to
the surface by elevated sources are artesian wells. Non-artesian
springs may simply flow from a higher elevation through the earth to a
lower elevation and exit in the form of a spring , using the ground like a
drainage pipe. Still other springs are the result of pressure from an
underground source in the earth, in the form of volcanic activity. The
result can be water at elevated temperature such as a hot spring.
A catchment delineated strictly by topographical divides of the terrain.
The topographical catchment includes all the surface water from rainfall
runoff, snowmelt, and nearby streams that run downslope towards a
shared outlet. This is the correct catchment if all discharge is surface
flow (i.e. no groundwater). The topographical catchment is often a good
approximation to the catchment, particularly for larger catchments.
A facility, either on land or sea, with instruments and equipment for
measuring atmospheric conditions to provide information for weather
forecasts and to study the weather and climate.
A wetland is a land area that is saturated with water, either permanently
or seasonally, such that it takes on the characteristics of a distinct
ecosystem . The primary factor that distinguishes wetlands from other
land forms or water bodies is the characteristic vegetation of aquatic
plants, adapted to the unique hydric soil. Wetlands play a number of
roles in the environment, principally water purification, flood control,
carbon sink and shoreline stability.
340
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1 Introduction
This annex to the final report of the study of the flows in the Silala Wetlands and Springs System
documents an analysis of the climate of the Silala Springs System in Bolivia close to the Chilean
border.
Silala has a desert climate with highly variable precipitation from year to year. As the water of
the Silala Springs is very old and the observed discharge exhibits limited seasonality, climate
influences on the spring discharge act over a long period of time (several years or possibly
longer). An assessment of the recharge conditions in the Silala catchment as well as detailed
analyses of the impact of the manmade canals in the Silala Springs nearfield therefore requires
consistent and reliable climate data input, in the form of multi-year time series of precipitation ,
reference evapotranspiration (Et0) and temperature.
This annex presents the available climate data for the area including precipitation ,
evapotranspiration and temperature, and our analyses of their spatial and temporal variations. It
gives our best estimates of long-term distributed climate series, to be used in the catchment
water balance studies described in Annex E and in the detailed integrated groundwater - surface
water studies of the Silala Nearfield, see Annex H and Annex G. The density of climate stations
in the area is low and the harsh climate conditions in combination with the remote location
reduces the accuracy of some records. Since the most relevant climate parameters
(precipitation, potential evaporation and temperature) all vary significantly in mountain areas, it
is however important to make use of local data.
The analysis is therefore based on the most reliable long-term climate series from locations
close to the Silala wetland and springs system combined with satellite observations of the
spatial variation of the most essential climate variables inside the catchment areas.
2 Precipitation
Daily records of precipitation are available for a number of stations in and around the Silala
catchment in both Bolivia and Chile. Senamhi (the Bolivian secretariat for meteorology and
hydrology) has provided data for three stations in Bolivia (SENAMHI , 2017) and station data has
been extracted for six stations operated by Direci6n General de Aguas (DGA) in Chile. The
stations are listed in Table 1 and the locations are shown in Figure 1.
It should be noted that station data for Laguna Colorada is both available for a period from 1979-
2001 and more recently from 2010-2017. However, the new Senamhi weather station was out of
order for part of the period from 2010 to2015. For the earlier period, the rainfall data looks
reasonable with an annual average of 59 mm/year, although this seems low compared to the
other longer records from DGA (see discussion below). For this analysis, the earlier data for
Laguna Colorada from 1979-2001 have been used and the more more recent data have been
disregarded.
The data record for Silala from Senamhi has large gaps in parts of the record and a full record is
only available for 2012 and 2013. Furthermore, in 2012, only 17 mm/year was recorded
compared to 248 mm/year at DGA Silala and lnacaliri. In 2013, rainfall was also low at 43
mm/year versus 80 mm/year at DGA Silala and 91 mm/year at DGA lnacaliri. While rainfall is
expected to vary spatially, it seems strange that the recorded rainfall was so much lower given
the close proximity of the stations and could possibly indicate a problem with the Silala rain
gauge.
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8
Table 1 Overview of weather stations with rainfall in Bolivia and Chile.
Station Source Distance from Altitude Period Years Used in
Silala (km)
(m.a.s.l)
analysis
Silala*** Senamhi 0 4402 121612013-301912017 4.5 No
Laguna Senamhi 4278 111111979-311812001 22+ Yes
Colorada*
28 181912010-251912017 6 No
Sol de Manana Senamhi 53 4916 11112012-111712017 5.5 No
Siloli*** DGA 2 4000 2511012012-11812017 4.5 No
lnacaliri** DGA 6 4040 11211969-281212017 48 Yes
Silala** DGA 2 4305 11112001-281212017 16 Yes
Ollague DGA 90 3707 11111971-281212017 46 No
Linzor DGA 25 4100 111111973-3111212015 42 Yes
Caspana DGA 40 3246 121612012-301912017 4 No
*) Very large values for 2010-2017-likely due to problems with new station
**) Identical values for longer periods - not raw data but it looks like one station may have been gap filled
with values from the other station by DGA
***) Large gaps in the records
Figure 1
• Caapana •
Li~or
~. ... .., .
~ ...
(j ,. ~ . ,..,<;,".-.. .,<[
Conten1 y not relleGI Natoona l'Geographl,; s<;urrenl map ?Qllcy Source~ Nati4~graphlc Esr Delorme
HERS..,U P WCMC OSGS NASA ESA METI NRCAN GESCO NO .-i!rc,ement P ~ - /
Locations of weather stations with rainfall data in Bolivia and Chile (Senamhi stations in
green)
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2.1 Annual average rainfall
As the stations in Bolivia generally only have a few years of rainfall and also have several gaps
in the records, three stations from DGA in Chile and one long record at Laguna Colorada from
Bolivia have been used for analysing the long-term variations in rainfall and to establish a longterm
annual average rainfall for the Silala catchment. The other stations are located too far away
from the catchment for the data to be representative of the climatology.
The DGA rain gauges at lnacaliri and Silala (hereafter named DGA-Silala) are located closest to
the study area and both have long records. However, it was noted that, for some years after
2010, the rainfall is identical at the stations. This could indicate that one of the stations may not
have been operating properly and some gap filling was undertaken.
The long-term average annual rainfall at DGA-Silala is 87 mm/year compared to 98 mm/year at
lnacaliri for the period from 2001-2017 (16 years). The average rainfall at lnacaliri for the full
data period from 1969-2017 ( 48 years) is 116 mm/year. The other two stations, Linzor and
Laguna Colorada , have annual average rainfall of 152 mm/year for 1974-2015 and 59 mm/year
for 1980-2000, respectively. However, the record at Laguna Colorada has large gaps for some
years and if these years are removed from the calculation , the average rainfall is 64 mm/year.
Figure 2 shows the annual rainfall for the four stations.
It is evident from the data that there are large variations in the average annual rainfall between
stations. Particularly at Laguna Colorada the annual rainfall is very low compared with the
stations located closer to the catchment whereas the rainfall at Linzor is much higher. As all four
stations are located at approximately the same altitude, the differences in elevation do not
explain the differences in annual rainfall. For the water balance estimation, the rainfall at DGA
lnacaliri and DGA Silala are considered to be most representative of the catchment climate but
the data from Linzor and Laguna Colorada have also been considered in a sensitivity analysis.
500
450
400
350
E i. 300
C
0
'.p 250
1'l ·a.
·u 200
1'
"-
150
100
50
Figure 2
-
~
~ - - ,- - - - ,- - - -- ---- -- -
ff - 1-i - -11~ t- II 1l 11l- 11 Ir ---~-r. ~ 1- • morlNrn~~w~oomorlNrn~~w~oomorlNrn~~w~oomonNrn~~w~oomonNrn~rnww
mw~m~m~~m~m~~m~m~~momoomoomomoomomoomoomomoomomoomommmmmmmmmmmmmmmmmmmmomoaoooooaoooaoooaoononoraloralrolarolrrlo~
rlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlrlNNNNNNNNNNNNNNNNNW
~
■ lnacaliri mm/year ■ Silala mm/year ■ Unzor mm/year ■ Laguna Colorada mm/year
Annual precipitation at lnacaliri, Silala, Linzor and Laguna Colorada.
343
10
2.2 Annual and seasonal variation
The inter-annual variation in precipitation is very high, as illustrated in Figure 2 above and in
Figure 3, which shows the annual rainfall at lnacaliri and Silala. The calendar years 2003, 2009
and 2010 were particularly dry years. Although the inter-annual variation may partly be
explained by large-scale atmospheric variations such as the El Nino effect, all three years are
only moderate El Nino years. On the other hand, 2015 was very strong but was not particularly
dry in the records. Hence, the inter-annual variation in precipitation does not seem to have a
very strong El Nino correlation. A similar inter-annual pattern is observed at the other DGA
stations.
It is also interesting to note that the dry years seem to be drier after 2001 than for the previous
period. Whether this and the detected generally lower average precipitation at lnacaliri is due to
a general global long-term change in climate or whether it is a local decadal variation cannot be
determined from the available data.
400
350
300
E 2so .s
C:
~ 200
j'l ·a.
·o
~ 150
100
50
Figure 3
-- -- - -- -
-
----- -
- - - - - - - ---- - ------ - - - - - -
rl-- l - - -1 - - - ---- - - T- -~ 1f -- ;I 1111 I I I I I • I
■ lnacaliri mm/year ■ Silala mm/year
Annual precipitation at the lnacaliri and Silala gauges.
Most of the precipitation in the Silala catchment occurs during the austral summer months
between December and March (Figure 4) and very little precipitation is observed during the
winter months from April until September. Snow has been recorded and observed in the Silala
catchment during the winter but this may not be captured adequately by the weather stations. In
fact, the stations inspected on the Bolivian territory were not equipped with instruments suitable
for catching snow. The station data from lnacaliri and DGA-Silala has some minor precipitation
events during the winter month for some years but no winter precipitation has been observed at
the two stations after 2005.
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so ~----------------------------~
45
40 -
35
E
S 30
C
0
-~ 25 -
:g- 20
<IJ
ii
10
Figure 4
1 0
■ lnacallri mm/month ■ Silala mm/month
Monthly average precipitation at the lnacaliri (1969-2016) and Silala gauges (2001-2016).
2.3 Snow formation
In order to investigate the importance of snow events in more details, MODIS satellite data
(https://modis.gsfc.nasa.gov/data/dataprod/mod 10.php) was acquired , with a spatial resolution
of 500 m showing the snow cover of the catchment on a daily basis from 2000-2017.
Percentage snow cover in the Silala topographic catchment area indicates that some
precipitation falls as snow during the winter months. Particularly large snow (wet) events were
observed in July 2002, August 2011 and June 2013 (see Figure 5 and Figure 6). However, this
was not observed in any of the rain gauge data. Only a small amount of precipitation was
recorded at the lnacaliri station in 2002 and none during the other periods. While MODIS
provides snow cover, it is not possible to reliably estimate snow depth or snow equivalent from
the data alone but they indicate that the gauged precipitation underestimates total precipitation.
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[ml
[ml
Figure 5 MODIS satellite snow cover in the Silala catchment in June 2013.
346
~
~
0 u
~
.5;
100
90
80
70
60
50
40
30
20
10 - -
0
01/01/2000
•
-
July2002
t
.J I • I
I ~ I I I IW-
31/12/2001 01/01/2004
-
- - I ~. I
II H 11 I 11 I
31/12/2005 01/01/2008
--MODIS
I I U
11 11 II
01/01/2010
--Rainfal
August2011
June2013 ... I
T
j:-lli rnJ, I
01/01/2012 01/01/2014
Figure 6 Comparison of satellite snow cover (blue) to the north of the wetland on the ridge with rainfall daily recorded at lnacaliri (red).
