Volume 2 - Annexes 19-23.2

INTERNATIONAL COURT OF JUSTICE
DISPUTE OVER THE STATUS AND USE OF THE
WATERS OF THE SILALA
(CHILE v. BOLIVIA)
REJOINDER OF THE
PLURINATIONAL STATE OF BOLIVIA
ANNEXES 19 TO 23.2
VOLUME 2 OF 6
15 MAY 2019

LIST OF ANNEXES TO THE REJOINDER OF THE
PLURINATIONAL STATE OF BOLIVIA
VOLUME 2 OF 6
ANNEX
N°
TITLE PAGE
N°
(ANNEXES 19-23.2)
DOCUMENTATION FROM THE BOLIVIA-CHILE POLITICAL
CONSULTATION MECHANISM (ANNEX 19)
Annex 19 Minutes of the XIV Meeting of the Bolivia-Chile Political
Consultation Mechanism, 5 and 6 October 2005
(Original in Spanish, English Translation)
5
CHILEAN OFFICIAL DOCUMENTS (ANNEX 20)
Annex 20 Records of the Ministry of Foreign Affairs of Chile, 2009
(Original in Spanish, English Translation)
31
PRESS ARTICLES (ANNEX 21)
Annex 21 El Mercurio, “The Foreign Minister opts for integration”,
Santiago, 21 October 2001.
(Original in Spanish, English Translation)
39
TECHNICAL DOCUMENTS (ANNEXES 22 – 23.2)
Annex 22 R. Gómez García-Palao, “Transboundary Water Resources
between the Republics of Bolivia and Chile”, April 1997
(English Translation)
47
Annex 23 DHI, “Technical Analysis and Independent Validation Opinion of
Supplementary Technical studies concerning the Silala Springs”,
December 2018
(Original in English)
65
Annex
23.1
IHH, “Characterization and Efficiency of the Hydraulic Works
built and installed in the Silala Sector”, April 2018
(English Translation)
123
Annex
23.2
C. Barrón, “Study of Georeferencing, Topographic survey and
determination of the infiltration capacity in the event of possible
surface runoff in the area of the Silala springs”, May 2018
(English Translation)
299
Data DVD DVD-ROM containing supporting data Annexes from:
“Georeferencing, Topographic survey and determination of the
infiltration capacity in the event of possible surface runoff in the
area of the Silala springs”
389
Annex 19
Minutes of the XIV Meeting of the Bolivia-Chile Political
Consultation Mechanism, 5 and 6 October 2005
(Original in Spanish, English Translation)
6
REPUBLICA DE BOLIVIA
MINISTERIO DE. RELACIONES
EXTERIORES Y CULTO
PARA
DE
REF.
FECHA
NOTA INTERNA N° 270/2005
DIRECCl6N DE AMERICA
Dra. Yovanka Oliden Tapia
DIRECTORA GENERAL DE ASUNTOS JURIDICOS
MP. Marco Antonio Vidaurre Noriega
DIRECTOR GENERAL DE RELACIONES BILATERALES
Remisi6n de Acta y Notas Reversales
La Paz, 11 de octubre de 2005
Senora Directora General:
Tengo a bien remitir para fines consiguientes, el Acta de la XIV Reuni6n del
Mecanismo de Consultas Politicas Bolivia - Chile, realizada los dias 5 y 6 de
octubre de 2005, en la ciudad de lquique, Republica de Chile.
Asimismo, las Notas Reversales que intercambiaron los Vicecanci/leres de
Bolivia y Chile en la misma fecha , por las cuales ambos Gobiernos suscribieron
el Acuerdo para permitir la actividad remunerada de personas dependientes del
personal consular, administrative y tecnico que presta servicios en las
respectivas representaciones consulares en Bolivia y Chile.
Con este motive, reitero a usted las seguridades de mi distinguida
consideraci6n.
YAN
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Min. Relaciones Exteriores y Cullo
7
Republic of Bolivia
Ministry of Foreign Affairs and Worship
Internal Note N° 270/2005
America Directorate
For : Dr. Yovanka Oliden Tapia
General Director of Legal Affairs
From : Minister, 1st Class Marco Antonio Vidaurre Noriega
General Director of Bilateral Relations
Reference : Remission of Minutes and Diplomatic Notes
Date : La Paz, 11 October 2005
Madam General Director:
I kindly refer for consequent purposes, the Minutes of the XIV Meeting of
the Bolivia-Chile Political Consultation Mechanism, held on 5 and 6 October
2005, in the city of Iquique, Republic of Chile.
Likewise, the Diplomatic Notes exchanged by the Vice-Chancellors of Bolivia
and Chile on the same date, whereby both Governments signed the Agreement to
allow the remunerated activity of dependents of the consular, administrative and
technical staff that provides services in the respective consular representations
in Bolivia and Chile.
With this motive, I reiterate to you the assurances of my distinguished
consideration.
(Signature)
Minister, 1st Class Marco Antonio Vidaurre Noriega
GENERAL DIRECTOR OF BILATERAL RELATIONS
Ministry of Foreign Affairs and Worship
8
ACTA DE LA XIV REUNION DEL
MECANISMO DE CONSULTAS POLITICAS CHILE-BOLIVIA
En esta fecha se celebro la XIV Reunion del Mecanismo de Consultas Politicas
Chile Bolivia, presidida per el Subsecretario de Relaciones Exteriores de Chile, Sr.
Cristian Barros y el Vicecanciller de Bolivia Sr. Hernando Velasco. Esta reunion
estuvo precedida por una Reunion del Grupo de Asuntos Bilaterales, efectuada en
la mis ma ciudad en la vf spera.
La nomina de las delegaciones y la agenda del Mecanismo de Consultas Polfticas
se anexan a la presente Acta.
La Delegaci6n chμena dio la bienvenida a la Delegacion boliviana y destac6 el
interes del Gobierno de Chile por avanzar en el fortalecimiento de la relaci6n
bilateral de manera de dejar una buena base para los pr6ximos gobiernos de
ambos paises.
La Delegaci6n boliviana agradeci6 la bienvenida, destacando las recientes
reuniones bilaterales a nivel de Presidentes y de Ministros, y la coincidencia con
Chile en cuanto a sentar las bases de la relacion entre ambos paises para los
futures gobiernos.
Habiendose acordado el programa y la metodologf a de trabajo, se procedi6 al
tratamiento de los temas de la agenda.
Terna Silala
En relaci6n a este tema ambas delegaciones intercambiaron ideas acerca de
c6mo avanzar en materia de recurses hfdricos compartidos, los estudios tecnicos
programados sabre el Silala que se precisaran a la brevedad, y acerca del
esquema mediante el cual se acordara su aprovechamiento en mutuo beneficio.
Ambas Delegaciones coincidieron en el interes por encontrar un marco
satisfactorio para ambos pafses sobre este tema dentro de un espfritu amistoso,
en el contexto de lo conversado per los Presidentes de ambos pafses.
Los resultados de los estudios programados deberan constituir un elemento
importante para los procesos de decision gubernamental y para una soluci6n
definitiva del tema.
Libre transito
Habilitaci6n del Puerto de lquique:
9
Minutes of the XIV Meeting of the
Bolivia-Chile Political Consultation Mechanism
On this date the XIV Meeting of the Chile-Bolivia Political Consultation
Mechanism was held, chaired by the Undersecretary of Foreign Affairs of Chile,
Mr. Cristian Barros and the Vice-Chancellor of Bolivia Mr. Hernando Velasco.
This meeting was preceded by a Meeting of the Bilateral Affairs Group, held in
the same city on the eve.
The list of delegations and the agenda of the Political Consultation Mechanism
are attached to this Minutes.
The Chilean Delegation welcomed the Bolivian Delegation and highlighted the
interest of the Government of Chile to move forward in the strengthening of the
bilateral relationship in order to leave a good basis for the next governments of
both countries.
The Bolivian Delegation thanked the welcome, highlighting the recent bilateral
meetings at the level of presidents and ministers, and the coincidence with
Chile in laying the foundations of the relationship between both countries for
future governments.
Having agreed on the program and the work methodology, the topics on the
agenda were addressed.
Silala Issue
In relation to this issue, both delegations exchanged ideas about how to move
forward in the area of shared water resources, the technical studies scheduled
on the Silala that will be required as soon as possible, and about the scheme by
which their use will be agreed upon for mutual benefit.
Both Delegations agreed on the interest to find a satisfactory framework for
both countries on this issue in a friendly spirit, in the context of what was
discussed by the Presidents of both countries.
The results of the programmed studies should constitute an important element
for the governmental decision processes and for a definitive solution of the
issue.
Free Transit
Enabling the Port of Iquique:
10
La Delegaci6n boliviana reiter6 su interes en que el perfeccionamiento de la
habilitaci6n del Puerto de lquique al regimen de libre transito se pueda
implementar a la brevedad posible. La Delegaci6n chilena reiter6 la voluntad de su
Gobierno de habilitarlo al regimen de libre transito. Ambas Delegaciones
destacaron el inicio de un ejercicio aduanero, continue y prolongado, que como
parte del Plan Pilato se convino realizar en dicho puerto, en concordancia a los
acuerdos alcanzados en las V y VI Reuniones del Grupo de Trabajo de Libre
Transite y la coordinaci6n realizada par las Aduanas de ambos paises.
Para concretar la habilitaci6n de lquique, la Delegaci6n chilena propuso establecer
un cronograma conducente a ese fin que permita resolver con antelaci6n las
situaciones complejas que presenta el proceso a nivel interno. La Delegaci6n
boliviana expres6 su interes par conocer el alcance y contenido de dicho
cronograma a la brevedad posible, entendiendo que el mismo conducira a la plena
habilitaci6n del Puerto de lquique.
La Delegaci6n chilena destac6 asimismo, la necesidad de preservar el derecho de
opcion para el usuario boliviano en cuanto a poder acogerse a la modalidad de
transporte en transito hacia terceros paises prevista en el Acuerdo sobre
Transporte Internacional Terrestre de los pafses del Cano Sur, ATIT.
Por su parte, la Delegaci6n boliviana expreso que el perfeccionamiento de la
habilitacion del Puerto de lquique debera regirse por el Tratado de 1904 y los
Acuerdos complementaries que establecen el regimen de libre transito y la
presencia del Agente Aduanero Boliviano en los puertos chilenos debidamente
habilitados. Asimismo, reitero que la modalidad de transporte prevista en el ATIT
es un instrumento compatible con dicho regimen.
Libre transito de la carga boliviana:
Ambas delegaciones concordaron en la conveniencia de realizar una nueva
reunion del Grupo de Trabajo sobre Libre Transito, en la ciudad de Arica, en lo
posible dentro del mes de noviembre pr6ximo, a fin de tratar distintos asuntos
relacionados con esta materia. La Delegaci6n de Bolivia destac6 la conveniencia
de establecer en el seno de ese Grupo un · Mecanismo de Soluci6n de
Controversias. Ambas Delegaciones coincidieron en incluir en la agenda de la
reunion la renovaci6n del mandate a la Comisi6n ad-hoc para la elaboracion del
nuevo Manual Operative y el tratamiento de las cargas IMO.
lntegraci6n Fisica
Se acord6 que este tema y el de la habilitaci6n del Hite LX, sean tratados en la
pr6xima reuni6n del Comite de Fronteras programada para los dias 17 y 18 de
octubre en La Paz.
La Delegaci6n chilena presentara en dicha reunion una evaluaci6n acerca del
funcionamiento del ferrocarril Arica - La Paz.
11
The Bolivian Delegation reiterated its interest that the improvement of the
enabling of the Iquique Port for the free transit regime could be implemented as
soon as possible. The Chilean Delegation reiterated the will of its Government
to enable it for the free transit regime. Both Delegations highlighted the
beginning of a customs exercise, continuous and prolonged, which as part of
the Pilot Plan was agreed to be carried out in said port, in accordance with
the agreements reached in the V and VI Meetings of the Free Transit Working
Group and the coordination carried out by the Customs of both countries.
To establish the enabling of Iquique, the Chilean Delegation proposed to
establish a timetable conducive to this purpose that allows resolving in advance
the complex situations that the process presents internally. The Bolivian
Delegation expressed its interest in knowing the scope and content of said
timetable as soon as possible, understanding that it will lead to the full enabling
of the Iquique Port.
The Chilean Delegation also stressed the need to preserve the right of option
for the Bolivian user to be able to benefit from the mode of transport in transit
to third countries provided for in the Agreement on International Terrestrial
Transport of the Countries of the Southern Cone (ATIT by its acronym in
Spanish).
For its part, the Bolivian Delegation expressed that the improvement of the
enabling of the Port of Iquique should be governed by the 1904 Treaty and
the Complementary Agreements that establish the free transit regime and the
presence of the Bolivian Customs Agent in the Chilean ports duly enabled.
Likewise, it was reiterated that the transportation modality foreseen in the ATIT
is an instrument compatible with said regime.
Free transit of the Bolivian cargo:
Both Delegations agreed on the convenience of holding a new meeting of
the Working Group on Free Transit, in the city of Arica, as much as possible
within the month of November, in order to address various issues related to this
matter. The Delegation of Bolivia stressed the convenience of establishing a
Dispute Resolution Mechanism within that Group. Both Delegations agreed to
include in the agenda of the meeting the renewal of the mandate to the ad-hoc
Commission for the preparation of the new Operating Manual and the treatment
of IMO cargo.
Physical Integration
It was agreed that this issue and that of the enabling of Milestone LX, be
addressed at the next meeting of the Borders Committee scheduled for October
17th and 18th in La Paz.
The Chilean Delegation will present in said meeting an assessment regarding
the operation of the Arica-La Paz railway.
12
Facilitaci6n Fronteriza
Plan Piloto para la circulaci6n de turistas con Cedula de ldentidad:
Ambas Delegaciones coincidieron en la necesidad de formalizar bilateralmente la
pr6rroga indefinida de la utilizaci6n de la Cedula de ldentidad para la circulaci6n
de turistas entre ambos paises, acordada por los Presidentes de Bolivia y Chile en
la Cumbre Sudamericana de Naciones. Las Delegaciones concordaron en que
dicha formalizaci6n se haga efectiva de la manera mas expedita posible.
La evaluaci6n de esta iniciativa prevista, en el acta de la I Reunion del Grupo
Bilateral Chile - Bolivia, se realizara en la pr6xima reunion del Comite de
Fronteras.
Turismo
Ambas Deleqaciones acordaron realizar un Encuentro de Operadores Turisticos,
con la participaci6n de autoridades de turismo, transporte y de obras publicas de
ambos paises, en la ciudad de San Pedro de Atacama, los dias 17 y 18 de
noviembre, cuyo temario sera detallado en la pr6xima reunion del Comite de
Fronteras.
Ta~eta 0nica Migratoria:
Ambas Delegaciones acordaron continuar tratando este tema en la pr6xima
reuni6n del Comite de Fronteras.
Controles lntegrados de Frontera:
Ambas Delegaciones informaron sobre el estado de aprobaci6n legislativa del
Convenio de Controles lntegrados en sus respectivos pai ses.
La Delegaci6n de Bolivia reiter6 su interes en la realizaci6n del ejercicio de control
integrado de larga duraci6n, que propuso en la Reunion para la Profundizaci6n del
Acuerdo de Complementaci6n ACE 22, a efectuarse en los meses de octubre,
noviembre y diciembre del presente afio, de manera simultanea en los pasos
Visviri - Charafia, Chungara -Tambo Quemado, Colchane - Pisiga y Ollague -
Avaroa. La Delegaci6n chilena concord6 con la importancia realizar ejercicios de
larga duraci6n, por lo que propone efectuar ejercicios prolongados de dos
semanas cada uno, en los distintos pasos en lo que resta de este ario, con el fin
de probar la eficiencia practica del sistema.
Asuntos Consulares:
En cuanto a la rebaja de aranceles por visas, la Delegaci6n boliviana inform6 que
existen inconvenientes legales para que se rebajen los aranceles consulares en
13
Border Facilitation
Pilot Plan for the circulation of tourists with Identity Card:
Both Delegations agreed on the need to formalize bilaterally the indefinite
extension of the use of the Identity Card for the circulation of tourists between
both countries, agreed by the Presidents of Bolivia and Chile at the South
American Summit of Nations. The Delegations agreed that such formalization
should take effect as expeditiously as possible.
The assessment of this planned initiative, in the minutes of the First Meeting
of the Chile-Bolivia Bilateral Group, will take place at the next meeting of the
Borders Committee.
Tourism
Both Delegations agreed to hold an Meeting of Tour Operators, with the
participation of tourism, transport and public works authorities of both
countries, in the city of San Pedro de Atacama, on November 17th and 18th,
whose agenda will be detailed in the next meeting of the Borders Committee.
Single Migratory Card:
Both Delegations agreed to continue discussing this issue at the next meeting
of the Boards Committee.
Integrated Border Controls:
Both Delegations reported on the status of the legislative approval of the
Integrated Controls Agreement in their respective countries.
The Delegation of Bolivia reiterated its interest in carrying out the long-term
integrated control exercise, which it proposed at the Meeting for the Deepening
of the [Economic] Complementation Agreement (ACE 22), to be carried out in
the months of October, November and December of this year, simultaneously
in the crossing points of Visviri-Charaña, Chungara-Tambo Quemado,
Colchane-Pisiga and Ollagüe-Avaroa. The Chilean Delegation agreed with
the importance of performing long-term exercises, so it proposes to carry out
prolonged exercises of two weeks each, in the different crossing points in the
remainder of this year, in order to test the practical efficiency of the system.
Consular Affairs:
Regarding the reduction of tariffs for visas, the Bolivian Delegation informed
that there are legal disadvantages for the reduction of consular fees in the
14
los tramites de legalizaci6n de documentos chilenos ya legalizados por los
Consulados bolivianos. Este tema sera vista en el Comite de Fronteras.
Asimismo, la Delegacion boliviana manifesto su disposici6n a analizar las
mecanismos que permitan la rebaja de aranceles por visas para el caso de
estudiantes.
Cooperaci6n Fronteriza
Vigilancia Fronteriza:
En relaci6n a la cooperacion sobre vigilancia fronteriza, ambas Delegaciones
convinieron en que este tema sea vista en el pr6ximo Comite de Fronteras.
La Delegacion de Bolivia inform6 que ya ha sido nombrada la autoridad
competente en materia de lucha contra el narcotrafico y que va a proponer una
fecha para realizar la VII Reunion de la Comisi6n Mixta del Acuerdo sabre Control,
Fiscalizacion y Represion del Trafico llfcito de Estupefacientes y Sustancias
Sicotropicas y Productos Quimicos Esenciales y Precursores.
Desarrollo Fronterizo
Cooperaci6n entre comunidades fronterizas:
Ambas Delegaciones tomaron conocimiento de que se realizaron los contactos
preliminares entre representantes de fondos de inversion social a objeto de
establecer una agenda de cooperacion en el ambito de los municipios y
comunidades fronterizas.
Temas de Salud:
La Delegaci6n chilena anunci6 que pr6ximamente visitara Bolivia una m1s1on
tecnica para explicar el avance del Programs de Pasantias del Ministerio de Salud
para profesionales bolivianos del area.
Cooperaci6n en Educaci6n, Cultura, Ciencia y Tecnologia
Las Delegaciones de Chile y Bolivia manifestaron su satisfaccion y conformidad
con los acuerdos alcanzados en la Reunion Tecnica de Educaci6n, celebrada en
la ciudad de La Paz los dias 26 y 27 de septiembre del presente aria, con ocasi6n
de la visita del Ministro de Educacion de Chile, Sergio Bitar.
15
procedures for legalization of Chilean documents already legalized by the
Bolivian Consulates. This issue will be seen in the Borders Committee.
Likewise, the Bolivian Delegation expressed its willingness to analyze the
mechanisms that allow the reduction of tariffs for visas for students.
Border Cooperation
Border Surveillance:
In relation to cooperation on border surveillance, both delegations agreed that
this issue be seen in the next Border Committee.
The Delegation of Bolivia informed that it has already been appointed the
competent authority in the fight against drug trafficking and that it will propose
a date to hold the VII Meeting of the Joint Commission of the Agreement on
Control, Oversight and Suppression of Illicit Traffic in Narcotic Drugs and
Psychotropic Substances and Essential Chemicals and Precursors.
Border Development
Cooperation between border communities:
Both Delegations learned that preliminary contacts were made between
representatives of social investment funds in order to establish a cooperation
agenda in the area of municipalities and border communities.
Health Issues:
The Chilean Delegation announced that Bolivia will soon visit a technical
mission to explain the progress of the Ministry of Health’s Internship Program
for Bolivian professionals in the area.
Cooperation in Education, Culture, Science and Technology
The Delegations of Chile and Bolivia expressed their satisfaction and approval
with the agreements reached at the Technical Meeting on Education, held in the
city of La Paz on 26 and 27 September of this year, on the occasion of the visit
of the Minister of Education of Chile, Sergio Bitar.
16
En particular expresaron su satisfacci6n con el prograrna de trabajo acordado en
rnateria de calidad de la educac i6n; educaci6n intercultural bilingue ; ciencia y
tecnologia y el prograrna de pasantias y becas.
De igual rnodo , arnbas delegaciones expresaron su valoraci6n y aliento a la
in iciativa de historiadores bolivianos y chilenos por desarrollar el proyecto "Chile -
Bolivia , Bolivia-Chile 1820-1930" .
Convenio sabre Protecci6n y Restituci6n de Bienes del Patrirnonio Cultural:
Arnbas Delegaciones acordaron efectuar una reunion tecnica antes de fin de aria
para analizar este terna.
Cooperaci6n e intercarnbio entre gestores culturales y/o directores de rnuseos :
La Delegaci6n chilena inforrn6 sabre la realizaci6n de un encuentro de Gestores
Culturales de arnbos pafses, el cual se realizarfa en Santiago los dias 2 y 3 de
noviernbre . La Delegaci6n boliviana acord6 respaldar dicha propuesta .
Programa de Trabajo para la Profundizaci6n del Acuerdo de
Complementaci6n Econ6mica N° 22, Prornoci6n Comercial, Econ6mica, de
lnversiones y Turismo.
Los responsables de la Adrninistracion del ACE 22 de arnbos pafses inforrnaron de
los resultados de la Reunion de Trabajo para profundizar este acuerdo efectuada
en La Paz, Bolivia , las dfas 17 y 18 de agosto pasado.
Arnbas Delegaciones se congratularon de las avances logrados para dicha
profundizaci6n siguiendo el principio de una asirnetrf a a favor de Bolivia
cornplernentada con acuerdos de cooperaci6n para facilitar el desarrollo
exportador boliviano.
Se torn6 conocirniento de las acuerdos que se vienen adoptando a partir de la
aplicaci6n de un tratarniento asirnetrico a favor de Bolivia, el cual , adernas del
terna arancelario, incorporara previsiones para un tratarniento integral (sanitario,
fitosanitario, de cooperaci6n, prornoci6n , norrnas tecn icas y otras disciplinas que
se acuerden) que prornuevan efectivarnente el incrernento del cornercio bilateral.
En esta oportunidad se avanz6 en una negociaci6n para la profundizaci6n del ACE
22 y se estableci6 la realizaci6n de una reunion el dfa 12 de octubre de 2005 , en
Arica , Chile , presidida por el Vicerninistro de Relaciones Econ6rn icas y Cornercio
Exterior de Bolivia y el Director General de Relaciones Econ6rnicas de Chile, con
el objeto de avanzar en esta rnateria .
Educaci6n , Cultura, Ciencia y Tecnologfa:
17
In particular, they expressed their satisfaction with the agreed work program
on the quality of education; intercultural bilingual education; science and
technology and the internships and scholarships program.
Likewise, both Delegations expressed their appreciation and encouragement to
the initiative of Bolivian and Chilean historians to develop the “Chile-Bolivia,
Bolivia-Chile 1820-1930” project.
Convention on Protection and Restitution of Cultural Heritage Assets:
Both Delegations agreed to hold a technical meeting before the end of the year
in order to discuss this issue.
Cooperation and exchange between cultural managers and/or museum
directors:
The Chilean Delegation reported on the holding of a meeting of Cultural
Managers from both countries, which would be held in Santiago on November
2nd and 3rd. The Bolivian Delegation agreed to support this proposal.
Work Program for the Deepening of Economic Complementation
Agreement N° 22, Commercial, Economic, Investment and Tourism
Promotion.
Those responsible for the administration of the ACE 22 from both countries
reported the results of the Work Meeting to deepen this agreement made in La
Paz, Bolivia, on last August 17th and 18th.
Both Delegations welcomed the progress made in this deepening, following the
principle of an asymmetry in favor of Bolivia, complemented with cooperation
agreements in order to facilitate the Bolivian export development.
We learned about the agreements that have been adopted from the application
of an asymmetric treatment in favor of Bolivia, which, in addition to the tariff
issue, will incorporate provisions for a comprehensive treatment (sanitary,
phytosanitary, cooperation, promotion, technical standards and other disciplines
that are agreed) that effectively promotes the increase of the bilateral trade.
On this occasion, progress was made in a negotiation to deepen the ACE 22 and
a meeting was set up on 12 October 2005, in Arica, Chile, chaired by the Vice-
Minister of Economic Relations and Foreign Trade of Bolivia and the General
Director of Economic Relations of Chile, with the aim of making progress in
this matter.
Education, Culture, Science and Technology:
18
Las Partes decidieron constituir una Comisi6n Bilateral de Educaci6n, Ciencia y
Tecnologia y una Comisi6n Bilateral de Cultura . Estas Com isiones seran
presididas por autoridades de los Ministerios respectivos y la coordinaci6n de sus
actividades se realizara a traves de sus Cancillerf as.
Mecanismos lnstitucionales del dialogo bilateral:
Al mismo tiempo , las Partes resolvieron institucionalizar el Grupo de Trabajo sobre
Asuntos Bilaterales, creado en junio pasado, en atenci6n a la utilidad que este ha
revelado en el proceso de preparaci6n del Mecanismo de Consultas Politicas
establecido entre ambos pa ises.
Convenci6n del Derecho del Mar de Naciones Unidas:
En relaci6n a este tema, teniendo • en cons ideraci6n el interes expresado por
Bolivia sabre la participaci6n en actividades de investigaci6n cientf fica oceanica,
asf coma en excedentes en la Zona Econ6mica Exclusive de Chile, la Delegaci6n
chilena expres6 su disposici6n para continuar efectuando las consultas internas y
las evaluaciones correspondientes conforme a las disposiciones de dicha
Convenci6n .
Terna Maritime:
En el esp[ ritu de la Declaraci6n · de Algarve , de una agenda bilateral sin
exclusiones, la Delegaci6n chilena tom6 nota de las planteamientos formulados
par la Delegaci6n de Bolivia respecto del tema maritime y coincidi6 en la
importancia de mantener esta materia en la vision de una agenda de future.
Otros Temas
Convenio en materia de Seguridad Social:
La Delegaci6n chilena present6 para su analisis un proyecto de Acuerdo en
materia de Seguridad Social.
Convenio que permite el Trabajo de las C6nyuges, del Personal Consular,
Administrative y Tecnico :
Las Partes expresaron su complacencia par el intercambio de Notas que forrnaliza
este Acuerdo.
Contactos interparlamentarios :
Ambas Delegaciones destacaron la importancia de la reunion de alto nivel que
celebraran Parlamentarios de Chile y Bolivia, durante el mes de noviembre
pr6ximo en Bolivia.
19
The Parties decided to establish a Bilateral Commission of Education, Science
and Technology and a Bilateral Commission of Culture. These Commissions
will be chaired by authorities of the respective Ministries and the coordination
of their activities will be carried out through their Foreign Ministries.
Institutional Mechanisms of the bilateral dialogue:
At the same time, the Parties resolved to institutionalize the Working Group on
Bilateral Affairs, created last June, in view of the usefulness that it has revealed
in the process of preparing the Political Consultation Mechanism established
between the two countries.
United Nations Convention on the Law of the Sea:
In relation to this subject, taking into consideration the interest expressed by
Bolivia regarding participation in oceanic scientific research activities, as well
as in surpluses in the Exclusive Economic Zone of Chile, the Chilean Delegation
expressed its willingness to continue conducting internal consultations and the
corresponding evaluations in accordance with the provisions of said Convention.
Maritime Issue:
In the spirit of the Algarve Declaration, of a bilateral agenda without exclusions,
the Chilean Delegation took note of the proposals made by the Delegation
of Bolivia regarding the maritime issue and agreed on the importance of
maintaining this matter in the vision of a future agenda.
Other Issues
Agreement on Social Security:
The Chilean Delegation presented a draft agreement on Social Security for its
analysis.
Agreement that allows the Work of the Spouses of the Consular, Administrative
and Technical Personnel:
The Parties expressed their satisfaction with the exchange of Notes that
formalizes this Agreement.
Interparliamentary Contacts:
Both Delegations highlighted the importance of the high-level meeting to
be held by Parliamentarians from Chile and Bolivia, during the month of
November in Bolivia.
20
Situaci6n de los ex trabajadores de AADAA:
Los Directores Jurfdicos de ambos pafses se reuniran en Bolivia en el marco del
pr6ximo Comite de Fronteras.
La presente Acta fue suscrita en la ciudad de lquique, a los seis dias del mes de
octubre del ano 2005.
i
Ii
r , \ ~ ~Ii JIA(\;L~ ~~
POR t ~l~ILE
\
;li<M~
POR BOLIVIA
21
Situation of ex-workers of the Autonomous Administration of Customs Warehouses
of Bolivia (AADAA for its acronym in Spanish):
The Legal Directors of both countries will meet in Bolivia in the framework of
the next Borders Committee.
This Minute was signed in the city of Iquique, on the sixth day of the month of
October of the year 2005.
(Signature) (Signature)
FOR CHILE FOR BOLIVIA
22
Agenda de la Reuni6n del XIV Mecanismo de Consultas Politicas
Chile - Bolivia
Grupo de Trabajo sobre Asuntos Bilaterales
1. Agenda sin exclusiones Bolivia - Chile
2. Mecanismos institucionales de dialogo bilateral
Libre Transito
3. Puerto de lquique (habilitaci6n al regimen de libre transito)
4. Puerto de Arica
5. Manuel Operativo del Sistema lntegrado de Transito
Comite de Frontera
6. Eliminaci6n de Pasaportes para la circulaci6n de Turistas con Cedula de
ldentidad entre ambos pafses.
7. Controles lntegrados de Frontera
8. Cooperaci6n Aduanera
9. Grupo Tecnico Mixto sabre lnfraestructura GTM y ATIT
Educaci6n, Cultura, Ciencia y Tecnologfa
1 O. Analisis sabre el establecimiento de una Comisi6n Mixta sabre
Educaci6n, Cultura y Ciencia y Tecnologfa.
11. Proyecto de Acuerdo sabre protecci6n y restituci6n de bienes del
Patrimonio Cultural.
12. Encuentro de Gestores Culturales Chile - Bolivia.
13. Memorandum de Entendimiento Cultural.
Convenios
14. Convenio para el trabajo remunerado de familiares del personal
consular, administrative y tecnica. *
15. Acuerdo para Evitar la Doble Tributaci6n
16. Convenio de Servicios Aereos (1993)
Temas Econ6micos y Comerciales
17. Profundizaci6n del ACE 22
18. Turismo
Cooperaci6n
Varios
23
Agenda of the XIV Meeting of the Chile-Bolivia Political Consultation
Mechanism
Working Group on Bilateral Issues
1. Bolivia-Chile agenda without exclusions
2. Institutional mechanisms for bilateral dialogue
Free Transit
3. Port of Iquique (enabling for the free transit regime)
4. Port of Arica
5. Operational Manual of the Integrated Transit System.
Border Committee
6. Elimination of Passports for the circulation of Tourists with Identity Cards
between both countries.
7. Integrated Border Controls
8. Customs Cooperation
9. Joint Technical Group on Infrastructure of the Joint Technical Group on
Infrastructure (GTM) and the Agreement on International Land Transport
(ATIT).
Education, Culture, Science and Technology
10. Analysis on the establishment of a Joint Commission on Education, Culture
and Science and Technology.
11. Draft Agreement on protection and restitution of Cultural Heritage Assets.
12. Meeting of Chile-Bolivia Cultural Managers.
13. Memorandum of Cultural Understanding.
Agreements
14. Agreement for paid work of family members of consular, administrative
and technical personnel.*
15. Agreement to Avoid Double Taxation
16. Air Services Agreement (1993).
Economic and Commercial Issues
17. Deepening of ACE 22
18. Tourism
Cooperation
Various
24
(*) Respecto al Convenio para el trabajo remunerado de familiares del personal
consular, administrativo y tecnico, se sugiere efectuar el intercambio de Notas de
las conclusiones de la reunion y firrna del Acta.