The expert in WATER ENVIRONMENTS
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70
60
50
E
~
40 -:c:-
~ so ·ro
"'
~
20
~ I .I~ l I 11 II, I ir
10
0
01/01/2016
13
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2.4 Spatial distribution of rainfall
14
Due to the limited number of rainfall stations with longer-term rainfall records in and around the
Silala catchment area, it is difficult to make a reliable assessment of the spatial distribution of
rainfall. Based on long-term rainfall records at a large number of DGA stations in Chile Munoz,
et al. , 2017 has developed a simple rainfall-altitude relationship and used it, combined with local
elevation data, to make an assessment of the annual average rainfall for the Silala catchment
delineated by them. However, there is a large spread in the rainfall data at heights above 3,500
meters as illustrated in Figure 7. It was therefore decided to look at satellite data to see if a more
reliable relationship could be established from a combination of station data and local satellite
data.
Climate Hazards Group Infrared Precipitation with Station data (CHIRPS) was used for the
analysis (http://chg.geog.ucsb.edu/data/chirps). The data consists of daily gridded values with a
resolution of 0.05 degrees or approximately 5 km, covering a 30-year period starting in 1981.
Other gridded remote sensing rainfall series were also considered for the analysis including
TRMM (https://trmm.gsfc.nasa.gov), GPM (https://pmm.nasa.gov/GPM) and PGFv3
(http://stream .princeton.edu/LAFDM/WEBPAGE/) but since these have a much lower spatial
resolution (0 .25°, 0.1 ° and 0.25° compared with 0.05°), CHIRPS is considered the best source
of distributed precipitation available for the Silala catchment. Furthermore, GPM data is only
available for 2015-2017. Persiann data (http://chrsdata.eng.uci.edu/) with a resolution of 0.04
degrees was also considered but as the seasonal rainfall pattern looked unrealistic with rainfall
all year the data set was disregarded. According to an analysis of satellite data for Chile
performed by (Zambrano-Bifiarini, et al. , 2017) PGFv3 and CHIRPS data perform best in the
region due to the use of local rain gauges in the bias correction procedure to adjust estimates. It
is unclear whether this also applies to Bolivia in the area of interest due to the scarcity of rain
gauge data in this region but for the analysis, CHIRPS is currently assessed to be the best
available satellite product for looking at the spatial variation of rainfall.
Like the ground station records in the area, the CHIRPS data does not record any precipitation
outside the austral summer months. Hence, CHIRPS does not capture any snow events in the
winter months. The spatial variation of long-term annual average rainfall indicates that the
highest amount of rainfall is seen in the north-eastern part of the Silala catchment, reducing
towards the south-west. This is consistent with the fact that precipitation in the basin is mainly
caused by convective activity in a north-east south-west direction. More than 90% of the
precipitation in the basin occurs between January and March, as a result of atmospheric
moisture coming from the east. During the rest of the year, the atmospheric moisture in the air
decreases due to dry winds from the west.
Based on the CHIRPS data within and near the Silala catchment, a relation between
precipitation and altitude has be established (Figure 8 below). There is a fairly clear correlation
in the data at lower altitude (on the Chilean side of the border) but a lot of scatter at elevations
above 4000 m. This is similar to what was observed by (Munoz, et al. , 2017) (see Figure 7).
Mountainous regions generally pose significant challenges in estimating the spatial variation in
rainfall and in this case, a clear relation between altitude and rainfall could not be established.
As an alternative, the spatial distribution of long-term average rainfall was derived from CHIRPS
data. Contours based on CHIRPS indicate an increasing amount of rainfall in a northeasterly
direction (Figure 9) and no obvious altitude dependency. Annual average rainfall from CHIRPS
was checked against station values in the region but no correlation was apparent. However,
standard rainfall measurements have limited spatial support and often cannot accurately predict
precipitation in certain locations due to the impact of wind, flawed installation, wetting losses,
missing snow monitoring equipment and other errors. A map of terrain elevation (shaded) and
rain-gauged annual mean rainfall by (Garraud, et al., 2003) shown in Figure 10 supports the
tendency for higher rainfall in a north-easterly direction. Overall CHIRPS currently constitutes
the best available data for assessing the spatial variation of rainfall given the lack of rain gauges
in the catchment.
348
180
160
E 140 ..s
g 120
~ :g. 100
~
a. 80
"::',
~ 60
C
""'' 40 ::e
20
0
0
Figure 7
200
1 80
- 160
E
E
- 1 40
C
0
~ 1 20
·;,_
·u
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::, BO
~
1a 60 .,
:;;; 40
20
0
0
Figure 8
500 1,000 1,500 2,000 2,5 00 3,000 3 ,500 4,000 4,500
Elevat ion (m)
Mean annual precipitation gradients for the stations located in the Second Region , Chile
taken from Munoz et al. , 2017.
1,000
• Chirps
2,000 3,000
Ele vation (m)
4,000 5,000
• Stations --"M unoz et a l., 2017" •····· Linear (Chirps)
6,000
Regional annual average precipitation as a function of altitude based on CHIRPS data from
1981-2017 compared with station data at Silala, Linzor, Ollague and Laguna Colorada and
precipitation-elevation relationship derived by Munoz et al. , 2017.
The expert in WATER ENVIRONMENTS 15
349
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16
Figure 9 Contours of annual average precipitation over the Silala topographic catchment
based on CHIRPS data from 1981-2017 and NASA 30 m DEM.
6S
8S
10S
12S
HS
16S
18S
20S
22S
Annual maan ra inlall
24S 0-100mm . 101-200mm : • 201-400 mm :
26S e 401-700mm:
28S 9 >'.(?1mm
Figure 10 Terrain elevation (shaded} and rain-gauged annual mean rainfall over the central
Andes and adjacent lowlands taken from Garraud et. a/. , 2003
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2.5 Catchment rainfall
As input to the water balance assessment, station data at DGA lnacaliri and DGA Silala was
used in combination with the distribution from CHIRPS data to generate spatial precipitation
distribution estimates across the basin over time. For comparison, the derived precipitationaltitude
relation and long-term station data from the lnacaliri weather station was also used to
produce an estimate. The combination of local ground station data and spatial variation from
CHIRPS data is, however, deemed to give the best estimate of the daily precipitation over the
catchment.
The average annual rainfall obtained from using lnacaliri and Silala combined with the CHIRPS
rainfall distribution is 125 mm/year for lnacaliri (48 years) and 94 mm/year for Silala (16 years).
The annual rainfall using lnacaliri for the shorter period from 2001-2016 is 101 mm/day. This is
lower than the rainfall obtained using lnacaliri combined with the rainfall-altitude relation of 137
mm/year and the value derived by Munoz et al. , 2017 of 165 mm/year, which was based on
Chilean regional data processed to represent a smaller catchment area the one used in our
analyses. For comparison, the average annual precipitation based directly on area weighted
CHIRPS data for the Silala catchment is 146 mm/year, about 20% higher than using the lnacaliri
station data. Using Linzor and Laguna Colorada instead of lnacaliri or Silala the annual
catchment rainfall is 164 mm/year and 64 mm/year, respectively .
It is clear from the analysis that catchment rainfall is uncertain due to the variation in station
rainfall. The combination of station data from lnacaliri with CHIRPS data is currently deemed to
provide the best estimate of long-term annual average rainfall due to the close vicinity of the
station to the catchment and length of the record. However, data from the other stations have
been included in the water balance assessment in a sensitivity analysis.
3 Evapotranspiration
Potential reference evapotranspiration records (Eta) have been calculated using weather station
data provided by Senamhi for three weather stations: Silala, Laguna Colorada and Sol de
Manana listed in Table 2. Furthermore, daily potential evapotranspiration was collated for seven
stations in Chile also included in the Table. Data for the Bolivian stations comprise of mean, max
and minimum daily temperatures, mean relative humidity, solar radiation and wind speed , which
have been used for estimating daily potential evapotranspiration rates. Due to their large
distances from the Silala Springs, the potential evapotranspiration from the Chilean stations
have been used only for reference to get a rough estimate of the likely range of
evapotranspiration for comparison with the calculated values for the Bolivian stations.
Table 2 Overview of weather stations in Bolivia used for reference evapotranspiration (Eta)
estimation and Eto provided for stations in Chile.
Station Source Distance Altitude Period Years
from
(m.a.s.l)
Silala (km)
Silala Senamhi 0 4402 15/6/2013-30/9/2017 4.5
Laguna Colorada Senamhi 28 4278 18/9/2010-25/9/2017 6
Sol de Manana Senamhi 53 4916 14/5/2011-11/7 /2017 5.5
Socaire DGA 177 3276 18/11/2010-18/5/2017 6.5
Toconao DGA 130 2480 4/9/2010-18/5/2017 6.5
Caspana DGA 40 3246 1/ 12/2012-18/5/ 2017 4.5
San Pedro de Atacama DGA 104 2419 18/11/2010-18/5/2017 6.5
Chiu Chiu* DGA 73 2560 3/9/2010-18/5/2017 6.5
Calama Rural DGA 107 2248 11/9/2010-18/5/ 2017 6.5
Ollague* DGA 90 3707 17 / 12/2010-18/5/2017 6.5
* Large gaps in the records
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18
Estimates have been derived using the Eta calculator, a software tool developed by the Land
and Water Division of FAO (http://www.fao.org/land-water/databases-and-software/ Etocalculator/
en/), which calculates reference evapotranspiration (Eta) according to FAO standards
based on temperatures, mean relative humidity, solar radiation and wind speed using the
Penman-Monteith equation. The method is recognized worldwide for reliable approximations of
Eta over a wide range of locations with different climates. It is physically based and explicitly
incorporates both physiological and aerodynamic parameters.
3.1 Annual average reference evapotranspiration
Figure 11 shows the potential evapotranspiration estimates for the three locations in Bolivia. For
Silala, the evapotranspiration is higher in 2013/14 than later years, which is due to an abrupt
change in average wind speeds in 2014, from around 12 m/s to less than 5 mis. This indicates
some problems with the station. Unfortunately, it has not been possible to establish what has
caused the change. For Laguna Colorada, reference evapotranspiration is generally higher than
for the other two stations, which is mainly due to high average wind speeds of 15 m/s. At Sol de
Manana, the average wind speed is less than half (7 mi s). This indicates that the potential
evapotranspiration is highly sensitive to wind speeds in this region.
The average annual Eta ranges from 1268 mm/year at Sol de Manana to 1940 mm/year at
Laguna Colorada with around 1472 mm/year at Silala. Compared to the range of Eta from
nearby Chilean DGA stations (Figure 11 ), these values seem reasonable.
9.0
8.0
7.0
6.0
>_g 5.0
e
E
~4.0
3.0
2.0
1.0
a.a
01/01/2011 01/01/2012 31/12/2012 31/ 12/2013 01/01/2015 01/01/2016 31/ 12/2016
- - max of Chilean records - - minofChtlean records - Sol de Manana - Laguna Colorada - Silala
Figure 11 FAO reference Eto for Silala, Laguna Colorada and Sol de Manana (30 day moving
averages) compared with the range (min to max daily values) of 7 nearby Stations from DGA
Chile.
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3.2 Spatial variation of reference evapotranspiration
The relationship between elevation and average annual evapotranspiration rates for the three
Bolivian stations and five DGA stations is shown in Figure 12. Although a downward trend in
evapotranspiration with elevation is detected, it is small (-100mm/1000m) corresponding to less
than 7% change in EP rate of the Silala station, over the whole altitude range of the Silala
catchment. Furthermore, the slope of the trend line is uncertain due to the large spread in the
data. Consequently, the potential evaporation has been assumed to be uniformly distributed
over the catchment.
2100
1900
• Chiu Chiu
• L.aguana Colorada
• Ollague
1700 f-------~-.-san-Pedro~il!'""At.1ca"' .~.. ·=··~-.-..-. .-...-....-. --------------I
• catama Rural ·· •····•·· •• ··· ••• ········ ~ lSOO e--------------~. - ~casp-an- •------~. ~S~ila~la--------<
ill
<:
E uoo .s
,0_
UJ 1100
900
700
• Sol de Manana
500 r---~---~---~---~---~--~---~-----i
1500
Figure 12
2000 2500 3000 3500
Altitude (m.a.s.l)
4000
Regional annual reference Eto as a function of altitude.
3.3 Catchment reference evapotranspiration
4500 5000 5500
Since the Silala station is located inside the catchment, the series from this station is deemed to
be most representative for the catchment conditions. In order to use the data for the water
balance assessment the time series had to be extended to cover a longer period corresponding
to the period covered by rainfall at lnacaliri.