Nomina de la Delegacion chilena
Emb. Cristian Barros
Subsecretario de Relaciones Exteriores
Ministerio de Relaciones Exteriores
Emb. Roberto Ibarra
Director de America del Sur
Ministerio de Relaciones Exteriores
Emb. Maria Teresa Infante
Directora Nacional de Fronteras y Limites
Ministerio de Relaciones Exteriores
Emb. Francisco Perez Walker
Consul General en La Paz
Sr. Anselmo Pommes
Director de Fronteras
Ministerio de Relaciones Exteriores
Sr. Gustavo Vergara
Director Regional Subrogante de la Aduana de Iquique
Sr. German Fibla A.
Jefe Departamento Normativo de Aduanas
MC Economico Enrique Soler
Director Oficina Comercial
C. Juan Pablo Crisostomo
Encargado del Escritorio Bolivia
Ministerio de Relaciones Exteriores
Sr. Enrique Ceppi
Jefe del Departamento ALADI
Direcci6n General de Relaciones Econ6micas lnternacionales
Ministerio de Relaciones Exteriores
SS. Felipe Saez
25
(*)Regarding the Agreement for the remunerated work of relatives of consular,
administrative and technical personnel, it is suggested to exchange the Notes of
the conclusions of the meeting and sign the Minutes.
List of the Chilean Delegation
Amb. Cristian Barros
Under-Secretary of Foreign Affairs
Ministry of Foreign Affairs
Amb. Roberto Ibarra
Director of South America
Ministry of Foreign Affairs
Amb. Maria Teresa Infante
National Director of Borders and Boundaries
Ministry of Foreign Affairs
Amb. Francisco Perez Walker
Consul General in La Paz
Mr. Anselmo Pommes
Director of Borders
Ministry of Foreign Affairs
Mr. Gustavo Vergara
Acting Regional Director of the Iquique Customs
Mr. German Fibla A.
Head of the Customs Regulations Department
Minister Economic Counselor Enrique Soler
Commercial Office Director
Counselor Juan Pablo Crisostomo
Head of the Bolivian Desk
Ministry of Foreign Affairs
Mr. Enrique Ceppi
Head of the ALADI Department
General Directorate of International Economic Relations
Ministry of Foreign Affairs
Second Secretary Felipe Saez
26
Gabinete Subsecretario
Ministerio de Relaciones Exteriores
Sr. Hernan Acuna
Agencia de Cooperaci6n Internacional
Sr. Patricio Campana
Gerente General
Empresa Portuaria de Arica
Sr. Sergio Retamal
Gerente de Explotacion Comercial
Empresa Portuaria de Antofagasta
Sr. Rolando Varas
Gerente de Operaciones TP A
Sr. Rodrigo Pinto
Empresa Portuaria de Arica
Mariela Fuentes
Direcci6n de Prensa
Ministerio de Relaciones Exteriores
TS. Andres Aguilar
Escritorio Bolivia
Ministerio de Relaciones Exteriores
N6mina de Delegaci6n boliviana
Emb. Hernando Velasco Tarraga
Viceministro de Relaciones Exteriores y Culto
MC. William Torres Armas
Director General de Limites y Fronteras
Emb. Edgar Pinto Tapia
Director General de Relaciones Multilaterales
MP. Marco Antonio Vidaurre Noriega
Director General de Relaciones Bilaterales
27
(Cabinet Undersecretary
Ministry of Foreign Affairs
Mr. Hernan Acuña
International Cooperation Agency
Mr. Patricio Campaña
General Manager
Port Company of Arica
Mr. Sergio Retamal
Commercial Exploitation Manager
Port Company of Antofagasta
Mr. Rolando Varas
Operations Manager TPA
Mr. Rodrigo Pinto
Port Company of Arica
Mariela Fuentes
Press Office
Ministry of Foreign Affairs
Third Secretary Andres Aguilar
Bolivian Desk
Ministry of Foreign Affairs
List of the Bolivian Delegation
Amb. Hernando Velasco Tarraga
Vice-Minister of Foreign Affairs and Worship
Minister Counselor William Torres Armas
Director General of Boundaries and Borders
Amb. Edgar Pinto Tapia
General Director of Multilateral Relations
Minister First Class, Marco Antonio Vidaurre Noriega
General Director of Bilateral Relations
28
C. Isabel Cadima Paz
Directora de America
MC. Mauricio Dorfler Ocampo
Director General de Integracion y Asuntos Comerciales
Dr. Ramiro Prudencio Lizon
Asesor en Politica Exterior
MC. Roberto Finot Pabon
Consul General a.i. de Bolivia en Santiago
Regina Hennings
Consul Adjunto de Bolivia en Santiago
Edgar Choque Armijo
C6nsul de Bolivia en lquique
TS. Yuri Arce Navarro
Encargado de) Escritorio Chile
29
Counselor Isabel Cadima Paz
Director of America
Minister Counselor Mauricio Dorfler Ocampo
General Director of Integration and Commercial Affairs
Dr. Ramiro Prudentcio Lizon
Foreign Policy Advisor
Minister Counselor Roberto Finot Pabon
Acting Consul General of Bolivia in Santiago
Regina Hennings
Deputy Consul of Bolivia in Santiago
Edgar Choque Armijo
Consul of Bolivia in Iquique
Third Secretary Yuri Arce Navarro
Head of the Chile Desk

Annex 20
Records of the Ministry of Foreign
Affairs of Chile, 2009
(Original in Spanish, English Translation)
32
Ministerio de
Relaciones
Exteriores
Gob!orno do O,h
Memoria del Ministerio de Relaciones
Exteriores de Chile
Ano 2009
Archivo General Hist6rico
Ministerio de Relaciones Exteriores de Chile
33
Records of the Ministry of Foreign
Affairs of Chile
Year 2009
Historical General Archive
Ministry of Foreign Affairs of Chile
34
DIFROL colabor6 con otras Direcciones del Ministerio de Relaciones Exteriores
y organismos del Estado, en el seguimiento de expediciones cientfficas
marftimas en aguas jurisdiccionales chilenas por parte de naves de terceros
pafses, que se someten a la reglamentaci6n contenida en el D. S. 711 de 1975,
asf como de investigaciones que se realizarfan en zona fronteriza con
participaci6n de personas residentes en el exterior.
d. Transferencias de inmuebles situados en zona fronteriza
Autorizaciones al Ministerio de Bienes Nacionales
Tftulos Gratuitos
80
Ventas
Directas
66
Arriendos
52
2. Direcci6n de Umites (DIRLIM)
Concesiones
29
a. Departamento de Estudios Limftrofes
Programa especial de fronteras y If mites
Saneamientos
97
El Departamento de Estudios Limftrofes continua las actividades y estudios
tecnicos del Programa Especial de Fronteras y Umites, el cual comprende los
temas de Campo de Hielo Sur, recursos hfdricos fronterizos-con particular
acento en el rfo Silala/Silala-, Umites Marftimos y Plataforma Continental
Extendida. Este es un Programa de alcance confidencial, sabre el cual ha
existido permanente trabajo. Algunos antecedentes de difusi6n publica, se
presentan a continuaci6n:
Terna Rfo Silala
Se realizaron dos reuniones del Grupo Tecnico Chile-Bolivia sabre el rfo Silala.
La V Reunion sabre el tema, y primera del ano, se llev6 a cabo el 3 de abril, en
Santiago. En representaci6n de Chile asistieron delegados de DIFROL y del
Ministerio de Relaciones Exteriores, de la Direcci6n General de Aguas (DGA) y
del Servicio Nacional de Geologfa y Minerfa (Sernageomin). Par parte de
Bolivia, concurrieron representantes de la Cancillerfa y del Ministerio del
Agua. En dicha oportunidad, se continua desarrollando el programa de trabajo
para tratar el tema del rfo Silala a nivel tecnico, asf coma el proyecto de
Acuerdo lnicial.
Posteriormente, se llev6 a cabo la VI Reunion sabre el tema, los dfas 18 y 19
de mayo en La Paz - Bolivia, ocasi6n en que las delegaciones llegaron a un
proyecto de acuerdo que elevaron a sus respectivos Gobiernos. En efecto, el
Grupo de Trabajo finaliz6 la redacci6n de un proyecto de acuerdo inicial, el
que serfa sometido a instancias superiores para su consideraci6n y aprobaci6n
272
35
[...]
2. Direction of Boundaries (DIRLIM)
a. Department of Border Studies
Special program for borders and boundaries
The Border Studies Department continued the activities and technical studies
of the Special Border and Boundary Program, which includes the themes of
Southern Ice Field, Border Water Resources –with particular emphasis on the
Silala/Silala River–, Maritime Boundaries and Extended Continental Shelf.
This is a Program of confidential scope, on which there has been permanent
work. Some background information on public dissemination is presented
below.
Silala River Issue
Two Chile-Bolivia Technical Group meetings were held regarding the Silala
River. The V Meeting on the issue, and first of the year, took place on April
3rd, in Santiago. Delegates from DIFROL and the Ministry of Foreign Affairs,
the Directorate General of Water (DGA) and the National Geology and Mining
Service (SERNAGEOMIN) attended on Chile’s behalf. On the Bolivian side,
representatives of the Ministry of Foreign Affairs and the Ministry of Water
attended. On that occasion, the work program to address the issue of the Silala
River at the technical level, as well as the draft Initial Agreement, continued to
be developed.
Subsequently, the Sixth Meeting on the subject was held on 18 and 19 May in
La Paz, Bolivia, on which occasion the delegations reached a draft agreement
that they submitted to their respective Governments. Indeed, the Working
Group finalized the Draft Initial Agreement, which would be submitted to
higher instances for their consideration and approval
272
36
respectiva, con miras a su pr6xima suscripci6n. Estos trabajos, fueron asistidos
por el Servicio Nacional de Meteorologfa e Hidrologfa, el Servicio Nacional de
Hidrograffa Naval, el Servicio Nacional de Geologfa y Minerfa de Bolivia, la
Direcci6n Nacional de Fronteras y Umites y la Direcci6n General de Aguas, de
Chile.
En noviembre, en el seno del Mecanismo de Consultas Polfticas presididas por
los Viceministros de ambos pafses, concluy6 la negociaci6n del acuerdo inicial
con los siguientes objetivos:
1. Establecer un acuerdo bilateral para la preservaci6n, sustentabilidad,
uso y desarrollo del sistema hfdrico del Silala o Siloli, en beneficio de
ambos pafses
2. Conducir estudios e investigaciones para determinar, entre otros
fines, la naturaleza, el balance hfdrico, la conducta hidrometrica, el
registro del agua, los flujos superficiales y subterraneos y la influencia
de las obras civiles sabre el volumen del agua. Esto, empleando
metodologfa cientffica validada de comun acuerdo, la que proveerfa
una base para establecer el porcentaje de las aguas de libre
disponibilidad de las partes.
3. Establecer un mecanismo para que Bolivia autorice el uso de las aguas
de su libre disponibilidad, en su territorio, a fin de que fueran
captadas y conducidas hacia Chile, con una compensaci6n. En caso
alguno el acuerdo inicial contemplaba el pago del agua por el Estado
chileno por el simple hecho de su paso por la frontera.
El Departamento de Estudios Limftrofes continu6 en este perfodo con la
recopilaci6n y clasificaci6n del material cartografico y bibliografico relacionado
con el rfo Silala, y particip6 en reuniones tecnicas con Bolivia, incluso en
terreno.
Expediciones cientificos y deportivas al sector de Campo de Hielo Norte
(CHN), Campo de Hie/o Sur (CHS) y zonas englaciadas, durante el ano 2009
Expedici6n CHS
Fecha: 1 Febrero - 30 Julio 2009
Actividades: Esta actividad tuvo coma objetivo realizar una travesfa deportiva
en la zona de CHS, caminata y kayak.
Participantes: Christian Clot, suizo y Mellusine Mallender, britanica
15!! Expedici6n Alemanes, Universidad de Trier
Fecha: 9 Marzo - 16 Abril 2009
Actividades: Expedici6n cientffica a la zona del Gran Campo Nevada, Peninsula
Munoz Gamero, en la cual se desarrollaron estudios climaticos y glaciol6gicos.
Participantes: Rolf Kilian, Sascha Serna, Tobias Sauter, Marco Moller, Frank
Lamy, Helge Arz, Gerlinde Castel, de nacionalidad alemana y Marcelo Arevalo
de nacionalidad chilena.
273
37
with a view to its next subscription. These works were assisted by the National
Meteorology and Hydrology Service, the National Naval Hydrographic Service,
the National Service for Geology and Mining of Bolivia, the National Direction
of Borders and Boundaries and the Chilean Directorate General of Water.
In November, within the Mechanism of Political Consultations chaired by the
Vice-Ministers of both countries, the negotiation of the initial agreement was
concluded with the following objectives:
1. Establish a bilateral agreement for the preservation,
sustainability, use and development of the Silala or Siloli
water system, for the benefit of both countries.
2. Conduct studies and research to determine, among
other purposes, nature, water balance, hydrometric behavior,
water recording, surface and groundwater flows and the
influence of civil works on the water volume. This, employing
scientific methodology validated by common agreement,
which would provide a basis for establishing the percentage
of water freely available to the Parties.
3. Establish a mechanism for Bolivia to authorize the
use of freely available waters in its territory, in order to
collect and transport them to Chile, with compensation. In
no case did the initial agreement contemplate the payment of
water by the Chilean State for the simple fact of its crossing
the border.
The Department of Borders Studies continued in this period with the compilation
and classification of cartographic and bibliographic material related to the Silala
River, and participated in technical meetings with Bolivia, even in the field.
[...]
273

Annex 21
El Mercurio, “The Foreign Minister opts for integration”,
Santiago, 21 October 2001.
(Original in Spanish, English Translation)
40
0 ► Domingo 21 de Octubre de 2001
Canciller apuesta a integraci6n
Soledad Alvear, ministra de RR. EE.
La ministra de Relaciones
Exteriores hablo sobre los
temas contingentes de la A~or: Alimen:o del alma
" I • • H1Jos: Bend1c1on de D1os region y. as ausp1. c1osas ., Mu i.e r: y o soy una y .1 a muc ho
proyecc1ones de integrac1on orgu1101
con los paises vecinos Polftica: Clave para progresar en
paz y justicia
Por Pablo Matamoros A. Democracia Cristiana: Mi querido
Patricio Vega C. pa rtido
Norte: Grande y bello
Menuda. De tono suave y Pobreza: iDebemos eliminarla!
amable, pero con innegab le Cobre: Gracias por apoyar nuestro
poder de conviccion. As[ es la progreso
ministra de Relaciones Exteriores, Soledad Alvear, quien tiene a su lnteligencia: Admiro ambas, la
cargo las riendas de la polftica exterior del pafs. racional y la emocional
No es casualidad que esta mujer ocupe una de las carteras mas Periodismo: Clave en una
estrategicas del Presidente Ricardo Lagos. Su curriculum deja en claro democracia
su sello en los dos ultimas gobiernos de la Concertacion, donde uno de lnjusticia: Me duele y me moviliza
sus "hijos predilectos" es la Reforma Procesal Penal. para repararla
Tampoco es un misterio que sea una de las figuras publicas mejor Cordillera: Me emociona verla
evaluadas y con mayor credibilidad en la ciudadanfa, al punto que su nevada
nombre suena como presidenciable para las elecciones del 2005. Atentados: Irracionalidad criminal
En medio de su recargada agenda (q ue inclu ye por estos dfas una gira Reform a Procesal: Haberla
a Singapur), la ministra hablo sobre temas de contingencia para la encabezado, como ministra de
Segunda Region y que han le vantado mas de alguna polemica, Justicia, junto a un equipo
especialmente en el caso de las relaciones interna ciona les con Bolivia. humano con gran mfstica, es una
de mis grandes satisfacciones.
CORREDOR MARITIMO
Existe la posibilidad de un corredor marftimo para Bolivia. En vista de la alternativa de sacar la produccion
de la minera boliviana San Cristobal por Tocopilla y una red de gasoducto hacia Mejillones, lestan
avanzados estos proyectos?
• Las autoridades de la Segunda Region, principalmente Obras Publicas, se encuentran estudiando en
forma conjunta con la empresa Minera San Cristobal la coparticipacion de esta ultima en el mejoramiento
de la infraestructura caminera para satisfacer las necesidades de dicha empresa para llevar su produccion
al Puerto de Tocopilla. Estos proyectos estan bien encaminados.
El diputado Waldo Mora incluso habla de entregar una franja de terreno para Bolivia cerca de caleta Cobija
para que se desarrollen proyectos turfsticos, lcual es la posicion del Gobierno en este tema?
• Quiero reiterar que el Gobiemo de Chile no se encuentra negociando la cesion, a ningun tftulo, de
porciones de su territorio.
Un problem a pendiente con Bolivia esta en la propiedad de las aguas del Silala. ,Como el Gobierno
enfrentara el millonario cobro de una empresa altiplanica por el uso de agua?
- Nuestra Cancillerfa ha seguido el mandate presidencial de celebrar re uniones tecnicas, participando en
varias sesiones yen una visita conjunta a terreno. La pa rte chilena ha propuesto que se trabaje una
formula practica, que garantice un beneficio economico para Bo livia y sobre la base de que el recurse es
compartido, reconociendo una porcion del caudal que pasa por superficie para cada pafs.
41
Sunday, 21 October 2001
Foreign Minister opts for integration
The Foreign Minister of Foreign Affairs spoke of the issues related to the region
and the promising integration projections with neighboring countries
By Pablo Matamoros A.
Patricio Vega C.
Petite, of a soft tone, and friendly, but with an undeniable power of conviction. This
is the Minister of Foreign Affairs, Soledad Alvear, who is in charge of the country’s
foreign policy.
It is no coincidence that this woman occupies one of the most strategic portfolios of
President Ricardo Lagos. Her curriculum makes clear her support for the latest innovations
of Concertacion [political party], one of her “preferred children” of which is the
Criminal Procedure Reform.
Nor is it a mystery that she is one of the public figures best evaluated and with greater
credibility among the citizens, to the point that her name as Presidential candidate for
the 2005 elections has already been mentioned.
Among the subjects included in her renewed agenda (which includes a tour to Singapore
these days), the minister spoke of issues related to the Second Region that have
given place to more than one polemic, particularly in regard to international relations
with Bolivia.
MARITIME CORRIDOR
Is there a possibility for a maritime corridor for Bolivia? In view of the alternative
of shipping production from the Bolivian mine of San Cristobal through
Tocopilla and a pipeline network to Mejillones, is progress being made with any
of these projects?
- The authorities of the Second Region, mainly those related with Public Works, are
studying with San Cristobal mining company the latter’s participation in the improvement
of the road infrastructure to meet the needs of said company to ship its production
to Tocopilla port. These projects are well on track.
Deputy Waldo Mora has even talked of a strip of land for Bolivia near Cobija
inlet to implement touristic projects. What is the government’s position on this
issue?
- I want to reiterate that the Government of Chile is not negotiating the cession, at no
cost, of portions of its territory.
A pending problem with Bolivia lies in the proprietorship over the waters of Silala.
How will Government face the millionaire request of payment made by the
Bolivian company for the use of water?
- Our Foreign Ministry has the presidential mandate to hold technical meetings, participating
in several sessions and in a joint visit to the field. The Chilean side has
proposed that a practical formula be developed to guarantee an economic benefit for
Bolivia and, on the basis of the fact that the resource is shared, to recognize a portion
of the flow that passes through each country.
42
TRATADO MINERO
Chile propicia una politica de integracion con los paises vecinos. lQue importancia le da al Tratado Minero
con Argentina y como incentivara la actividad economica de la region?
- El Tratado de Integracion y Complementacion Minera con Argentina es un paso de suma importancia en
el proceso de integracion binacional. Las proyecciones y potencialidades del tratado, que ya se encuentra
plenamente vigente, son enormes y, por tanto, constituye por si mismo un incentivo importante a la
actividad economica de la region. El objetivo esencial se orienta a posibilitar a los inversionistas la
exploracion, explotacion y comercializacion de los recursos mineros fronterizos existentes a ambos lados
de la cordillera. Se estima que este instrumento generara inversiones superiores a US$ 20 mil millones.
El Mercosur promete convertirse en un gran mercado, lCual sera la oferta que el norte del pais brindara en
el aspecto comercial y de servicios?
-Tenemos confianza en que el Mercosur, como Union Aduanera, rapidamente em piece a retomar su
dinamismo comercial, una vez que se comience a superar la crisis que viven los paises miembros en la
actualidad. En este contexto, todo el no rte del pais debera intensificar la conexion con el noreste argentino
fortaleciendo su vinculacion comercial y optimizando la oferta de servicios, especialmente el sector
portuario, financiero, telecomunicaciones y de transportes.
MEGAPUERTO
Iquique tiene cierta rivalidad con el proyecto megapuerto de Mejillones porque se dice que ha sido
"privilegiado por el Gobierno". lla Cancilleria apoya la posicion que Mejillones sea el futuro puerto
exportador para Chile?
- Esta es una decision del Gobierno en su conjunto, en la que participan varios estamentos con idoneidad
en la materia y cuyas decisiones se basan sabre estudios tecnicos, medioambientales, juridicos y otros, y
que descansan en el reconocimiento pleno de la capacidad de elegir opciones por pa rte del sector privado.
La Segunda Region pavimento el Paso de Jama bajo la administracion del ex Presidente Eduardo Frei,
lque falta ahora para concretar el intercambio economico con la Zona de Integracion del Centro Oeste
Sudamericano (Zicosur)?
- Desde 1992 que existe con Argentina un Plan Maestro General de Pasos Fronterizos, eminentemente
tecnico, que ha priorizado un tota l de 13 Pasos a lo largo de la frontera. Desde que se inicio el proceso de
integracion binacional, ha sido el interes de ambos paises ir mejorando la infraestructura fisica que los
une. El Paso lama juega un papel fundamental en la integracion del Norte Grande con el Noroeste
argentino y el Centro Oeste Sudamericano. Cumplido el papel del Estado respecto de dicho paso, la
pavimentacion corresponde ahora a los beneficiarios de el, es decir, a las personas y sus actividades de
concretar el intercambio economico.
ALMACENES FRANCOS
En 1969 se firmo un convenio de almacenes francos entre Chile y Paraguay, pero hasta ahora nose dicta
el reglamento para su funcionamiento en el puerto de Antofagasta. ,Es posible reactivar esta iniciativa de
integracion?
- Todas las iniciativas de integracion son absolutamente prioritarias para el Gobierno de Chile. Este caso
especifico no constituye en modo alguno una excepcion a esa vocacion integradora que estimamos
prioritaria. Efectivamente, hemos reactivado este convenio que descanso en el olvido durante mas de 30
afios, yen atencion a que se ha hecho necesario efectuar ciertas actualizaciones de caracter
administrativo, tributario y otros, se encuentra en funciones una Comision interdisciplinaria integrada por
diversas reparticiones publicas que es presidida por el Ministerio Secretaria General de la Presidencia.
Otro problema que enfrenta la region pasa por los multiples campos minados que existen en su frontera
con Bolivia y Argentina. lExiste un plazo para eliminar estas areas peligrosas?
- El jueves 13 de septiembre, en la Quebrada de Santa Cruz, se llevo adelante la destruccion de mas de
43
MINING TREATY
Chile promotes a policy of integration with neighboring countries. How important
is the Mining Treaty with Argentina? And how will economic activities in the
region be encouraged?
- The Treaty of Mining Integration and Complementation with Argentina is an important
step in the binational integration process. The projections and potentials of
this treaty, which is already fully in force, are enormous and it, therefore, constitutes
an important incentive to the economic activity of the region. The essential objective
is intended to make possible for investors to explore and commercialize the existing
border mining resources on both sides of the mountain range. It is estimated that this
instrument will generate investments that will surpass the US $ 20 billion.
The Mercosur promises to become a big market, what offer will the country of the
north provide in commercial and service provision related aspects?
- We are confident that Mercosur, as a Customs Union, have just begun to resume commercial
dynamism, once we have the opportunity to overcome the crisis experienced
by member countries at present. In this context, the entire north of the country should
intensify the connection with the northeast of Argentina by strengthening its commercial
connections and optimizing the provision of services, particularly in regard to the
port, financial, telecommunications and transport sectors.
MEGAPUERTO
Iquique has some rivalry with the Mejillones mega-project project because it is
said that is has been “privileged by the Government.” Does the Foreign Ministry
support the position that Mejillones is Chile’s future exportation port?
- This is a decision of the Government as a whole, in which several strata are involved
with suitability in the matter and whose decisions are based on technical, environmental,
legal and other studies, and which rest on the full recognition of the private sector’s
ability to choose options.
The Second Region paved the Paso de Jama under the administration of former
President Eduardo Frei, what is needed now to concretize the economic exchange
with the Integration Zone of the Central South American (Zicosur [for its Spanish
acronyms])?
- Since 1992 there has been a General Master Plan for Border Crossings with Argentina,
eminently technical, which has prioritized a total of 13 passes along the border.
Since the binational integration process began, it has been the interest of both countries
to improve the physical infrastructure that unites them. Paso Jama plays a fundamental
role in the integration of the Norte Grande with the Argentine Northwest and the South
American Western Center. Once the role of the State has been fulfilled with respect to
this step, the paving now corresponds to its beneficiaries, that is, it is now the role of
the people and their activities to concretize the economic exchange.
FREE WAREHOUSES
In 1969 an agreement of free warehouses was signed between Chile and Paraguay,
but until now the regulations for its operation in the port of Antofagasta have not
been issued. Is it possible to reactivate this integration initiative?
- All the integration initiatives are absolutely priorities for the Government of Chile.
This specific case does not constitute in any way an exception to that integrating vocation
that we consider a priority. In effect, we have reactivated this agreement that rested
in oblivion for more than 30 years, and, in light of the fact that it has become necessary
to carry out certain administrative, tax and other updates, an interdisciplinary committee
composed of various public agencies is in operation. It is chaired by the Ministry
General Secretariat of the Presidency.
Another problem that the region is facing has to do with the multiple minefields
that exist on its border with Bolivia and Argentina. Is there a deadline to eliminate
these dangerous areas?
- On Thursday, 13 September, in the Quebrada de Santa Cruz, the destruction of more than
44
10 mil minas antipersonal. Con este acto, Chile mostr6 su prop6sito de cumplir en las hechos con el
compromiso adquirido cuando suscribi6 la Convenci6n de Ottawa, sabre Prohibici6n, Transferencia y
Destrucci6n de Minas Terrestres Antipersonal.
Los atentados en Nueva York demostraron que ning(m pais puede estar ajeno al flagelo del terrorismo.
,Como Chile enfrentara este problema de seguridad global?
- Nuestro pars ha asumido compromisos claros relacionados con el com bate contra el terrorismo. Samas
parte de la Comunidad Internacional que ha manifestado un rotunda rechazo a las atentados del 11 de
septiembre y que considera fundamental adoptar medidas tanto en el ambito interno coma en conjunto
con otros parses para enfrentar este conflicto. Ahora bien, nuestro aporte al com bate contra el terrorism a
esta vinculado con nuestras reales capacidades.
◄ VOI.VlR
( Sumipciones) ( Clasifono ) ( Telefonos ) ( Contactos )
Abaroa 2051, Calama
45
10 thousand antipersonnel mines was carried out. With this act, Chile showed its intention
to comply with the commitment acquired when it signed the Ottawa Convention
on the Prohibition, Transfer and Destruction of Antipersonnel Land Mines.
The attacks in New York showed that no country can be unmindful of the scourge
of terrorism. How will Chile face this global security problem?
- Our country has assumed clear commitments related to the fight against terrorism.
We are part of the international community that has expressed outright rejection to the
September 11 attacks and considers it essential to adopt measures both internally and
together with other countries to confront this conflict. However, our contribution to the
fight against terrorism is linked to our real capabilities.

Annex 22
R. Gomez-Garcia Palao, “Transboundary water resources
between the Republics of Bolivia and Chile – Silala”, April 1997
(English Translation)

49
REPUBLIC OF BOLIVIA
MINISTRY OF FOREIGN RELATIONS AND WORSHIP
FOREIGN POLICY ANALYSIS UNIT – UDAPEX
ANDEAN DEVELOPMENT CORPORATION
Final Report on the Study regarding:
TRANSBOUNDARY WATER RESOURCES BETWEEN
THE REPUBLICS OF BOLIVIA AND CHILE
Elaborated by: Dr. Eng. Rene Gomez-Garcia Palao
La Paz, April 1997
Rene Gomez-Garcia Palao
Civil
Engineer
R.N.I. 3917
* * *
TABLE OF CONTENTS
List of Annexes VI
List of Figures VI
List of Maps VI
List of Charts VII
Abbreviations and Acronyms VIII
Dimensions and Units IX
Executive Summary X
REPUBUCA DE BOLMA
MINISTERlO OE RElACIONES EXTERIORES YCULTO
UNl!WlOE~OEPOUTICAEXTEJOOR•I.IDAPEX
SI LALA
RECURSOS HIDRICOS TRANSFRONTERIZOS
ENTRE LAS REPUBUCAS OE BOUVIA Y CHILE
50
7. SILALA CASE
The Silala (Siloli) is a transboundary hydrographic catchment basin, whose
upper basin is located in Bolivian territory and at the height of 3,640 meters
above sea level, it enters the current Chilean territory.
The area of the basin is of 41 km2, plus 35 km2 corresponding to the surface
of the Caguana sub-basin, in which water exploitation works are observed in
order to transfer a certain volume to the Silala basin. Therefore the concept of
successive course is not applicable in the Silala case, basically because there
is no flow that generates a current of water through the course. In addition, the
concept of contiguous course is not applicable in this case either.
7.1 Background Information
In this section we review the actions referring to water exploitation works in
the transboundary basins and in the second we make a list of pertinent legal
provisions.
May – 1887 The Antofagasta Nitrate & Railway Company sells the
railroad to the Huanchaca Mining Company. Mr. Enrique
Villegas transfers the right to supply drinking water to
the city of Antofagasta for the benefit of the Huanchaca
Mining Company.
21 January 1888 Chilean concession for the use of waters from the Loa
River basin for the benefit of the Huanchaca Mining
Company.
29 November 1888 Concession of the Sub-Prefecture of Porco, Department
of Potosi, for the use of waters from the Silala springs for
the benefit of the Huanchaca Mining Company for the use
of the railroad. Copy registered in archives of documents
of the Ministry of Foreign Affairs and Worship.
8 December 1888 The English company “The Antofagasta (Chili) and
Bolivia Railway Company Ltd.” acquires the Antofagasta-
Uyuni railroad from the Huanchaca Mining Company.
25 June 1889 Extension of the Chilean concession to the English
company for the use of water in the basins of the Cebollar,
Amunaha and Polapi rivers.
51
1904 The construction of works for the use of Silala waters by
the English railway company begins.
1904 Concession to the English company “The Antofagasta
(Chili) and Bolivia Railway Company Ltd.” for the
provision of drinking water to the city of Antofagasta.
6 October 1908 Concession testimony for the use of water from the Silala
springs to the Antofagasta and Bolivia Railway Company,
located in the Quetena vice-canton, South Lipez Province,
with the purpose of feeding the railway machines. There
is an unofficial copy issued by the Railways Office of
1940. The management is carried out under the leadership
of the manager of the English railway company, Josias
Harding, who during the War of the Pacific was an advisor
of the Chilean Government, participated in the assault
on Antofagasta and was part of the first bi-national
commissions to delimit borders.
29 June 1940 Mr. Pablo Boudoin denounces the misuse of the Silala
waters. The Permanent Fiscal Commission declines
jurisdiction, 18 October 1940.
23 October 1959 The Inter-institutional Study Commission is constituted.
November 1959 The Chancellery, the Army Major Command, plus the
National Commission for Coordination and Planning
[pronounce] themselves with respect to the arbitrary use
of the Lauca River waters.
1962 The Direction of Limits reaffirms that the waters “benefit”
Chuquicamata. Complaint by Mr. Augusto Valdivia about
expansion of works in the Silala.
1965 The Irrigation Department of the Ministry of Public
Works of Chile charges $ 0.20 x m3. Maritime Action
denounces the Supreme Council of National Defense.
Regarding the first antecedent of the use of Silala waters, it goes back to 29
November 1888, when the Antofagasta Nitrate and Railway Company signed
a contract with the Bolivian State, for the exploitation of saltpeter and was
granted the use of the Silala waters.
During that time the legal situation of the Littoral Department was not defined,
since the Truce Pact of 4 April 1884
52
was in force, which according to its Second Article, Chile was in possession of
our territories until the signing of a definitive peace treaty that was defined in
1904.
The rights of the Antofagasta Company were acquired by Mr. Aniceto Arce
with the company name of Huanchaca Company of Bolivia, which continued
with the construction of the Bolivian railway section to Uyuni.
The Huanchaca Mining Company transfers its rights to another company with
a predominance of English capital on 21 March 1889. This company completed
the construction of the Antofagasta-Uyuni railway on 25 November 1889.
The company named (Antofagasta (Chili) and Bolivia Railway Company
Limited) later continued operating the railroads of Bolivia under the name of
Bolivian Railway Company which was later nationalized.
7.1.1 Testimony of Concession of Use of Silala Waters
The unofficial copy of the concession document is included in Annex 7 of the
study.
As established in Article 217, the Prefect of the Department of Potosi signed
the concession for the use of the waters of the Silala springs, whose most
significant aspects are indicated below:
Number forty-eight – Deed of concession and consequent adjudication of the
use of water, which form some springs called “Siloli” existing in the region
of the Quetena vice-canton of the South Lipez Province of this Department.
It is granted by the acting Prefect Mr. Rene Calvo Arana, in his capacity as
Superintendent of Finance of the Department, in favor of the company “The
Antofagasta (Chili) and Bolivia Railway Company Limited,” represented in
a legal and correct manner by the attorney general, Mr. Theodosius Graz, as
recorded by the power constituted, page 10, of the works of the matter, granted
by the original legal representative – Benjamin Calderon in the city of La Paz
on September 7th of the current year.
“By the previous report given by the President of the Municipal Board of South
Lipez it is stated that the water springs of the place called Siloli are located in
the Vice-Canton of Quetena in a deserted place, in which any community or
property makes use of the water, and with the protest that is made to leave the
third part of the water abstracted, for those who want to use it later. Grant the
use of the referred waters in merit of Article 217 of the Decree of 8 September
1879, raised to the rank of Law on 28 November 1906.”
53
The aforementioned petitioner company and in its condition of having fulfilled
the requirements of the law and in force of this public instrument is further
covered with the character of true and only concessionaire and adjudicator of
use of the Siloli waters, without any person being able to claim better rights,
therefore deed testimony must serve as sufficient title.
“…The Antofagasta (Chili) and Bolivia Railway Company Limited, having informed
of this relative deed, accepts in all its parts in favor of the company it
represents by ratifying with the same solemnity as the Prefecture of the Department,
making the formal denunciation that the concessionaire will comply
strictly the prescriptions of the law and regulations that govern the subject in
the future. Testimony of this, they said, is granted and signed with me by the
Notary Public of the Treasury and the instrumental witnesses of his choice who
were the citizens in office Manuel Zubieta and Honorato Vela, Bolivians and
able to testify.”
“…For being in accordance with the prescriptions to the law of all that I give
faith, the signatories are Rene Calvo Arana.-.-.-. Teodosio Graz.-.-.-. Manuel A
Zubieta.-.-.-. Honorato Vela and Francisco lñiguez, Notary Public.”
Additionally, we must emphasize that the object of the concession testimony
emphasizes the use of springs or water eyes. The document does not specify
that the Silala had been known as a river. On the contrary, its name originates
from the pampas of the same name, desert plains covered by sand.
7.1.2 Complementary Background Information
The first official complaint known for the use of water –with different uses than
the one granted to the railway– is that carried out by Mr. Pablo Baudain G., in
June 1940, signed with his lawyer Z. Echeverria, where it is stated that the concessionary
“Company” not only used the water for the purpose of the authorization
or concession, but negotiated with them for so many years and continues
to negotiate, selling drinking water to Antofagasta, meaning that it defrauded
the Bolivian State, selling its wealth and monthly receiving more than 500,000
Chilean pesos for this concept. The permanent Fiscal Commission had admitted
the denunciation through its Decree of 26 June 1940, with the signature
of its President, Rafael Parada Suarez. After almost four months of this legal
instance, the Commission decided to decline jurisdiction and competence by
means of a Resolution dated 18 October 1940.
On 23 October 1959, the Bolivian Acting Foreign Minister, Dr. Walter Guevara
Arce, informed the President of the Republic, Dr.
Page 7 - 4
54
Hernan Siles Zuazo, of this situation and received instructions to constitute an
Inter-institutional Commission to study the matter.
The commission was formed in November 1959 with delegates from the Foreign
Ministry, the Army General Staff and the National Coordination and Planning
Commission.
In 1962 the then Directorate of Limits of the Ministry of Foreign Affairs informed
that the waters granted for the railroad were now “benefiting” Chuquicamata.
In 1965, Acción Marítima (Maritime Action) filed a complaint with the Supreme
National Defense Council regarding the 1908 concession, stating that there is
no Decree or authorization from the Supreme Government regarding the use of
water for drinking water, charging the sum of 0.20 cents per cubic meter, by the
Irrigation Department of the Ministry of Public Works of Chile, which exploits
this wealth. On 23 November 1965, the Supreme Council of Defense stated that
the said use only refers to “the surplus” of said waters.
In May of 1996, civic institutions and some media in the national press reported
the existence of infrastructure works for the use of water resources by a Chilean
company in Bolivian territory.
7.2 Hydraulic Analysis
Based on hydro-meteorological data read in Bolivia and by the FCAB in
Bolivian territory through the precipitation station installed 2 km upstream of
the borderline (see photo 56, Annex 6), the Silala is a hydrographic basin whose
yield and surface runoff is minimal, 48 liters per second when there is rainfall
with a sheet greater than 5 millimeters, whose annual probability is of 0.002.
Complementarily, due to the characteristics of volcanic soils and sands in the
superficial strata of the basin –which are the cause of high infiltration rates– it
is irrational to assume the existence of surface runoff processes of rainfall with
minimal incidence in the formation of eventual, seasonal or base flows in the
main drainage course, see Plan BC-009.
Therefore, it is incorrect to define the Silala as a river and much less as a river
of successive course.
The basic information available about the specific area of study is worryingly
poor. Data on hydrology, geology and climate are scarce in Bolivia. The study
had to resort to Chilean and North American research sources in order to cover
the necessary information.
Page 7 - 5
55
7.2.1 Location
The upper basin of Silala is registered in Canton Quetena, Province of South Lipez
with capital San Pedro de Lipez in the Department of Potosi. Geographically,
it is delimited between parallels 21°58' and 22°04' south and meridians 67°57'
and 68°05' west. Attitudinally, it varies from 5,600 meters above sea level at
the peak of Silala Grande Hill, from 4,280 meters above sea level in the Silala
Pampas to approximately 3,600 meters in the current borderline.
Physically, the basin is delimited to the north by the watershed defined between
the Grande Silala and Negro hills, to the west by the Inacaliri Hill and the
transect between the border milestones LXXIII and LXXIV, to the south by the
Silala Chico and Caguana hills and to the east by the pampas of Silala.
7.2.2 Identified Water Sources
The main source of water in the Silala basin is that produced by filtering and
transporting underground water from the Eastern Mountain Range of the Andes
to cuts of land with lower altitudes. 94 water eyes or springs were counted in
the development of this study, (8 and 9 January 1997), which, according to the
hydrological analysis –see Annex 4– produces a gross flow on site of 1,470
liters per second.
Water from underground and surface sources originating within the national
territory is stored in natural water bodies. These aquifers retain and discharge
important volumes of water due mainly to conditions of energy balance in the
interior of the earth. The discharged water is transported guided by the gradient
or hydraulic slope and due to natural conditions of permeability of the soils.
A part of this water crosses trajectories that intersect with the natural cuts of
the relief of the land, these cuts are formed from abrupt depressions that form
valleys and canyons; the Silala basin is one of these cases.
The description of the previous scenario allows creating areas with atypical
humidity conditions for the landscape in general. The bofedales originate from
springs, watersheds or water eyes, which in an artesian manner emanate certain
water flows to the surface. The characteristics of humidity and saturation of
soils allow the formation of vegetation on the surface and basically create
conditions that allow a process of natural regulation of the volume of stored
water, establishing in this way an ecological balance between each of the
elements of nature.
Page 7 - 6
56
Therefore, we again argue that it lacks technical sense to speak of international
waters in the Silala case, when it is verified that these are waters generated and
retained in a natural way in Bolivian territory.
The distance of the watercourse from the furthest point where the springs,
watersheds or water eyes are located to the borderline is of 18 km at an altitude
of 4120 meters above sea level. As well as from the nearest water eye or spring
–observed– up to the borderline is 750 meters, at an altitude of 3,740 meters
above sea level.
7.2.3 Water Yield and Hydraulic Structure
According to the methodology exposed at the beginning of Chapter 5, of the
geophysical and climatic characteristics described in Chapter 2, based on the
hydro-meteorological information detailed in Annex 3 and with the analytical
sequence expressed in Annex 4, we obtained the estimate of water yields
expressed in the following table:
The total area of the catchment basin is of 76 km2, of which 76 km2 corresponds
to the upper basin or water exporter basin. The minimum volume of water
produced per year is 22.85 million cubic meters. The volume used per year is
9.15 million cubic meters and the annual volume of wastewater available is
13.70 million cubic meters.
Table 7-1. Water Balance, Silala Transboundary Basin
Source: own elaboration
The infrastructure present in the basin has a hydraulic structure based on
obtaining economic efficiencies beneficial to the investor. The spring water
catchment works are rustic chambers that allow concentration in the direction
of the flow. These small chambers are built with stone and in few cases with
stone and mortar masonry. In all the cases observed, the signaling is confirmed
with sulfur-based tincture.
Page 7 - 7
Code Unit Minimum Maximum Flow Rate Flow Rate Observations
flow rate flow rate Used 1/s Available
produced produced 1/s
1/s 1/s
5-4-1 North Silala 584 621 120 464 to Chile
5-4-2 South Silala 865 901 460 405 to Chile
5-4 Silala 1449 1522 580 869
57
From each water catchment work, channeling networks have been built,
dimensioned according to the flow produced by each spring, watershed or
water eye. These canals constructed with dry masonry or turf have rectangular
or trapezoidal sections respectively, with canal bases that vary in a range of 15
cm to 50 cm, and canal heights that vary in a range of 20 cm to 60 cm.
As primary channeling elements, collector canals have been constructed that
converge in a main collinear canal to the main drainage axis of the Silala basin.
These collector canals of rectangular section have dimensions –base by height–
that vary in a range of 60 cm by 60 cm in the intermediate section up to 1 meter
by 60 cm in the current borderline. The base of the canals is consolidated with
stone masonry and the walls are sealed with a mortar coating.
The water catchment works not only channel the surface flow. The Silala
hydraulic system captures and channels water through open canals and
pressurized pipes.
The first hydraulic control work is located 470 meters above the current
borderline. This work simultaneously fulfills the functions of loading chamber
for the 10 and 12 inch pipes that come out of it; decanter functions or primary
water treatment plant; and functions of discharge control dam to the downstream
canal system, the construction detail can be seen in the BC-011 and BC-012
plans.
The second work of control has constructive characteristics similar to the first,
the discharge speeds are greater due to a greater capacity downstream. The
dimension of the canals is 25% higher and there are two 12-inch pipes coming
out of the loading chamber.
This system has a central control point in the current Chilean territory, which
serves the water catchment works of San Pedro, Inacaliri and Silala. A control
dam is built 5.5 kilometers downstream from the current borderline. This work
has significantly greater dimensions, 13 meters of elevation and approximately
300,000 cubic meters of control storage. It drifts its waters to a pipe of 24
inches in diameter and a minimum capacity of 650 l/s. This flow of water is
channeled to the aqueduct system of the Loa River basin, through the San
Pedro River. From this system –owned by the FCAB and administered by the
National Irrigation Department of Chile– water is distributed for the following
uses in order of distance:
• Agricultural irrigation systems
• Minor populations between the lower basin of Silala and Antofagasta
• The cities of Calama and Chuquicamata
Page 7 - 8
58
• The mining center of Chuquicamata
• The cities of Antofagasta, Mejillones and Tocopilla
It should be noted that the network of aqueducts converges in the city of Calama,
which functions as a discharge center, which is distributed through a complex
network of aqueducts to the cities of Tocopilla, Mejillones and Antofagasta, as
well as to intermediate points.
This study has not found evidence of use of water resources for the generation of
hydroelectricity by means of micro-centrals, however we consider it reasonable
to estimate that the natural fall of 1,500 meters with available flow rates greater
than one cubic meter per second has the potential to generate electricity in the
current Chilean territory.
7.2.4 The Silala Hydraulic System
The system of catchment, channeling, control and storage of water from the
Silala basin has the following dimensions:
• 94 small water catchment works
• 27,000 meters of canals covered with dry masonry
• 2,500 meters of canals covered with stone masonry with mortar
• 17,600 meters of 10-inch pipe laying
• 4,600 meters of 12-inch pipe laying
• 1 combined work, loading, unloading, decantation and control in Bolivian
territory.
• 1 combined work, loading, unloading, decantation and control in current
Chilean territory.
• 1 storage and control work in current Chilean territory.
7.2.5 Hydraulic Capacity and Efficiencies of the System
There are three channeling systems that transport the volume of water abstracted
in the upper basin of Silala; the main open canal, the 10-inch pipe and the 12-
inch pipe. Each of them has the following capacity:
• Open canal from 210 l/s to 320 l/s
• 10-inch pipe from 85 l/s to 100 l/s
• 12 inch pipe from 130 l/s to 160 l/s
• Silala Hydraulic System from 425 l/s to 580 l/s
Page 7 - 9
59
• Equivalent to an annual yield in the range of 13.4 million cubic
meters to 18.3 million cubic meters.
The estimation of system capacity values from a given range is due to the lack
of accurate data on the slope on which the pipeline is laid and the open canal.
The hydraulic efficiency of the constructed works that operate the system is
40%, see Table 5-5. This value is substantially high if we compare it with the
referential values of water efficiency in the country, such as 21% of the Tiraque-
Punata system, 10% of the Yura system or 4% of the Tacagua system.
7.2.6 Water Requirements of Chile
Studies carried out during the last twenty years by the Catholic University of
the North have calculated the water requirements corresponding to the first two
Regions of Chile:
First Region: Arica 7,500 l/s or 236 million cubic meters of
water
Second Region: Antofagasta 11,500 l/s or 363 million cubic meters of
water
The first region obtains 45% of its water requirements through surface water
catchment works in the Lauca River basin.
The Second Region obtains 20% of its water requirements from the water
catchment works in the piedmont of the Andes Mountain Range. We estimate
that the waters from the Silala represent between 5% and 6% of the total water
required and consumed by the Second Region of Chile.
The volume of remaining water required and consumed by the Second Region,
9,200 l/s, is abstracted through the pumping of underground water from
wells drilled in the plains and pampas of the current Chilean territory. This
underground water comes from infiltration processes from the Andes Mountain
Range and the Altiplano. Studies have shown that the yield of wells has not
decreased during the last ten years, the flow rate remains constant, despite the
almost zero rainwater recharge of the Chilean desert. This constant flow is due
to the conditions of infiltration and transmissibility of waters from Bolivian
territory. Page 7 - 10
60
7.3 Evaluation of the Investment Made
The first water catchment works in the Silala basin were carried out by the
Antofagasta Railway and Nitrate Company in 1888. These works are mainly
rustic chambers for collecting water from springs and canals in dry masonry for
the channeling of water through a network of collector canals.
The laying of the 10-inch pipe and the construction of the first combined work
(loading chamber, decanter and control dam) were developed in 1913 by the
Antofagasta and Bolivian Railway Company. Likewise, the main collector
canal is covered with cement mortar.
The extension of the adduction system with 12-inch pipe, the transfer works of
the Caguana basin and the construction of the two control and storage works in
current Chilean territory was developed between 1938 and 1941 by the FCAB.
This study has made field measurements of all the relevant works present in
Bolivian territory, from this information have been generated plans of built
and combined works, as well as location and trace of the water catchment
and channeling system. The BC-09, BC-10 and BC-11 plans detail these
characteristics.
From this dimensioning we proceeded to quantify the existing works, as well as
to estimate unit prices for the site, consequently, this information has allowed
us to establish a first monetary estimate of investment volume present in the
Silala.
Table 7-2. Estimation of Investment Costs, Silala
Source: own elaboration
Page 7 - 11
ITEM DESCRIPTION QUANTITY PRICE
USD
100 REINFORCED CONCRETE 350 M 3 77,000
200 MASONRY WITH CONCRETE 2750 M 3 165,000
300 DRYWALL 31,500 M 3 1,260,000
400 OPEN FLOW CONTROL WORKS GLOBAL 75,000
500 10-INCH PIPE, CAST IRON 17,600 ML 1,056,000
510 12-INCH PIPE, CAST IRON 4,600 ML 345,000
520 PRESSURE FLOW CONTROL, VALVES GLOBAL 70,000
600 EXCAVATION, MOBILIZATION, ETC. 30% PARTIAL 893,400
700 OVERHEAD CONSTRUCTION 25% PARTIAL 744,500
TOTAL 4,685,900
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The estimated amount of the investment is four million six hundred and eighty
five thousand nine hundred American dollars.
7.3.1 Silala System Management
The Silala hydraulic system is operated, maintained and managed by the
Chilean company Antofagasta Railway to Bolivia (FCAB), located in the city
of Antofagasta.
This company has a technical department with an “Adduction Directorate”
based in the city of Calama. This personnel is in charge of the operation and
maintenance of the System.
Engineer Mario Rivera is the Director of the Technical Department, having
Engineer Carol Galvez as his assistant, both based in the city of Antofagasta.
The Director of Adductions, based in the city of Calama and directly responsible
for the Silala System, is Engineer Rene Villalobos. In the area of the project
work two turners, in charge of field work, one of Chilean nationality: Santos
Gonzalez and the other, recently hired and of Bolivian nationality: Pedro Cortez;
the latter is in charge of basic maintenance, in Bolivian territory. Likewise, this
Bolivian citizen, originally from Ollagüe and with a strong Chilean accent, is
in charge of reading the instruments of control and data collection installed in
Bolivian territory.
The Antofagasta Railway to Bolivia Company makes use of the economic
benefits derived from the sale of water. This company sells the water coming
from the Silala to a central system of discharge of flows controlled by the
Irrigation Department of the Ministry of Public Works of Chile. According to
information obtained in Antofagasta, the sale price has a range that depends
on the weather station: between 16.80 to 21.80 Chilean pesos. Approximately,
equivalent to between 4 and 5.2 cents of a dollar per cubic meter measured
upon reaching the central aqueduct system of the Second Region of Chile.
This aqueduct system distributes the water according to the detail shown in the
previous section.
Based on the annual yield developed previously, we can conclude that the gross
economic performance of the Silala basin has the following characteristics:
For a minimum of 13.4 million cubic meters of water and an average price of
5 cents of a dollar per cubic meter, the economic return is $ 670,000 per year.
For an estimated average value of 18.3 million cubic meters of water and an
average price of 5 cents per cubic meter, the economic return is $ 915,000 per
year. Page 7 - 12
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Of the previous economic income, the Bolivian State has never received any
tribute or participation during the last 84 years that the Silala Hydraulic System
works.
7.4 Recommendations
1. It is not convenient to use the term water diversion, since the waters do not
flow to any place, they are stored in a natural way in bofedales registered in the
Silala basin in Bolivian territory.
2. Legally, the case should be dealt with initially by the investigating court
in the Province of South Lipez, in the context of private law under Bolivian
jurisdiction.
3. The concession was granted to the Antofagasta (Chili) and Bolivian
Railway Company Limited by the Prefecture of Potosi. The date of 30 September
1908 marks the beginning of the concession. According to the Law of 1906
(Water Regulation) this concession lasts 99 years. Therefore, theoretically this
concession ends on 29 September 2007, within ten years.
4. The concession deed must be reviewed by the District Attorney of Potosi,
since it offers discrepancies in dates of granting powers after the start of the
procedure before the Municipal Council of the South Lipez Province in San
Pablo de Los Lipez.
5. The concession is specific and grants water for use in the railroad machines
of the Antofagasta (Chili) and Bolivian Railway Company Limited, as of today
that company does not exist.
• Its original address in Valparaiso does not exist and was not changed before
the national authorities that keep the registry of mining and water concessions.
• The awarded company never paid for the concession, as specified by the
Law of 1906.
• The water is sold to third parties, and no taxes are paid to Bolivia for
Bolivian water.
• The concession is not valid today. This should be said by a judge in Potosi.
6. It is recommended that the local judge or competent authority notify the
Chilean company of the invalidity of the concession of 1908, based on the
Page 7 - 13
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absence of legally valid records that legitimize the use of the Silala waters.
7. The claim of a Bolivian legal or natural person must be promoted about
the use and exploitation of Silala waters, through the processing of a new
concession to a private third party.
8. A historical economic balance of the profit enjoyed by the Chilean
company with the value of the existing infrastructure should be carried out.
Proceed to the confiscation of its assets for lack of payment of taxes and grant
a new concession. Based on this mechanism, the State could have an additional
income of approximately 5 million dollars for the collection of the facilities
built on the site, as well as tax payments and royalties to the region.
9. It is recommended the immediate installation of instruments that allow
the continuous and systematic collection of basic information for the study,
evaluation and planning of the use of natural resources in the border areas.
The network of hydro-meteorological border stations can be installed based
on hydrological research projects and programs with broad support from the
international scientific community.
10. Following the previous point, it is recommended that the Bolivian
authorities initiate diplomatic efforts to allow academic and operational Bolivian
institutions to participate in the “Andean Hydrology Research Program”
developed at the Catholic University of the North in Antofagasta under the
auspices and financing of the French ORSTOM. Bolivia as a transboundary
country has as much right as Chile to participate in this important research
effort.
11. It is recommended that research institutions in the country conduct a
scientific research regarding the behavior of debris glaciers and infiltration
processes in the Altiplano and in the Western Mountain Range of the Andes,
which feed the aquifers in the pampas and coastal plains in the current Chilean
territory.
12. It is recommended that the Bolivian Foreign Ministry participate in the
drafting process of the Water Law, led primarily by the Ministry of Economic
Development. In this process, the geopolitical importance of dealing with the
transboundary issue must be highlighted.
13. The potential for generating geothermal energy is important in the area, it
is recommended not to abandon the 8 million dollars already invested by the
National Electricity Company Bolivia (ENDE) in the area, and continue based
on guidelines that include the presence component and national possession at
the borders.
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14. Currently, the institution with the greatest presence in the area is the
Eduardo Abaroa Reserve, it is recommended to coordinate with this institution
tasks that include the monitoring of basic information, as well as national
security tasks
15. It is recommended to encourage national tourism in the southwestern area
of Bolivia.
16. It is recommended to propose to the Armed Forces of the Nation the
development of a strategic border plan, where not only work from the budgetary
and operational limitations of today, but to coordinate a national work based on
short, medium and long-term objectives in all border areas.
17. It is recommended to undertake serious studies on the use of the Sica Sica-
Arica pipeline, for the purpose of marketing water to the coastal population.
Page 7 - 14
Annex 23
DHI, “Technical Analysis and Independent
Validation Opinion of Supplementary
Technical studies concerning the Silala
Springs”, December 2018
(Original in English)

67
Technical Analysis and Independent
Validation Opinion of Supplementary
Technical studies concerning the Silala
Springs
International Consultancy Contract by Product
CDP-I No. 41 /2018
Single Product,
D~
The expert in WATER ENVIRONMENTS
Pluri-national State of Bolivia,
Ministry of Foreign Affairs,
DIREMAR
Dec 2018
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This report has been prepared under the DHI Business Management System
certified by Bureau Veritas to comply with ISO 9001 (Quality Management)
I Approved by
Kim Wium Olesen, Head of Department
Water Resources Department
Signed by: Kim Wium Olesen
The expert in WATER ENVIRONMENTS
Pluri-national State of Bolivia,
Ministry of Foreign Affairs,
DIREMAR
Dec 2018
70
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Technical Analysis and Independent
Validation Opinion of Supplementary
Technical studies concerning the Silala
Springs
International Consultancy Contract by Product
CDP-I No. 41/2018
Single Product
Prepared for:
Pluri-national State of Bolivia, Ministry of Foreign Affairs, Diremar •
Project manaqer Roar Aska9r Jensen
Quality supervisor Torsten Vammen Jacobsen
Project number 11820137
Approval date 21 December 2018
Revision 2
Classification Confidential
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final reviewreport_single product amended_revt.docx/ Initials/ raj-mm-14-12-18
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Table of Contents
Executive Summary ........................................................................................................................ 1
0 Introduction ................................................................................................................... 7
0 .1 Objective . . . . . . . . . . . . . . . . . . .... . . . 7
0.2 Scope ................................ ....... ................... ................... ...................................................... ....... 7
1 Review of Hydraulic Study: "Characterization and efficiency of the hydraulic
works built and installed in the Silala sector" ........................................................... 9
1.1 Objectives of the Study ..................................................................... ....... ........... ........................... 9
1.2 Methodology and content of the study . .............. .. .... ..... .. ..... ... . ... 9
1.3 Discussion of results and conclusions .. ..... .......... .. 13
1.4 Validation of the Results and Conclusions . . .............. 14
2 Review of "Study of geo-referencing, topographic survey and determination
of the infiltration capacity in the event of possible surface runoff in the area
of the Silala springs." ................................................................................................. 15
2 .1 Objectives of the Study. . . . . . . . . . . . ...... ..... . ... 15
2.2 Methodology used.................... .... ........ ...................... .............. .... . .............................. 15
2.2.1 Topographical study.. .......................................... ............. ........ ..15
2.2.2 Soil property study.... .......... ..... .. ................... ........ ............. ..16
2.3 Discussion of results and conclusions......... ........ .................. ......... ......... . .... 16
2.3.1 Topographical study .............. ...... .. .16
2.3.2 Soil property study......... ......... ........ ..17
2.4 Validation of the Results and Conclusions.. ....................... ..18
2.4.1 Topographical study .......... ............ ..18
2.4.2 Soil property study ............................................................................................. ........................ 18
2.5 References.. .............. . .......... ........... ....... .... ............... ......................................... ............ ........ 19
3 Review of "Environmental Impact Assessment Study in Silala" Part 1 ................ 21
3.1 Objectives of the Study............................ . ... 21
3.2 Methodology used.................................... ........... ....... . ... 21
3.2.1 Determination of the area of the bofedals .... 21
3.2.2 Field works........................................... ........... ..... ...... . ... 23
3.3 Discussion of results and conclusions. . ... 25
3.4 Validation of the Results . . .... ..... ........ . ... 27
3.5 References.............. . .... .......... ... ........................... . ..... .............. . ... 27
4 Review of "Environmental Impact Assessment in the Silala, Part 2 -
Palynology" ................................................................................................................. 29
4.1 Objectives of the Study ............................................................................................................. 29
4.2 Methodology used.. ................. ..................................... . .................................. 29
4.3 Stratigraphic description ................................................................................. .......................... 31
4.4 c,. dating method................................................................ .. ......... .......... . ............................ 31
4.5 Geochemical analysis.... ... . .... ..... ..... ... . ............ . . .... ..... ...... . ... 32
4.6 Palynologic analysis (pollen analyses) .............. ... ...................... . ... 32
4. 7 Discussion of results and conclusions ............... ........................ 33
4.8 Validation of the Results ...... ..... ............ . ....... 35
4.9 References................................ ........... ........ ....... ... . ... 36
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5 Review of study: "Technical Analysis of Geological, Hydrological,
Hydrogeological and Hydrochemical Surveys Completed for the Si/ala
Water System" ............................................................................................................. 37
5.1 Summary ............................................................ ....... ............... ......................................... ........... 37
5.2 Objectives of the Study ................................................................................................................ 38
5.3 Methodology used ....................................................................................................................... 38
5.3.1 Overview................... .. .... .......... ...... .. .... ............... .. ........................................... 38
5.3.2 Igneous Geology ...... .... .............. .... ....... .. .... ............. .. ............................................. 38
5.3.3 Quaternary Geomorphology. .......... .. ....... ... .. ....... 38
5.3.4 Structural Geology....... .... ......... .... .. ...... 39
5.3.5 Hydrology........... .......... .. ...... .. ...... 39
5.3.6 Hydrogeology ............... .. ....... 39
5.3.7 Hydrochemistry............ .. ..... .40
5.4 Discussion of Results and Conclusions... .................. .. ........ .40
5.4.1 Formation of the Silala Spring System and Proxy Sites .................. ................. ..40
5.4.2 Recharge - Discharge Relationships................................................................. .. ......... 41
5.5 Validation of the Results. .... .. .. .... .. .. .... ...... ................. ............... .... .......... .. ........ 41
5.6 References ......................................................... .. ....... ........................................................ ......... 43
6 Final validation of the results of all studies .............................................................. 44
7 Bibliography (references) ........................................................................................... 47
ANNEXES
Annex 1 - Reviewed Hydraulic Studies, Containing:
IHH in English and Spanish Versions
Annex 2 - Reviewed Topographic and soil surveys Containing:
Final Report Campos Barron in English and
Spanish Versions
Annex 3 - Reviewed environmental studies Part 1 Containing:
FUNDECO, Part 1 in English and Spanish
Versions
Annex 4 - Reviewed environmental studies Part 2 Containing:
FUNDECO, Part 2 in English and Spanish
Versions
Annex 5 - Reviewed hydrologic / hydrogeologic study Containing:
Technical Analyses by F. Urquidi in English
and Spanish Versions
final review report_single product amended_revt.docx/ Initials/ raj-mm-14-12-18
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Executive Summary
On the request of DIREMAR the following documents have been reviewed by DHI:
1. Hydraulic study: "Characterization and efficiency of the hydraulic works built and installed in
the Si/ala sector" Authors : Dr. Eng. Jose Luis Montano Vargas, Dr. Eng. Jose Antonio Luna
Vera, MSc. Juan Pablo Fuchs Arce, MSc. Eng. Juana Dolores Mejia Gamarra, MSc. Eng.
Javier Carlos Mendoza Rodriguez
2. Topography and soil property studies: "Study of geo-referencing, topographic survey and
determination of the infiltration capacity in the event of possible surface runoff in the area of
the Si/ala springs". Prepared by: Consultores Tecnicos lngenieria y Construccion Campos
Barron S.R.L., La Paz Bolivia for 0/REMAR
3. Environmental Impact Assessment Study in Si/ala, Part 1: Coordinating author Luis F.
Pacheco, D. C. Director of the Institute of Ecology (UMSA) et.al.
4. Survey of Environmental Impact Assessment Study in Sila/a,Part 2 PAL YNOLOGY.
Coordinating author Luis F. Pacheco, 0. C. Director of the Institute of Ecology (UMSA) et.al.
5. Hydrogeological study: "Technical Analysis of Geological, Hydrological, Hydrogeological and
Hydrochemical Surveys Completed for the Si/ala Water System". Author: Fernando Urquidi
Barrau, Bolivian geological consultant
1st Review, Hydraulic study:
"Characterization and efficiency of the hydraulic works built and installed in the Silala
sector"
The scope of the report is to register and characterize the hydraulics work in Silala and asses
their effects on the bofedals and springs. Based on a field survey and previous field data
collection the hydraulic works are described and classified section by section with total canal
lengths calculated. The field work provides a detailed description of extent and properties of the
canals. Photos and measurements also demonstrate the extensive drainage and its negative
impact on the bofedals.
Field visits and analysis of flow measurements by SENAMHI has led to the conclusions that flow
rates are constant and that the Silala spring system is fed by groundwater with no traces of
runoff generated by rainfall in the catchment.
Based on field data collected a canal hydraulics model is developed and applied. The results
derived from the model include canal Froude numbers and flow velocities. Based on model
results and by comparing to flow rates of porous media it is concluded that the canals have
altered the flow regime.
Observations from the field suggest that sediment transport is limited, but no final conclusion is
made.
The report also concludes that the term 'river' is not a suitable description of the bofedal flow
system and that the hydraulic works and canals were constructed for drainage and conveyance
purposes.
The review points out unclear sentences or sections, contradictions within the report and minor
inconsistencies regarding methodology.
The expert in WATER ENVIRONMENTS
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The study provides detailed evidence of the extent and properties of the canals. Photos and
measurements also demonstrate the extensive drainage and the negative environmental impact
on the natural bofedals.
Overall the review finds that the report provides valuable documentation which supports the
conclusion on canal system impacts in agreement with field survey and analysis presented in
earlier studies such as (OHi, 2018 b).