Two different approaches were employed. The first approach simply repeats the time series
back in time to form a long multiyear time series. However, with this approach short-term
anomalies in the data could result in unrealistic evapotranspiration in some years. In order to
avoid this a second approach was used where an average evapotranspiration record was
generated for one year by averaging the daily values and then calculating a 15-day moving
average (see Figure 13 below). According to the graph, similar trends are apparent in the
records for all three stations and this pattern is also observed in the raw data for individual
years. The reference evapotranspiration for the average year was repeated to form a long
record.
To account for the uncertainty illustrated by the rather large differences in ETo levels between
the three Bolivian stations, a sensitivity analysis of the impact on the modelled groundwater
recharge was undertaken for the water balance assessment. This was performed by looking at
the effect of using the long average annual record at Silala repeated for the whole period
compared with the series from Sol de Mariana and Laguna Colorada, respectively.
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9.0
8.0
7.0
6.0
3.0
2.0
1.0
0.0
01/01
Figure 13
02/03 02/05 02/07 01/09 01/11
--Sol de Manana --Si lala --Laguna Colorada
--Manana - 15 day average--Silala - 15 day average --Laguna - 15 day average
Average daily reference Eto for stations Silala, Laguna Colorada and Sol de Manana
including 15 day- moving averages. An average value for each day of the year has been
calculated for each station for the periods in Table 2.
4 Temperature
20
Daily temperature records for three Bolivian weather stations in Table 3 below have been used
in the analysis and longer-term daily records have also been collected for two Chilean DGA
stations: lnacaliri and Linzor. Hourly temperature data are available at Laguna Colorada.
Table 3 Overview of weather stations in Bolivia and Chile with temperature data.
Station Source Distance Altitude Frequency Period Years
from Silala (m.a.s.l)
(km)
Silala Senamhi 4402 Daily 15/6/2013- 4.5
0 31 /7/2017
Laguna Senamhi 4278 Daily 18/9/2010- 5.5
Colorada Hourly 25/9/2017 5.5
17/10/2010-
28 25/9/2017
Sol de Manana Senamhi 4916 Daily 14/5/2011- 6
53 11 /7/2017
lnacaliri DGA 4040 Daily 8/1/1969- 13
6 31/12/1981
Linzor DGA 4100 Daily 28/1/1973- 14
25 31/12/1986
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4.1 Annual average temperature and spatial variation
The annual average temperature varies considerably between stations, with an average
temperature at lnacaliri of 5.71 °C compared with 1.49 °Cat Silala. The lowest average annual
temperature of -0.4 °C was observed at Sol de Manana.
The temperature gradient based on this dataset as a function of elevation is illustrated in Figure
14. It should be noted that the average temperature was calculated for different time periods.
However, the gradient is still quite clear from the graph. At an altitude between 4 and 5
kilometers, this corresponds to a reduction in temperature of 7.1 °C/km compared to 4.6 °C
derived by Munoz et al. , 2017 who used station data for a larger region. 7.1 °C/km is also high
compared to general global numbers of 4-6 °C/km but the regression of the nearby stations in
Figure 14 seems to strongly support this lapse rate.
10
• lnacali ri
• unzor ....
t------·-· · •= -------------------------<
1---------------·=····= ----------------1
-2
4000 4100 4200 4300
• Silala ....
4400 4500
Al t itude (m.a.s.l)
....
. ...
4600 4700
Figure 14 Annual mean temperature gradient as a function of altitude.
4.2 Catchment temperature
•• · • •• .• • Sol de Ma 1ana ······
4800 4900 5000
Based on the daily time series records from lnacaliri, Linzor, Silala and Laguna Colorada, a
long-term time series of daily temperature for the period 1969-2017 representative for Silala has
been constructed. However, data for the period 1986-2010 is not available and has therefore
been gap-filled with data from Laguna Colorada and Silala from 2011-2016.
In order to be able to model snow formation and melting as accurately as possible, hourly
temperature data has been used for the water balance assessment. Hourly data for Laguna
Colorada for the period 2011-2016 was used for testing a diurnal model developed by De Wit et
al. (1978) (Reference 18). Based on average, minimum and maximum daily temperature can be
used for generating hourly data. This method was then used for converting daily data at Silala
for 2016 into hourly data. As minimum and maximum values were not readily available for the
Chilean stations, the hourly data from 2011-2016 based on Laguna Colorada and Silala data
have been used for long-term water balance calculations.
An analysis of the temperature data showed that the annual average temperature is 2.2 °C with
a minimum annual average temperature of 1.9 °C and maximum of 3 °C. Maximum daily
temperatures are in the range 17.3-21 .5 °C with an average of 19.6 °C. Minimum temperatures
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vary more between -24 °C to -16 °C with an average of-19.6 °C. Overall, the inter-annual
temperature pattern is fairly similar.
It was therefore considered most reasonable to repeat the data for the period from 1969-2010 in
order to generate a long-term temperature time series. Some variation in temperatures for
specific years will not be captured and this could have some impact on snow formation for the
earlier period. However, as some of the snow events in the austral winter months are not
captured in the rainfall data, this is a more important influence on accuracy and may mean that
infiltration rates using the rainfall data may be slightly underestimated for some years. For the
water balance assessment, the long-term hourly record is used in combination with the
temperature-altitude relationship to describe temperature across the catchment.
5 Summary
22
Climate time series have been determined for the Silala catchment by combining local ground
based observations, from within the catchment or very close to it, with the terrain information of
the catchment. Where local ground based data have been insufficient to construct reliable
spatial climate variations satellite observations of the local area have been used. This
combination of ground based and remote sensing observations of the local area is assessed to
provide more reliable local estimates for the Silala catchment than trying to correlate
observations over long distances for other catchments with different characteristics as presented
by (Munoz, et al. , 2017).
The main findings of the analysis are summarised here:
• Rainfall for the hydrological catchment is highly uncertain due to a shortage of rainfall
gauges in the area. The combination of station data from lnacaliri with satellite data
(CHIRPS) is currently deemed to provide the best estimate of long-term annual average
rainfall due to the close vicinity of the station to the catchment and length of the record.
Average rainfall is 125 mm/year for lnacaliri (48 years) which is 25% lower than the 165
mm/year derived by Munoz et al. , 2017 for the smaller topographic catchment.
• Mountainous regions generally pose significant challenges in estimating the spatial
variation in rainfall. Simple rainfall-altitude relationships could not be established with
any certainty in the mountainous areas at heights above 3,500 meters. As an
alternative, the spatial distribution of long-term average rainfall was derived from
satellite data. This was deemed more reliable although it could not be verified by station
data. Given the lack of long term raingauge observations in the catchment, its relatively
high spatial resolution and long consistent record, the CHIRPS satellite data set
currently constitutes the best available data for assessing the spatial variation of rainfall.
• The inter-annual variation in precipitation is very high and although the variation may
partly be explained by large-scale atmospheric variations such as the El Nino effect, the
correlation does not seem to be very strong. The precipitation in the Silala catchment is
mainly caused by convective activity in a north-east south-westerly direction with most
of the precipitation occurring during the austral summer months between December and
March and very little precipitation during the winter months from April until September.
• Snow has been observed in the Silala catchment during the austral winter months and
also recorded from satellites but is not captured by the existing weather stations as
these are not generally equipped with snow monitoring equipment. Snow events were
not captured by any of the rain gauges although satellite images and anecdotal
evidence point to snow being of importance for precipitation. Gauging station rainfall is
therefore most likely underestimated but it is not possible to quantify by how much
based on available satellite information.
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• Evapotranspiration (ETo) from the Silala weather station (1472 mm/year) is assessed to
be most representative for the catchment conditions being located inside the catchment.
In order to use the data for a water balance assessment the time series have been
extended to cover a longer period corresponding to the period covered by rainfall at
lnacaliri (1969-2016).
• Long term average hourly temperature records at Silala have been constructed based
on station data from Laguna Colorada and Silala for the period 2011-2016 which have
been repeated to form a long-time series. An altitude temperature gradient of 7.1 °C/km
was very clearly seen in the station data compared to 4.6 °C derived by Munoz et al.,
2017 who used station data for a larger region. The annual average temperature for the
Catchments is assessed at 2.2 °C a temperature variation over the year from -24 °C to
21.5°C.
6 References
Garraud R., Vuille M. and Clement A. "The climate of the Altiplano: observed current
conditions and mechanisms of past changes" [Journal] // Palaeography, Palaeoclimatology,
Palaeecology. - 2003. - Vol. 194. - pp. 5-22.
Munoz J.F. [et al.] "Hydrology of the Silala River Basin, International Court of Justice over the
status and use of the waters of Silala" [Report]. - [s.l.] : Memorial of the Republic of Chile,
Volume 5, Annex VII , 2017.
SENAMHI "Implementation , monitoring and measurement of network of water flows and
provision of meteorological informationin the area of the Silala Water-Springs" [Report]. - 2017.
Wilson E.M. "Engineering Hydrology" [Book]. - Stanford : TheMacmillan Press LTD., 1978.
Zambrano-Bifiarini M. [et al.] "Temporal and spatial evaluation of satellite-based rainfall
estimates across the complex topographical and climatic gradients of Chile. , Hydrol. Earth Syst. ,
Sci. , 21, 1295-1320" [Journal] // Hydrological Earth Systems. - 2017. - pp. 1295-1320.