Based on field data collected a canal hydraulics model is developed and applied. The model
results shows high canal fiow velocities. In a natural bofedal the flow regime consist of slow
porous media fiow in the peat in combination with excess discharge in the form overland fiow
distributed in a braded two dimensional pattern across the wetland vegetation. As such regime
is different from the concentrated high velocity fiows in the present canals the study confirms
that the canalization has changed the flow pattern of Si/ala.
The methodology applied is, however, not valid for assessment of the quantitative impacts of the
canalisation on the surface discharge rates from the Silala. This would require quantification of
the water exchange between the canals and the wetlands and between the groundwater and the
wetlands as in the analyses of (OHi, 2018 b).
2nd Review, Topography and soil properties:
"Study of geo-referencing, topographic survey and determination of the infiltration
capacity in the event of possible surface runoff in the area of the Silala springs"
The Study consist of two independent parts:
Chapter 1 Geo-referencing and topographical Survey
Chapter 2 Assessment of soil properties in the area with focus on hydraulic properties.
A new detailed topographical survey has been executed which has: Established and
georeferenced 8 boundary points along the main canals in the Silala Spring area, leveled all
springs and piezometer boreholes and established georeferenced cross sections of all canals
with a minimum distance of 10 m. The output of the study is a series of maps and tables
attached to the report. It is not clear if the digital elevation model of the area has been updated.
The detailed topographical survey is certainly relevant for hydrological and hydrogeological
studies in the area. Unfortunately, the new survey does not include specific comparisons to the
previous topographical surveys carried out for OIREMAR and applied to geo-reference springs
and piezometers by previous studies. Particularly the reference to the previously surveyed
detailed digital elevation model (DIREMAR, 2017) or the possible corrections necessary to align
it with the new benchmarks is lacking. Such information would add considerable value to the
output
To compare the survey with the previous digital elevation model of the area the review has
made a few spot checks on the produced elevation maps and compared the average slopes of
the northern, the southern and the principal canals. These checks suggest that the new survey
may confirm the previous digital elevation model with minor overall corrections. If this is the case
the new survey is not likely not to change the conclusions of former assessments such as OHi,
2018 markedly
The soil property study concludes that there is a predominant presence of sandy soils
throughout the study area. The soils are highly permeable, with high infiltration capacities. At 15
locations pits were excavated to depths from 0.3 to 1.8 m below the terrain (limited by the topsoil
thickness above fractured rock). In the 14 excavations located outside the wetlands moisture
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contents at the bottom of the pits were found to be rather low and none of these excavations
reached the groundwater table.
The field experiments reported suggest ten times higher infiltration capacities than used in the
previous studies. Although these values may be uncertain and even too high; the experiments
indeed confirm the findings of the previous studies regarding absence of surface runoff outside
the wetlands and of the discharge of the Sil ala Springs and wetlands therefore originating
almost entirely from groundwater.
3,d Review:
"Environmental Impact Assessment Study in Silala, Part 1"
The objective of the study was to determine whether the canalisation of the bofedals has had an
impact on the ecosystems and if the impacts has caused a risk of survival of the bofedals and
their special vegetational patterns and species.
To assess the conditions of the Silala bofedals, located in the Bolivian Andes, seven different
surveys were performed to determine the actual influence of the anthropologically caused
changes in the form of canalization of the bofedals. The surveys included analysis of vegetation,
ichthyofauna, herpetofauna, avifauna and macrofauna.
The findings showed that the vegetation structure in the bofedals has been altered and it has
created a more fragmented (dis-integrated) and degraded vegetation cover and diversity. The
status of the Silala bofedals showed evidence of areas with the typical bofedal vegetation types
but also of areas, with typical dry land vegetation. The study considers the canalization to be the
main reason of development of the dry areas and for the deterioration of the environmental
conditions for both biotic and a biotic factors. The main evidence came from the study of the
vegetation/ species distribution in the bofedals and comparing the findings with studies of other
undisturbed bofedals in the region.
The studies confirmed that the bofedals at Silala have more species and areas covered with
plants normally dedicated to the dry margin-zones, whereas the vegetation types commonly
associated with the bofedals were fewer and did only cover a small portion of the bofedals.
The approach taken by the research team to describe the current conditions in the bofedals in
relation to flora and fauna, is considered a standard well proven approach and the results of the
individual studies are presented in the report. The conclusions are drawn mainly on basis of the
distribution of the vegetation types, related to dry and wet soils, while the studies of fish, birds,
herpetofauna and macroinvertebrates did not add much to the overall conclusion.
This study provides the first quantitative analyses documenting the poorer environmental status
of the Silala as compared to similar undisturbed bofedals in the Altiplano area. Hereby, it
substantiates the qualitative assessments and observations made in previous studies. The
findings are in accordance with the hydrological analyses and field studies documenting the
drainage effects of the canals (e.g. (DHI , 2018 b) and the hydraulic study reviewed above).
4th Review:
"Survey of Environmental Impact Assessment Study in Silala, Part 2 PAL YNOLOGY"
The objective of this study has been to reconstruct the history of the development of the
vegetation during the last 100-120 years to detect whether the canalisation of the bofedals had
caused any changes and effects on the vegetation.
The expert in WATER ENVIRONMENTS 3
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The bofedals in the two valleys in Silala have gone through a change, which has been observed
during the last century, allegedly because the water from the area was diverted and utilised for
steam trains in Chile. The results of the undertaken survey are based on applying four globally
recognised methods for assessing changes over time in habitats/soils.
It is verified that the observed changes in the two bofedals from the original peat-bog habitats to
more dry habitats have taken place during the last century. The survey has found indications
that the flow paths of the bofedals has changes from small braided streams and seepage
through the vegetation to a situation, where the canals route the water faster through the
bofedals. This change may be one of the main reasons for the alterations in the habitats, which
have taken place during the last century.
The review can conclude that the methods used to assess the past century conditions were
successful and in line with similar studies in the region. However, it should also be mentioned
that the assessment of the previous vegetation in the Northern and Southern bofedal were only
based on full analyses on one core in the Northern bofedal and two in the Sothern bofedal. In
addition, the two cores from the Southern bofedal showed large variation in the stratigraphy,
indicating long-term dynamic changes to the bofedal , most properly caused by long-term natural
changes in how water has flown through the bofedals.
In summary the first of the two environmental impact assessment documents quantitatively that
the Silala Bofedal is inhabited by species that are mostly linked to dry land and to a lesser extent
species associated with healthy bofedals, as found in other bofedals. The analysis of the second
impact assessment study has shown that the changes have taken place during the last century,
during which the canalisation was implemented.
5th Review:
"Technical Analysis of Geological, Hydrological, Hydrogeological and Hydrochemical
Surveys Completed for the Silala Water System"
Fernando Urquidi, a geological consultant, compiled a technical analysis (the report) based on
reviewing the following third-party documents:
• The National Geology and Mining Service of Bolivia report, Study on the Geology,
Hydrology, Hydrogeology, and Environment of the Silala Springs Area (SERGEOMIN,
2003).
The National Geology and Mining Service of Bolivia report, Structural Geological
Mapping of the Area Surrounding the Silala Springs (SERGEOMIN, 2017).
Tomas Frias Autonomous University report, Hydrogeological Characterization of the
Silala Springs (UATF, 2017).
DHI report, Groundwater Flows (DHI , 2018a).
DHI report, Study of the Flows in Silala Wetland and Spring System (DHI , 2018b).
Isotope analyses results from Hydroisotop Laboratory (Urquidi, 2018).
The author has provided the following brief summary of the principal assertions and conclusions
of his study:
The Silala area was geologically formed during volcanic episodes in the Upper Miocene,
7.5 to 8-myr that created the Silala lgnimbrite (dominant aquifer).
The valleys in the Silala were later modified with glacial geomorphological processes
such as glacier movement and melt water events.
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• The surface waters observed in the bofedals and springs in the Silala are groundwater
dependent.
• The average flow from the main channel in the Silala is estimated at 160 to 210-I/s; 60-
percent of this flow is believed to originate from the North and South bofedals.
• Fault zones in the ignimbrite are believed to be the dominant contributor to groundwater
flow in the Silala groundwater system.
• The hydraulic properties of the Silala aquifer imply semi-confined conditions at depth
and unconfined conditions in shallow piezometers.
• The chemistry of water found in the North and South bofedals is significantly different;
water discharged into the North Bofedal is younger in age and contains lower
concentrations of dissolved solids and bicarbonate. The groundwater discharged in the
North Bofedal may be recharged locally. Based on groundwater age and constituents,
the South Bofedal is believed to be recharged from the Silala Fault.
• Based on geology, hydrology, hydrogeology, and hydrochemistry, the Silala
groundwater system is transboundary in nature.
Overall Urquidi presents a large amount of data from secondary sources in his report; the
majority of the material appears to be a reproduction of the documents that were reviewed for
the technical analysis. However, due to the lack of referencing, it is difficult to differentiate from
secondary source material and the author's technical analysis (i.e. subjective conclusions).
Overall the author's conclusions are largely drawn from either the OHi 201 Ba report or variants
of reports that were used in the OHi study. The findings are largely consistent with those of OHi.
There are some inconsistencies in data used and conclusions drawn, which contradict the
findings of OHi 201 Bb. Key contradictions have been highlighted in preceding sections and
largely focus around the role of glaciation in development of the Silala ravine and recharge -
discharge relationships in the Silala area. However, numerous other contradictions exist and
resolution of these would provide a more coherent and consistent technical assessment.
In OHl's opinion:
Our conclusions on the recharge -discharge relationship, although related with uncertainty,
still seems more trustworthy than those of the author, as OH l's conclusions are based on a
broader selection of data sources (satellites, ground stations, reported spatial trends and
other studies) and more comprehensive analyses of these data,
The near continuous discussion of the glaciation of the Silala Ravine itself is irrelevant to the
present day hydrogeologic system. It is thought that inclusion of these assertions may
provoke unnecessary debate that does not affect transboundary groundwater or surface
flows or the management of said flows.
In general, the information provided does not materially change any previous OHi conclusions or
study outcomes, including estimates for transborder flow.
The expert in WATER ENVIRONMENTS 5
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0 Introduction
The Bolivian Strategic Office for the Maritime Claim, Silala and International Water Resources -
DIREMAR has Under the International Contract by Product CDP-I No. 41 /2018 contracted DHI
(Reviewer) for the execution of:"Technical Analysis and Independent Validation Opinion of
Supplementary Technical studies concerning the Silala Springs" during December 2018.
This report constitutes the second and last deliverable of the contract:
Technical Analysis and Independent Validation Opinion of Supplementary Technical studies
concerning the Silala Springs, Final review.
0.1 Objective
The objective of the review is to carry out a technical analysis and issue an independent opinion
of validation of five technical-scientific reports provided by DIREMAR in relation to the Silala
springs.
0.2 Scope
The scope of the project is to review the following five studies which has been made available to
DHI by DIREMAR:
1. Hydraulic study: "Characterization and efficiency of the hydraulic works built and installed in
the Silala sector" Authors : Dr. Eng. Jose Luis Montano Vargas, Dr. Eng. Jose Antonio Luna
Vera, MSc. Juan Pablo Fuchs Arce, MSc. Eng. Juana Dolores Mejia Gamarra, MSc. Eng.
Javier Carlos Mendoza Rodriguez
2. Topography and soil property studies: "Study of geo-referencing, topographic survey and
determination of the infiltration capacity in the event of possible surface runoff in the area of
the Silala springs". Prepared by: Consultores Tecnicos lngenieria y Construccion Campos
Barron S.R.L., La Paz Bolivia for DIREMAR
3. Environmental Impact Assessment Study in Silala, Part 1: Coordinating author Luis F.
Pacheco, D. C. Director of the Institute of Ecology (UMSA) et.al.
4. Survey of Environmental Impact Assessment Study in Silala,Part 2 PAL YNOLOGY.
Coordinating author Luis F. Pacheco, D. C. Director of the Institute of Ecology (UMSA) et.al.
5. Hydrogeological study: "Technical Analysis of Geological, Hydrological, Hydrogeological and
Hydrochemical Surveys Completed for the Silala Water System". Author: Fernando Urquidi
Barrau, Bolivian geological consultant
This review has only considered the translated English version of the report (attached as Annex
2 to this report). The output data of the topographic study include a large number of cross
sections and topographic maps which have not been checked in details as part of this review.
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1 Review of Hydraulic Study: "Characterization and efficiency of
the hydraulic works built and installed in the Silala sector"
DIREMAR has contracted DHI to make the following independent technical review of the study
"Characterization and efficiency of the hydraulic works built and installed in the Si/ala sector''.
The study is prepared Dr. Eng. Jose Luis Montano Vargas, Dr. Eng. Jose Antonio Luna Vera,
MSc. Juan Pablo Fuchs Arce, MSc. Eng. Juana Dolores Mejia Gamarra, MSc. Eng. Javier
Carlos Mendoza Rodriguez.
This review has considered only the translated English version of the report (attached as Annex
1 to this report).
1.1 Objectives of the Study
The objective of the report is clearly stated: To characterise and asses the effect of the hydraulic
works built and installed in the Silala Springs area.
1.2 Methodology and content of the study
The report includes a 'Methodology' section which says that first a field study is carried out to
gather information and provide a technical description and an inventory of hydraulic features
built in Silala and their effects. It is followed by a literature study of historical documents
describing the early intervention by canals and hydraulic works. Finally, the data collected in
IHH-UMSA and SENAMHI field surveys along with topographical data are processed and used
in a hydraulic model of the canals.
Chapter 2 discusses an international paper (Fox 1922) written by R.H. Fox, Chief Engineer of
hydraulics works at the Antofagasta and Bolivia Railway Company Limited. The chapter evolves
in some linguistic discussion of the words "river" and "stream" that does not serve the purpose of
the study's objective. It is noteworthy, though , that Fox, the engineer in charge of the first intake
in Silala, wrote the quoted paper in 1922 - 12 years later than the construction of the first intake,
but 6 years before the canalization of the wetlands in 1928 (Arcadis 2017). Hence, when Fox
describes the intake as "a small dam across the stream which has a daily flow (with very slight
variation) of 11 ,300 cubic meters" he refers to the pre-canalized conditions.
One can therefore not conclude (as done in Chapter 2 page 7) that "the water intake work that
currently exist in Bolivian territory corresponds to the works described by Fox". However, it is
probably correct to assess that the constant surface flow, as described by Fox, means that the
flow, also at that time, originated from upstream groundwater springs.
Chapter 3, 'Natural conditions' presents a geological map and briefly describes the main hydromorphological
processes shaping the surface. The upward directed groundwater flow from the
fractured ignimbrite deposits are mentioned. The hydrogeological properties, aquifer units and
an expanded description of groundwater flow at the larger scale feeding the bofedals is missing
(see reference, DHI report).
The report states that 'The analysis of the water movement through the bofedals in its natural
state is done considering the body of water as a unit: water-soil-biotope.' It is correct that a
hydro-ecological approach is essential in order to understand how the bofedals rely on the
hydrological conditions but no 'analysis' is presented. The bofedals are sensitive and have
formed slowly due to the presence of a steady, diffuse groundwater supply.
Regarding surface runoff the authors write: 'The field studies support the absence of surface
runoff caused by precipitation. A complete tour of the basin allows distinguishing that there are
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no traces of surface water movement; there is no evidence of surface laminar flow, as can be
seen in the photographs presented in Figure 5.' The reviewer finds it unclear which field studies
are referred to. It is correct according to the field survey (DHI 2018) that no signs of surface
runoff are visible throughout the area. A photo with absence of surface runoff is hardly
'evidence'.
The authors write 'The reach of confluence of the North and South Bofedal, although it is of
greater slope than in the high part, it is distinguished by the presence of peat that has developed
under natural conditions (see Figure ?a), but that has, due to the effect of the developed actions,
abstraction intake and water conveyance canals, originated the predominance of "intrusive"
species as is the case of the grasslands.' The sentence is difficult to understand but the
reviewer assumes that peat formations associated with the pre-canal situation are found at the
canal confluence, but they are being replaced by invasive grasses due to the canalisation'
When the authors refer to the Northern and Southern bofedals as having 'fully saturated soils' it
is not meaningful. It does not make sense to talk about saturation across the entire Northern or
Southern wetlands. The saturation is highly variable from the perimeter of the wetlands to the
areas adjacent to canals and to inundated areas. The effect of drainage is visible in terms of
lower water tables, drier soils and consequently changes in vegetation and habitat. Later the
authors state: 'The saturation of the North Bofedal reaches 100% while in the South Bofedal it
reaches 76%.' This contradicts the previous statement. It does not make sense to talk about %
saturation for an entire wetland based on a few samples. It cannot be used for any general
characterization. One apparent effect of the canals is areas of lower groundwater tables and soil
water contents below saturation.
Regarding the figures in chapter 3, Figure 8 does not show the canals and it is unclear it
corresponds to a 'natural or 'canalized ' situation. According to the text referring to Figure 9 it
should show 'unhealthy wetlands' but the figure does not show anything relating to unhealthy
wetlands. Finally Figure 10 and 11 cannot be read as legends are missing.
Also, in chapter 3 the authors write "As a result of the geophysical studies carried out in the
zone corresponding to the North Bofedal, plenty of underground water has been identified .' It is
assumed that ii refers to a COFADEN report. The word 'plenty' is not a technical term and ii is
very ambiguous in this context. Despite the presence of water being visible in the geophysical
profiles the groundwater can equally well be described as 'scarce' in Silala.
The authors introduce the Darcy flow equation for estimating flow rates in a porous medium. In
the Darcy flow approximation is should be noted that groundwater flow occurs both in the
fractured ignimbrite rock and the sediment layer in which case a soil permeability is not
necessarily representative. In addition, the upward head gradient driving upward groundwater
flow is not necessarily equal to the slope of the terrain as the aquifer is confined or semiconfined.
In any case the flow rates are low as demonstrated by the calculations. Flow restricted
to the near surface soil does not reflect the actual situation in the Northern or Southern bofedals.
Due to low soil permeability and/or shallow soils the groundwater tables are forced to the
surface creating ponded water and diffuse flows across the surface.
The reviewer finds the paragraph in page 3-16 confusing: 'In general, the bofedals with
intermittent regime, that is to say temporary, the flow of water is defined by two scenarios.
During rainy season, the precipitation generates a surplus that floods the wetlands and that
allows the water levels to be high enough to overcome the terrain's rugosity and cause the water
to find "small channels", where it can move due to gravity towards lower areas, generating a
network of several stream branches on the surface of the bofedal. Under these conditions and
depending on the magnitude of the excess precipitation, runoff can even cause localized erosion
processes, allowing the transport of sediments.' This is unclear, and it does not make sense to
talk about bofedals 'in general'. The reviewer understands that this section about bofedals in
general is supposed not to be applicable to Silala.
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It is stated that "The inventory of springs made by SENAMHI and OIREMAR (2018) and the
geophysical study using resistive electrical tomography - ERT, carried out by COFAOENA
(2017), show that the source of the water fed by the Silala bofedals are the springs that emerge
along the entire length of the waterbody' This is correct , but according to 'Study of the Flows in
the Silala Wetlands and Springs System, OHi for OIREMAR, Final Report, 2018' diffuse infiows
which are not registered at any specific spring locations contribute significantly to canal flows,
e.g. in the ravine section outside the bofedals.
In Chapter 4, 'Flow regime', the authors write that ' ... therefore, a hydrological regime of the
fluvial type cannot be defined for this basin'. The term 'fluvial type' is not clear. It is not a
common term or definition. The reviewer understands this as 'a basin without surface runoff.
Further, it is stated that 'The spatial variation of the flow of the South Bofedal in the Silala
generally has a growing pattern according to the length and the development of the topographic
differences, which goes from the gauging station in the triangular weir C1 until C5, see Figure
12' The sentence is not understood, the reviewer understands it as: 'The flow increases along
the canal from C1 to C5', which would be correct.
On the subject of increasing canal flows the report says: 'From this control point the fiow
increases significantly until reaching control point S-10, because there is a greater concentration
of springs'. This is not entirely correct as there are relatively few (visible) springs in this reach.
The diffuse inflow may be considerable. The report also says that 'Although there is a discharge
of flows through a canal, it must be taken into account that there are no significant fiows in the
confiuence reach , since the variation of flows in the last control points (gauging stations) remain
almost constant (see Figure 15). The reviewer is not sure what this sentence says. If it says that
there is little or no inflow to the canal along this reach it would make sense.
In chapter 5, 'Physical Characterization of Hydraulic Works' , categories and classes used in the
systematic registration and characterization of the canal and hydraulic works of Silala is
presented.
The methodology of the field work is described as (page 34 ):
• Topographic survey in detail of the location of the canals.
• Survey of the geometry of the canals.
• The detailed description of the materials used in the canals.
• Geometric and hydraulic layout of the canals.'
It is written that 'The detailed measurements of the geometric configuration of the canals have
been taken and there is a quantification of the longitudes of each type.' This is an unclear
sentence and the reviewer assumes that canal geometry, lengths and total distances have been
measured.
The location of sites inspected is not clear. In some cases, coordinates are specified but no
overview map is provided.
Chapter 5 presents a detailed account and description documenting the extent and physical
properties of the hydraulic works in Silala. The description corresponds well to field visit
observations reported in 'Study of the Flows in the Silala Wetlands and Springs System, OHi for
OIREMAR, Final Report, 2018'
Chapter 6 describes and classifies the canal system.
A terminology of 'specific catchment' and 'longitudinal catchment' is presented. This is an
unusual description. Commonly the canals collecting spring flows would be called 'secondary or
tertiary canals' while the main canals would be referred to as 'primary canals'. When using the
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term catchment (or sub-catchment) in an area with no runoff, it is unclear if it refers to
groundwater sub-catchments.
The report says: 'According to what has been indicated, it has been demonstrated that the
longitudinal collection works capture the water longitudinally along its entire length, as can be
seen in Figure 67, the same one that develops through the permeable walls. This is a way of
lowering the originally upwelling water table (see Figure 68), this descent channels a flow of the
bofedals towards the canals; in this way it is possible to drain the bodies of water located in the
bofedals (see similar canals from Figure 70 to Figure 72)'. The formulation is unclear and
Figures 67 and 68 do not show what the text says. Figure 67 does not show the effect of canal
drainage on wetlands and Figure 68 b) shows a horizontal water table (blue line) which does not
make sense.
Chapter 7 describes transport of sediments in the canals. It is not possible to draw any final
conclusions if sediment transport occurs in the Canals.
It is concluded that: 'there is no surface runoff that can cause laminar erosion'. This is probably
true under current conditions. Material may be deposited by slides, rock face collapses or by
wind.
The authors state that 'The limnogram of the aforementioned Figure 77 shows that there are no
spikes that indicate a hydrological response to precipitation'. This is probably correct, but the
period observed is too short to reach a general conclusion on runoff.
Chapter 8 describes the development and application of a hydraulic model.
It is stated that 'The objective of the present hydraulic analysis is to evaluate the hydrodynamic
conditions of the flow or surface runoff of water. . .'. This is surprising considering previous
statements that no surface runoff is generated in Silala. The work does not seem to address
surface runoff but only canal flow.
Regarding specific variables included in the model the report says: ' ... . or variables of the system
in order to characterize the flow regime, velocity, water depths, Froude number, Energy Line,
etc.'. It is unclear how these variables can be used to 'evaluate the influence of the 'artificial
interventions'? There is a discrepancy between scope and methodology.
The authors write: 'For the present case, where the temporal evolution is not a factor to be taken
into account and the flow is eminently one-dimensional, this model is sufficient, although it has
been modeled two-dimensionally.' Confusing sentence - unclear if it is a one-dimensional or
two-dimensional model.
The methodology for development of the hydraulic model is presented by a bullet list. Model
calibration is not included the list. Model calibration is a required and necessary step before
applying a numerical model in analysis. The Manning coefficient is a calibration parameter and it
should be verified that the model produces realistic water levels with the Manning values
applied. Canal slope is described as a model parameter. This is not correct. It should be a
model input derived from measured canal bed elevations.
The report says that 'The gradient can be extracted from the geometric model, from the
topography or from the digital elevation model.' The report fails to specify which one was
actually used in the model.
It is not possible to determine what Figures 82 and 84 in chapter 5 are supposed to show due to
missing legend or explanations. Figure 84 does not appear to reflect the actual conditions in
Silala.
The sentence, "The flowrate in the system determines the flow depth necessary for a
determined flow, in addition to other hydrodynamic parameters of the environment in which the
water flows .' is not understood by the reviewer.
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With respect to the model the authors add that 'In the present study, the surface flow of the
system under the baseline average-flow hydrological scenario was simulated for the period with
available data' which the reviewer interprets as a steady-state flow simulation.
The model results are presented accompanied by the sentence: 'The hydraulic profile shows
that there are slight depressions where a certain amount of water accumulates (in these
sections the depth is greater than the average and the water flows out of the main canal).
Reference is made to figure 84. The reaches with inundation according to the model are not
compared to field measurements and they do not seem to match observations in neither bofedal
nor canal reaches. Comments are needed to explain the results.
In the conclusion on model results ranges of canal flow velocities and Froude numbers are
mentioned but it is unclear how they relate to the scope of work and the effect of canals.
Hydraulic conditions in the canals do not describe the effect of canalization on bofedals or flow
rates.
1.3 Discussion of results and conclusions
In Chapter 9 conclusions are presented. It says that 'Within this framework, the waters of the
Silala are fully integrated to the high mountain wetlands, independent of the extension, gradient,
and vegetation and flow characteristics. Therefore, the water moves within this category [of
wetlands] .' and 'Although there is a short section in the southern branch where, due to the
geological conditions, the movement is superficial over a channel in the rock, the body of water
assumes again its status as a bofedal category at the confluence.' This is an unclear
formulation, although it is true that the flow pattern vary from the uppermost springs to the
international border under influence of groundwater conditions, wetland soils and canal works.
Further it is concluded that 'From a technical point of view, the natural movement of the Silala
through the Silala bofedals does not respond to the technical definition of a river, i.e. "a largescale
water stream that drains a basin in a natural way'. This is out of context and the scope of
work would not support technical definitions of a river. As opposed to the drained and canalized
bofedals the flow through the natural state bofedal is not concentrated in confined surface flow
stream/river branch features but diffuse across wide surface and subsurface sections.
Regarding 'Purpose of these interventions' the field work has documented impacts, causes and
effects with respect to drainage by the canals but the original purpose or intention of the canal
construction is beyond the scope of work of this report.
When stating that 'The introduction of the works in the Silala waterbodies have had
characteristics of significant "aggressiveness" to the environment '. The reviewer understands
that the canals have significant negative environmental impact.
With respect to the model it is concluded that 'The results of the hydraulic modeling performed
for this survey show that the water movement conditions in the Silala waterbodies have been
modified significantly. The incorporation of hydraulic works has changed the natural conditions
of water movement in porous medium and has turned an unconcentrated surface flow into a free
surface flow in the drainage canals implemented.' The reviewer does not find this conclusion
substantiated. The field work shows that the water flow in Silala are changed due to the impacts
of canals, but the model results do not. Firstly, the hydraulic model simulates canal flow only,
which does not account for impacts on e.g bofedals. Secondly, in order to describe changes, it is
necessary to compare model scenarios with and without canals. The model cannot and has not
been used to simulate a scenario without canals. Consequently, the model results do not
describe changes due to canalisation e.g. that water bodies have been modified.
Differences in flow velocities between a porous media and a canal is not an appropriate
measure of change or modification. Surface flow may be generated without canals. If the porous
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media cannot fully drain the groundwater it will rise to the top of the bofedal and runoff on the
surface (given the topographical gradient is present). This is seen in similar undisturbed
bofedals and supported by the original wetland vegetation in Silala. Typical undisturbed
wetlands of this type will have diffuse surface water flows. Water table changes across the area
would be a better indicator of impacts.
1.4 Validation of the Results and Conclusions
14
In the context of the technical work carried out at the Silala springs, 2016-2018, this report
provides valuable contributions in terms of the detailed description of the canal and hydraulic
construction work based on field inspections. It also documents the impacts on the bofedals in
terms of drainage effects and ii provides a sediment transport assessment. The hydraulic works
built in the Silala constitute an extensive and efficient water collection and conveyance system.
The field survey reported clearly shows the degradation of wetlands and the contrasts between
canalized and drained wetland sections versus undisturbed patches. The canal and bofedals
description is consistent with report 'Study of the Flows in the Silala Wetlands and Springs
System, DHI for DIREMAR, Final Report, 2018'.
The field work carried out clearly shows the extent and properties of the hydraulic works,
including canals and their impact on wetlands, but does not address effects on canal or cross
border flow rates.
The report concludes that the spring and wetland system is fed by groundwater with no sign of
basin surface runoff. Constant measured canal flows are associated with groundwater discharge
and not intermittent rainfall-runoff events. This is consistent with 'Study of the Flows in the Sil ala
Wetlands and Springs System, DHI for DIREMAR, Final Report, 2018
The output of the hydraulic modeling study is simulated canal flow velocities and Froude
numbers. The report argues that canal flow velocities are much higher than estimated saturated
flow velocities of wetland soils. The impact of current canalized conditions compared to an
undisturbed bofedal system are well described by the field study documentation, but simulated
flow velocity differences is not a suitable measure of wetland impact. The integrated hydrological
and hydraulic modeling study reported in 'Study of the Flows in the Silala Wetlands and Springs
System, DHI for DIREMAR, Final Report, 2018' provides estimates of discharge and water
balance impact considering both canalized and non-canalized conditions.
Conclusions regarding intentions and purpose of the original hydraulic works are out of scope of
a field survey and the numerical model study. 'Effects', e.g. drainage effects can be documented
as part of the field study but the original 'purpose' cannot.
The discussion of terminology and definitions in relation to the flow features, e.g. the term 'river'
appears out of context considering the scope of the work. It is, however, correct that the flow in
undisturbed bofedals is likely diffuse across a wider section and not concentrated in onedimensional
flow features.
The work reported supplements other studies in Silala, but it also overlaps significantly with the
work of. 'Study of the Flows in the Silala Wetlands and Springs System, DHI for DIREMAR,
Final Report, 2018' presenting the same or similar analysis of e.g. flow data but without
referencing the report. The methodologies, analysis, conceptual understanding and results are
not identical. Since the report does not reference the previous work ii appears to have been
carried out in a standalone parallel effort. It will be possible to extract estimates, assessments
and analytical results from the two reports which are not fully aligned but possibly based on the
same datasets.
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2 Review of "Study of gee-referencing, topographic survey and
determination of the infiltration capacity in the event of possible
surface runoff in the area of the Silala springs."
DIREMAR has contracted DHI to make the following independent technical review of "Study of
gee-referencing, topographic survey and determination of the infiltration capacity in the event of
possible surface runoff in the area of the Silala springs". The study is prepared by Consultores
Tecnicos lngenieria y Construccion Campos Barron S.R.L., La Paz Bolivia for DIREMAR and is
dated May 2018.
This review has considered only the translated English version of the report (attached as Annex
2 to this report). The output data of the topographic study include a large number of cross
sections and topographic maps which has not been checked in details as part of this review
2.1 Objectives of the Study
The objectives for the topographical study (Chapter 1) is: To carry out the gee-referencing in the
area of the Silala Springs. The gee-referencing shall include the hydraulic infrastructure, springs
piezometers and reference points in the area.
For the soil characterization study (Chapter 2) the objective is: "To determine the maximum
infiltration capacity and physical properties of the soil at fifteen assigned points on the basis of
field tests in the area of the Silala Springs and the vicinities so as to assess the occurrence of
surface runoff'.
The specific objective of the soil study is:
• To excavate 15 open trial pits
• To identify the soil types of the area by means of the uses (Universal Soil
Classification System) and
• To take samples and perform tests in the field to identify the physical and
hydraulic properties of the different hydrological units of the soil and the surface
level.
2.2 Methodology used
2.2.1 Topographical study
Advanced GPS technology was used to gee-reference eight boundary points (bench marks)
located strategically along the southern and northern wetlands and the principal ravine between
the confluence of the canals and the border to Chile. The Boundary points were subsequently
leveled from the bench mark at the military post, which has previously been established and
leveled from Laguna Colorada by the Military.
The boundary markers were subsequently used to gee-reference the piezometers, springs weirs
and canals by tachymetering.
The review considers the implemented survey methodology viable for the objective of the study.
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2.2.2 Soil property study
The applied methodology of assessing the important saturated infiltration capacity by double
ring infiltrometer assumes vertical drainage by gravity (low lying groundwater table), conditions
that seem to be fulfilled outside the wetlands. Only one of the test locations (SSL-1) is located
Inside the wetlands where groundwater is found close to the surface, and here infiltration test
was (correctly) omitted.
At all test points exploration pits were excavated to depths below ground surface between 0.3 m
and 1.8 m (depending on the soil depth). Disturbed soil samples were taken out at the bottom of
each of the 15 excavation pits and send to the laboratory to classify them according to texture,
identify their Atterberg limits and to determine the natural soil moisture.
Although tests on intact soil samples would have been preferable, as they allow for relevant
analyses for porosity and natural and saturated water contents, the disturbed samples also
provide important information on the types of soils and drainage conditions in the area.
Atterberg limits of the soils plastic and liquid states are, however, more relevant for geotechnical
foundation and stability issues than for hydrological aspects such as infiltration capacity, soil
evaporation and surface runoff generation. Retention conditions, field capacity and wilting point
would have been much more relevant hydrological properties to assess, since these parameters
are essential for drainage and evapotranspiration analyses.
70% of the soil samples are taken 0.5 m below ground surface or deeper. Although soil
properties at depth hold less information on the infiltration capacities than intact samples at the
surface they do indeed provide valid information about the typical soil types of the area and their
drainage properties.
2.3 Discussion of results and conclusions
2.3.1 Topographical study
16
Eight boundary markers (Bench marks) have been established and georeferenced (Projection:
UTM WGS84, Zone 19S). The marks are distributed along the main canals of the northern and
southern wetlands and along the principal canal from the confluence point to the international
border.
The results include maps with 2 m terrain contours and with locations and elevations of
boundary markers and canal structures. However, it is not stated from where these 2 m contours
originate. Although they seem to resemble the contours of the previous detailed digital elevation
model (DIREMAR, 2017) the study does not mention this source and more importantly it does
not mention if this DEM has been adjusted to the new boundary points (bench marks) and the
adjustment applied.
Canal cross sections are surveyed and mapped at a maximum distance of 10 m along the
canals. Also, all marked springs, piezometer boreholes, and hydraulic weirs have been
surveyed, georeferenced and mapped. Longitudinal sections along the main canal have been
elaborated and plotted. Field measurements of the canals are also available from previous
studies.
The survey of the springs and weirs is very detailed; but future use of the results may be
hampered by lack of unclarity on the actual georeferenced points (the spring water level or a
spring benchmark, the V-notch or a local weir benchmark).
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2.3.2 Soil property study
The study makes conclusions on the geology of the area, the origin and deposition of the soils
and the system of joints in the igneous rocks. This is unfortunate, since these aspects are not
parts of the objectives of this study, not covered by its analyses, and these statements, true or
not true, are not supported by references or analyses. Although such unsupported statements
tend to weaken the credibility of a technical study, these statements do not have any bearing on
the conclusions of this particular study.
Furthermore, it is stated that: "It (red.: the area) does not present areas of erosion that could be
a problem for sandy materials. It presents slopes with apparent stability due to the quality of the
rock presented by families of discontinuity". This statement is not clear, but more importantly the
objective of the study is not to discover if erosion takes place, but to establish the infiltration
capacity of the soils in the area and the possible existence of surface runoff. Absence of signs of
recent water erosion in sloping sandy soils with very sparse vegetation is indeed an indicator of
surface runoff not taking place, and therefore of local rainfall intensities being lower than the
infiltration and drainage capacities of the soils. The fact that no such signs of erosion are
observed is therefore very relevant, but its importance is not clearly formulated in these
statements. It is however touched upon briefiy in another paragraph (point 5) of the conclusions.
According to the Uniform Soil Classification System the soil samples from 14 of the 15 locations
have been classified as sand (9 of the samples (60%) as Silty sand, 4 (26%) as silty to clayey
sand and 1 sample (7%) as Clayey sand). Only Sample no 15, located in the principal ravine
close to the border, was classified as silt.
The study concludes that there is a predominant presence of highly permeable sandy soils
throughout the study area. Only at location no. 1 (close to the canal confluence in the center of
the wetland) were silt and clay layers visually observed in the excavation pit.
The study also concludes that spatial variability exists in the natural water content. This is not
surprising considering that the sampling points were selected to represent, as well as possible,
the range of soil types in the area, and because the samples are taken at different depths below
ground surface, which could easily influence their moisture contents.
The analyses of the soil samples confirm that soils outside the wetlands are dominantly coarse
textured, sandy and well drained soils with the low natural water contents most of which are
below 11 % (by weight) and probably close to or lower than field capacity. Only sample no 1
close to the canal confluence shows a natural water content over 20% (by weight). This is
probably close to saturation, which is in accordance with the soil sample being taken close to
the water table.
The infiltration rates determined are actually not the maximum rates (as stated in the study), but
the important saturated rates under free drainage which are consistent with the saturated
hydraulic conductivity. The less characteristic maximum infiltration rates normally occur when the
soil is dry and conductivities low, but the tension gradients driving the infiltration very high.
The study presents Infiltration capacities as obtained from in-situ infiltrations test from 9 of the
15 locations. At these locations the soil is classified as Silty sand (6 locations), silty to clayey
sand (2 locations) and Silt (1 location). At all locations the infiltration capacity is found to be very
high (20-60 cm/hour). The observed capacities are based on observations with a rather large
scatter (figures 12 -20) which indicates quite some uncertainty in the results.
Furthermore, the obtained infiltration capacities are around ten times higher than the literature
values for normal sandy soils also quoted in the report (2.5-5.0 cm/hour).
However, the study does not make any direct conclusion as to the possibility of surface water
runoff with the determined infiltration capacities and it does not discuss the results of the field
tests in relation with the literature values.
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2.4 Validation of the Results and Conclusions
2.4.1 Topographical study
Canal
reach
Northern
Canal
Southern
Canal
Principal
Canal
A detailed topographical survey such as this one is certainly relevant for the studies of the Silala
wetlands and was also requested for the completed hydrological and hydrogeological studies
(e.g. DHI 2018). Unfortunately, the new survey has not been related to the previous
topographical surveys carried out for DIREMAR and used to level springs and piezometers by
previous studies such as (DHI 2018) - if such important relations have been established they
are not reported.
To compare the survey with the previous digital elevation model of the area the review has
made a few spot checks on the produced elevation maps and compared the average slopes of
the northern, the southern and the principal canals (See Table 2-1 ). These checks suggest that
the new survey may confirm the previous digital elevation model with minor overall corrections.
If this is the case the new survey is not likely not to change the conclusions of former
assessments such as DHI, 2018 markedly
Table 2-1 Comparison of canal slopes from the present study (Campos Barron) and the former topography
used by (DHl,2018)
Study Campos Barron Survey Former Survey
Chainage Level
Delta
De lta H Slope Chainage level
Delta
Delta H Slope
Slope
Point ID Chainage Chainage diff
(m) (m) (m) (m) % (m) (m) (m) (m) % %
upstream
point 0 4362 0 4365
Confluence 688 4318 688 44 6.4 688 4320 688 45 6.5 -0.15
upstream
point 0 4407 0 4410
Confluence 2881 4318 2881 89 3.1 2940 4320 2940 90 3.1 0.03
Confluence 2881 4318 2940 4320
border 3579 4277 698 41 5.9 3560 4282 620 38 6.1 -0.26
2.4.2 Soil property study
18
Both the infiltration capacities measured by two different methods on the Chilean side of the
border (Arcadis, 2017) (1-8 cm/hour) and the VanGenuchten assessments used in (DHl,2018)
(2-5 cm/hour) are fully in line with the literature values quoted in the report (2.5-5 cm/hour). The
detailed infiltration modelling carried out in (DHI 2018) with saturated infiltration capacities 2-5
cm/hour did not generate any superficial runoff in the areas outside the wetlands with a 40-year
precipitation series representative for the area.
The field experiments reported here suggest ten times higher infiltration capacities than the
above mentioned and although these values are uncertain and maybe even too high, the
experiments do indeed confirm the findings of the previous studies regarding absence of surface
runoff outside the wetlands and of the discharge of the Silala Springs and wetlands therefore
originating from groundwater inflow to the wetlands.
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2.5 References
DIREMAR, 2017 Digital Surface Model (DSM) based on measurements taken during the drone
flight in last half of 2016.
DHI, 2018: Contract CDP-I No 01 /2018, Study of the Flows in the Silala Wetlands and Springs
System. Product No.2 -2018 Final report.
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, Appendix E.
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3 Review of "Environmental Impact Assessment Study in Silala"
Part 1
The review carried out in this section is fully based on the English version of the report
"Environmental Impact Assessment Study in Sita/a" and it has not been cross-checked with the
original Spanish version. If there are contradicting interpretations, it may be due to an incorrect
translation between the two documents.
3.1 Objectives of the Study
The objective of the environmental study has been to determine whether the present bofedals
are in a steady state or in a state of being reduced in size and whether the observed changes
were caused by the influence of anthropological induced changes in the form of canalization of
the two bofedals.
The environmental study of the Silala bofedals, Part 1 focuses on providing a wide assessment
of the many biological elements, living in the two valleys. The study also looks at the unique
characteristics, ecology and occurrence of bofedals in the Altiplano of Bolivia. Accordingly, there
are several references to other studies carried out in the region concerning the presence of
bofedals in the highlands of Bolivia and other countries of South America. Two images from
Bolivian Andes have been presented in the study report as an example of well-preserved
bofedals.
3.2 Methodology used
The Silala bofedals are described as very important habitats in the Altiplano and the area has
been designated as a Ramsar Convention site, which is an international treaty for the
conservation and sustainable use of wetlands. It is also a part of the Eduardo Abaroa Andean
Fauna National Reserve established in 1973. The protection status of the area indicates the
significant importance for the preservation of its environmental values.
The Silala area is naturally divided into three distinct sub-areas: Southern Bofedal, Northern
Bofedal and Confluence Area. The division is substantial and highlights the specificity of each
zone, from which the Southern Bofedal is described as the most fragmented and at the same
time the biggest of the two bofedals. Transparent maps of each area are presented in the report.
The study has been performed based on a range of field surveys carried out during March and
April 2018, literature sources of abiotic and biotic factors, as well as interviews with citizens of
surrounding areas, who helped to understand the historical background of the region.
3.2.1 Determination of the area of the bofedals
Delimitation of the bofedals was made according to the presence of typical vegetation in the
mentioned area. The Oxychloe andina were pointed out as the main indicator species in the
region in association with Phylloscripus deserticola or Zameioscripus atacamensi, which was
supported by several references. As indicators of the margin formations of the bofedals, the
species Carex cf. maritime and Deyeuxia spicigiera were used. The species mentioned above
have been used to identify the area of bofedals based on the method Normalized Difference
Vegetation Index (NOVI), which is a method based on analyzing satellite images.
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NOVI is the most common index being used in remote sensing technology. In general,
vegetation indices are quantitative indicators of biomass of plant origin . To define them , the red
(RED) and near infrared (NIR) spectral channels are used and the vegetation index is an
artificial image created by dividing selected spectral channels. The higher the NIR reflection and
the smaller the RED, the more plants are green and the NOVI value is higher.
NOVI always ranges from -1 to +1 . However, there isn't a distinct boundary for each type of land
cover. The image of the vegetation index is interpreted as an indicator of biomass. The higher
the value of this index, the higher the value of biomass. The negative values of NOVI
correspond to the sites devoid of vegetation, e.g. uncovered soil , water and concreted areas.
There are several sectors where NOVI has being applied to, like for example in the agricultural
sector to measure biomass, in the forestry sector to quantify forest supply and in assessments
of land degradation.
For the analysis the satellite image representing the end of wet season from March 2016 was
used. The NOVI analysis showed the threshold of bofedal vegetation occurrence was given an
index value of 0.6, whereas the other formations classified as drier were expressed with the
index values 0.3, 0.4 and 0.5.
To assess recent changes and to utilize the NOVI method, two example images were chosen for
the comparison of changes of bofedals range (Figure 3-1). The image from 2004 was used as
the first of the high-resolution image available, which gave the best possible difference in time
for this method to be used. The image from 2004 was used as an image from the dry season ,
whereas the image from 2016 was taken during the wet season. This difference between both
age of the images and the fact that one image represents the dry season and the other image
represents the wet season might cause the wrong interpretation of the data, and this difference
of dry season/wet season vegetation is not clearly presented in the document. Nevertheless, the
images clearly show the range of the main bofedal area, where the bofedal indicator species
Oxych/oe andina occurs which is wet during the whole year.
Figure 3-1 Vegetation coverage of the soil in the Southern Bofedal.
The identification of vegetation types was performed during the field works and the border of the
bofedals were indicated based on indicator species and marked using the GPS system. The
particular steps of determining the borders were described in detail by using analytical features
in the ArcMap 10.3 program.
To identify the recent historical range of the bofedal, interviews with local community were
carried out and based on their knowledge, and with the use of GPS, the recent historical borders
of the bofedals were recorded and added to the GIS maps.
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3.2.2 Field works
The investigations of the Northern and Southern bofedals and the Confluence area were done
with the involvement of a wide range of biological assessment methods, each dedicated to
specific sections of the biology. In total , seven major groups of flora and fauna were
investigated, and the results are shown in the table below. Each of the groups are further
described below the table.
Table 3-1 Overview of the seven areas of investigation and the outcome, based on total number of
species/families identified (Cf. p49 of report)
Taxonomic Group N' of -o of N' of N E"W ~ -E'W N° of
tornl endemic eudange1·ed 1·ecords records typical
species spede-s species for Potosi fo l' bofedal
for Bolivfo species
Bolivia.
Flora 86 I 9 17 2 13
.Nfacro-im·e1 ·rebrates • 26 0 I 15 I 6
Fish I .
Amphibians 2 I I
Repriles 4 2
Birds 35 2 19
Mm11111a /s 13* I I # " 0
Vegetation
For vegetation identification the transects and quadrants methods were used. They are two
ecological tools that allow the user to quantify the relative abundance of environmental units in
an area. The quadrat is a square sample plot or unit for a detailed analysis of vegetation.
Transects were appointed along the bofedals and the transverse lines were installed. The
longest transect line was 50 m and one record was taken out for every 50 cm. Each transect
consists of approximately 100 records. Several quadrants of 1 x 1 meter were made on each
transect and all vegetation inside the quadrant was recorded. Information about total number of
transects in each sector was not given. Besides vegetation cover and species assessment in
each quadrant, the following physical measures of the bofedals were made: compaction and the
depth of the organic matter.
The weighted weight statistics were performed to evaluate occurrence of each species in the
area. Based on data analysis the mapping of categorized plants was performed. The report
does not have a direct reference to the produced map.
The analysis included abundance range curves or Whittaker curves, which are used by
ecologists to display relative species abundance. The interpretation of graphs was given with
references to Feinsinger 2004.
In addition, the Principal Component Analysis (PCA) was performed to visualize patterns of the
organization of the species. The method is widely used in various fields of investigation and for
different tasks including environmental surveys. The objective of principal component analysis is
to identify hidden pattern in a data set, and to identify correlated variables. Additionally, the
Coronary Canonical Analysis (CCA) was used to determine which environmental variables
significantly affect plants communities.
The environmental impacts to the bofedals caused by the artificial canal system were defined
based on quadrant data and multivariant analysis. The vegetation units were established and
the frequency of them was quantified. The ecological quality evaluation of bofedals was used
based on the reference Meneses et al, 2012 and 2014, who did several studies of bofedals in
Bolivia. Unfortunately, the cited literature is either not published or in Spanish. The study from
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2014 (Metodos para cuantificar diversidad y productividad vegetal de los bofedales frente al
cambio climatico) looked at other bofedals in the Altiplano and the thesis was that the bofedals
would most properly be reduced due to the recession of glaciers as the water-feeding system for
many of the bofedals.
Aquatic macroinvertebrates
During additional surveys performed in three types of canals (with stone, without stone and
naturalized) the aquatic macro-invertebrates were identified. The surveys were performed on 20
sampling stations with 3 subsamples per station. The samples were further analyzed in an
external Institute to assess diversity.
Furthermore, on each station the physical-chemical basic parameters and morphologicalstructural
parameters were studied.
The method for collecting the samples are not described in detail, but it is assumed that the
sampling method is the standard kick-net method used globally, where kicking the streambed
along three transects moves the bed-dwelling macroinvertebrates up into the water column and
then they are moved by the flow into the net.
lchthyofauna / Fish
To determine occurrence of the species of fish , hand nets were used. The highest attention was
put on the populations of trout (Oncorhynchus mykiss) as the rainbow trout was widely
introduced to the aquatic system of the Bolivian Altiplano since the 1940s. This exotic species
was characterized in detail, and a description of its life cycle was given. It was defined that the
trout of the Silala area comes from the fish farming program that was launched in 2013. The
authors underlined that the number of this species identified in the waters of Silala could not be
estimated. The present study did not catch any fingerlings, which could be caused by the use of
nets for catching the fish instead of using electro-fishing. The current density of trout in the area
is estimated as 20 to 54 trout per linear kilometer.
It was explained that presence of trout might influence on erosion processes in the margin
canals and as a consequence accelerate the flow of the water from the canals. Given the fact
that the fish fauna plays an insignificant role, using more than two pages for the description of
the inversive trout may be bit out of proportion.
The method using hand nets is usually only used to catch larger fish, whereas fingerlings may
easily escape. If the focus had been on the fish, it would have been expected that electric fishing
would have been used. However, the review found that the fish fauna is considered having only
a minor, if any, effect on the development of the bofedals, although much effort has gone into
the investigations. It is also the assessment with most references.
Herpetofauna I Amphibians / Reptiles
The amphibians and reptiles were captures, using the Free capture method. The assessments
were carried out both during the day and the night through walks in the terrain. Criteria of
estimations were explained, however, there are no references to any of them.
The method used is a standard way of recording amphibians and reptiles, although methods
using various types of traps are also common.
Avifauna / Birds
To observe the presence of the bird fauna, the transect method was used. Here an observer
goes through the terrain once a day for three days. The method is considered standard, while
use of nets are mostly used for recording migratory birds.
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Macrofauna
The bofedals are used as grazing areas for the Viscacha's and the Vicuiias, and these species
were observed during the surveys. Other larger animals representing medium or large mammals
were identified by their feces, tracks and dens.
The assessment of the macrofauna was carried out using traps. In each of the three study
areas, a number of rodent-traps were set out during the day and checked the following morning.
This was done for 3 days. When the animals were captured, the standard characteristics were
taken (length, weight, sex and reproductive status).
The approach and methods used in the study are thus considered applicable
3.3 Discussion of results and conclusions
Historical background of anthropogenic use of the Silala area were given, paying particular
attention to canalization of Silala waters. Based on interviews performed among local people,
the observation of the drying out the area of bofedals was confirmed , which was substantiated
by the decreasing number of typical vegetation of bofedals and other specific flora species for
this region (yareta).
Local climatic conditions were described and compared with a study performed in 2004 by
Urquidi. Results were collated in a table, where the specific differences were identified.
However, the study does not look further into other climatic aspects such as potential climatic
changes during the last 100-120 years to assess whether such changes could have been the
cause for some of the observed changes to the bofedals.
The lack of some physical-chemical parameters was noticed e.g. morphological-structural
parameters. However, the factors mentioned in the table were clearly described.
Quadrant data results were presented in the table, categorized and confirmed by studies of
Pa/abral-Aguilera performed in 2016. In these studies, the increasing number of dry zones
related vegetations were noted. Information stored by the National Herbarium of Bolivia
concerning the diversity of plants from the South Lipez Province were compared to the results of
the study. The results showed that registered number of family, genera and species were lower
in Silala region comparing to whole mentioned province. The number of endangered and
vulnerable species was given for both regions and the report has listed that three of four species
of vegetation occurring in Silala region are endangered or vulnerable species.
The results of macro-invertebrates were presented superficially. The taxonomic list of the
macro-invertebrates is the result of the first macro-invertebrate survey ever done in the bofedals
of Silala. The study of the macro-invertebrates did not add additional information to the overall
interpretation of the changes in the bofedals and the results have not been used substantially to
underline the overall findings.
Data analysis results concerning ichthyofauna were presented exhaustively. Description of the
results is complex with references and supported by distribution map of typical species of
ichthyofauna most common in the surrounding region that corresponds well with the descriptions
presented in the methodical chapters. However, native fish species found elsewhere in the
altiplano were not found in the Silala streams. The report does not look further into reasons for
the missing fish fauna.
Data obtained from survey of herpetofauna and avifauna were described well. All information
was presented in clear and accessible way. Both photographs, tables and reviews are included.
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Statistics
Two statistical tools were used to better interpret the data.
The main method used was Principal Component Analysis (PCA). It is very widely used in
multidimensional comparative analysis, which allows the user to compare objects or sets
consisting of several variables and find relatively quickly, the most important features and
properties of these sets. Multidimensional comparative analysis leads to reduction of a large
number of variables, characterizing objects to a few basic ones, which can be subjected to
detailed analysis. It is also used for grouping of objects characterized by very similar properties
and isolation of the most typical phenomena or processes which results in a reduction in the
time and cost of research and explanation of the structure of links between the characteristics of
objects. The PCA results were presented in the form of biplots showing among others the plant
species examined as a function of the dominant species of the Northern and Southern bofedals
and the Silala Confluence (Figure 3-2).
,"?.Ji_. "' ~ 0
- 0 N
a.
E
0 u
"0 '
9
9
-0.15
-2 -1
-0.05 0.05 0.15
Comp.1 (24%)
Figure 3-2 Example of biplot used in the report to present articulation of the plant species examined as
a function of the dominant species of the Northern (N) and Southern (S) bofedals and the
Silala Confluence. The circles depict the different plant groups. This analysis allows
depicting the differential impacts of the canalization works on the plant species of the South
and North bofedals. The direction and length of the arrows show the correlation between the
variables and the principal components. The codes are presented in Annex 2 of the report.
Color Green depicts the quadrants of the North (N) fragment; Pink represents the S_A
quadrants; Black the S_B quadrants; Red the S_C quadrants; Brown the S_D quadrants;
cherry the S_E quadrants; Blue the S_F quadrants; and purple the confluence sites (CONF).
The Canonical Correlation Analysis (CCA) method was used for abundance and composition
variations on basis of the main substrate types found in the Silala bofedals. CCA is a method for
exploring the relationships between two multivariate sets of variables and has been developed
to allow ecologists to relate the abundance of species to environmental variables. In the report
CAA method were used to perform the abundance and composition variations (Figure 3-3).
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N 82 Cl /.omp D.
N 7 C6 N A2~CI
-- - r),B I C2
83111- - - H:lt -; _CJ
N_ 2_ ·2
-0.4
Jsli
Lmac
Zmur Caca
Eata
OandLoli
FrigFpot
Mgla Demi
A~tsp
1~~c0eyspl
Stusp
ossp L10lllp_DS
llfri
Ptub Ggay
N_Cl _C ~ >-----+-_ _ zot•~-----~
1.2 -0.6 Prim(' r eje 1.2
Figure 3-3 Analysis performed to explain the abundance and composition variations on basis of the
main substrate types found in the Silala bofedals. Bi plot of the canonical correspondence
analysis, presenting the environmental variables (based on the Spanish acronyms). To the
left, species and environmental variables biplot (morg and hcam). To the right, quadrants
present in the bofedals and environmental variables.
The data collected during the survey were appropriate to be used by these types of analytical
methods.
3.4 Validation of the Results
The environmental study of the Silala bofedals has shown that the bofedals have apparently
shrunk in size, and it is suggested that the introduction of canals in the early 1910-1920s could
be the main cause for the changes. Overall , it seems that the reduced area of the bofedals could
be linked to a change in the run-off pattern due to the canals, which could have changed the
drainage patterns in the bofedals and thereby reducing the areas with permanent wetland
status.
The canalization has been a significant factor for the degradation of the bofedals. Their current
area is estimated at 0,76 hectares, whereby researches carried out in the Silala region gave
raise to assume that the maximum possible extension of bofedals in the past could have
covered up to 11 hectares.
This study, in combination with the palynological study, does not indicate a significant change in
the amount of water flowing from the two valleys, but the vegetation patterns and the
assessment of the stratification in the soils indicate that vegetation close to the canals are
represented by typical bofedal species and vegetation further away from the canals are
represented by typical dry-land species.
Currently, the Silala bofedals shelter a variety of species and among those also endangered
species. However, as a result of the canalisation , the bofedals are now in a fragmented ,
degraded state of high vulnerability and bringing the bofedals back to previous size and species
diversity will require immediate restoration actions.
3.5 References
Several references are cited in the report, although not every method described in the report
was supported by references. To ease access to the literature cited, it is proposed to keep the
original titles of Spanish literature, which will enable an internet search of the references.
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Most of the literature cited is up to date and in many cases not older than 2010, which makes
the information included contemporary. That confirms the interest of the region of bofedals and
their value. Several publications were checked and assessed and can be considered as credible
and reliable, and several of the references are from similar work done in Bolivia or neighboring
countries. Below are a few assessments of cited literature.
The reference to Rambaud et al. (2009) (p74) related to changes in species diversity in streams
with or without canalization. The cited article, although it is related to French streams, showed
that changing the physical structure of a stream through canalization will alter the species
composition.
The works carried out by Meneses et al. and used in the report with three references only leads
to one published article from 2014, whereas the other two works cited have not been published
and are thus not available for scrutiny.
The reference of Legendre and Caceres, (2013) (p16) was used in relation to the PCA method
and the formula used in the statistics to correct for the presence of double zeros between pairs
of sites.
Willerslev et al., 2014 is cited, referring to potential usage of antient environmental DNA in
sedimentary environments to confirm the presence of fishes in the past. Willerslev focuses in his
work on studies of flora in Arctic regions.
The bibliographic references included Dangles et. all (2017), however this article has not been
cited in the report.
Overall, the cited literature was considered relevant for the study.
In summary, the Silala bofedals have been subject to changes influencing their ecological status
comprehensively presented in the report. The anthropological influence in terms of canalization
system introduced to the natural environment of bofedals may be an important factor
responsible for the changes, as it changed the flows from small braided streams and seepage
through the vegetation towards canalized flow.
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4 Review of "Environmental Impact Assessment in the Silala,
Part 2 - Palynology"
This review has been carried out based on the English version of the report "Survey of
Environmental Impact Assessment in the Si/ala - Pa/yno/ogy" and it has not been crosschecked
with the original Spanish version. If there are contradicting interpretations, it may be
due to an incorrect translation between the two documents.
4.1 Objectives of the Study
The objective of the "Survey of Environmental Impact Assessment in the Si/ala - Palyno/ogy"
report under review has been to determine, though various techniques, what has taken place in
terms of changes in the vegetation and habitats in the Northern, Southern and Confluence
Bofedals of Silala since 1908, when the water in the natural stream was first utilised for feeding
steam trains in Chile and later, when a network of smaller and larger canals were dug to
improve the flow of water towards Chile. To a large extent this report builds on the findings of
the other "Environmental Impact Assessment Study in Si/ala ", which used a wide range of
species-investigations of the three sites in Silala. The assessment is mainly focusing on
developing a time-line for the last 100-120 years of the development of the bofedals, since 1908
when the utilisation of water from the area started.
The development of the bofedals over time, and especially after the construction of the canals
after 1908, has been discussed several times, and the approach in this study has taking several
methods into use to assess the different developments in time and space in the bofedals. It is
obvious that the canals have changed the drainage conditions in the bofedals and the actual
change to specific habitats depends on distance to the canals, where water conditions will
determine the development possibilities for the vegetation. Water from precipitation is very
limited in the Silala area and the major part of the water comes from groundwater fed springs.
The overall conclusion in the report indicate that substantial changes to the vegetation cover
and composition have taken place over the last 100-120 years and that the changes most
properly can be related to the initiation of the development of the network of canals in both
bofedals. The Southern bofedal has almost completely lost the water- and vegetational features
found in an undisturbed bofedal , and the sampling of cores in the outskirts of the valley have
also shown that the extent of the bofedal was larger before the canals were introduced in 1928.
The change towards more dry conditions can also be observed when looking at the geochemical
results. The geochemical results have also shown that the desiccation was much more
advanced between the 1950s and 1960s, which can be taken as an indicator that natural
variation may also be a substantial part of the reason for the observed changes. The Northern
bofedal seems to have suffered less that the Southern and the report concludes that the
geomorphology may play a substantial part in this.
The change towards more dry conditions is also supported by the pollen analyses, which
showed a decrease in bofedal and wetland species, incl. algae, from the time of the introduction
of the canals. Since 1908 there was an increase in the pollen from vegetation types more
associated with dryer conditions.
4.2 Methodology used
The techniques used in the study were carried out on a limited number of soil cores and
encompassed the c,.- carbon dating method, the pollen dating method, a stratigraphic
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description and finally the geochemical dating method. The report shows how the combination of
the different types of dating methods have added knowledge to better understand the
development of the bofedals both before and after the canalisation. Each of the dating methods
was used individually and then the results combined to substantiate the findings from each of
the methods.
The dating process was carried out only on two cores from the Southern bofedal (stations BSP2
and BSP14) and one core from the Northern bofedal (BNP?), although seven cores were taken
in Southern and four cores taken in the Northern bofedal.
The C1• dating of the Southern two cores showed large differences between the cores. The c,.
method mainly works on organic matter and cannot be used for mineral sediment deposits,
unless the deposits are interspaced with organic matter or organic matter is embedded in the
mineral sediments.
To exemplify the methods used for this report, the core taken out at BSP2 (total depth of the
core approximately 40 cm) had a distinguished organic layer on the top, although only 8 cm
thick and with the two underlying sediment layers (Cf. Figure 4-1 ). The upper organic 8 cm was
estimated to represent the last 68 years, from 1950 to 2018. The underlying 17 cm was
considered to represent to time back to approximately 1880, nearly 30 years before the unset of
the utilisation of the water and the consecutive canalisation. The age-profile was also used to
add timelines for various metals and their variations during the same years. The sediment layers
showed the effects of free-flowing water to carry the sediments, whereas the deposits of organic
matter indicate that there were periods with stable and stagnant waters, improving the possibility
for the plants to grow and slowly build up an organic layer. However, the vegetation that made
the organic layer has been done by species, which are more associated with wetlands and
grassland and to a much lesser extent to the expected development of a bofedal.
The development of the flora in the bofedals during time was also assessed by analysing the
appearance of pollen in the cores. It is important to realise that pollen is transported with wind
and accordingly some types of pollen may come from the outskirts of the bofedals and even
from areas beyond the valley. However, the closer to the place of growth, the larger the pollen
deposits would usually be.
For BSP2 it was clear that there has been a change from vegetation traditionally associated with
the bofedals to vegetation, which to a higher extent represent species, living in more dry land.
Remnants of some of the dry-land species were also found in the deeper layers from before the
canalisation , but they were most probably growing in the vicinity of the bofedals.
A)
10
20
30
40
c,r..,
ih! ~~
H
8am, AreM Grava
B) .:~~
2000
1990
1980
1970
1960
1950
1940
1930
1920
1910
1900
1890
1880
Figure 4-1 Core BSP2 from Southern Bofedal: Example of an age-model, based on a stratigraphic
description and the C14 dating method.
The study has used 4 different methodologies to interpret the development of the soil- and
sediment conditions in the three bofedals; The Southern, the Northern and the Confluence area.
Each of the four methods have added results to a full description of the development of the three
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sites. This chapter looks into whether the methods used are relevant and have been applied in
other places. It also considers known precaution and errors when using the methods.
The cores, which have been used for the assessments have all been taken out with a "Russian
Perforator" or "Russian Drill ", which is a manual drill, capable of taking undisturbed soil cores.
The use of this type of drill is widely used to extract undisturbed soil cores and the method is
used widely for assessments similar to the present project.
4.3 Stratigraphic description
The stratigraphic description of the cores is basically a description of the different layers in the
core with indications of colour, texture, soil type, grain size (organoleptic or mechanically from
subsamples). Depending on the soil conditions and the stratigraphy of the core, it may
sometimes be possible to find objects directly identifiable, e.g. bones, roots and other artefacts.
The present study made observations of the layers with high organic contents, indicating
vegetational growth as opposed to the sediment layers, indicating conditions with sediment
transport in water.
The description is combined with measuring the thickness of specific layers in the core. In
principle the stratigraphic description does not say anything about the age of the different layers,
but the method can be used to pick out specific layers, which can then be used for additional
analyses like C14 or other methods. Depending on the conditions in the locality being
investigated, the soil descriptions may change substantially on samples take a few meters apart
and such diversity was also found in the assessment of the soil cores taken in the three bofedals
(Cf. Figure 6 and Figure 14 in the report).