The expert in WATER ENVIRONMENTS 23
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Danish Hydraulic Institute (DHI), Study of the Flows in the
Silala Wetlands and Springs System, 2018
Annex C: Surface Waters
(Original in English)
358
359
Contract CDP-I No 01 /2018, Study of
the Flows in the Silala Wetlands and
Springs System
Product No. 2 - 2018 Final Report
Annex C: Surface Waters
Plurinational State of Bolivia, Ministry of Foreign Affairs, Diremar
July 16, 2018
• Agern Alie 5 • • DK-2970 H0rsholm • Denmark
Telephone: +45 4516 9200 • Telefax: +45 4516 9292 • [email protected] • www.dhigroup.com
360
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CONTENTS
Glossary
1
2
2.1
2.2
2.3
2.4
2.5
2.6
2.6.1
2.6.2
2.6.3
2.6.4
2.7
2.7.1
2.8
2.9
3
3.1
3.2
3.3
3.4
3.5
3.5.1
3.6
3.7
4
5
..................................................................................................................................... 4
Introduction ................................................................................................................. 7
Conceptual understanding ........................................................................................ 8
Overall description ....................................... .. ......... ... ........ .. ........ ....... .... ...... .......... ....................... 8
Near border zone (zone 5) .............. .......... .................... ................. ..... .... ..... ...... .......... .................. 8
Southern Canal Ravine (zone 4) ................................................................................................... 9
Mid-section (zone 3) ........................................................................... .. ... .. ........ ... ....... ................ 10
Wetlands (zone 1 and 2) .............................................................................................................. 11
Canalisation and manmade interventions .... ... ..... ... ... .. .. .. ... ...... .... ..... ..... ... ....... ... .. .......... ........... 14
Exposed springs ......... ..... ................ .. ....... .. .. .. ....... ..... ................ ... .. ...... ... ..... ....................... .... ... 14
Drainage networks, pipe, wetlands ....................... ........................................... ............................ 15
Excavations ........................................................................ .......................................................... 16
Main canal .................................................................................................................................... 17
Later manmade changes .............................................................................. ..... ............... ........... 17
Key factors and processes for the Silala Near Field area .. .. .... ................................................... 18
Summary of manmade changes accounted for ........................................................................... 19
Implementation of the conceptual model in the numerical model ............................................... 20
Simultaneous flow observations ............................................................................. 21
Flow measurement overview .. .................. .. .. ... .. ... ...... ..... .. .................... .. ... .. ..... ..... ..... ..... ........... 21
Simultaneous canal flow data .... .......... ... .. .. .. ... ..... ...... .... .. .... ...... .... ....... .. ... .. .. ... ..... .......... .... .. ..... 21
Simultaneous spring flow data .................. .. .. ... .. ... ...... ..... ...................... ... .. ....... ..... ..................... 26
Spatial distribution of flows in the system ..................... ............................................................... 27
Temporal flow variation .................................... .................. .. ............... ......................................... 33
Long term Bolivian and Chilean flow records ................. ..... .......... ... .. ... .. ..... ..... ..... ..... ... .. ........... 33
Continuous flow data of installed flumes ....... ..... .................................................... ... .. ... .. ........... 35
Data consistency and uncertainty ............. .. .. ... .. ..... .... ..... .. .................... ... .. .. ..... ..... ..... ................ 36
Summary and conclusions ...................................................................................... 37
References ................................................................................................................ 39
FIGURES
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
2
Approximate extent of the Silala near field . (Figure slightly revised from (Mulligan, et al.,
2011) .............................................................................................................................................. 8
lgnimbrite outcrops and vegetation hiding the canal in a typical section of zone 5 facing
downstream ................ .......... ............... .... ... .. ... ... ... .. ................... ... ..... ... ... ..... .. ......... .......... ... ... .. ... 9
Small wetland downstream of water fall in the Southern Canal Ravine ...................................... 10
Blocked (and dry) reach of the main canal in zone 3 where the flow has been diverted to a
flat wide cross section with manmade obstructions to restore wetland areas .. ........................... 11
Drainage canals and vegetation in the upper end of the Southern wetland ................................ 12
Southern wetland overview map showing extent (red polygon), canal network (blue line),
springs (yellow dots) and overall flow directions by gray and blue arrows. Drained and
drier wetland area with clear signs of vegetation changes are highlighted by orange
circles .......................................................................................................................................... . 12
12
Northern wetland overview map showing extent (red polygon), canal network (blue line),
springs (yellow dots) and overall flow directions by gray and blue arrows .................................. 12
362
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
Figure 17
Figure 18
Figure 19
Figure 20
Figure 21
Figure 22
Figure 23
Figure 24
TABLES
Table 1
Table 2
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Northern wetland facing downstream. Exposed peat soil faces are visible along the canal. .. .... 13
Typical wetland hillslope element. ... ... ..... ... ... ....... .. ... ............. .... ... ........... ... .. ... ........ ......... ... ....... 14
Photo showing exposed springs piped directly to the main canal. .. ..... ....... ..... ... ..... ... ...... ..... ..... 15
Photo showing drain pipe .... ....... ..... ..... ..... ......... ..... .... .... ...... .. ...... ..... ....... .... ... ... .. .. ....... ...... ..... ... 16
Photo of an excavated section and vertical peat profile at the edge of an undisturbed
wetland patch in the Northern Wetland .. ..... .......... ...... .. .............. ... ..... ... ... ........ ........ ............ ....... 17
Canal modification. The stone lining of the canal has been removed from the sides and
bottom of the canal and applied to block the canal and inundate a formerly drained part of
the wetland .. ...... ................... .. ... ..... .. ................................ ....... .......................................... .. .. ... .... 18
Overview of flow measurement locations (SENAMHI) ............... ................. .. ........ ... .... ............... 22
Longitudinal simultaneous flow profile Southern Canal (S1- C5) ........ ...... .............. .... .. ........ .. .... 23
Simultaneous flow profiles, Northern Canal (S-18 to C-6) ........ ............. ...................................... 24
Simultaneous flow profiles, in the Principal branch from the confluence to border (C-7 to
S-21 ) .. ..................................... ...... .......................................... ............... ................. ....... ... .... ....... 25
Southern canal profile (S-1 to C-5) comparing canal elevations and observed groundwater
and spring levels with observed discharge (average of 10 campaigns) ..................... .... ....... .. .... 29
Northern canal profile (S-18 to C-6) comparing canal elevations and observed
groundwater and spring levels with observed discharge (average of 10 campaigns) .. ...... .... ..... 30
Principal canal from the confluence to the international border (C7 - S21) comparing
canal elevations and observed groundwater and spring levels with observed discharge
(average of 10 campaigns) ...... .. ... .. ...... ......... ..... ... .... ...... .... .... ..................... .... ...... ... ..... ...... ....... 31
Mapping of flows and net inflows based on simultaneous mean canal flow measurements
(in 1/s) . ......... ......................... ... ...... .......................................... ................................ ....... ... .... ....... 32
Long-term series of measured Silala Canal flows close to border, 2013-2017 blue curve:
manual readings C7, yellow curve: automatic floater instrument C7, turquoise curve: daily
average from the new pressure sensor C7; red curve daily data from DGA's Siloli station
just downstream of the border . ....... ..... ..... ......... ..... .... .... ...... .. ...... ..... ....... .... ......... ........ ...... ..... ... 34
Impact on the flow series (red curve from direct rainfall runoff (blue columns) ......... ............ .. .... 35
Continuous (shown as lines) and simultaneous (shown as circles) flow measurement
data, July-September 2017 .................................... ................... ....... ............................................ 37
Overview of key processes affecting flows ........... .. .... ....... ........ ............. .... ............. ......... .......... 19
Canal flows by section, accumulated upstream spring inflows and derived diffuse inflows.
The flows represent the average of all 10 campaigns . .. .... ........ .... ..... ....... ...... ..... .... ........ ...... ... .. 27
DOCUMENTATION OF THE STUDY
Main Report Containing the summary and conclusions
Technical Annexes:
Annex A.
Annex B.
Annex C.
Annex D.
Annex E.
Annex F.
Annex G.
Annex H.
Annex I.
The Silala catchment
Climate analysis
Surface waters (This Annex)
Soil analyses
Water balances
Hydrogeology
Integrated surface water - groundwater modelling
Natural flow scenarios
Questionnaire put by the Plurinational State of Bolivia to DHI
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4
Glossary
Term
Aquifer
Austral summer
Basin
Catchment
Confined aquifer
Depression, terrain
depression or sink
Desert climate
Digital elevation model
(DEM)
Discharge
El Nino
Evapotranspiration
Meaning/Definition
Geological formation capable of storing, transmitting and yielding
exploitable quantities of water.
Summer period in the Southern Hemisphere.
Area having a common outlet for its surface runoff.
The whole of the land and water surface contributing to the discharge at
particular stream cross section. This means that any cross section of a
stream will have a unique catchment of its own. (Wilson, 1978).
Confined aquifers are aquifers that are overlain by a confining layer,
often made up of clay or other geological formations with low
permeability.
A depression (or sink) is a low point in the terrain surrounded by higher
ground in all directions. If the soil is impervious, the depression collects
rain water from a local catchment. Surface water or groundwater inflows
will accumulate in the depression until:
- the water level reaches the nearest terrain threshold and runs off or
- the evaporation from the depression is equal to its combined surface
water groundwater inflows. However, a depression may also drain subsuperficially
to lower lying areas through pervious soils, geological
faults or groundwater aquifers.
Desert climate (in the Koppen climate classification BWh and BWk,
sometimes also BWn), also known as an arid climate, is a climate in
which precipitation is too low to sustain any vegetation at all, or at most
a very scanty shrub and does not meet the criteria to be classified as a
polar climate.
Data files holding terrain levels often organised in a quadratic grid with
a certain cell size (e.g. 30m by 30 m). They are very convenient tools
for and often used as standard tools in Geographic Information
Systems (GIS) for delineation of topographical catchment and for many
other purposes.
Volume of water flowing per unit time, for example through a river
cross-section or from a spring or a well.
El Nino is the warm phase of the El Nino Southern Oscillation
(commonly called ENSO) and is associated with a band of warm ocean
water that develops in the central and east-central equatorial Pacific
(between approximately the International Date Line and 120°W),
including off the Pacific coast of South America. El Nino Southern
Oscillation refers to the cycle of warm and cold temperatures, as
measured by sea surface temperature (SST) of the tropical central and
eastern Pacific Ocean. El Nino is accompanied by high air pressure in
the western Pacific and low air pressure in the eastern Pacific. The cool
phase of ENSO is called "La Nina" with SST in the eastern Pacific
below average and air pressures high in the eastern and low in western
Pacific. The ENSO cycle, both El Nino and La Nina, causes global
changes of both temperatures and rainfall.
Combination of evaporation from free water and soil surfaces and
transpiration of water from plant surfaces to the atmosphere.
364
Food and Agriculture
Organization of the
United Nations (FAQ)
Geographic
Information System
(GIS)
Groundwater
Hydrogeological
Conceptual Model
(HCM)
Hydrogeological
Framework Model
(HGFM)
Hydrological
catchment
Infiltration
Penman-Monteith
Recharge
Reference
evapotranspiration
(Eto)
D ~
Specialized agency of the United Nations that leads international efforts
to defeat hunger. FAO is also a source of knowledge and information,
and helps developing countries in transition modernize and improve
agriculture, forestry and fisheries practices, ensuring good nutrition and
food security for all.
A geographic information system (GIS) is a system designed to
capture, store, manipulate, analyse, manage, and present spatial or
geographic data.
Subsurface water occupying the saturated zone (i .e . where the pore
spaces (or open fractures) of a porous medium are full of water).
The conceptual understanding of the individual components in a
hydrologic system (i.e. groundwater, surface water, and recharge) and
the processes involved between each component.
A three-dimensional geologic model that defines the spatial extent of
stratigraphic and structural features. The development of the HGFM
incorporates topographic, geologic, geophysical, and hydrogeologic
datasets.
The hydrological catchment is the total area contributing to the
discharge at a certain point. The hydrological catchment includes all the
surface water from rainfall runoff, snowmelt, and nearby streams that
run downslope towards a shared outlet, as well as the groundwater
underneath the earth's surface. Since groundwater may cross the
topographical divides a hydrological catchment to a point may be larger
than the corresponding topographical catchment as indicated in the
Princi le sketch below.
// topogrophicol
water divide
surfac
/ rain I catchment
A
runof catchment
B
Hydrological catchment B
The movement of water from the surface of the land into the
subsurface.
Method for estimating reference evapotranspiration (Et0) from
meteorological data. It is a method with strong likelihood of correctly
predicting ETo in a wide range of locations and climates and has
provision for application in data-short situations.
Contribution of water to an aquifer by infiltration.
The evapotranspiration per area unit under local climate conditions from
a hypothetical grass reference crop with an assumed crop height of
0.12 m , a fixed surface resistance of 70 s m-1 and an albedo of 0 .23.
The reference surface closely resembles an extensive surface of green,
well-watered grass of uniform height, actively growing and completely
shading the ground. A good approximation to the maximum
evapotranspiration that under a certain climate can evaporate from an
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6
Remote sensing
Satellite
Sensitivity analysis
Spatial variation
Spring
Topographical
catchment
Weather station
Wetland
area unit covered by an ever-wet short green vegetation (e .g. a
wetland)
Acquisition of information about an object or phenomenon without
making physical contact with the object and thus in contrast to on-site
observation. In current usage, the term "remote sensing" generally
refers to the use of satellite- or aircraft-based sensor technologies to
detect and classify objects on Earth, including on the surface and in the
atmosphere and oceans, based on propagated signals (e.g.
electromagnetic radiation).
Artificial body placed in orbit round the earth or another planet in order
to collect information or for communication.
Sensitivity analysis is the study of how the uncertainty in the output of a
mathematical model or system (numerical or otherwise) can be
apportioned to different sources of uncertainty in its inputs.
When a quantity that is measured at different spatial locations exhibits
values that differ across the locations.
A spring is a place where groundwater emerges naturally from the rock
or soil. The forcing of the spring to the surface can be the result of a
confined aquifer in which the recharge area of the spring water table
rests at a higher elevation than that of the outlet. Spring water forced to
the surface by elevated sources are artesian wells. Non-artesian
springs may simply flow from a higher elevation through the earth to a
lower elevation and exit in the form of a spring, using the ground like a
drainage pipe. Still other springs are the result of pressure from an
underground source in the earth , in the form of volcanic activity. The
result can be water at elevated temperature such as a hot spring.
A catchment delineated strictly by topographical divides of the terrain.
The topographical catchment includes all the surface water from rainfall
runoff, snowmelt, and nearby streams that run downslope towards a
shared outlet. This is the correct catchment if all discharge is surface
flow (i .e. no groundwater). The topographical catchment is often a good
approximation to the catchment, particularly for larger catchments.