The stratigraphic method is widely used and recognized as an efficient, cheap and reliable
method, and in this project, it must be considered basic and necessary for the description of the
development of the bofedals over time. As also concluded during the dating processes, it was
possible to take out cores, representing nearly 1000 - 1500 years of development in the
bofedals.
4.4 C14 dating method
The C14 method is based on determining the amount of radioactive C14 in a sample of organic
origin (plant, tree, bone etc). Due to the natural decay rate of C1 4, it is possible to calculate the
age of a specimen with some uncertainty, depending on the age and the condition of the
analysed specimen.
The C14 method was used to determine the age of the layers recognised in the cores taken out
in the two bofedals. As stated above the C14 method can only be used on elements of organic
origin , which made it a valid method to determine the different layers in the cores and also
because the key interest was narrowed down to the last 100-200 years, where the method is
relatively precise in determining the age of the elements in the core.
However, it is important to understand that the method for C14 dating of soil cores can be
hampered through bioturbation, where organic matter from the surface or from the deeper layers
may be transported through biological activities (e.g. rodents, or other cave-dwelling animals) up
and down in the soil. This may create false dating profiles for a soil as reported by in a paper by
Yang Wang et al 1996. Whether this factor has been investigated in the present survey is not
stated in the report.
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4.5 Geochemical analysis
The geochemical analysis, which makes use of X-ray to analyse the composition of specific
metals, has been used in this study. The method was developed in the early 1900'ies and has
been refined over the years. The principle is to look for certain metals and look at the interaction
between the metals. The metallic composition shows variations under wet and dry conditions
and the results can be used as indicators of the soil conditions.
Certain metals like lead (Pb) has a natural occurrence but increases in the contents in most soils
in the 20th century co-insides with the use of lead in gasoline and peaks in the lead-profile can
be used to a certain extent as rough dating of the soil layers. The soil samples from Silala also
show the same trend for lead.
Most of the literature, explaining about the use of the method, are from 1950'ies to 1980'ies and
the method is still very common for assessments like the one presented in the report.
4.6 Palynologic analysis (pollen analyses)
32
The three methods described above can all in combination provide an estimate of the age of a
core, whereas the palynology method can add additional information about the vegetation
distribution at specific time-frames down through the soil core. The pollen analysis is widely
used to investigate the flora at specific periods. The method has many advantages, but it
requires skills in identifying the pollen in the sediments. There are some important draw-backs to
consider when working with the method and these are not explicitly described in the study.
These are among others:
• It is not always possible to identify specific species through the pollen analysis, often
only down to family level. In addition, pollen from some species are easily degraded and
may not survive in the soil for long
• There is a wide difference in how much pollen the different species produce, and this
may lead to an assumption, where a few species seem to be dominant, but in principle it
is more about the quantity of pollen produced from the specific species. Flora, where
germination is based on interaction with insects, may produce much less pollen than
species, who mostly rely on wind-driven germination. Having specific knowledge about
such differences can be used to make corrections to the pollen-count.
• The physical size of the plant may also provide large differences in how high above
ground pollen is released and thus how far it will fly. Some species are known to have
"wind-bags" on the side of the pollen kernel , which makes the pollen fly very far.
Transport in streams of pollen from terrestrial plants may transport pollen to areas far
from where the plant grew and may therefore skew the observation, when the pollen is
deposited together with sediments, maybe several kilometres away from the place of
growth.
• Bioturbation may move pollen both up and down in the soil and may this create
uncertainties in the interpretation of the composition for a given stratigraphic layer
(Tayler et al, 2000)
The assessments of vegetation habitats and species diversity made for the two bofedals were
based on pollen analyses, but the description of the use of the method does not mention the
potential uncertainties, which are exemplified above.
The results from the pollen analyses made on the two samples from the Southern bofedal and
one from the Northern bofedal seem to indicate changes in the composition of the vegetation,
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which could be interpreted as a change from a situation of with another horizontal distribution of
water to a situation, where the water is drained into canals and thus a shift from bofedal- and
wetlands species to dryland species (especially a substantial growth in species of grass).
The combination of several methods for assessing age and habitat development over longer
time spans has also be carried out by other authors in the Argentinian altiplano. Schittek et al
(2015) have used the same methods and built their age-developments on the same principles,
which proves that the methods used in the report is comparable with similar studies, although
the other studies did not include the element of assessing water distribution. The study made by
Schittek et al, both in 2015 and 2016 showed that grazing of the peatlands/bofedals may change
the soil structure and eventually increase the compaction of the soil, which may change the
porosity and change the water flow in the soil. This aspect has not been assessed in the report,
although seasonal grazing and utilisation by humans may indicate potentials for the same
situation. Whether the changes in the compaction could also be a reason for the bofedal
changes is not assessed any further.
4.7 Discussion of results and conclusions
The assessments carried out in the Silala bofedals in March and April 2018 were made with the
aim to prove whether the conditions in the bofedals had gone through a change from wet to dry
within the last 100-120 years.
Four methods were used in the assessment: C 14 carbon dating, stratigraphy, pollen analysis and
geochemical analysis. The research team has combined the results from each of the analyses
and have tried to provide an age model for the two bofedals. In addition, the age model for each
of the three analysed cores has been further developed by adding the results from the pollen
analysis and the geochemical analysis.
The combined models for each of the three cores analysed indicate changes in the vegetation
patterns with an increase in species adapted to dryer land and a reduction of species adapted to
wet land over time. Due to the variations in the findings, the results can be used to indicate that
changes in the surface hydrological regime during the last 120 years could have changed the
bofedals from a domination of the "original" peat-bogs towards the present situation, where the
peat bogs are diminished and only represent a few percentages of the vegetation/habitat cover
in the Southern and Northern bofedals.
Due to the very limited number of cores analysed in the two bofedals, the results can only be
used as indicators of general changes. However, they show that the bofedals have gone
through several structural changes, caused by changes in the hydrology. The cores taken in the
Northern bofedal, shown in Figure 4-3, have very different stratigraphic conditions and depths,
which indicate that the conditions over time and space have not been constant. This is indicated
by the interspersed layers down through the cores. It is therefore important to use the results
from the core analyses with caution, when using the results to be representative for the whole
area.
The cores used for the analyses in the Southern and Northern bofedals (Cf. Figure 4-2 and
Figure 4-3) showed that even within the relatively short distance between the cores BSP2 and
BSP14, there are very large differences in the soil stratigraphy and also in the age-depth
models, which again indicates that the conditions in the bofedals are and have been very
dynamic. The same is the case in the Northern bofedal (Cf Figure 4-3)
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'
,_.,
A A)
·::
10
20
BJ i
"::':· BSPti , ....... h
... , 10
20 C
10 30
20 40
30
50
•o
Figure 4-2 Overview of the four cores taken in the Southern Bofedal. The blue arrows indicate the
position of the two samples used in the analyses, BSP2 and BSP14.
B C ... ... ~
~
10 10
20
30 30
40 •o
50
60
70
80
90
20
30
Figure 4-3 Overview of the four cores taken in the Northern Bofedal. The red arrow indicates the
position of the sample used in the analysis, BNP?.
All analysed cores are taken from the central part of the valleys and cannot be used to estimate
the extension of the vegetation cover for the bofedals. The report does not discuss the known
limitations in e.g. the pollen analyses, where biological perturbation or grazing activities may
change the pollen contents in the soil profiles.
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The introduction of canals in the last century have changed the natural flow-patterns in the
bofedals reducing the area with overland flow from large parts of the bofedal surface to the
natural topographical "brook" in the lowest part of the valleys. Such change in the flow pattern
would likely cause changes in the vegetation cover corresponding to the ones observed.
4.8 Validation of the Results
The overall review of the "Survey of Environmental Impact Assessment in the Si/ala -
Palyno/ogy" is that the results provided are gained from using recognised methods, which have
also been used in other places, both in the region and globally, with the same aim to investigate
changes in habitats and soils over time, especially over the last 1000-2000 years.
The results from the core analyses indicate that the central part of the bofedals have gone
through a change over the last century from vegetation types associated with wet conditions to
vegetation types associated with drier conditions. Assuming a constant groundwater inflow to
the bofedals the changes in how the water is drained from the area could be the cause of the
observed vegetation changes. Figure 4-4 below show the main stone-lined canal in the
Southern Bofedal and Figure 4-5 shows the confluence with the two sloping streams coming
from the two valleys and flowing towards Southwest.
Figure 4-4 View towards the Northeast in the Southern Bofedal. Observe the stone-lined canal (From
OHi 2018)
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Figure 4-5 The confluence area. Please observe both the slope of both streams.
Globally, drainage of wetlands has always led to changes in the vegetation cover and have
changed the habitats, because the direct access to water for the individual plants have changed.
The canals in the bofedals must have led to the same changes, even though the lowering of the
groundwater table may only have been a few centimetres. As the main source of water in the
Silala area comes from groundwater, the precipitation does only add a limited amount to the
water balance in the area and the precipitation by itself is not enough to support the peat-bogs in
the valleys.
The impacts from the canalisation is in particular prominent in the Southern Bofedal, where most
of the land has vegetation types, mostly linked to dryer land and not to the bofedals. The
discontinuation of the maintenance of the canals in the 90's seems to have altered the
conditions slightly towards bofedal-type of land at least in the area, where the pollen analyses
for the soil core BSP2 has an increase in typical bofedal species from the Juncaceae family.
In conclusion, the results in the report clearly point towards observed changes in the two
bofedals, and there are also indications that the changed water flow caused by canalisation,
may be one of the main reasons for the changes, which have taken place during the last
century.
The limited time has not provided possibilities to look at changes by altering the canal
conditions.
4.9 References
36
Several references are cited in the report and the review has taken out a limited number of
these for assessment, whether they can be considered trustworthy and whether the references
are made to proper scientific journals.
The relevance of radiocarbon dating is discussed on page 16 and Hattie and Juli are cited in
relation to how far back the c,. method can be used. Searching for the original article did
unfortunately not give any results, but the article by Hattie & Juli has been cited at least 29
times, which indicate that the reference must be considered acceptable. Other research work
from Bolivia has been using the same method for assessing changes in the climate in the
Cordillera Real, e.g. Abbott MB, Wolfe BB, Aravena R, Wolfe AP and Seltzer, G. 0., in their
article from 2000.
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5 Review of study: "Technical Analysis of Geological, Hydrological,
Hydrogeological and Hydrochemical Surveys Completed for the
Si/ala Water System"
5.1 Summary
OHi Water & Environment (OHi) has been commissioned by Strategic Office for the Maritime
Claim, Silala and International Water Resources (OIREMAR) to conduct a review of Bolivian
geologist, Fernando Urquidi Barrau's Technical Analysis of Geological, Hydrological,
Hydrogeo/ogica/ and Hydrochemica/ Surveys Completed for the Si/ala Water System (Urquidi,
2018). Urquidi (the author1), a geological consultant, compiled a technical analysis (the report)
based on reviewing the following third-party documents:
• The National Geology and Mining Service of Bolivia report, Study on the Geology,
Hydrology, Hydrogeology, and Environment of the Silala Springs Area (SERGEOMIN,
2003).
• The National Geology and Mining Service of Bolivia report, Structural Geological Mapping of
the Area Surrounding the Silala Springs (SERGEOMIN, 2017).
• Tomas Frias Autonomous University report, Hydrogeological Characterization of the Silala
Springs (UATF, 2017).
• OHi report, Groundwater Flows (OHi , 2018a).
• OHi report, Study of the Flows in Silala Wetland and Spring System (OHi, 2018b).
• Isotope analyses results from Hydroisotop Laboratory (Urquidi, 2018).
The original report generated by the author was translated from Spanish to English and is 263-
pages in length, including annexes. The annexes, which contribute to 60-percent of the report,
or 159-pages, consist of the referenced SERGEOMIN and UA TF reports, and the isotope
chemistry results provided by the Hydroisotop Laboratory.
OH l's review has been focused on the author's content, the first 104-pages of the document,
covering: the summary of the geology, hydrology, hydrogeology, hydrochemistry of the Silala
water system; the author's statements within the body of the document; and the author's general
conclusions (i.e. bulleted points limited to the final four pages of the report). The annexes of the
report were reviewed in a cursory, high-level manner and where the annexes are referenced in
the main body of the report, as the focus of the review was the main document. The annexes
have not been reviewed in total but only to the extent they are referenced in the main body of
the report.
This memorandum documents OHl's review of the author's report, specifically providing the
following:
• a high-level summary of the secondary material presented; and a subjective review of the
content and general conclusions.
1 Ph.D (Applied Geochemistry) and member of the Bolivian National Academy of Sciences.
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5.2 Objectives of the Study
No objectives are articulated in the report. However, it is understood that the intent is to provide
a comprehensive recapitulation of the hydrogeological work completed to-date by various
agencies, universities and consultants on the Silala area.
5.3 Methodology used
As noted above, the study does not include original field investigations or analysis but rather is a
recapitulation of a number of studies, including DHI 2018b. The majority of the material in the
General Conclusions section is a reproduction of material from the DHI report, Study of the
Flows in Silala Wetland and Spring System (DHI, 2018b), and therefore does not constitute a
primary technical analysis.
The author's principal findings are summarized in the proceeding subsections.
5.3.1 Overview
The Silala is a transboundary groundwater system located on the Western Cordillera of the
Andes, straddling both Chile and Bolivia. The system contains multiple aquifers, over 70 springs,
and streams that feed local wetlands (i.e. bofedals). The springs originate from fractured/jointed
ignimbrite aquifers that are dacitic, andesitic and rhyolitic in composition. Flow through the
aquifers is dominated by secondary porosity, in fractures and joints. The two, local bofedals of
concern are the North Bofedal (Cajones) and the South Bofedal (Oriental). Groundwater from
areas of the Silala are believed to daylight as springs in areas of the Negra Ravine located
within Chile, and in the Main Ravine in Bolivia. The survey of 37 springs in the Main Ravine
show that 27 of the springs originate from joints in the ignimbrite on the walls of the ravine, and
1 O springs originate from the floor of the ravine. Surface water flows through the Silala have
been modified by engineering (i.e. artificial channelization via stone channels) to deliver water
from the watershed in Bolivia across the border into Chile. These stone channels drain the two
bofedals of concern .
5.3.2 Igneous Geology
The igneous geological framework of the Silala area is made up of three layers of semi-welded
volcanic ash (i.e. Silala lgnimbrite 1, 2 and 3), two episodic volcanic detritus flows, and a thin luff
layer below the second volcanic detritus flow. The Silala lgnimbrite 1 (Nis1) is believed to be the
unit that contributes groundwater flow to the springs within the Silala.
5.3.3 Quaternary Geomorphology
38
The valleys in the Silala are filled and covered with Quaternary deposits consisting of the
following:
glacial moraines (i.e. evidence of three groups of moraines at 4,500, 4,600, and 4,800-
masl);
fluvial-glacial deposits (volcanic and pyroclastic rocks deposited on the outlet of glacial
valleys);
colluvial-fluvial deposits (deposited on embankments and product of gravity and intermittent
runoff);
colluvial deposits (blocks, boulders and gravels forming cones at the bases of inactive
volcanoes);
alluvial fans; and
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alluvial deposits (very fine sediments, consisting of mostly organic matter found in the
bofedals).
5.3.4 Structural Geology
The general fracture system of the Silala area displays four structural trends. The four domains
observed are:
The main system has a general NE-SW trend with open fractures causing the SEE sector
springs.
The second system has a longitudinal NW-SE trend with closed fractures and lacks springs.
The third system has a general N-S trend, with volcanoes aligned in the same direction; this
system contains closed fractures and lacks springs.
The fourth, and final domain, presents lineaments in an E-W and E-NE direction with open
fractures that lead to springs in the NWW sector.
5.3.5 Hydrology
The North Bofedal and South Bofedal contain a total of 23 and 21 streams, respectively. Each of
the streams has an engineered 0.3-m collector channel that flows into a stone-lined main
channel, with a width varying between 0.8 to 1-m. The flow in the main channel on the Bolivian
side of the Silala has been estimated at 160 to 210-1/s. Approximately 60-percent of the flow in
the main channel is from springs in the North and South bofedals2
.
5.3.6 Hydrogeology
A spring survey in the Silala identified 70 springs in four different zones. Physical and chemical
parameters (i.e. temperature, pH, dissolved oxygen, salinity, total dissolved oxygen, electrical
conductivity, and flow) were collected from each surveyed location. Based on deductions and
observations from the spring survey, the bofedals located in the Silala are interconnected to,
and are dependent on, groundwater discharge. Geophysical studies conducted in the area
confirm that groundwater moves through fractures in the ignimbrite aquifers and from
consolidated/unconsolidated rock that feed the bofedals.
Four 2.5-inch diameter, 10-m deep, piezometers exist in the North Bofedal. Water levels
collected from the piezometers were observed between 0.4 and 0.67-m above ground level.
A hydrogeological study was completed by DHI with wells drilled and hydraulic testing
conducted by SERGEOMIN and Maldonado Explorations SRL. DH l's study was based on the
following work:
drilling of 35 standpipe piezometers at 29 locations to collect water levels and groundwater
quality samples;
single-well slug testing (i.e. slug testing on wells less than 15-m);
single-well packer testing (a total of 10 Lugeon and 12 Lefranc tests); and
constant-rate pumping test on DS-4P in the South Bofedal with multiple observation
piezometers at various depths.
Data and information gained from DH l's hydrogeological study was used to develop conceptual
and numerical groundwater models, delineating seven Hydrogeological Units (HGUs). DHI
identified HGU-7 (Silala Fault) being the most important as ii hosts the largest number of springs
and exhibited the largest hydraulic conductivity (i.e. geometric mean above 7.0-m/d). Hydraulic
2 Reviewer's note: The remaining 40% originate from diffuse groundwater inflow along the canals (OHi (2018b)
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testing showed HGU-6 (ignimbrite with high degree of welding) with the lowest hydraulic
conductivity (i.e. geometric mean below 1.0-m/d).
5.3. 7 Hydrochemistry
The Bolivian Ministry of Environment and Water carried out four, water quality sampling events
in 2017. The sampling campaigns collected water from springs, wells, and channelized surface
flows. Results from water quality sampling show a contrast in chemistry between the North and
South Bofedals. The samples collected from the South Bofedal contained higher levels of
bicarbonate, calcium , magnesium and chloride. Additionally, the South Bofedal contained lower
bicarbonate-magnesium ratios. Both bofedals contained water with uniform high silica
concentrations (i.e. 22.5-mg/l). Sampling results classify the water type in the Silala springs as
sodium bicarbonate.
For radiocarbon dating, 12 samples were collected from the Silala for 14C analyses.
Radiocarbon dating results indicate that the water in South Bofedal is approximately 10,000-
years older than that in the North Bofedal.
Additional water samples were collected (i.e. 25 surface samples, and nine groundwater
samples) for isotope analyses, specifically stable oxygen and hydrogen (i.e. 180 and 2H ratios)
and tritium. Results from stable isotope analyses suggest two main groundwater sources: 1)
shallow and local recharge; and 2) deeper and older flows from the Silala Fault system. The
concentration of tritium was zero, indicating that the water sampled was older than the past 90-
years. Furthermore, the isotope analyses suggest that precipitation in the area (at the time
where the groundwater infiltrated) did not originate from the Pacific Ocean but was derived from
the Atlantic Ocean or from the macro-Amazon basin to the east.
5.4 Discussion of Results and Conclusions
The discussion below is not exhaustive and does not include every occurrence of
unsubstantiated conclusions by the author. Furthermore, it also does not address potential
translation errors, reference discrepancies or subtle misuse of technical terms or concepts such
as the difference between groundwater age and apparent age and oxygen-18 versus delta
oxygen-18, which are pervasive throughout the text.
The following is a discussion of the key results or conclusions provided by the author that:
1. provide new information or data that may materially affect DHl's 2018 study;
2. are discordant with DH l's own findings as part of the 2018 study; or
3. are considered relevant to the estimates of the Silala trans-border flows.
The effect of having inconsistent conceptual models and interpretations, as well as, conclusions
not well supported by technical data as part the study is not considered as part of this review.
5.4.1 Formation of the Silala Spring System and Proxy Sites
40
The author states that the Main and North Ravines were formed by glacial processes, and that
the valleys exhibit typical glacial geomorphology features such as: "U-Shaped" forms; glacial soil
profiles; and striation marks on valley walls. However, the profile could also be interpreted as
box-cut, formed by large event, fluvial or glaciofluvial processes (e.g. large melt-water event). It
would seem that the description in Annex 2, which emphasizes the glaciofluvial processes along
previous zones of weakness (i.e. Silala Fault Zone), appears more reasonable. Regardless, it is
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immaterial whether the Silala ravine was formed by glacial or glaciofluvial processes and
introduction of this material into the technical discussions is unnecessary.
Similarly, there is not a well-developed scientific case presented for Negra ravine being a
reasonable proxy for the natural conditions of the Silala ravine system. The spring discharge
rates, streambed slopes and geologic controls on flow have not been shown to be comparable.
While the ultimate source of the discharging water at Negra ravine is likely the same as the
southern wetland based on the water quality comparisons, there are many other considerations
that would need to be evaluated to argue it can be used for a proxy of pre-channelized
conditions in the Silala ravine.
5.4.2 Recharge - Discharge Relationships
There are a number of discrepancies between the precipitation reported by the study, its
appendices and DHI (2018b). Precipitation is an important parameter as it provides insights into
the degree to which modern precipitation shapes the geomorphology of the area and the
potential for modern groundwater recharge. Furthermore, some of the data relied upon by these
studies was shown to be of dubious quality (DHI , 2018b}.
The author states that water produced by the mass melting of glaciers was an important source
of the current groundwater stored in the Silala Aquifer and that glacial thawing and copious rain
of the Tauca Facie is the biggest source of the current groundwater stored in the Silala Aquifer.
No data is used to support these statements and thus the case for this hypothesis cannot be
reasonably evaluated. Based on the data available to DHI, all that can be stated presently is that
the apparent age of groundwater in association with the South Bofedals is older than 10,000
years. Therefore, while perhaps it is not unreasonable from a timing perspective, the origins of
the deeper water discharging to the South Bofedals remains poorly defined.
The conclusion that recharge in the Silala area is not possible (Annex 3) due to the water deficit
is inconsistent with DHI 2018b, as well as other studies in the Andes that demonstrate that while
modern recharge may not happen every year it does occur in response to large events
(Houston, 2002; Houston, 2007 etc.).
Not all water discharging to the springs is interpreted as artesian, as stated in the report. Some
of the springs along the margins appear to be seepage faces associated with the phreatic
surface. Furthermore, available time series data 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
15-25 I/s lower than the Bolivian ones. However, the assertion that flows are constant relies on
the limited time periods measured which are not sufficient for a final conclusion, see (DHI
2018b}.
The statement "the quantity of surface water was highly modified by artificial channelization",
while likely true, it is stated without evidence to support this assertion. For the a technical study
of this type to appear confident and unbiased, such types of strong statements, emblematic of
much of the text, should be moderated to reflect the certainty by which the statement can be
supported, and be backed by technical analyses and data. It would be of significantly more
value to reference the findings of the DHI study and any other information/studies used to
develop various concepts and conclusions. Furthermore, the reviewer recommends limiting the
findings to technical determinations rather than non-technical conclusions such as whether
Silala is an international river course.
5.5 Validation of the Results
Overall the author's conclusions are largely drawn from either the DHI 201 Ba report or variants
of reports that were used in the DHI study. The findings are largely consistent with those of DHI.
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However, the author's narrative seems not solely based on technical objective interpretation of
data and analyses presented. This impression stems from the numerous unsupported
statements and lack of presentation of or referencing materials on which the author's
conclusions are drawn.
There are also inconsistencies in data used and conclusions drawn, which contradict the
findings of DHI 2018b. Key contradictions have been highlighted in preceding sections and
largely focus around the role of glaciation in development of the Silala ravine and recharge -
discharge relationships in the Silala area. However, numerous others contradictions exist and
resolution of these would provide a more coherent and consistent technical assessment.
In DHl's opinion:
• Our conclusions on the recharge -discharge relationship, although still rather uncertain, still
seems more trustworthy than those of the author, as DH l's conclusions are based on a
broader selection of data sources (satellites, ground stations, reported spatial trends and
other studies) and more comprehensive analyses of these data,
• the discussion of the glaciation of the Silala Ravine itself is irrelevant to the present day
hydrogeologic system. It does not affect present transboundary groundwater or surface flows
or their management.
In general, the information provided does not materially change any previous DHI conclusions or
study outcomes, including estimates for transborder flow.
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5.6 References
Yang Wang et al (1996); Radiocarbon dating of soil organic matter. Quaternary Research , Vol
45, Issue 3, pp 282-288.
Taylor et al (2000); The extent and significance of bioturbation on 137Cs distributions in upland
soils. Catena 43 -2001. pp81-99
Urquidi, 2018, "Technical Analysis of Geological, Hydrological, Hydrogeological and
Hydrochemical Surveys Completed for the Silala Water System," June, 2018, The Strategic
Office for the Maritime Claim, Silala and International Water Resources (DIREMAR), La Paz,
Bolivia.
OHi, 2018a, Study of the Flows in the Silala Wetlands and Spring System - Provisional Report 4
- Groundwater Flow. January, 2018,
OHi, 2018b, Contract CDP-I No 01/2018, Study of the Flows in the Silala Wetlands and Springs
System Product No. 2 - 2018. March 2018.
Houston J. 2002. Groundwater recharge through an alluvial fan in the Atacama Desert, northern
Chile: mechanisms, magnitudes and causes. Hydrological Processes 16: 3019-3035.
Houston J. 2007. Recharge to groundwater in the Turi Basin, northern Chile: an evaluation
based on tritium and chloride mass balance techniques. Journal of Hydrology 334: 534-544.
SERGEOMIN, 2003, "Study on the Geology, Hydrology, Hydrogeology, and Environment of the
Area of the Silala Springs," June, 2003, The National Geology and Mining Service of Bolivia, La
Paz, Bolivia.
SERGIOMIN, 2017, "Structural Geological Mapping of the Area Surrounding the Silala Springs,"
2017, The National Geology and Mining Service of Bolivia, La Paz, Bolivia.
UATF, 2018, "Hydrogeological Characterization of the Silala Springs," 2017, Tomas Frias
Autonomous University, Potosi, Bolivia.
The expert in WATER ENVIRONMENTS 43
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6 Final validation of the results of all studies
44
This section describes the overall results of the five studies and evaluate if they affect the
findings of previous studies and how they contribute to a better technical understanding of the
environmental, and water aspects of the Sita/a Springs System.
1st Review, Hydraulic study:
"Characterization and efficiency of the hydraulic works built and installed in the Silala
sector"
The study provides detailed evidence of the extent and properties of the canals. Photos and
measurements also demonstrate the extensive drainage and the negative environmental impact
on the natural bofedals.
Overall the review finds that the report provides valuable documentation which supports the
conclusion on canal system impacts in agreement with field survey and analysis presented in
earlier studies such as (OHi, 2018 b).
Based on field data collected a canal hydraulics model is developed and applied. The model
results show high canal flow velocities. In a natural bofedal the flow regime consist of slow
porous media flow in the peat in combination with excess discharge in the form overland flow
distributed in a braded two dimensional pattern across the wetland vegetation. As such regime
is different from the concentrated high velocity flows in the present canals the study confirms
that the canalization has changed the flow pattern of Sita/a.
The methodology applied is, however, not valid for assessment of the quantitative impacts of the
canalization on the surface discharge rates from the Silala. This would require quantification of
the water exchange between the canals and the wetlands and between the groundwater and the
wetlands as in the analyses of (OHi, 2018 b).
2nd Review, Topography and soil properties:
"Study of geo-referencing, topographic survey and determination of the infiltration
capacity in the event of possible surface runoff in the area of the Silala springs"
The methodology used to produce the detailed topographical survey is deemed to be valid for
the purpose and the output of the study is certainly relevant and valuable for further hydrological
and hydrogeological studies in the area.
Unfortunately, the new survey does not include specific comparisons to the previous
topographical surveys carried out for OIREMAR and applied to geo-reference springs and
piezometers by previous studies. Particularly the reference to the previously surveyed detailed
digital elevation model OIREMAR (2017) or the possible corrections necessary to align it with
the new benchmarks is lacking. Such information would add considerable value to the output.
The soil property study documents a predominant presence of sandy soils throughout the study
area. The soils all have high infiltration capacities and are considered well drained since none of
the test locations outside the wetlands encountered free groundwater tables.
The field experiments reported suggest ten times higher infiltration capacities than used in the
previous studies. Although these observations may be uncertain and even too high; the
experiments indeed confirm the findings of the previous studies regarding absence of surface
runoff outside the wetlands and of the discharge of the Silala Springs and wetlands therefore
originating almost entirely from groundwater.
3rd Review:
119
"Environmental Impact Assessment Study in Silala, Part 1"
The findings showed that the vegetation structure in the bofedals has been altered and it has
created a more fragmented (dis-integrated) and degraded vegetation cover and diversity. The
status of the Silala bofedals showed evidence of areas with the typical bofedal vegetation types
but also of areas, with typical dry land vegetation. The study considers the canalization to be the
main reason of development of the dry areas and for the deterioration of the environmental
conditions for both biotic and a biotic factors. The main evidence came from the study of the
vegetation/ species distribution in the bofedals and comparing the findings with studies of other
undisturbed bofedals in the region .
The studies confirmed that the bofedals at Silala have more species and areas covered with
plants normally dedicated to the dry margin-zones, whereas the vegetation types commonly
associated with the bofedals were fewer and did only cover a small portion of the bofedals.
The approach taken by the research team to describe the current conditions in the bofedals in
relation to flora and fauna, is considered a standard well proven approach and the results of the
individual studies are presented in the report. The conclusions are drawn mainly on basis of the
distribution of the vegetation types, related to dry and wet soils, while the studies of fish, birds,
herpetofauna and macroinvertebrates did not add much to the overall conclusion.
This study provides the first quantitative analyses documenting the poorer environmental status
of the Silala as compared to similar undisturbed bofedals in the Altiplano area. Hereby, it
substantiates the qualitative assessments and observations made in previous studies. The
findings are in accordance with the hydrological analyses and field studies documenting the
drainage effects of the canals (e.g. DHI 2018b and the hydraulic study reviewed above).
4th Review:
"Survey of Environmental Impact Assessment Study in Silala,Part 2 PAL YNOLOGY"
The results of the undertaken survey are based on applying four globally recognised methods
for assessing changes over time in habitats/soils.
It is verified that the observed changes in the two bofedals from the original peat-bog habitats to
more dry habitats have taken place during the last century. The survey has found indications
that the flow paths of the bofedals has changes from small braided streams and seepage
through the vegetation to a situation, where the canals route the water faster through the
bofedals. This change may be one of the main reasons for the alterations in the habitats, which
have taken place during the last century.
The review can conclude that the methods used to assess the past century conditions were
successful and in line with similar studies in the region. However, it should also be mentioned
that the assessment of the previous vegetation in the Northern and Southern bofedal were only
based on full analyses on one core in the Northern bofedal and two in the Sothern bofedal. In
addition, the two cores from the Southern bofedal showed large variation in the stratigraphy,
indicating long-term dynamic changes to the bofedal, most properly caused by long-term natural
changes in how water has flown through the bofedals.
In summary the first of the two environmental impact assessment documents quantitatively that
the Silala Bofedal is inhabited by species that are mostly linked to dry land and to a lesser extent
species associated with healthy bofedals, as found in other bofedals. The analysis of the second
impact assessment study has shown that the changes have taken place during the last century,
during which the canalisation was implemented.
5th Review:
"Technical Analysis of Geological, Hydrological, Hydrogeological and Hydrochemical
Surveys Completed for the Silala Water System"
The expert in WATER ENVIRONMENTS 45
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Overall the author's conclusions are largely drawn from either the DHI 2018a report or variants
of reports that were used in the DHI study. The findings are largely consistent with those of DHI.
However, the author's narrative seems not solely based on technical objective interpretation of
data and analyses presented. This impression stems from the numerous unsupported
statements and lack of presentation of or referencing materials on which the author's
conclusions are drawn.
There are some inconsistencies in data used and conclusions drawn, which contradict the
findings of DHI 2018b. Key contradictions have been highlighted in preceding sections and
largely focus around the role of glaciation in development of the Silala ravine and recharge -
discharge relationships in the Silala area. However, numerous other contradictions exist and
resolution of these would provide a more coherent and consistent technical assessment.
In DHl's opinion:
• Our conclusions on the recharge -discharge relationship, although related with uncertainty
(mainly from the climate), still seems more trustworthy than those of the author, as DH l's
conclusions are based on a broader selection of climate data sources (satellites, several
ground stations, reported spatial trends from other studies) and more comprehensive
analyses of these data.
• The discussion of the glaciation of the Silala Ravine itself is irrelevant to the present day
hydrogeologic system and does not affect transboundary groundwater or surface flows or the
management of said flows.
In general, the information provided does not materially change any previous DHI conclusions or
study outcomes, including estimates for transborder flow.
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7 Bibliography (references)
Campos Barron (Consultores Technicos lngenieria & Construcci6n CB s.r.l., La Paz Bolivia)
2018: Study of georeferencing, topographic survey and determination of the infiltration capacity
in the event of possible surface runoff in the area of the Silala Springs
FUNDECO, (lnstituto de Ecologia de la Universidad Mayor de San Andres, La Paz - Bolivia),
2018, Environmental Impact Assessment Study in Silala, Part1.
FUNDECO, (lnstituto de Ecologia de la Universidad Mayor de San Andres, La Paz - Bolivia),
2018, Environmental Impact Assessment Study in Silala, Parle 2, Palinologia ..
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.
IHH (lnstituto de Hidraulica e Hidrologia, Universidad Mayor de San Andres),
2018:Characterization and effiency of the hydraulic works built and installed in the Silala Sector.
Ministerio de Energias, 2017. Analisis Fisico Quimico de Aguas, La Paz, Bolivia: lnstituto
Boliviano de Ciencia y Tecnologia Nuclear Centro de lnvestigaciones y Aplicaciones Nucleares
Unidad de Analisis y Calidad Ambiental
DIREMAR, 2017 Digital Surface Model (DSM) based on measurements taken during the drone
flight in last half of 2016.
OHi, 2018: Contract CDP-I No 01 /2018, Study of the Flows in the Silala Wetlands and Springs
System. Product No.2 -2018 Final report.
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, Appendix E.
Wealer and Peach, 2017: Expert Report 1 by. P17, Memorial of the Republic of Chile. Vol.1
Yang Wang et al (1996); Radiocarbon dating of soil organic matter. Quaternary Research, Vol
45, Issue 3, pp 282-288.
Taylor et al (2000); The extent and significance of bioturbation on 137Cs distributions in upland
soils. Catena 43 -2001 . pp81-99.
Urquidi, 2018, "Technical Analysis of Geological, Hydrological, Hydrogeological and
Hydrochemical Surveys Completed for the Silala Water System," June, 2018, The Strategic
Office for the Maritime Claim, Silala and International Water Resources (DIREMAR), La Paz,
Bolivia.
OHi, 2018a, Study of the Flows in the Silala Wetlands and Spring System - Provisional Report 4
- Groundwater Flow. January, 2018,
OHi, 2018b, Contract CDP-I No 01 /2018, Study of the Flows in the Silala Wetlands and Springs
System Product No. 2- 2018. March 2018.
Houston J. 2002. Groundwater recharge through an alluvial fan in the Atacama Desert, northern
Chile: mechanisms, magnitudes and causes. Hydrological Processes 16: 3019-3035.
Houston J. 2007. Recharge to groundwater in the Turi Basin, northern Chile: an evaluation
based on tritium and chloride mass balance techniques. Journal of Hydrology 334: 534-544.
122
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SERGIOMIN, 2003, "Study on the Geology, Hydrology, Hydrogeology, and Environment of the
Area of the Silala Springs," June, 2003, The National Geology and Mining Service of Bolivia, La
Paz, Bolivia.
SERGEOMIN, 2017, "Structural Geological Mapping of the Area Surrounding the Silala
Springs,'' 2017, The National Geology and Mining Service of Bolivia, La Paz, Bolivia.
UATF, 2018, "Hydrogeological Characterization of the Silala Springs," 2017, Tomas Frias
Autonomous University, Potosi, Bolivia.
Annex 23.1
IHH, “Characterization and Efficiency of the Hydraulic Works
built and installed in the Silala Sector”, April 2018
(English Translation)

125
OfARAffiRIZA TION ANO lf-lKIEICY' Of TMf Hn>AAUUC W~ BUUT AHO INSTAlltO IN THE SllAlA SECTOI
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC
WORKS BUILT AND INSTALLED IN THE SILALA SECTOR
lhh
lnstltutode Hldrlull<1. Hldroloefa
Uolv,rsld,d M,yor d, Sio Andrft
FINAL REPORT, APRIL 2018
126
OtAAActtalZA TION ANO lfflCIENCY Of nu H'l'tl«A.UUC woas IUllT AHO INSTALUO IN THE su.u. UCTOII
HIGHER UNIVERSITY OF SAN ANDRES
FACULTY OF ENGINEERING
CIVIL ENGINEERING MAJOR
INSTITUlE OF HYDRAULICS AND HYDROLOGY
' CHARAClERIZATION ANO EFFICIENCY OF THE HYORAUUC WORKS BUILT ANO INSTALLED IN THE
SILALA SECTOR'
This study has been carried out by the research professionals of the Institute of Hydraulics and
Hydrology-UMSA (Higher University of San Andres):
Or. Eng. Jose Luis Montano Vargas Dr. Eng. Jose Antonio Luna Vera
MSc. Juan Pablo Fuchs Arce MSc. Eng. Juana Dolores Mejia Gamarra
MSc. Eng. Javier Carlos Mendoza Rodriguez
Director of the Institute of Hydraulics and Hydrology - UMSA (Higher University of San Andres): Institute
of HydrauJic:s and Hydrology, University Campus, Cota Cota Zone, CP 699, la Pai,. Bolivia
April, 2018
(Footer on all pages Oiremar and IHH's logos)
127
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC
WORKS BUILT AND INSTALLED IN THE SILALA SECTOR
MAIN DOCUMENT
INDEX
LIST OF FIGURES
LIST OF TABLES
ACRONYM LIST
SURVEY SUMMARY
1 INTRODUCTION
1.1 BACKGROUND
1.2 OBJECTIVE
1.3 STRUCTURE OF THE REPORT
1.4 LOCATION
1.5 METHODOLOGY
2 DOCUMENT REVIEW AND ANALYSIS REPORT
2.1 CONCESSION FOR THE EXECUTION OF HYDRAULIC WORKS
2.1.1 Fox Report (1922)
2.2 SPRING ABSTRACTION AND CHANNELING WORKS
3 NATURAL CONDITIONS
3.1 WATER BODIES OF SILALA
3.1.1 Bofedales
3.1.2 Characteristics of the Silala bofedales
3.1.3 Movement of water in the bofedales
3.2 GROUNDWATER SOURCES – SPRINGS
4 FLOW REGIME
4.1 FLOWS IN THE SOUTH BOFEDAL
4.2 FLOWS IN THE NORTH BOFEDAL
4.3 CONFLUENCE REACH OF THE SOUTH AND NORTH BOFEDAL
5 PHYSICAL CHARACTERIZATION OF HYDRAULIC WORKS
5.1 GENERAL ASPECTS
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5.2 WORKS IN THE SOUTH BOFEDAL
5.2.1 DETAILED DESCRIPTION
5.2.2 STONELINED CANALIZATION REACHES
5.2.3 SYNTHESIS OF THE WORKS OF THE SOUTH BOFEDAL
5.3 WORKS IN THE NORTH BOFEDAL
5.3.1 SYNTHESIS OF THE WORKS OF THE NORTH BOFEDAL
5.4 CONFLUENCE SECTION CANAL
5.4.1 DETAILED DESCRIPTION
5.4.2 SYNTHESIS OF THE WORKS OF THE CONFLUENCE SECTION
6 DESCRIPTION AND CLASSIFICATION OF THE ABSTRACTION
WORKS
6.1 ABSTRACTION WORKS
6.1.1 CLASSIFICATION
6.1.2 MINOR ABSTRACTION WORKS
6.1.1 LONGITUDINAL ABSTRACTION WORKS
6.1.2 MAJOR ABSTRACTION WORKS
6.1.3 HEADRACE WORKS
7 DESCRIPTION OF THE SEDIMENT TRANSPORT PROCESS
7.1 PROCESSES RELATED WITH LAMINAR EROSION
7.2 SEDIMENT TRANSPORT IN THE CANALS
8 SURFACE FLOW HYDRAULIC MODEL IN HEC-GEORAS
8.1 SPECIFIC OBJECTIVE
8.2 HYDRAULIC MODEL
8.3 METHODOLOGY
8.4 GEOMETRY OF THE HYDRAULIC SYSTEM
8.5 SLOPE OF THE DRAINAGE SYSTEM
8.6 MANNING COEFFICIENT (N)
8.7 HYDROLOGICAL SCENARIO OF THE SYSTEM
8.8 FLOW HYDRAULIC REGIME
8.8.1 Gauging campaign of April 2018
8.9 HYDRAULIC SIMULATION OF SURFACE FLOW IN HEC-RAS
8.10 HYDRAULIC MODEL RESULTS
9 CONCLUSIONS
9.1 NATURAL CONDITIONS
9.2 STATE OF INTERVENTION ON THE WATERBODIES
9.3 SYNTHESIS
REFERENCES
10 ANNEXES
ANNEX 1: DETAILED CHARACTERIZATION OF THE SOUTH, NORTH
AND CONFLUENCE CHANNELS BOFEDALS
DESCRIPTION OF THE SOUTH BOFEDAL PHYSICAL CHARACTERISTICS
- PROGRESSIVE 0+000 – 0+099.04
DESCRIPTION OF THE SOUTH BOFEDAL PHYSICAL CHARACTERISTICS
- PROGRESSIVE 0+170 - 0+288.08
DESCRIPTION OF THE SOUTH BOFEDAL PHYSICAL CHARACTERISTICS
- PROGRESSIVE 1+760 TO 1+783.66
DESCRIPTION OF THE SOUTH BOFEDAL PHYSICAL CHARACTERISTICS
– REACH 1
DESCRIPTION OF THE SOUTH BOFEDAL PHYSICAL CHARACTERISTICS
– REACH 2
DESCRIPTION OF THE SOUTH BOFEDAL PHYSICAL CHARACTERISTICS
– REACH 3
DESCRIPTION OF THE SOUTH BOFEDAL PHYSICAL CHARACTERISTICS
– REACH 4
DESCRIPTION OF THE SOUTH BOFEDAL PHYSICAL CHARACTERISTICS
– REACH 5
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129
DESCRIPTION OF THE SOUTH BOFEDAL PHYSICAL
CHARACTERISTICS – REACH 6
DESCRIPTION OF THE NORTH BOFEDAL PHYSICAL
CHARACTERISTICS – PROGRESSIVE 0+260 – 0+360
DESCRIPTION OF THE CONFLUENCE CANAL PHYSICAL
CHARACTERISTICS – PROGRESSIVE 2+920 TO 2+970
ANNEX 2: SOUTH BOFEDAL CANALS CHARACTERIZATION
ANNEX 3: MEASUREMENT STANDARDS FOR WATER QUALITY IN
THE SILALA SPRINGS CANALS
iv
130
List of Figures
Figure 1. Location of the study area
Figure 2. Quaternary deposits (SERGEOMIN, 2017)
Figure 3. Body of water as a unit
Figure 4. Underground origin of the Silala waters, a) North Bofedal, b) South
Bofedal
Figure 5. Evidence on the absence of traces of surface runoff
Figure 6. Vegetation cover, a) North Bofedal, b) South Bofedal
Figure 7. Confluence reach, a) presence of peat, b) access road
Figure 8. Cross-sectional schematic of the Silala bofedal
Figure 9. Silala bofedal category according to the water period (Jackson,
Thompson & Kolka, 2014)
Figure 10. Springs recorded in the South Bofedal (MGI, 2016)
Figure 11. Springs recorded in the North Bofedal (MGI, 2016)
Figure 12. Monthly Flow Series (l/sec) – C1 to C7 Gauging Stations. Source:
Own elaboration based on
(SENAMHI, 2018)
Figure 13. Spatial variation of the flow in the South Bofedal. Source: Own
elaboration based on
SENAMHI - DIREMAR data (SENAMHI – DIREMAR, 2018)
Figure 14. Spatial variation of the flow in the North Bofedal. Source: Own
elaboration based on
SENAMHI – DIREMAR data, (2018)
Figure 15. Spatial variation of the flow in the North Bofedal. Source: Own
elaboration based on
SENAMHI - DIREMAR (SENAMHI, 2018)
Figure 16. Mean monthly flowrate series (l/s) – Simultaneous measurement
stations – South Bofedal. Source: Own elaboration based on SENAMHI-DIREMAR
data (2018)
Figure 17. Mean monthly flowrate series (l/s) – Simultaneous measurement
stations – North Bofedal. Source: Own elaboration based on SENAMHI-DIREMAR
data (2018)
Figure 18. Mean monthly flowrates (l/s) – Simultaneous measurement stations
– Confluence section. Source: Own elaboration based on SENAMHI-DIREMAR
data (2018)
Figure 19. Location of hydric control points, continuous gauging in the Silala
Springs. Source: Own elaboration based on SENAMHI-DIREMAR data
(2018)
Figure 20. Hydric control points map, simultaneous gauging in the Silala
Springs. Source: Own elaboration based on SENAMHI-DIREMAR data (2018)
Figure 21. Location map of the Silala Springs. Source: Own elaboration based
on data from SENAMHI-DIREMAR (2018)
Figure 22. Arrangement of the canal network of the Silala Springs
Figure 23. Springs 01 to 04
Figure 24. Water retaining dam and springs at the headwaters of the South
Bofedal
Figure 25. Intake work and desilting chamber
Figure 26. Sediments in the area above the South springs and bofedals zona
superior de manantiales y bofedales del sur
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131
Figure 27. Bed covered with sediments formed by angular gravels
Figure 28. Water conveyance chamber and pipe
Figure 29. Spring water conveyance canals
Figure 30. Ancient artificial union of canals and current outlet to measure the
flow
Figure 31. South Bofedal after the extraction of water through drainage actions
Figure 32. Dry sectors in the South Bofedal
Figure 33. Storage tank
Figure 34. Native species (toad)
Figure 35. Characteristics of the canal and bofedal around Weir 3
Figure 36. Ditch for vehicular crossing through a piped reach of the bofedal
Figure 37. Bofedal that narrows and canal excavated by the bofedal
Figure 38. Canal covered by very developed scrubland
Figure 39. Canal in the reach of the Silala Military Outpost
Figure 40. Narrowing of the canal’s reach with natural flow
Figure 41. Reach of the natural canal and the intervened canal in proximity of
Weir 3
Figure 42. Waterfall and reach of the bofedal in the canal’s zone – South Bofedal
Figure 43. Reach found within the ravine and canalization near the end point
of the South Bofedal
Figure 44. Reach found within the ravine and canalization at the end point of
the South Bofedal
Figure 45. Location of stone-lined reaches in the South Bofedal. Source: Own
elaboration based on data from DIREMAR, GOOGLE EARTH
Figure 46. Upper part of the North Bofedal
Figure 47. Jointed rocks on the sides of the North Bofedal
Figure 48. Upper area of the North Bofedal
Figure 49. Upper reach of the drainage canal in the North Bofedal
Figure 50. Canal bottom and slope in the North Bofedal
Figure 51. Ditch for vehicular passage and pipe for water flow
Figure 52. Reach of minor canalizations (secondary canals)
Figure 53. Flooded zone in the North Bofedal
Figure 54. Abstraction of springs through pipes and canals of accommodated
rock
Figure 55. Spring protection and dome channeling
Figure 56. Collection of water from springs
Figure 57. View of spring 50
Figure 58. Panoramic view 1 of the network of canals in the North Bofedal
Figure 59. Panoramic view 2 of the network of canals in the North Bofedal
Figure 60. View of the confluence of canals of the South and North Bofedales
Figure 61. View of the masonry canal towards the border with Chile
Figure 62. Intake works, desilting chamber and load chamber near the border
Figure 63. Panoramic view of the exit canal towards the border
Figure 64. Collection of water from springs
Figure 65. Longitudinal stone-lined abstraction canals
Figure 66. Canals of the North Bofedal
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132
Figure 67. Wetland waterbodies: a) natural and b) intervened
Figure 68. Water abstraction in the bofedales, a) before the canals were built
and b) after canal construction
Figure 69. Main and secondary canals of the North bofedal
Figure 70. Main and secondary canals of the South bofedal
Figure 71. Main and secondary canals of the North bofedal
Figure 72. Panoramic view showing the main canal of the North Bofedal
Figure 73. Water intake work, desiltation chamber and loading chamber near
the border
Figure 74. Intake works (source: DIREMAR)
Figure 75. North Bofedal flank where indications of erosion are abstent
Figure 76. Sediments in the canals and flanks in the higher area of the bofedales
Figure 77. Water levels in the C1 to C6 for the December-2017 to March-2018
Figure 78. Topographic Survey Map with Level Curves every 1 meter and
every 20 cm. (Source: Own elaboration, based on the topography provided by
DIREMAR)
Figure 79. Map of the Digital Terrain Model and generation of the Geometric
Model in ArcGIS. (Source: Own elaboration, based on the topography provided
by DIREMAR)
Figure 80. Geometry in the HEC-RAS Model (Digital Elevation Model
(DEM), Progressives, Cross
Sections). (Source: Own elaboration, based on the topography provided by DIREMAR)
Figura 81. Geometry in the HEC-RAS Model (Digital Elevation Model
(DEM), Progressives, Cross
Sections). (Source: Own elaboration, based on the topography provided by DIREMAR)
Figure 82. Longitudinal Profile of the Main Course. (Source: Own elaboration)
Figure 83. Hydraulic System of Silala and continuous Gauging
Points of SENAMHI
Figure 84. Presentation of the Hydraulic Simulation in
RAS Mapper (Silala)
Figure 85. Base and longitudinal profile of the South Canal in the section between
0+000 to 0+099.04 – South Bofedal, Silala Springs. (Source: Own elaboration
based on data from DIREMAR)
Figure 86. Base and longitudinal profile of the South Canal in the section between
0+170 to 0+288.08 – South Bofedal, Silala Springs. (Source: Own elaboration
based on data from DIREMAR)
Figure 87. Base and longitudinal profile of the South Canal in the section between
1+760 to 1+783.66 – South Bofedal, Silala Springs. (Source: Own elaboration
based on data from DIREMAR)
Figure 88. Base and longitudinal profile of the first section between 2+060 to
2+092 – South Bofedal, Silala Springs. (Source: Own elaboration based on
data from DIREMAR)
Figure 89. Base and longitudinal profile of the second section between 2+092
to 2+310 – South Bofedal, Silala Springs. (Source: Own elaboration based on
data from DIREMAR, GOOGLE EARTH)
Figure 90. Base and longitudinal profile of the third section between 2+310
to 2+377 – South Bofedal, Silala Springs. (Source: Own elaboration based on
data from DIREMAR, GOOGLE EARTH)
Figure 91. Base and longitudinal profile of the fourth section between 2+380
to 2+462 – South Bofedal, Silala Springs. (Source: Own elaboration based on
data from DIREMAR, GOOGLE EARTH)
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133
Figure 92. Base and longitudinal profile of the fifth section between 2+618 to
2+710 – South Bofedal, Silala Springs. (Source: Own elaboration based on
data from DIREMAR, GOOGLE EARTH)
Figure 93. Base and longitudinal profile of the sixth section between 2+710
to 2+800 – South Bofedal, Silala Springs. (Source: Own elaboration based on
data from DIREMAR, GOOGLE EARTH)
Figure 94. Base and longitudinal profile of the North Canal section between
0+260 to 0+360 – North Bofedal, Silala Springs. (Source: Own elaboration
based on data from DIREMAR, GOOGLE EARTH)
Figure 95. Base and longitudinal profile of the Confleunce section canal between
2+920 to 2+2970 – Confluence Bofedal, Silala Springs. (Source: Own
elaboration based on data from DIREMAR, GOOGLE EARTH)
Figure 96. Detail of the hydraulic model for the North Branch of Silala in HECRAS.
(Source: prepared by the authors)
Figure 97. Detail of the hydraulic model for the South Branch of the Silala in
HEC-RAS
Figure 98. Detail of the hydraulic model for the Confluence Branch of the Silala
in HEC-RAS
Figure 99. Detail of the Hydraulic Model of the Confluence Reach of the Silala
in HEC-RAS
Figure 100. Hydraulic profile in the North Branch Silala in HEC-RAS
Figure 101. Hydraulic profile of the South Branch of the Silala in HEC-RAS
Figure 102. Hydraulic profile of the Confluence Branch of the Silala in HECRAS
Figure 103. Hydraulic Profile of the velocities in the North Branch of the Silala
in HEC-RAS
Figure 104. Hydraulic Profile of the velocities in the South Branch of the Silala
in HEC-RAS
Figure 105. Hydraulic Profile of the velocities in the Confluence Branch of the
Silala at HEC-RAS
Figure 106. Hydraulic Profile of the Froude Number and Velocities in the North
Branch of the Silala in HEC-RAS
Figure 107. Hydraulic Profile of the Froude Number and Velocities in the South
Branch of the Silala in HEC-RAS
Figure 108. Hydraulic Profile of the Froude Number and Velocities in the Confluence
Branch of the Silala in HEC-RAS
Figure 109. Profile of the Gradient, Energy Line, and Depth in the North Branch
of the Silala in HEC-RAS
Figure 110. Profile of the Gradient, Energy Line, and Depth in the South Branch
of the Silala in HEC-RAS
Figure 111. Profile of the Gradient, Energy Line, and Depth in the Confluence
Branch of the Silala in HEC-RAS
Figure 112. Hydraulic Simulation in Ras Mapper for the North Branch of the
Silala in HEC-RAS
Figure 113. Hydraulic Simulation in Ras Mapper for the South Branch of the
Silala in HEC-RAS
Figure 114. Hydraulic Simulation in Ras Mapper for the Confluence Branch of
the Silala in HEC-RAS
Figure 115. Cross-sections of the North Branch of the Silala in HEC-RAS
Figure 116. Cross-sections of the South Branch of the Silala in HEC-RAS
Figure 117. Cross-sections of the South Branch of the Silala in HEC-RAS
(Continued)
Figure 118. Cross-sections of the Confluence Branch of the Silala in HEC-RAS
viii
134
List of Tables
Table 1. General details of the Silala Springs (SENAMHI-DIREMAR, 2018)
Table 2. Category and amount of the South and North bofedales (SENAMHIDIREMAR,
2018)
Table 3. Reach classification based on a slope range. Detailed physical characterization
of the stone-lined reach, South Bofedal
Table 4. Summary of the lengths of the South Bofedal canals
Table 5. Summary of the lengths of the North Bofedal canals
Table 6. Summary of the lengths of the confluence section
Table 7. Referential values of the Manning roughness coefficient (Source: Ven
Te Chow)
Table 8. Referential values of the Manning roughness coefficient (Continued).
(source: Ven Te Chow)
Table 9. Mean measured flows in the continuous gauging site, code “C”.
(Source: own elaboration based on data from SENAMHI)
Table 10. Incremental mean flows in the continuous gauging points, code “C”.
(Source: own elaboration based on data from SENAMHI)
Table 11. Hydraulic characteristics at the measurement points of the April 2018
campaign
Table 12. Hydraulic characteristics at the measurement points of the April 2018
campaign
ix
135
List of Acronyms
ALC Latin America and the Caribbean
DIREMAR Strategic Office for the Maritime Claim HAA
High Andean Wetlands
IHH Institute of Hydraulics and Hydrology, UMSA
UMSA Higher University of San Andres
IGM Military Geographic Institute of Bolivia
MMAyA Ministry of Environment and Water MPD Ministry of
Development Planning
SENAMHI National Service of Meteorology and Hydrology of Bolivia
SERGEOMIN Bolivian Geological and Mining Service
SNHN National Service of Naval Hydrography of Bolivia
VIPFE Vice-Ministry of Public Investment and External Financing
x
136
STUDY SUMMARY
The study shows that the level of intervention in the Silala bofedals has been
remarkably high, a situation that is reflected by the magnitude of the works
built and by the high level of efficiency of water abstraction and channeling.
The length of the canals built exceeds 6 kilometers and the catchments in the
major contribution springs reach almost a hundred works. The flow with very
low velocities –in its natural state– has reached comparatively much higher
values, due to the water channeling through the built canals.
The interventions have not only affected the natural water supply of the springs
to the bofedals, but they have also affected the body of the bofedales themselves,
causing the drainage of these by means of the implementation of permeable
canals.
The hydraulic works have caused a strong impact on the natural environment,
since the initial condition of these bodies of water has not been respected as
natural reservoirs and regulators of the soil–water–biotope system.
The conservation of water bodies has been subordinated to a vision of intervention
with the basic principle of improving the amount of water abstraction for use
purposes.
In short, the main objective has been to drain the bodies of water from the
springs and bofedals.
xi
137
1 INTRODUCTION
1.1 BACKGROUND
With the purpose of studying the legal alternatives to assume the defense of
the Silala Springs and other water resources before competent international
instances, by means of Supreme Decree N° 2760 of 11 May 2016, the Strategic
Office for the Defense of the Silala Springs and all the Water Resources on the
Border with the Republic of Chile (DIRESILALA) was created.
On 6 June 2016, the Republic of Chile filed a claim with the International Court
of Justice against the Plurinational State of Bolivia, regarding the dispute over
the Status and Use of the Waters of Silala (Chile vs. Bolivia), with a deadline
for the presentation of the Counter-Memorial of the Plurinational State of Bolivia.
In this framework, the Government of the Plurinational State of Bolivia, by
means of Supreme Decree N° 3131 of 29 March 2017, determined the merger
of the Strategic Office for the Maritime Claim (DIREMAR) with the Strategic
Office for the Defense of the Springs of Silala and all the Water
Resources on the Border with the Republic of Chile (DIRESILALA), establishing
the Strategic Office for the Maritime Claim, Silala and International Water
Resources, maintaining the institutional acronym DIREMAR.
With the purpose of structuring the technical procedural defense of the waters
of the Silala Springs, and in order to know the characteristics of the constructed
infrastructure that caused an impact on the water flows that emerged naturally
from the springs, as well as the hydraulic efficiency intentionally increased to
abstract more water volume, it has been deemed necessary to carry out hydraulic
technical studies already mentioned above, therefore, the Strategic Office
for the Maritime Claim, Silala and International Water Resources, within the
framework of its competences, has entrusted the Institute of Hydraulics and
Hydrology (IHH), dependent on the Higher University of San Andres (UMSA),
the elaboration of the “STUDY OF THE CHARACTERIZATION AND EFFICIENCY
OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN
THE SILALA SECTOR.”
1
138
1.2 OBJECTIVE
The general objective of the consultancy work is:
Carry out a technical study of the characterization and ef
ficiency of the hydraulic works built and installed in the
Silala Springs area.
1.3 STRUCTURE OF THE REPORT
The report is composed of the following chapters:
1. Documentation review and technical analysis report. The chapter makes a
description of the previous documents that are related to the hydraulic
works built in the Silala springs area.
2. Natural conditions. It shows the characteristics of possible water movement
within the existing bodies of water, in their natural conditions, before
being intervened.
3. Registration and description of the materials used. It includes the description
of the field works carried out for the survey of the hydraulic works and
other infrastructure built.
4. Quantification of the hydraulic works that are in the Silala. It refers to the
quantification of the interventions carried out.
5. Detailed physical characterization of all hydraulic works (length, surface
area, sections, diameters, gradients, and others).
6. Description and classification of the water intakes built in the springs.
7. Detailed physical characterization of the sections without canalization
(lengths, surfaces, sections, diameters, slopes and others).
8. Evaluation of sediment transport that occurs in the sector.
9. Simulation of the hydrodynamic behavior of the flows in the main canal
network through the mathematical model HEC- GeoRAS (Hydrologic Engineering
Center, 2011) in the current conditions.
10. Conclusions.
1.4 LOCATION
The Silala waters are located in the Quetena Chico Canton, of the Municipality
of San Pablo de Lipez (Figure 1); it is part of the South Lipez Province of
the Department of Potosi. The bodies of water are classified according to their
location as follows:
• Northern reach where the North Bofedal is located.
• Southern reach that is composed of the South Bofedal.
• Reach of confluence and exit to the Bolivia–Chile border.
2
139
The use of the previous name corresponds to the conditions of water movement
depending on the existing hydraulic works and their operating characteristics.
1.5 METHODOLOGY
The investigation consists in a detailed examination of the field and analysis
of the available bibliographic information, both the one that was already published
in past years and the one documented in other international publications
that date back to when the Silala Springs were intervened. All the related documents
are referred to in the bibliography presented herewith.
Through field inspections and information gathering in situ, the IHH-UMSA
has carried out an inventory of the hydraulic works [of Silala] at a geographical,
topographic, documental, and hydraulic scientific-technical level in order
to detail and describe the functioning of the hydraulic works installed in the
Silala Springs and their effects.
The analysis of data, research and conclusions to which this document has arrived
are supported by a technical inspection works completed in the field. It
should be noted that earlier works have also been completed, i.e. hydrometric
measurements performed by the National Service of Meteorology and Hydrology
of Bolivia (SENAMHI), as well as by the Military Geographic Institute of
Bolivia (IGM, 2016) and the topographic studies and canal surveys carried out
by the CB Engineering and Construction Technical Consultancy Company in
2018.
The data obtained in the field has been processed and incorporated in a hydraulic
simulation to determine the hydrodynamic conditions of the canal flows.
3
140
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CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA SECTOR
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141
2 DOCUMENT REVIEW AND ANALYSIS REPORT
2.1 CONCESSION FOR THE EXECUTION OF HYDRAULIC WORKS
2.1.1 Fox Report (1922)
One of the documents where a description of the first actions carried out on
the bodies of water of the Silala is made corresponds to Fox (1922). In this
document, reference is made to the fact that “there are four sources of supply
from which the company has the right to take water”, below, reference is made
to a “Siloli Stream” located at 14,154 feet above sea level, which corresponds to
a height of 4,314 meters above sea level, that is, above the binational limit that
is 4,306 meters above sea level. The company to which the document refers is
The Antofagasta (Chili) and Bolivia Railway Company Limited.
In relation to the description made by Fox (1922) the following observations
can be made:
•The document refers to a “Siloli Stream”. In this regard it should be noted
that according to the International Hydrological Glossary (WMO, 2012),
“Stream” means a water current and has four meanings:
1) Mass of water flowing in a natural canal (channel).
2) Water flowing through an open or closed pipeline.
3) Water jet that flows from a hole.
4) Groundwater mass flowing in a karstic formation.
Thus, the description that is given to the Silala water body in the Fox document
is “stream”, a word that does not correspond to the physical process of water
movement developed in the water bodies of Silala, because in its natural
state there was no natural canal (natural channel), but the movement of
water developed in its natural state, as indicated later, in an interaction
between water, soil and biotope.
•In the Fox document reference is made to the other possible sources for the
company: “San Pedro River”, “Palpana Springs” and “Polapi Springs”. In
first instance, the San Pedro River description is clearly differentiated from
the Silala stream concept, because the Silala is not qualified as a river, but
as a current, although in fact the Silala water body does not fit within the
definition of current (stream).
It should be clarified that the WMO document (No. 385) defines the term
“river” as a “large water stream that drains a basin in a natural way”,
throughout Fox’s document no reference is made or, the category of “river”
is not given to the bodies of water of the Silala [sic]. Additionally, the term
“spring”, according to the WMO, is a “Place where water emerges naturally
from a rock or the ground and flows towards the surface or towards a
mass of surface water,” which reflects that the characteristics of the Silala
waterbodies, owing to their condition as springs, in terms of its origin.
5
142
•Fox indicates that in the Siloli a small dam was built crossing the current
and that it generates a daily flow (with very small variations) of 11,300 cubic
meters. In this regard it is necessary to make the following assessments:
■ There is no evidence in Bolivian territory about the existence of a small dam,
although later the author indicates that this work would be the “abstraction
work” (intake), which would have the highest altitude in the world, therefore
the water intake work that currently exists in Bolivian territory corresponds
to the work described by Fox. Similarly, Fox (1922) indicates that in order to
provide good quality water, a water conveyance pipeline was implemented
in the year 1900 in several distant springs located in the Andes Mountain
Range.
■ It is indicated that the flow has “very small variations.” In this regard it
is pertinent to note that “conventional” river basins that react to a certain
precipitation have significant flow variations, in the dry season the water flow
rates are low while in the rainy season flows are high, typical regime of a river
(which responds to the rainfall- runoff relation in a basin). By indicating that
there are “very small variations” in flow, the recognition of the characteristics
of the water is demonstrated, in the sense that the contribution of the Silala
body of water comes from the upwelling of groundwater manifested through
the contribution of the springs, a flow that shows “very small variations,”
namely, said flow is practically constant throughout the year. This assertion
corroborates the fact that the waters of Silala do not respond to a rainfall –
runoff relation in its basin (precipitation that does not give rise to runoff).