A facility, either on land or sea, with instruments and equipment for
measuring atmospheric conditions to provide information for weather
forecasts and to study the weather and climate.
A wetland is a land area that is saturated with water, either permanently
or seasonally, such that it takes on the characteristics of a distinct
ecosystem . The primary factor that distinguishes wetlands from other
land forms or water bodies is the characteristic vegetation of aquatic
plants, adapted to the unique hydric soil. Wetlands play a number of
roles in the environment, principally water purification, flood control,
carbon sink and shoreline stability.
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Introduction
This annex to the final report of the study of the flows in the Silala wetlands and springs system
documents the analyses of the present surface water flows of the Silala springs system in
Bolivia close to the Chilean border.
Groundwater continuously discharges in the Silala wetlands and ravines as surface water
through seepage faces and springs. In the present situation, the surface flow is collected by the
artificial drainage and canal network and is conveyed through the manmade main canal across
the border to Chile.
A key objective of the project is to quantify flows both under current conditions and under natural
conditions assuming that the canals are closed and removed.
Data from canal flow measurements, May-September 2017 were received and analysed (the
canal flow measurement campaign continued until December 2017). Proven and reliable
measurement methods have been applied to reduce uncertainties and provide a solid basis for
analysing the current Silala surface water flows.
In combination with hydrogeological information, collected in the groundwater field survey
program (Annex E), the distributed pattern of canal inflows and losses, which has been derived
from the flow measurements constitutes an important basis for the conceptual understanding of
the system . An understanding which in turn has made it possible to establish and calibrate a
numerical model and simulate the flows in a natural situation without the manmade canals as
described in Annex G and Annex H to the main report.
Section 2 of this annex presents our conceptual understanding of the surface water system in
Silala and how it has been changed by the man-made canalization. It also discusses the key
factors and processes through which the channelization has influenced the surface flows in the
system .
Section 3 describes and analyses the flow observations in the Silala system and assesses the
present flow regime and its spatial and temporal variations. The surface flow analyses establish:
• The canal flow rate at the permanent border site including mean rates and temporal
variations under current conditions
• The spatial distribution of canal flows and inflows, from the wetlands to the border,
during the May-September 2017
• The temporal variation of surface water flows during May-September 2017
• Flow measurement and water balance consistency checks
The summary and conclusions of the surface water study are described in Section 4.
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2 Conceptual understanding
Summary: This section presents our understanding of the surface water component of the Si/ala
Wetland and Spring System and formulates a conceptual model based on this understanding.
The conceptual model identifies the most important processes and factors affecting the surface
flows at the border under the current conditions. As described in Annex G, these processes and
factors have been represented appropriately in the numerical model to make it capable of
simulating the flows in a natural system without the canals.
2.1 Overall description
The canal flow crossing the Bolivian-Chilean border is the focus of this study. To understand
and describe the origin of water entering the canal and the hydrological processes, a definition
of a 'Near Field' area and a 'Far Field' area have been adopted . The Near Field area covers all
surface water features and immediate surroundings including springs, wetlands and canals as
shown in Figure 1 .The source of these springs is groundwater originating from a larger
upstream catchment, the Far Field area. The boundaries of this Far Field are uncertain and its
area is still unknown as described in Annex A.
The Near Field area has been sub-divided into 5 zones that recognise the different hydrological
characteristics and properties in each of these zones (See Figure 1 ). The characterisation is
based on information collected through a series of field inspections and the data collection
campaigns executed by DIREMAR during 2017. Starting at the border and moving upstream,
the key characteristics and processes of each zone are described below.
------
Figure 1
l':or th Canal
N A
-- ' ---
Prin~l!.,a l Canal
' '
,
Zone 2 - FCAB ;_
intake
Zone 5 ',
--, ~o ~--:~c. ~' .... '-ef, \ :!____
0 1.5km
Approximate extent of the Silala Near field. (Figure slightly revised from (Mulligan, et al. ,
2011 ).
2.2 Near border zone (zone 5)
8
From the Bolivian-Chilean border and upstream to the confluence between the Northern Canal
and Main Canal (Southern Canal), the Silala Canal runs through a relatively narrow ravine.
Steep ignimbrite rock faces line the valley floor on each side (Figure 2). The valley floor is 10-20
m wide and the canal bed slope is rather steep and constant, dropping approximately 35 m
along the 650 m reach. The canal is intact and the surface water level is confined within the
canal cross sections. A narrow riparian zone with grassland vegetation can be observed along
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the sides of the canal. A shallow discontinuous soil layer is found along the canal. The
outcropping rock is fractured, but no springs or inflows to the canal have been registered or
recorded in this zone during recent or previous site visits. These characteristics of zone 5
suggest that inflows and outflows along the canal are limited and any losses are mainly due to
seepage and evapotranspiration in close proximity of the canal.
Figure 2 lgnimbrite outcrops and vegetation hiding the canal in a typical section of zone 5 facing
downstream.
2.3 Southern Canal Ravine (zone 4)
From the confluence between the Northern Canal and Main Southern Canal, the Main Southern
Canal runs through a relatively narrow ravine. Steep ignimbrite rock faces line the valley floor on
each side. The canal bed is still very steep, dropping approximately 55 m along the 1000 m
reach but with varying slope. At the top of the ravine, a small waterfall of around 2 m discharges
into a stretch with more gentle slopes where an inundated wetland with grass vegetation and
ponded water covers the entire valley bottom (Figure 3). Further downstream again, the profile
gets steeper with running water confined to the canal cross section. The Southern Canal Ravine
is only 10-20 meters wide at the bottom and vegetation is in most of the zone confined to a
narrow riparian zone with grassland vegetation along the canal. The outcropping rock is
fractured and springs are found mainly on the left (northern) bank often more than a metre
higher than the valley bottom.
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Figure 3 Small wetland downstream of water fall in the Southern Canal Ravine.
2.4 Mid-section (zone 3)
10
The mid-section of the Southern Main Canal extends from the downstream boundary of the
Southern Wetland, where the Silala Canal enters the upper reaches of the Silala Valley, to
approximately 600 m downstream of the Military Camp where the canal enters the steeper and
confined section of zone 4. The flow is generally not restricted to the canal in this section but
extends over 30 m wide, shallow cross sections. The original manmade canal has been
removed or blocked in some locations (Figure 4) and the more moderate slopes create a wide,
mostly one-dimensional flow section encompassing pools, riparian zone, narrow wetlands and
spring flow features . A number of minor loops where flow branches off, interacts with shallow
inundated areas and re-joins the main canal, are found along the reach, in particular
downstream of the Military Camp. Seven individual springs discharging into the canal have been
registered along this reach. At the wide and shallow flow sections, the riparian zone, aquatic
vegetation and open water surfaces spread across the width of the valley floor.
370
Figure 4 Blocked (and dry) reach of the main canal in zone 3 where the flow has been diverted to a
flat wide cross section with manmade obstructions to restore wetland areas.
2.5 Wetlands (zone 1 and 2)
The Northern and Southern wetlands (bofedales) play a key hydrological role in relation to
surface water flows. The extent and functioning of the wetlands are closely linked to the spring
system discharges and the topography. Water availability and the distribution of water across
the wetland determine the wetland features, which range from relatively dry land conditions
along the wetland edges, drier patches along canal features and in parts of the wetland not
receiving any inflows, grassland areas in partially disturbed (Figure 5) or fully drained areas and
variably inundated undulating distichia areas with constant or regular access to water.
Figure 5 Drainage canals and vegetation in the upper end of the Southern wetland.
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The less disturbed areas with no significant signs of excavations, canal construction or drainage
are limited but are assumed to best resemble the original wetland conditions prior to
canalisation.
Figure 6
Figure 7
Southern wetland overview map showing extent (red polygon), canal network (blue line),
springs (yellow dots) and overall flow directions by gray and blue arrows. Drained and drier
wetland area with clear signs of vegetation changes are highlighted by orange circles.
Northern wetland overview map showing extent (red polygon), canal network (blue line),
springs (yellow dots) and overall flow directions by gray and blue arrows.
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The wetlands have been formed in depression areas and over time sediments and peat soils
have accumulated across these areas. The availability of water is reflected by the vegetation
with a distinct transition at the edges of the wetlands to the surrounding dry land with little or no
vegetation .
Figure 8 Northern wetland facing downstream. Exposed peat soil faces are visible along the canal.
In contrast to the dry areas with shallow sediment layers and outcropping base rock surrounding
the wetland, the wetlands themselves have continuous vegetation cover (Figure 8). They exhibit
thicker soil and peat layers and water tables have in boreholes both in the Northern and
Southern wetlands been found at or just below ground surface.
Figure 9 shows the surface and subsurface structure of a typical hillslope element extending
from the dryland into the wetland . As the ground elevations drop toward the wetland , the
groundwater table reaches the surface and groundwater discharges through fractures and
springs. In some areas along the edge of the wetlands , moist soil and vegetation are indicative
of seepage faces which extend further up the slope above the springs.
Standpipes located in the lowest part of wetland cross sections indicate water level above
ground level and thus upward directed groundwater pressure and flow. This is consistent with
the springs along the wetland edges often being found at higher levels than the canals. In
addition, a comparison of the gauged canal flows and gauged flows from the springs flows
(Section 3 .3 ) suggest a considerable diffuse inflow to the wetlands from the subsurface in
addition to the visible and gauged springs.
If not routed directly from springs into the drainage system and into the main canal spring water
passes through the wetland and peat soil layers. Water is transported into the peat layer by
gravity (from higher springs) or by capillary rise or upward water pressure from groundwater in
the highly weathered and fragmented upper part of the ignimbrite base rock underneath the
peat.
From the saturated or partially saturated peat soils water is lost to the atmosphere by plant
transpiration in the root zone, by soil evaporation and by evaporation from free water surface,
such as shallow inundated areas or pools generated on the wetland surface.
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Surface runoff may be created during high intensity precipitation events adding to the wetland
inflows. There are, however, few signs of surface water morphological features such as erosion
gullies or rill formation suggesting larger, regular surface inflows.
To quantify flows from the springs through the wetlands and the Near Field catchment to the
border it is, as illustrated by the hillslope (Figure 9), necessary to address:
• Spring, drainage and canal flow distribution within the wetland area
• Interception and storage in the peat soil layer
• Subsurface interaction (seepage) between drainage network, canal, groundwater and
unsaturated soil
• Surface water interaction and redistribution between drainage network, canals and inundated
wetland areas
• Flow and water levels in the drainage and canal network
Figure 9
Bedrock
Outcrog
Typical wetland hillslope element.
Rain
Seepage
face
Exposed
Spring
Drains
Main Canal
2.6 Canalisation and manmade interventions
2.6.1
14
The impacts of manmade interventions on the wetlands are clearly visible in the field and on
aerial photos and satellite images (e.g. Figure 8 and Figure 6). Both the drainage and
canalisation work and more recent local decommissioning or modifications of sections of the
canal are visible.
Exposed springs
Most of the upstream ends of the manmade drainage network constructed within both the
northern and southern wetlands originate in a spring. At these spring discharge points, the soil
and any underlying layers of coarser material or rocks have been completely removed to
enhance both the emerging spring flow rates and effectiveness of surface water routing
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2.6.2
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downstream. In the old natural wetland spring water emerging as individual springs or across
larger seepage faces have been intercepted by coarse or fine sediments and organic deposits of
the wetland. By excavating the soil and exposing the spring, the hydraulic resistance to the
groundwater discharge into or below the wetland peat soil layer has been reduced .
By diverting the water directly into the manmade channels, the spring water is no longer retained
in the wetland soils. This has reduced the size of wetlands, and decreased the amount of
evaporation and transpiration, which has increased the wetland discharges in comparison with
the situation prior to canalisation.
Figure 10 Photo showing exposed springs piped directly to the main canal.
Drainage networks, pipe, wetlands
A dense network of drainage canals is found in both the Southern and Northern wetlands. The
drainage canals have been dug as 2nd order and 3rd order branches collecting the water at the
individual springs and discharging it into the main canal. The original soil cover, typically in the
depth range of 0.2 - 1.0 m, has been removed along the drainage canals down to the underlying
bedrock.
The drainage canals cut through most of the wetlands and apart from collecting spring water,
they hydraulically separate wetland sub-systems and lower water tables in the peat soils. The
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2.6.3
16
effect of this is a reduced availability of water for the wetland vegetation, creating corridors for
invasive dryland grasses. Since a large part of the spring water no longer enters the wetland
system, parts of the original wetland are suffering from lack of water or have already died.
Figure 11 Photo showing drain pipe.
Excavations
Excavations are clearly visible not only at the springs and along drainage and main canals but
also across large parts of the wetland areas (Figure 12). In the Northern wetland, drainage pipes
linking up with the open canal drainage network are found (Figure 11 ). They have been installed
by excavating trenches. After laying down the pipes, they have been covered by soil leaving
large parts of the wetland disturbed and dug through (Figure 10). Only smaller coherent patches
of undisturbed soils and wetland vegetation are found in both wetlands. Especially in the
Northern wetland , peat soils have been turned and peat in varying stages of decomposition is
visible. As degradation of organic soil material is normally linked to subsidence of such soils, it is
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reasonable to assume that the natural terrain levels of the wetland have been higher than those
of today. Higher terrain levels mean higher hydraulic resistance both to groundwater inflow to
the natural wetland which will reduce the overland discharge of the natural wetland as compared
to the canalized one.
Figure 12 Photo of an excavated section and vertical peat profile at the edge of an undisturbed wetland
patch in the Northern Wetland.
Main canal
The Main Southern Canal and the Northern Canal cut through the mid-section of the wetlands
collecting water from the second and third order drainage network. They have been constructed
in straight line sections with an approximately uniform slope and are lined by rocks for stability
and to reduce resistance to flow. The canals have been excavated and the canal bed elevation
as well as the observed canal water levels are below the topographical elevation of the adjacent
areas. In most places, the canal bed sits directly on the underlying base rock surface and as a
result of the pervious canal lining, seepage in and out of the canal occurs along its entire length.
Therefore, the main canals act not only as collectors for the surface drainage networks but also
as drains for the surrounding areas.
2. 7 Later man made changes
In recent years, the canal has been changed and modified in sections of the Silala Wetland and
Spring System. In parts of the southern wetland, the canals and drains have been removed,
filled in or blocked. This is visible as canal reaches without any rock lining, rocks being piled up
across the canals and drains raising upstream water level and diverting canal water to wetland
sub-systems. The changes appear to be partial attempts at wetland restoration. Despite these
modifications the discharge of the wetlands still predominantly takes place through the canals.
Apparently, the canal modifications were stopped several years ago. They can therefore be
considered an integrated part of the present system and their possible impacts are already
reflected in the flows observed during 2017 and before.
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2.7.1
18
Figure 13 Canal modification. The stone lining of the canal has been removed from the sides and bottom of
the canal and applied to block the canal and inundate a formerly drained part of the wetland.
Key factors and processes for the Silala Near Field area
A summary of the identified key factors influencing the discharge of the Silala Springs System is
listed in Table 1
378
Table 1 Overview of key processes affecting flows
Silala Near Field sub-area Process Specifics
Zone 1 : Northern Canal, Northern 1. Distributed spring inflows Attenuation by wetland storage
wetland
2 . Wetland interception and storage Capillary rise of peat soils
and
3. Evapotranspiration in wetlands and Canal spilling at canal blockages
Zone 2 : Main Canal, Southern riparian zone
Transpiration from wetland
wetland
4 . Canal and drain system seepage vegetation
gains/losses to soil and groundwater
Canal seepage
5. Diffuse inflows by groundwater
6 . Canal-wetland spills and
redistribution (1-D / 2-D)
7. Inundated areas and free water
surface evaporation
Zone 3 : Main Canal, middle 1. Distributed spring inflows Flow in wide flow section in nonsection
2 . Evapotranspiration in riparian zone
canalised reaches
3. Canal seepage gains/losses to
Riparian zone water uptake and
riparian fringe and groundwater
evapotranspiration
4 . Canal-wetland spills and
redistribution (1-D / 2-D)
5. Inundated areas and free water
surface evaporation
Zone 4 : Main Canal, narrow 1. Distributed spring inflows Restricted canal flow
valley section
2 . Evapotranspiration in riparian zone Narrow riparian fringe interaction
and
3. Canal seepage gains/losses to
with canal
Zone 5 : Near border section riparian fringe and groundwater Groundwater discharge in narrow
valley section
2.8 Summary of manmade changes accounted for
In summary, the manmade changes impact the wetland hydrology and flows as well as the
water balance of wetlands and Silala Canal discharges by:
• Excavations exposing springs reduce the hydraulic resistance, and potentially increases
spring flow rates
• By diverting the spring water away from the wetlands into the drain network and canals,
these manmade channels are lowering the water tables and drying out large parts of the
wetland area. This means that less water is retained within the wetland and less water is
lost through evapotranspiration from the wetland
• Outside the wetlands, where the natural flow would cover a wider shallower cross
section the canalisation has constrained the flow to a narrow, deeper and straightened
canal, which has smaller evaporation and seepage losses than the natural channel.
• The baseline model scenario reflects the Silala Springs System in its present state. It
therefore also includes the recent modifications to the canal system, the impacts of
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which are already reflected in the flow observations used for the model calibration. The
natural scenario describes a system in its natural state without any canalization and has
been established by removing all canals and excavations assuming that the discharge
from the natural wetland takes place either as superficial runoff on top of the wetlands or
in the beds of the ravines or as groundwater flow in the base rock as described in Annex
H.
All the above processes and changes are simulated in the numerical model of the Silala Springs
System to quantitatively assess not only the current Silala Wetland and Canal System flows but
also the likely impacts of drainage and canalisation on flow rates compared to undisturbed
(natural) conditions.
2.9 Implementation of the conceptual model in the numerical model
A surface water model has been built and subsequently coupled with sub-surface components,
whole or partly saturated soils and vegetation of the wetlands and upland areas of the Near
Field and a groundwater model of the saturated groundwater model based on the conceptual
hydrogeological model described in Annex F. The numerical modelling tool used in flow
assessments and scenario impact analysis is set up according to the conceptual surface water
and groundwater models and the key processes identified in the conceptual models are
represented in the physically based numerical model of the Silala Near Field area. Model input
data and parameters have been derived from field data.
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3 Simultaneous flow observations
3.1 Flow measurement overview
To gain full knowledge on the flow pattern in the canal system, the flow observations must
reveal both the spatial and the temporal flow variations.
Determination of the spatial flow pattern (the inflow distribution and the gaining and loosing
reaches) have to be based measurements at many points in the streams and at the springs.
Since the flows in the system vary over the day the measurements should ideally be made at
the same time at all points (simultaneously). The procedures for flow measurements have been
designed to take the measurements as close in time as possible at the various points.
The flow measurement should be as exact as possible and the best accuracy is normally
achieved at fixed weirs with well established hydraulic conditions such as the existing weir at the
desiltation chambers. This weir and six new ones (established 2017) were equipped with
automatic gauging equipment that allows for continuous measurements of flows with a high
frequency (minutes) and the data from these gauging sites reveal the temporal flow variation
over longer time periods as described in Sections 3.5 and 3.6 below.
Based on technical specifications prepared as part of this study, the Bolivian Secretariat for
Meteorology and Hydrology (SENAMHI} was contracted by DIREMAR to carry out the surface
flow measurement program. Simultaneous canal flow measurements were made at 21 fixed
locations, continuous flow records collected at flumes installed during 2017 and the permanent
flume flows recorded close to the Bolivian-Chilean border.
The flow measurements were carried out during May-Sept 2017. Figure 14 shows the 21
locations including springs (Ojos de Agua), of simultaneous flow measurement locations (S-1 -
S-21) and continuous flume flow gauges (C-1 - C-7) (SENAMHI (a), 2017). Prior to the
establishment of the flumes, simultaneous flow measurements have been carried out at both S-
1 - S-21 locations and at the locations C-1 - C7 where six new flumes were later installed.
3.2 Simultaneous canal flow data
The simultaneous flow measurement program provides a snapshot of flows in many points of
the canal network. In all, ten such surveys were performed during the campaign period. Initially
twice a week and later monthly frequency, measuring at all locations within 2-3 days. Micropropeller
measurements in multiple points of the cross section provide a cross-sectional velocity
profile, which is integrated to calculate the flow. The profile measurements have been carried
out twice at each location to verify results and, if necessary, to take prompt on-site action to
prevent errors.
Figure 15 shows the longitudinal flow profile along the Southern Canal with measurements from
the 10 different surveys. A top end of the Southern wetland, the flow is approximately
30 lls and increases to around 100 I/s at C-5 just upstream the confluence between the Northern
and the Southern Canal. The measured simultaneous flow rates are approximately constant in
time.
On the Northern Canal, the longitudinal flow profile on Figure 16 shows a total flow contribution
around 57 I/s mainly entering below S 18.
In the Principal Canal, between the confluence and the international border, the measurements
(Figure 17) show some uncertainty as to the flows particularly in S19. The measurements may
indicate a small flow increase at the start of the reach and a possible flow loss in the parts closer
to the international border.
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..:J....i ...,...,
0
..8.... ...,...,
0
N A
600500
~l-~-~-S-20 .,., ~ r
,.._ · .: ~- ·s-21
1 . • ---- · ~ -
"':.•J -~
600500
Figure 14
22
601000 601500
~-·
..
601000 601500
Overview of flow measurement locations (SENAMHI).
602000 602500 603000
Leyenda
A Aforos Continuos
• Aforos Sfmultaneos
• Aforos Manantiales (ojos)
-- Drenaje
_. Umite Internacional
0 :....;..: ..,...,.
0
0 ===,-,,,,====a::=:==::::IL, bee ..,,,,.,- ·=•-\ ---1-g
~ ~ --- -■~· C'~ ~--- :g
C-2
602000 602500 603000
...
..~,..., ....
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S-1 to C-5 flow profile
140.00
..V.._, 120.00 = 100.00 3:
0 = 80.00 ""(J
!.':' 60.00
~ ro 40.00
(IJ
~ 20.00
0.00
S-1 C-1 S-2 C-2 S-3 S -5 S-6 S-7 S-8 C-4 S-9 S-10 S-11 C-5
- May6-7 25.80 28.35 24.45 47.05 34.95 36.10 34.75 42.95 56.40 70.35 88.45 115.40 96.95 103.65
- May12-14 33.00 33.60 24.50 46.90 28.10 38.30 40.60 35.70 53.10 58.80 107.05 111.65 101.05 105.75
- May15-17 32.50 28.10 31.05 30.30 40.25 39.70 53.10 114.95
- May27-30 29.05 31.65 23.75 36.90 34.30 30.45 34.35 28.90 49.95 61.90 89.35 113.80 102.15 83.45
- June3-4 31.55 26.90 31.80 28.85 30.05 31.00 36.85 33.50 51.05 62.50 78.65 106.30 95.45 110.50
- June12-14 29.10 27.55 25.75 33.20 32.90 35.20 31.00 49.05 57.35 83.65 106.85 94.55 93.60
- June20-21 29.15 28.6 27.8 33.65 32.25 30.9 37.85 34.1 47.8 58.3 83.75 107.4 98.75 84.8
- July24-25 31.75 26.9 30.9 35.3 32.85 29.9 37.75 35.5 50.15 66.6 92.3 104 102.1 97.65
- Aug25-27 27.45 22.5 30.45 37 28.5 26.4 32.55 33.9 49.85 48.65 83.7 110.6 111.25 103.45
- sep 25-27 26.45 24.45 26.95 31.5 25.35 34.45 33.45 36.15 45.05 50.7 81.65 112.15 109.8 90.3
Figure 15 Longitudinal simultaneous flow profile Southern Canal (S1- C5)
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70.00
60.00
..~._ 50.00 = 3:
0 40.00 = -0
~ 30.00
~
ro
Q) ~ 20.00
10.00
0.00
S -18 S-16+5-17
--May6-7 6 .15 t 39.15
--Mayl2-14 6.20 t 43.25
--May15-17 ,.
--May27-30 7.05 37.40
t - June3-4 4.85 37.05
--June 12-14 t 5 .60 37.35
--June 20-21 t 3.95 37.95 t --July 24-25 455 34.45 + --Aug25-27 3.80 33.65
--Sep 25-27
Figure 16 Simultaneous flow profiles. Northern Canal (S-18 to C-6).
24
S-14+5-15
60.15
65.90
39.70
43.15
41.25
41.20
i-
51.40
i-
44.45
S-12
t 53.40
t 58.15
,.
51.35
t
46.60
t
52.30
t
52.45
t
53.35
t
51.05
C-6
62.65
63.85
60.40
55.15
53.85
56.65
65.35
42.50
384
250.00
~ 2=: 200.00
,:
0 = 150.00
7Cl
~
~
100.00
.",' 50.00 2'
0.00
--May6-7
--May12-14
--May15-17
--May27-30
--June3-4
--June 12-14
--June 20-21
--July 24-25
--Aug25-27
--sep 25-27
C-7
169.70
126.90
126.10
126.45
130.40
112.90
128.6000013
128.4499988
130.55
138.25
D ~
C-7 to S-21 flow profile
S-19 S-20
214.85 167.80
209.15 194.15
163.85 149.70
143.90 157.55
149.95 141.55
156.1000049 157.0999995
148.3500004 175.4000038
152.05 152.95
155.05 157.1
Figure 17 Simultaneous flow profiles, in the Principal branch from the confluence to border (C-7 to S-21 ).
The expert in WATER ENVIRONMENTS
S-21
179.45
169.30
147.15
156.60
148.45
155.55
173 .2500046
141.55
141.3
25
385
3.3 Simultaneous spring flow data
26
The program of simultaneous spring flow measurements was designed to assess flow rates at
individual springs and the total spring flow contribution of sub-systems. By comparing the
measured spring flows and canal flows, a measure of diffuse canal inflows has been derived.
Diffuse inflows describe non-point or hidden inflows, e.g. seepage faces where a single spring
was not clearly identifiable or the exchange of water between the surrounding groundwater and
the channels through the sides or base of these channels.
Springs (Ojos de Agua) have been mapped across the entire Silala Near Field system . They
include free flowing exposed springs, exposed springs with little or no flow and springs covered
by soil and visible only by wet soil seepage faces. The first type is suitable for measurement of
flow rates which has been carried out by collecting the spring discharge and deriving the flow
rate from volume and time.
From May 2017 and onwards, only approximately 20 high-flow springs are included.
Unfortunately, the spring locations selected for measurement and the applied spring-naming
convention are not consistent for all of the 10 measurement campaigns during May-September
2017. This means that measured flow cannot be referred to the identical same locations.
Table 2 compares the canal flows at the 7 continuous stations (average of all 10 simultaneous
campaigns) with the accumulated observed spring flows upstream of each of these locations
(average of all campaigns) and shows approximate upstream diffuse net inflows by location
estimated as the difference between measured mean canal flows and springs flows .
At the upstream reaches of the Southern Canal (C-1 - C-3), the measured spring flows are
almost equal to the measured canal flow, which implies limited diffuse inflows. However, on the
lower section (C4 - C5) where only a few springs have been mapped, a large diffuse inflow
indicates significant groundwater discharge to the Southern Canal in the upper part of the
ravine.
On the Northern Canal , the sum of spring flows accounts for 75-80 % of the canal flow, leaving
20-25 % for diffuse lateral net inflow. Similarly, derived total diffuse net inflows for the Southern
Canal are expected to be in the order of 35-45 %.
The measurements of simultaneous canal flow and spring flow are associated with uncertainty.
The spring flow measurement method is coarse and relies on capturing all of the spring flow
within a given time interval, preventing any bypass flow. Measurements of canal flows suggest
that the groundwater discharge is approximately constant. Consequently, spring flows should
accordingly be approximately constant. However, for the most frequently measured spring, the
flows vary between ± 40 % of the average value. The highest relative deviations are found for
springs with low flow rates. The variation in measured flow is not consistent across the springs,
suggesting that the variations are caused by measurement uncertainty and not hydrological
temporal variations driven by, for example, climate.
386
Table 2 Canal flows by section, accumulated upstream spring inflows and derived diffuse inflows.
The flows represent the average of all 10 campaigns.
Section Measured spring Measured Canal Difference, canalflow
(1/s) Flow(l/s) springs (1/s)
C1 , springs 1-12 (Zone 2) 23.8 27.8 4.0
C2, springs 1-20 (Zone 2) 41 .2 36.7 -4 .5
C3, springs 1-21 (Zone 2) 41.2 38.0 -3.2
C4, springs 1-22 (Zone 3) 45.2 59.5 14.3
C5, springs 1-32 (Zone 4) 56.9 97.0 40.1
C6, springs 33-64 (Zone 1) 46.1 56.9 10.8
C5+C6, springs 1-64 103.0 154.0 51.0
3.4 Spatial distribution of flows in the system
Figure 18, Figure 19 and Figure 20 show simultaneous flow measurements plotted along the
Southern, the Northern and the Principal canals respectively, together with the elevation profiles.
Since the measurement uncertainty in the individual point seems to be larger than the temporal
flow variations between the campaigns (indicated by the many crossing lines in Figure 15-Figure
17), the flows at each point are represented as the average of the 10 measurement campaigns.
The left axis shows elevations (m) of the canal bed and water levels (m .a.s.I) and the right axis
shows flow rates (I/s). In addition, the elevations of the ground water levels as determined from
spring elevations and boreholes along each of the profiles springs adjacent to the canal have
been marked.
On the Southern canal branch (Figure 18), the mean flow in the Southern wetland increases
from 30 I/s upstream at S-1 to 36 I/s downstream at S-6. On the upper canal reaches , the slope
is almost constant and from S-6 to C-4, the canal flow increases at an approximately steady rate
reaching 60 I/s at C-4. However, from C-4 to S-10, at the upper reach of the ravine , the surface
elevation drops and the canal bed slope increases. According to the measurements, a
significant inflow to the canal, in the order of 50 I/s, occurs along this section. Since only a few
springs have been recorded , the majority of the canal flow increase is due to groundwater
discharges through seepage entering the deepest section of the ravine as diffuse discharge to
the canal. The spring water level elevations have been plotted as an indication of the
groundwater table elevation along the canal. Between S-9 and S-10, the spring elevations are
significantly above the canal level. This is indicative of a relatively high water level gradient from
the groundwater towards the canal and consistent with the high inflow rates recorded.
The results suggest that the topography is a controlling factor of groundwater discharges to the
canal. As the surface elevations drop, the groundwater table is forced closer to the surface,
where it exchanges flow with springs, typically aligned with fractures, or directly to the canal.
Larger scale hydrogeological features, such as faults, may play a role with respect to canal
discharge patterns. On the steep canal section from S-10 to C-5, the mean flow decreases
significantly by approximately 10 1/s, which is attributed to either canal losses or measurement
errors.
On the Northern Canal branch (Figure 19), the slope is less variable. The increase in mean flow
is relatively high from S-18 to S-13, 5 I/s to 45 I/s. This section is characterized by a dense
drainage network distributed across the width of the wetland . This is also the section where the
The expert in WATER ENVIRONMENTS 27
387
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28
vast majority of the springs of the Northern wetland discharge into the drainage network. From
S-13 to C-6, close to the confluence between the Southern and the Northern canals, the wetland
is narrowly constrained by the ravine, with an approximately uniform canal bed slope. In this
section, only a few springs have been mapped and the mean flow rate increases from 45 I/s to
57 I/s along a distance of approximately 300 m.
In the Principal Branch from the confluence to the border (Figure 20) the average flow increases
slightly (around 8 %) from the confluence to S 19 about one quarter of the distance to the border.
From S19 to the border the flow rates seem to decrease slightly (to around 103 % of the
confluence flow) before reaching the border. While groundwater levels are observed at terrain
level near the confluence (borehole DS-35) the deeper groundwater levels are more than 10 m
below terrain in the ignimbrite layers close to the border. The canal could therefore be losing
water to the groundwater in the lower parts of Principal Canal.
Figure 21 shows a map of canal flows and canal net inflows in the Silala Near Field area based
on mean simultaneous flow measurements. The figure shows the flow at the continuous
measurements stations (C1 - C7), the inflow between the stations and the percentage of flow
relative to the downstream measurements, assuming that C7 flow equals the sum of C5 and C6
flows. The confluence point is seen as the point of the system with the most reliable flow
determination and the confluence point has therefore been used as reference (100%). In the
downstream principal reach flows first increases slightly (8%) and hereafter shows tendencies of
a slight flow decrease indicating flows at the border to be only 2% higher than at the confluence.
The flow assessment in this reach is however more uncertain which is the reason for not using
the flow at the border as the reference.
The net inflows to the canal are all the flow contributions minus all flow losses. The contributions
include: Inflows from springs, diffuse inflows along the canal or under wetlands and banks,
runoff and direct precipitation. Precipitation and runoff are, however, deemed to be negligible in
this case since precipitation is generally low in the winter months and the 10 campaigns which
are executed at different dates show very similar flow patterns. The losses include
evapotranspiration (from open water surfaces, wetlands and riparian areas) and seepage from
canals and wetlands to the groundwater aquifers.
Approximately 97 I/s or 63 % of downstream C-7 flows originate from the Southern Canal and
wetlands. Most of it (59 I/s) enters the canal on the C-3 - C-5 reach, which has relatively few
mapped springs, and thus the increasing canal flow from upstream to downstream must be
attributed to either diffuse seepage sources or groundwater discharging directly through the
base of the canal at the deepest section of the canyon .
388
4420
4400
I 1c-S
4380
vi
ro
E
;;-- 4360
..Q.... ro
>
~ 4340
5~64 / '
S-11
_,i
I
·◄ ~·
Profile A - Southern canal
SP-26
\
SP-27
SP-22
SP-25
SP-28
~----
D~
C I
. P
18
Barreno Punto 13
a 1cata unto l _ :m 140
r -20 SP 13
DS-13 --------.._ __ ;;.,.J JI r
120
100
Barreno Punto 16 J J SP-3 - -
Barreno Punto 14 ] I 80 ~
SP-4 I Q) e_o
60 ~
u
<I)
C-3 r S-6 I ci
- S-5 C-2 / S-2 ~ 40
/
4320 r Groundwater to canal
·- __... S-1
I
discharge zone 20
4300 --~---~--~---~---~--~---~--~---~--~~--~---~--~---~----+ 0
2800 2600 2400 2200 2000 1800 1600 1400 1200 1000 800 600 400 200 0
Canal chainage from upstream (m)
- canal bed elevation • Observed groundwater or spring level ----·Groundwater level ........ Discharge
Figure 18 Southern canal profile (S-1 to C-5) comparing canal elevations and observed groundwater and spring levels with observed discharge (average of 10 campaigns).
The expert in WATER ENVIRONMENTS 29
389
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4400
4390
4380
~ 4370
<ll
l'tl 4360
E
~ 4350
0
Profile B - Northern canal
Barreno punto 9
SP-42 ,,.,,v: \l L \ L
Barrena punto lb
Barreno punto 1
-~ 4340 ~ C-6
------------------
_::r .. :::::_~.,'"\' } - ------
> QJ w 4330
4320
4310
4300
700
Figure 19
30
600 500 400 300 200 100
Canal chainage from upstrem end of canal (m)
- canal bed elevation - .... -· Observed groundwater and spring levels -+-Observed Discharge
Northern canal profile (S-18 to C-6) comparing canal elevations and observed groundwater and spring levels with observed discharge (average of 10
campaigns).
160
140
120
100 ~
QJ
80 b,._O
l'tl
..c: u
<ll 60 i:S
40
20
0
0
390
4390
4370
::::? 4350
"?
!ti
Profile C - Principal canal
D~
180
160
140
120
~
_s 4330
C
100-;
0 ·.;:;
~ 4310
<Ll
w
4290
4270
37
80
60
40
-- ~ : 3:~ 31---- \ :~:~II ---------------------------------------------------------------------------------------------
20
4250 ~-~-------~--------~-------~~-------~--------~---------+ 0
3540 3440 3340 3240 3140 3040 2940
Canal chainage from confluence (m)
~
!ti
.c
u -~ 0
- surface elevation • Groundwater level - .. -. Groundwater levels (shallow) • Groundwater level (deep) --Discharge
Figure 20 Principal canal from the confluence to the international border (C7 - S21) comparing canal elevations and observed groundwater and spring levels with
observed discharge (average of 10 campaigns).
The expert in WATER ENVIRONMENTS 31
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167 1/s, 108%
162 1/s, 105%
157 1/s, 102%
59 1/s
Legend
0 Continuous Flow Stations
• Simultaneous Flow Stations
--WbalZooes
COORDENADAS_OJOS_AGUAS
tJ Canal Inflow
~
Figure 21 Mapping of flows and net inflows based on simultaneous mean canal flow measurements (in 1/s).
32
38 1/s ~
~
31 1,s v
25 % 24 % 18 %
392
3.5
3.5.1
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Temporal flow variation
Long term Bolivian and Chilean flow records
Long-term time series of the flows in the Silala Principal canal are available at two locations, one
at the old siltation chambers in Bolivia around 650 m upstream of the border and the other from
Chile's Direci6n General Del Agua (DGA), just downstream of the border on the Chilean side.
Given the locations and proximity (less than 1 km) of these permanent flumes , well correlated
records should be expected from the two gauging sites. The hydrogeological study (Annex F)
indicates low groundwater levels in parts of the reach between the two stations and therefore
the canal may be losing water by seepage in these parts into the underlying groundwater.
At the Bolivian gauging site, a flume is constructed in a rectangular concrete trench along the
old siltation chambers and equipped with a V-notch and automatic {electronic) water level
registration by floater with resolution around one mm. Hence, the station should be almost ideal
for measuring the narrow flow range of the canal. Water levels are measured both manually
(twice a day) and automatically {hourly). During July 2017, the automatic floater was
supplemented by a pressure sensor with an even higher temporal resolution. Each of the three
water level series has been converted into flows by a formula relating specific water level
observations to flows. Particularly for V-notch weirs, the standard formula is considered accurate
within 3-5 %.
Both manual and automatic water level readings and corresponding flow records exist. A
comparison of the available manual and automatic flow time series from the period August
2013- August 2017 is shown in Figure 22. The series is characterised by a constant base flow of
around 160 I/s, which clearly indicates that the canal is fed almost entirely by groundwater.
However, frequent abrupt changes in the calculated flows , sometimes from one-time step to the
next, are also observed . The rapid fluctuations in flow originate from similar changes in the
water level observations. It has, in general, not been possible to relate them to climatic
conditions, runoff events or seasonality. It seems likely that these fluctuations must be attributed
to uncertainty in water level observations, due to e.g. jamming of the float, ice or sediment
deposition in the stilling canal. The automatically gauged water levels include sudden jumps of
0.5 cm or 1 cm, although the resolution of the instrument is 1 mm. This also indicates possible
errors in the automated sensor registration. Despite the nearly ideal flow gauge conditions
provided by the weir, the uncertainty is therefore substantial, roughly assessed at 25-30 % of the
flow rate (corresponding to the unexplained abrupt fluctuations).
The Chilean flow time series also includes abrupt changes in flow. The Chilean flow series is
generally approximately 15-25 I/s lower than the Bolivian series. Although both series show
significant variations over time, 125-225 I/s for the Chilean series and 160-210 I/s for the shorter
Bolivian series, neither shows any clear sign of seasonality or a good correlation to the flow
series at the other station. Hence, the variation must be assigned to uncertainty in the
measurements.
The expert in WATER ENVIRONMENTS 33
393
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34
01-01 -2014 01-01-2015 01-01-2016 01-01-2017
Legend ______________ _
- Q-S. leh,-MAnu,,1 - Q-Si lelo-Auto-Thel irT>S - Chile_Sildi_upd111ed - Sil&la_Pre5uremeler-011ily
Figure 22 Long-term series of measured Silala Canal flows close to border, 2013-2017 blue curve:
manual readings C7, yellow curve: automatic floater instrument C7, turquoise curve: daily
average from the new pressure sensor C7; red curve daily data from DGA's Siloli station just
downstream of the border.
The impacts on the Silala flows from direct rainfall runoff have been investigated by comparing
the flow series with the lnacaliri rainfall station which has been found to be representative of the
area (see Annex B). As seen in Figure 23, the impacts on the flow series even from large rainfall
events are smaller variations (peaks) in the general flow regime corresponding to the direct
runoff from less than one square kilometer. The peaks are all short in duration and may very
well be explained by the direct rainfall on the wetlands and slopes of the ravines.
This confirms that by far the largest part of the catchment to the Silala Springs contributes to the
surface water flows only through infiltration and groundwater discharge, which is in line with the
absence of visible signs of recent overland flow in the catchment areas upstream the Near Field .
It is also noted that the rainfall impact is smaller than the uncertainty introduced by the
observation problems giving abrupt changes in the measured flows.
394
60 220
Le end
- P- inacaliri 210
-- Chile_Siloli_updated
50
200
40 190
E 180
.§.
:i§ 30
C:
'16
a: 170
20 160
10
0
08-01 -2012 22-01 05-02 19-02 04-03 18-03
Figure 23 Impact on the flow series (red curve from direct rainfall runoff (blue columns).
3.6 Continuous flow data of installed flumes
During May-June 2017, SENAMHI installed and calibrated six additional flumes and V-notch
weirs with the purpose of determining the flow rate at strategic locations in the canals of the
Silala Springs System as exactly as possible (SENAMHI {b), 2017).
All the weirs are equipped with continuous, automated pressure sensors, which provide
continuous records of high temporal resolution
The resulting time series cover the period July-Sept 2017. All series show a high base flow
level superimposed with a smaller periodic daily variation peaking around midday.
Unfortunately, the base flow in all series exhibits abrupt jumps at certain dates and sometimes
trends in the intermediate periods. None of these variations can be assigned to climatic events
and must therefore be due to malfunctions of the equipment or other error sources. Due to these
The expert in WATER ENVIRONMENTS 35
0
iii'
(')
~
Q)
<.C.
~
395
D~
uncertainties and the short gauging period, the continuous records have not been used in the
flow distribution calculation which has been based entirely on the simultaneous observations as
described in the previous section .
Although the daily flow variations may play a role in the uncertainty of the simultaneous
observations, they are too small to explain the spread in the simultaneous measurements at the
locations. The flows peaks at midday at all stations and daily variations can therefore not be due
to the daily variation in potential evaporation that peaks at the same time and therefore should
result in low canal flows at mid-day. Instead the flow variation must be caused by other factors,
maybe by freezing and thawing of the water in the wetlands.
The results from the two two-week periods, during which the data are most consistent, confirm
contributions from the Southern and Northern wetlands to be approximately 60 % and 40 % of
the confluence flow, respectively, and that the flow contribution in the ravine between C4 and C5
is a significant part of the flow at the confluence.
3. 7 Data consistency and uncertainty
36
The canal flows have been measured for different periods, at different locations and by different
methods. Comparison of the long-term flow records from the permanent flumes in Bolivia and
Chile, respectively, shows significant differences in both the mean flow levels and temporal
variation. None of the series from the two sites seems, however, to be free of gauging
inconsistencies, which may be due to the remote locations and harsh climate.
The more short-term continuous and simultaneous flow measurements carried out in JanuarySeptember
2017 exhibit inconsistencies both at the individual gauging points and also when
cross-comparing the data. Figure 24 shows C-5, C-6 and C-7 flow measurements in JulySeptember
2017. The measured continuous flows are significantly higher than the simultaneous
flow measurements for all three locations and there are unexplained, but significant differences
between the sum of C5 and C6 versus C-7 flows.
396
4
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Q (l/s)
-C-5 simult -C-6 simult -C:-7 simu lt
- C-5 - C-6 - C-7
•
1fcP6·2017
Figure 24 Continuous (shown as lines) and simultaneous (shown as circles) flow measurement data,
July-September 2017.
Summary and conclusions
• The continuous Silala canal flow measurements are available from the two permanent
gauging stations on Bolivian and Chilean territory immediately upstream and
downstream of the border. These data have been supplemented by new measurements
carried out by SENAMHI during January-September 2017. SENAMHl's field program
includes simultaneous micro-propeller flow measurements (21 locations), spring flow
measurements (20-33 Ojos De Agua) and six continuous flume water level recorders
converted to flows.
• The long-term time series from the Bolivian and Chilean permanent flumes show mean
flow rates around 160 I/s - 210 I/s with the series from Chile generally being 15-25I/s
lower than the Bolivian ones. The temporal variations in flow at both locations are
generally not mutually correlated or correlated with seasons, climate or runoff events.
• The flow data analysis shows that the flows are dominated by groundwater discharges
and approximately constant in time. The temporal variation observed in site-specific flow
measurements cannot be explained by responses in neighbouring measurement
locations or any climate or runoff events.
• Smaller impacts from rain events can be detected but reflect the runoff from a small
area in the order of one square kilometre probably consisting of the wetlands and slopes
to the ravines.
• The measured flows have been used to calculate the spatial distribution of inflows. The
spring inflows to the Northern and Southern wetlands account for roughly 60 % of the
total canal flow at the canal confluence. Diffuse inflows account for the remaining 40 %.
The expert in WATER ENVIRONMENTS 37
397
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38
• The flow measurements also show that the Northern and Southern wetlands contribute
to respectively around 40 % and 60 % of the confluence flow and that a significant part
of the flow in the Southern canal enters along the ravine upstream of the confluence.
• The comparison of flow measurements shows significant differences and deviations,
under what would be expected to be well-controlled flume measurements. The
additional measurements carried out in May-September 2017 have not narrowed the
flow range in the downstream reach between C-7 and the border. Despite independent
continuous and simultaneous flow measurements on the Chilean and Bolivian side of
the border, the actual canal flow at the border remains uncertain (160 -210 I/s).
• Smaller periodic daily flow variations have been detected at all of the seven continuous
gauging sites during the winter of 2017. They cannot be caused by wetland evaporation
but are likely to be the effect of freezing/melting of the water in the wetlands.
• The flow measurements have provided valuable information regarding the spatial
distribution of inflows and allowed a breakdown of water balances by reach. Although
considerable flows (approximately 95 I/s) enter through the springs at the Northern and
Southern wetlands, a large groundwater inflow contribution has been identified along
the Southern Canal between C3-C5, especially along the upper reaches of the ravine,
coinciding with a locally steep drop in topography and canal levels.
• The different flow measurements around C5-C7 just upstream the border revealed
inconsistencies between the flow records and have not contributed to narrowing the
canal flow range.
398
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5 References
Garraud R., Vuille M. and Clement A. "The climate of the Altiplano: observed current
conditions and mechanisms of past changes" [Journal] // Palaeography, Palaeoclimatology,
Palaeecology. - 2003. - Vol. 194. - pp. 5-22.
Mulligan B.M. and Eckstein G.E. "The Silala/Siloli Watershed : Dispute over the Vulnerable
Basin in South America" [Journal] // Water Resources Development Vol 27, no 3 .. - [s.l.] : Water
Resources Development Vol 27, no 3., 2011. - no.3: Vol. 27.
Munoz J.F. [et al.] "Hydrology of the Silala River Basin, International Court of Justice over the
status and use of the waters of Silala" [Report]. - [s.l.] : Memorial of the Republic of Chile,
Volume 5, Annex VII , 2017.
SENAMHI (a) Monthly Report, "implementation, monitoring andmeasurement of network of
water flows and sourcing of meteorological information in the area of the Silala Springs"
[Report]. - 2017.
SENAMHI (b) lnforme Mensual, "Establecimiento, monitoreo continua de niveles, caudales y
provision de informaci6n meteorol6gica en la zona de los manantiales del Silala" [Report]. -
2017.
Wilson E.M. Engineering Hydrology [Book]. - Stanford : TheMacmillan Press LTD., 1978.
Zambrano-Bifiarini M. [et al.] "Temporal and spatial evaluation of satellite-based rainfall
estimates across the complex topographical and climatic gradients of Chile., Hydrol. Earth Sys!.,
Sci., 21 , 1295-1320" [Journal] // Hydrologial Earth Systems. -2017. - pp. 1295-1320.
The expert in WATER ENVIRONMENTS 39