2.2 SPRINGS ABSTRACTION AND CHANNELING WORKS
Around 1928, specifically through Note N° 143 of 27 January 1928, the
construction of the abstraction and channeling works from the springs has been
proposed, this is the result of a request sent by the company The Antofagasta
(Chili) & Bolivia Railway Company Ltd. (1928), where the order N° 1441 is
made known, where it is indicated the need to execute the construction of open
canals from the springs of Siloli (The Antofagasta (Chili) & Bolivia Railway
Company Ltd.,1928.
In this document, the first possibility of implementing ground canals from
the upper springs to the already existing water intake works is proposed. The
second possibility is also proposed for the construction of concrete canals
instead of earth canals, although it is indicated that, as necessary, the earth
canals will be preliminary tasks to the construction of concrete canals. In the
facts concrete canals were not built; the earth canals were either left in place of
at most protected with joined stonework to drain the bofedals.
The main argument to intervene with canals in the bofedales
is based on the water quality, although in the document it is
considered as a “small difficulty” (little difficulty) of the source
6
143
in relation to the need to have a high level of water purity, this situation is justified
in the fact of “having found fly eggs” under microscopic examination.
Regarding the document presented by The Antofagasta (Chili) & Bolivia Railway
Company Ltd., the following considerations are made:
■It’s surprising that the arguments raised for the execution of the works in the
bofedales have relation with aspects related to the quality of water, that is,
with sanitary aspects, a situation that calls into question the fulfillment of
the concession granted by the Department of Potosi, whose objective was
to provide water for the “provision or supply for railroad machines”. If it is
indicated that the quality standards of the source are not desirable, it follows
that the water resources of the Silala have been expressly used in the provision
of water for human consumption.
■The document indicates “that for some time a small difficulty has been found
to keep the water from this source within a high level of purity,” in the document
it is recognized that the problem posed constitutes a “small difficulty”
since a situation described in this way is easily solved by subjecting the
water to a disinfection process, this way the pathogens are eliminated, in
this case the fly eggs; however, the substantive issue is that the central argument
that is posed to intervene in the bofedales does not explicitly manifest
it, which is to improve the efficiency of abstraction by increasing the flow,
and not so the arguments that are related to the improvement of the water
quality.
7
144
3 NATURAL CONDITIONS
3.1 WATER BODIES OF SILALA
3.1.1 Bofedals
The Quaternary deposits on the Silala constitute the physical scenario for the
formation of bofedales. The mapping performed by SERGEOMIN (2017) –
see Figure 2– distinguishes exogenous geological agents, mainly glacial, wind,
gravitational processes to a lesser degree fluvial processes in addition to weathering;
especially physical and erosion, distinguishing geo-forms of accumulation
and erosion. The glacial activity, together with the volcanic activity and
weathering, are those that modeled the current geo-morphological structures of
the region.
The water supply to the Silala bofedales originates in the upwelling of water from
fractured rocks. This is the case of the geological formations in the zone, such as
the Silala Ignimbrite 1 (Nls1), Silala Ignimbrite 2 (Nls2) and Silala Ignimbrite 3
(Nl3), the variation of the flow with respect to distance is shown in a later chapter, a
situation that shows that the underground contribution develops along the bofedals.
The analysis of the water movement through the bofedales in its natural state
is done considering the body of water as a unit: water–soil–biotope (see
Figure 3). There is a “physical–biological synapse” between these elements;
there is a “link between them.” It is evident that the biotope includes the
other two categories that are water and soil; however, it is intended to
link water and soil as elements that act on the eco-zone or eco-region.
The bofedales are High Andean Wetlands (HAA), they belong to a type of
ecosystem that is characterized by its perennial vegetation within the
semi-arid landscape of the Western Andes; they play an important role in the
provision and regulation of water in the basin (Eco-hydrological characterization
of high Andean wetlands using multi-temporal satellite images at the head of
8
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~ Oep Coluvial Can10s y bloques
~ Oep Fluveo glacial Grava s. arenas y arc,Uas
~ Oep Mo1Tenas Bloques. cantos. graves y arcillas
Figure 2. Quatemary deposits (SERGEOMIN , 2017).
145
the Santa river basin, Ancash, Peru, 2015). The Silala bofedales are bodies of
perennial water, they are fed by groundwater.
According to the Ramsar Convention
(2016), wetlands, in general,
are “extensions of marshes,
swamps and peatlands, or surfaces
covered with water, whether
natural or artificial, permanent
or temporary, stagnant or running,
sweet, brackish or salty.”
Wetlands are “areas where water
is the main factor controlling the
environment and the plant and
animal life associated with it.
Wetlands occur where the water
table is on or near the earth’s surface
or where the land is covered
by shallow water.”
The term bofedal is very typical of Bolivia, Chile and Peru; it is used to characterize
a wetland zone under natural grassland conditions, where there is a type
of natural vegetation always green and succulent with high forage potential. The
soil is permanently wet (saturated). Its name comes from the word “bofe” or soft
organic material that makes it up. They are fragile water systems.
3.1.2 Characteristics of the Silala bofedales
The main characteristics of the Silala bofedales are described below:
• The bofedales are fully related to the springs. The bofedales and springs are
related by groundwater mechanisms (see Figure 4). The source of water is entirely
underground, along the supply basin there is no trace of possible surface
runoff, caused by precipitation.
The field studies support the absence of surface runoff caused by precipitation.
A complete tour of the basin allows distinguishing that there are no traces of
surface water movement; there is no evidence of surface laminar flow, as can
be seen in the photographs presented in Figure 5.
9
.. AGUA .~
r "
, I, "
SUELO ~ .. BIOTOPO ~ ,.
Figure 3. Body of water as a unit.
b)
Figure 4 . undergrcund origin of the sllala waters, a) North Bofedal, b) south Bofedal.
146
■ The vegetation cover is permanent. Because bofedales have water in both
the dry season and the wet season, the vegetation of these natural reservoirs
is always green. The existence of high mountain peat is generally distinguished.
According to DIREMAR (2017), the bofedales of Silala (North and South)
have been formed in flat lands, in the bottoms of valleys, where its vegetation
contrasts markedly with that of its surroundings due to the lack of
humidity or because it is deeper. Coverage that is mainly controlled by the
amount and availability of water during the year, since they are considered
high altitude wetlands, giving rise to the so-called high Andean peatlands
or peatlands with evergreen vegetation, associated with a permanent water
supply, predominantly groundwater (see Figure 6).
The vegetation cover observed in the South Bofedal is characterized by vegetation
characteristic of bofedales such as Distichia sp, Andean Oxychloe
and/or Plantago tubulosa in some places, since there are areas with a lower
degree of humidity, there are also low-lying species with predominance of
Plantago sp, Gentiana sp, and others that inhabit bofedales without submersion
and superficial water table (DIREMAR, 2017).
10
Figure 4. Underground origin of the Si la la waters, a) North Bofedal, b) South Bofedal.
a) Slope in the upper zone of North Bofedal. b) Slope in the middle zone of the North Bofedal.
Figure 5. Evidence on the absence of traces of surface runoff.
147
The reach of confluence of the North and South Bofedal, although it is of
greater slope than in the high part, it is distinguished by the presence of peat
that has developed under natural conditions (see Figure 7a), but that due to
the effect of the developed actions, abstraction intake and water conveyance
canals, has originated the predominance of “intrusive” species as is the case
of the grasslands. The construction of the access roads has also markedly
modified the bofedals’ original nature (see Figure 7b).
■ Saturated floors. It is observed that both in the North and in the South
Bofedal, the soils are fully saturated.
North Bofedal. From the profiles studied by DIREMAR (2017) at the North
Bofedal, the depth of the soils varies between 0.55 and 1.4 of depth; below this
depth there is parental material, where the water table reaches depths between
0.4 and 0.1 meter. In terms of texture, the soils are sandy-loamy and loamysandy.
In general, the texture shows a predominance of sand with an average
11
a) b)
Figure 6. Vegetation cover, a) North Bofedal, b) South Bofedal
a) b)
Figure 7. Confluence reach, a) p resence of p eat, b) access road.
148
of 90%, 6% silt and 4% clay. The organic matter has a depth that varies
between 30 and 48 cm, in some cases up to 80 cm. The sand develops from
0.4 to approximately 1.0 meter.
South Bofedal. In the Bofedal Sur, the depth of the bofedal varies between
0.40 to 1.20 meters deep; underneath there is parental material. The organic
layer varies between 0.13 to 0.24 meters, where the water table is between
0.45 to 0.15 meters. In terms of texture there is a greater presence of sand
and less amount of sandy-loamy soil. In percentage terms, there is an average
of 91% sand, 5% silt and 3% clay.
It is distinguished that the North Bofedal has more organic matter than the
South Bofedal; the latter has a mostly sandy texture. The saturation of the
North Bofedal reaches 100% while in the South Bofedal it reaches 76%.
■ They regulate the water system. From the hydrological point of view and
the water regime, bofedales are classified as hydromorphic or udic, because
they contain water permanently.
Under natural conditions, the regulation of the water regime is developed in
the following areas:
■ It receives water contributions from springs.
■ It keeps the soil saturated.
■ It generates a storage process.
■ Water evaporates and evapotranspires according to weather
patterns, especially temperature.
■ Delivers water to an organic medium.
■ Delivers water slowly.
The North and South Bofedales of Silala receive water contributions from
springs, as shown schematically in Figure 8. There is no contribution of surface
water derived from rainfall; the latter is demonstrated by the measured flows,
which demonstrate the variability of its annual regime, a situation that is shown
in the next chapter.
12
Origen
mananbales
arenoso
Materia organica
T urberas
Escurrim iento
l.4edio saturado
Figure 8. Cross-sectional schematic of the Silala bofedal
Coluvio
149
The soils that make up the bofedales are saturated; the water tables are practically
located at the surface level (see Figure 8). As a result of the drainage
interventions carried out on the water bodies, part of the coverage area of
the bofedales gradually lost its natural condition, giving place to unhealthy
bofedales (see Figure 9) and allowing the invasion of species that do not require
saturated soils, as in the case of grasslands.
Associated to the water storage process of the bofedals are other processes that
occur between the soil – atmosphere interface, such as evaporation and evapotranspiration
of these waterbodies, whose mechanisms are linked to meteorological
conditions and present organic matter. In any case, it is possible to note
that due to the effect of low temperatures, surface water freezes.
The water coming from aquifers wells up at the points identified as springs and
is integrated into the porous and organic bofedal medium, generating a close
interaction between water, soil and biotope.
As a result of the geophysical studies carried out in the zone corresponding to
the North Bofedal, plenty of underground water has been identified, arranged
in the fractures of the ignimbrites. In the lower part of the valley we can see
strongly fractured and jointed rocks, in whose secondary porosity we find water
(Sangueza, 2016), which emerges to the surface by pressure difference.
In the South Bofedal it is shown that the waters that emerge come from low
depths. According to Sangueza (2016), the bofedal lost its natural storage capacity
as a result of the works implemented.
13
Hydroperiod
Tempora ry
Ephemeral
Vernal
Summer Wet
Winter Wet
Summer Dry
Autumnal
Aestival
Semipermanent
SP Aestival
Permanent
Perm. Aestival
Tidal
I I I I I I
I
I
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I '
I
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111111,, """',,,["""" """"" " '
I I I f
J FM A M J J A SON0 JFMAMJJ ASOND
Figure 9. Si'a1a bofeda1 category according to the water period (Jackson, et. aL 2014)
150
3.1.3 Movement of water in the bofedales
3.1.3.1 Darcy flow
The water movement conditions in the bofedales are governed by gravity,
both in the porous medium and on the surface. The movement in the porous
medium develops between the inter-granular spaces, while surface movement
is generally subdivided into small courses in a disperse and non-concentrated
movement.
The conditions of water movement in a porous medium –generally for
unsaturated and unconfined flow– are considered from the forces of gravity,
friction and suction, the latter corresponds to the force that joins water with
soil particles through surface tension. When the inter-granular spaces are filled
with water the suction force is reduced. In a saturated medium, however, it
practically disappears.
The movement of water in the porous medium can be represented by Darcy’s
Law:
In natural conditions, the flow of the Silala waterbodies develops in a saturated
medium; the suction load ψ is thus nil and the runoff velocity depends on the
permeability tensor and the hydraulic gradient.
The permeability tensor k=k(x,y,z) can vary in different directions. However,
in the case of the Silala bofedales, they are limited by the parental material. In
consequence, there is a predominance of permeability in terms of development
of the bofedal along the valley.
If a global analysis of the movement of water in the North and South Bofedales
is made, it is noticed that the hydraulic gradient is practically the slope of the
terrain, because the medium is saturated.
According to the results of the soil study (DIREMAR, 2017), the permeability
and porosity in the North Bofedal have values of 2.6 × 10-7 cm/s and a porosity
of 0.47, while in the South Bofedal there is an average permeability of 1.15
× 10-7 cm/s and an average porosity of 0.46. The flow velocity or referential
Darcy’s flow for the North Bofedal will be of 2.32 x 10-9 cm/s and the linear
velocity will be of 4.95 × 10-9 cm/s. The referential flow velocity for the South
Bofedal will be 6.54 × 10-9 cm/s, while the linear velocity will be of 1.42 × 10-8
cm/s.
At the referential velocities shown above, the effect of the organic material
acting on the inter-granular spaces is added, causing even greater interferences
to the movement.
14
Where:
dH
v = k(i/J ) -
dL
v is the velocity of water in the medium
k(i/J) is a permeability tensor that generally depends on the suction load 1/J.
dH / dL is the hydraulic gradient.
151
3.1.3.2 Non-concentrated surface flow
In general, the bofedales with intermittent regime, that is to say temporary, the
flow of water is defined by two scenarios. During rainy season, the precipitation
generates a surplus that floods the wetlands and that allows the water levels
to be high enough to overcome the terrain’s rugosity and cause the water to find
“small channels” where it can move due to gravity towards lower areas, generating
a network of several stream branches on the surface of the bofedal. Under
these conditions and depending on the magnitude of the excess precipitation,
runoff can even cause localized erosion processes, allowing the transport of
sediments.
The process of surface runoff described above is opposed to the movement of
water in the Silala bofedales, for two specific reasons:
- The precipitation that falls in the Silala contribution basin does not generate
an effective precipitation that could cause runoff.
- The precipitation is solid, so that when covering the surface, it has two possibilities:
on the one hand, it sublimates, thaws and infiltrates; the precipitation
in a liquid state does not manage to generate runoff.
By virtue of what has been described, the Silala bofedales do not receive any
surface runoff from rainfall. Therefore, there is no physical process that might
form or reach water levels that have the capacity to create a defined channel or
drainage network. In contrast, the flow develops as a scattered sheet (Jackson,
et. al. 2014) in an environment where micro-topography plays a very important
role, as defined by the irregular growth of peat and vegetation.
Under natural conditions, where the area of the bofedales was larger than the
current surface area, the flow on the surface was developed in a “disperse,
non-concentrated” manner in directions defined by the growth of the surface
vegetal mass, particularly peat; thus, in the facts there was no predominant
channel1, defined as such, but diffuse movements with components of velocity
in different directions.
3.2 GROUNDWATER SOURCES – SPRINGS
The inventory of springs made by SENAMHI and DIREMAR (2018) and the
geophysical study using resistive electrical tomography – ERT, carried out
by COFADENA (2017), show that the source of the water fed by the Silala
bofedales are the springs that emerge along the entire length of the waterbody.
The SENAMHI has identified 138 springs—differentiated in three categories
based on their inflows (See table 1) (between major and minor)—that emerge
mainly in the South Bofedal and North Bofedal; the springs listed correspond
to the most important in terms of contribution and in relation to the abstraction
and canalization works developed.The survey of the springs
1 According to the International Glossary of Hydrology (WMO, 2012) a channel is defined as:
1) Clearly defined water course through which water flows periodically or continuously.
2) Water course that connects two bodies of water.
3) Deepest part of a watercourse through which the main current flows.
15
152
carried out by the SENAMHI ends at the confluence between the south and
north branches with the most important springs.
In the South Bofedal (Figure 10), in the upper part, 49 springs of higher contribution
have been recorded (see Table 2); the average slope of the terrain is
0.9%. It can be indicated that the bofedal is the flattest in terms of slope; it is
the farthest body of water in relation to the border.
From the upper part of the South Bofedal and the confluence with the South
Bofedal (Figure 10), 10 important springs have been recorded. see Table 2.
16
153
In accordance with hydrometeorological measurements completed SENAMHI-
DIREMAR (2018), 45 springs of higher contribution have been recorded in
the upper part, in the North Bofedal (see Table 2), with a slope of 5.7%.
The bofedales located in the Silala Springs area are hydro-geologically interconnected
to adjacent masses of groundwater, although this degree of interaction
varies from one bofedal to another. In other words, both Bofedales (North
and South) are completely dependent on the water transfer mechanism and the
type of upwelling of groundwater in any climatic condition.
17
CATEGORY
1
2
3
Total
Figure 10. Springs recorded in the South Bofedal (Campos Barron- DIREMAR, 2018)
NO.
21
80
37
138
Table 1. General detail of the Silala Springs
(SENAMHI - DIREMAR, 2018)
SI LALA SPRINGS
DESCRIPTION
With greater surface inflows (measurable with micro-propeller).
With minor surface inflows (not measurable with micro-propeller).
With sub-superficial and perceptible flows due to the soil wetting.
154
18
Figure 11. Springs recorded in the North Bofedal (Campos Barron - DIREMAR, 2018)
Table 2. Category of the springs in the South and North Springs (SENAMHI-DIREMAR, 2018)
RAVINE 1sT 2ND 3RD No.
CATEGORY CATEGORY CATEGORY
South 10 39 12 61
North 11 34 32 77
155
4 FLOW REGIME
The estimated monthly flow values for all the water control points (Figure 12)
indicate that the hydrological regime of the basin does not have marked variations
in the months and seasons of the year. The first results of the flow analysis
in the gauging stations, indicate that there is no clearly differentiated seasonal
behavior during the year, therefore, a hydrological regime of the fluvial type
cannot be defined for this basin; although there is a discharge towards the Chilean
border and even when the flow is through an artificial canal. The hydrological
regime shown has similar characteristics to the production of an aquifer.
The flow monitoring in the sector of the Silala Springs area was carried out by
the SENAMHI, for which continuous gauging measurements were performed,
denominated with the acronym C, and simultaneous gauges, symbolized with
the letter S. In both cases the numbering is progressive towards the border.
4.1 Flows in the South Bofedal
The spatial variation of the flow of the South Bofedal in the Silala generally
has a growing pattern according to the length and the development of the topographic
differences, which goes from the gauging station in the triangular weir
C1 until C5, see Figure 12.
19
160
140
120
i
""O>
~
~ 80
.,!.
.;
'0 " 60
l3
40
20
0
SERIES DE CAUDAL ES MENSUALES (l/ltros/segundo) • Estaclones de Aloro ConUnuo y Slmultaneo C1 a C7
Perlodo de ani lisls: Mayo 2017 a Marzo 2018
Estaci6n de control hidrico C7 - Tramo de confluencia Bofedal Sur y Norte
i Esta: 6n de c4iir hid ric: C6 - Bofe~al Norte ~ :::t------" 4--
•
AGOSTO SEPTIEMBRE OCTUBRE NOVIEMBRE 01CIEMBRE ENERO FEBRERO
C1 C2 C3 C4 C5 C6 C7 Series8 Series9 Series10
-+- ~ --- --- --0- ~ ~ ~
-0
•
MA~
Figure 12. Mont hly Flow Series (1/s) -Cl to C7 Gauging Stat ions. Source: Own elaboration with data from SENAMHIDIREMAR
(2018).
156
In station C1 (Figure 13), flows are recorded from springs of the upper part
of the South Bofedal. From this control point, little increase of the flow is
observed up to the control point S-7, because in the reach there are few contributing
springs. From this control point the flow increases significantly until
reaching control point S-10, because there is a greater concentration of springs.
20
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Figure 13. Spatial variation of the flow in the South Bofedal (for the May 2017 to March 2018 period). Source: Own
elaboration based on data from SENAMHI, DIREMAR, (SENAMHI-DIREMAR, 2018).
157
4.2 Flows in the North Bofedal
The spatial variation of the flow of the North Bofedal in the Silala generally
has an increasing pattern according to the length and the development of the
topographic differences, which goes from the control point S-18 to C6, see
Figure 14.
At the control point S-18 flows are recorded from the springs in the sector.
From this control point, a gradual increase in flow is observed until reaching
station C6, because in the section there is a greater concentration of springs
which are drained to the North Bofedal canal.
21
VARIACION E.BPACSAL DEL CAI.JOU. EN EL BOFEDU. ■ORTE
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Figure 14. Spatial variation of the flow in the North Bofedal. Source: Own elaboration based on data from SENAMHIDIREMAR
(2018).
158
4.3 Confluence Reach of the South and North Bofedal
In the confluence section there is a low increase in flow from control station
C7 to S-19. From this point the flow remains almost constant up to point S-21,
because in this reach there are no springs that increase the flow.
Although there is a discharge of flows through a canal, it must be taken into
account that there are no significant flows in the confluence reach, since the
variation of flows in the last control points (gauging stations) remain almost
constant (see Figure 15).
22
1:2 500
220
200
180
!'
~ 160
~ 140
13 120
100
80
VARIACION ESPACIAL DEL CAUDAL EN EL TRAMO DE CONFLUECIA BOFEDAL SUR Y NORTE
SERES DE CAUDAL.ES MENSUALES(l/ seg) TRAMO DE OONFWENGA BOFE~ LSURY BOFEDAL NORTE
~ riododea'1alisis : Mayo 2017 a Marzo2018
S-20 S-21
REFERENCIAS
S .AFCPDSOONTIM.OSSEtWAHI
W 1-FCROS SIM Ll.TAt-EOS SENAUH I
0- SEWI.UHI_.Af"aIDS_HISTCRICOS
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PIE20M.ETROS_POZCS2018 IIAAGENPL8ADES 50an
CAI04_0E_AGUA
- LIMITE INTERWI.CIONAL
BASES GPS IGM
RGS c:::l
Figure 15. Spatial variation of the flow in the North Bofedal. Source: Own elaboration based on data from SENAMHI-DIREMAR
(2018)
159
23
IIOFEDAI. SUR · CAlllALES MEDIO MENSUALES (1/s) -Estaclones de Alon> Smlulaneo -l'ef1odo deAnilsls Mayo 2017 a Marzo 2013
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Figura 16. series de caudates Medlo Mensuates (1/s) - Estaclones Stmultaneas - Botedal Sur. Fuente: Propla con datos de SENAMHI-DIREMAR (2018).
C-1
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Figure 17. Average Monthly Flow Series (1/s) -Simultaneous Stations-North Bofedal. (Source: Own elaboration based on data from SENAMHI-DIREMAR (2018)
161
25
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TRAMO DE CONFLUENCIA • CAUDALES MEDIO MENSUALES (Useg) • Estacion es deAforo Continuo y Simultaneo C1 a C7 •
Periodo deAnalsis Mayo 2017 a Marzo2018
~~ --
...; -
C-7
Estaclones de control hidrtco continuo de C7 - Tramo de Confluencia
Estaclones de control hidr·tco simult.ineo de S- 19 a S.-2 0 - Tramo de Confluencla
S-19 S-21 S-20
- MAYO - JU'l.1O - JULIO - AGOSTO - s EPTIEMBRE - ocTUBRE - NOVIEMBRE - O1c 1EMBRE - EtERO _..... FEBRERO ---MARZO
C-7 5.19 S-21 S-20
MAYO 132.66 189.60 163.13 176.19
JUNIO 125.00 154.45 152.00 152.07
JULIO 144.34 148.35 173.25 175.40
AGOSTO 139.30 152.05 141.55 152.95
SEPTIEMBRE 134.25 155.05 157.10 14130
OCTUBRE 128.55 133.00 153.70 152.55
NOVIEMBRE 118.23 152.85 152.50 155.10
DIClEM8RE 137.70 147.90 152.20 164.90
ENERO 133.35
FEBRERO 138.20 157.15 153.90 15(1.35
MAR2O 135.82 145.80 145.30 151.68
CAUDAL MEDIO MEN.SUAL(l/s) 134.31 153.62 154.46 157.25
Figura 18. Caudales Medio Mensuales (1/s) · Estaciones Simultaneas - Tramo de Contluencia. Fuente: Propia con datos de SENAMHI-DIREMAR (2018)
162
26
--DE UBICACION PUNTOS DE CONTROL HiDRICO AFORO CONTINUO EN LOS aANAIITIALES DEL SIL.ALA
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Figure 19. Map of the Location of Hydraulics Control Points of Continuous Gauging in the Springs of Silala. (Source: Own elaboration
based on data from SENAMHI-DIREMAR (2018)
163
27
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Figure 20. Map of the Location of Hydraulics Control Points of Simu ltaneous Gauging in the Springs of Silala. (Source: Own elaboration based
on data from SENAMHI-DIREMAR (2018}}
164
28
--DE lRIICACION DE LOS IIANAIITIALES DEL SILALA
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Figure 21. Location Map of the Silala Springs. (Source: Own elaboration based on data from SENAMHI-DIREMAR (2018)).
165
5 PHYSICAL CHARACTERIZATION OF HYDRAULIC WORKS.
5.1 GENERAL ASPECTS
In order to characterize the hydraulic works, the main aspects of the existing
canals in the region of the Silala springs are detailed, such as their size, shape
and the function that they fulfill in the hydraulic system. As a first approximation
they are classified as:
• Main canals and
• Secondary canals.
The description of the works presented below is based on the geographical
location in the area, for which they are classified in:
• Works of the South Bofedal.
• Works of the North Bofedal.
• Works of the Confluence Reach.
In turn, in accordance with the previous classification, the description of the
works includes:
• Materials employed.
• Geometric characteristics of the canal network.
Regarding the type of material used in the interventions, four categories can be
defined:
• Canals without coating excavated in natural soil.
• Canals with dry masonry coating2 (rock coating without binder).
• Canals with stone masonry coating (rock coating with mortar).
• Canals in rock.
The base map showing the sites where the detailed description was made are
shown in Figure 22. From site 1 to site 26 they correspond to the South Bofedal,
from site 27 to site 43 to the North Bofedal and in the confluence reach there
are sites 44 to 45.
2.It is understood by dry masonry to the ordered arrangement of stones arranged without
binding elements, such as mortar, lime or cement.
29
166
30
-
......
0 0 . 125 0.25 o.s -----===== Km
1.7.500
N
w
s
E'-"'~OEt~OW
Al'ISt'AGAr'OS C '°°1
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UIIICACION DI! SITIOS Dl!SCRITOS l!N LOS MANANTIALl!S Dl!L SILALA
ClfOO
..,.,.
~ lhh
7
,...,.
Leyenda
s«ios
VIAS
- DRENAJE
-~ ~ BOFEDAL
EDIFICACIONES
-
-
- LIMITE INTERNACIONAL
Figure 22. Arrangement of the canal network of the Silala Springs.
- UMITE oe 80FEOALES. RED
DE DRENAJE V CANALES
BOFEOAL SUR Y NORTE
..,..,
COlfTEXTO GLOSAL.
....,.
i
I
...,,.
167
The methodological process used in the evaluation of the works, includes:
• Topographic survey in detail of the location of the canals.
• Survey of the geometry of the canals.
• The detailed description of the materials used in the canals.
• Geometric and hydraulic layout of the canals.
The description that follows sets out in detail the hydraulic works along the
canals of the South and North Bofedals and the confluence reach. The detailed
measurements of the geometric configuration of the canals have been taken and
there is a quantification of the longitudes of each type.
5.2 WORKS IN THE SOUTH BOFEDAL
5.2.1 DETAILED DESCRIPTION
Site 1: The water springs of this area are located in the upper area of the South
Bofedal (see Figure 22), located geographically at 4,414 meters above sea level,
E 603130 m and N 7565881 m (UTM System WGS1984). In this site the
protection of these water springs is perceived, the work consists of an old small
dam approximately 10 meters long, 0.5-meter-high and 0.24-meter-wide, in
order to generate a small storage. The water abstraction work has a perimeter
fence formed by callapos and barbed wire, with the purpose of preventing the
entry of animals or people (see Figure 23).
The photographs in Figure 23 show the location of four springs with small
flows and constant flow (with an approximate total of 2 l/s). Freezing water
was not detected during the field visit (April, 2018). The dam comprises earlier
constructions (Figure 24a).
31
168
Site 2: Exit of the water intake work. Two artificially constructed canal branches
are observed (canals excavated in natural soil, bofedal peat), as seen in Figure
24a. In addition, it is appreciated that the zone of the springs and canals at
the exit were part of the bofedal (see Figure 24b), with irregular terrain and
presence of small gravels that are a product of a fluvial-glacial disintegration.
The orderly arrangement of the rocks shows that they were artificially placed as
dry masonry works, built after the excavation (Figure 24b), and for the purpose
of retaining water, with a maximum depth of 25 cm.
32
CHARACTIRIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTAUED IN THE SIIAIA SECTOR
a) Spring 1 b) Spring 2
c) Spring 3 d) Dam and spring 4
Figure 23. Springs 01 to 04.
169
Site 3: There is a PVC tube with a diameter of 4 inches, perforations of 1 cm
and spaced every 5 cm (Figure 25a). The water abstracted at this site is taken
to a small cement pond protected by two movable lids (Figure 25b). From this
point the water is channeled to the Silala Military Outpost of the Armed Forces
of Bolivia, destined for the human consumption of the military that live in said
place (with an approximate flow of 0.5 l/s).
Site 4: The chamber is built in stone lined masonry, with refined walls in good
condition. Its dimensions are: 1.35 x 1.35 meters in the ground and 0.24 meters
thick.In the upper part there
33
a) Dam and spring protected with rock b) Springs protected by a dam of old rocks and recen
masonry.
figure 24. Water retaining dam and springs at the headwaters of the South Bofedal.
a) Pipe to divert water to t he pond. b) Re-:ent small pond.
Figure 25. Water intakewor< and desiltation chambe·.
170
is a ventilation pipe (see Figure 25b). The area described is geographically
located at the coordinates E 603104 m, N 7565867 m, 4,411 meters above sea
level (UTM System WGS1984).
Downstream there are water streams that form natural grooves formed by typical
high Andean wetland (bofedales)3 contours, as shown in Figure 26b. However,
the bases of some natural canal reaches have been lined with stones (canal
soles).
Sediment transport: At a distance of 1 meter from the dam of streams 01 to
04, the bed is formed by rocks and heavy gravel. Generally, the bases of the canals
have sediments deposited where [sediment] transport at the bottom is not
visible; only particles characteristic of gravels and angular sand lay at the bottom
of the canal in a static way. For the initial reach, no particle movement can
be appreciated. The main characteristics of the canal contours are composed of
granular sediments and peat, see Figure 26.
Figure 26 a shows the right side of the canal shown in Figure 26b; in the upper
part of this canal, there are sandy sediments and a small canal that comes
from above (as shown in Figure 26c). In the high areas, it is possible to observe
traces of former springs that lack any vegetation; only loose sands are found
with scattered rocks and vegetation formed by straw and dry Yareta are visible.
Site 5: The photographs in Figure 27 show the sediments that lie in the bed of
the canal excavated at the exit of springs 01 to 04. There is also a poorly dispersed
granulometry well accommodated in the bed, however, under this bed
there is peat. The sediments found in the bed of the canals generally come from
the surrounding contour of the canal. In the field inspection of the place, it has
been evidenced that the flow of the water does not produce movement of
3 In the classification of the RAMSAR agreement, wetlands are of different types, being that a
bofedal is a high Andean wetland with special characteristics; they form peat soils with varying
thicknesses and slopes. In addition, the soil is mixed with gravel and sand resulting from the
fluvial-glacial abrasion.
34
a) Sediments of sand and
grave l.
b) Peat sediments and rocks lining
canals.
c) Groove and old bofedal without
wate r.
Figure 26. Sediments in the upper zone of southern sp..-ings and bofedales.
171
particles, not even the smaller diameter particles, which further corroborates
the fact that the flows are practically constant.
The water conveyance for the supply of water at the military outpost consists
of a 3-inch PVC pipe (Figure 28a); next, the pipe connects with a poly-tube of
the same diameter, and then it extends along one side of the artificial canals
(Figure 28b) until the water is discharged into a pool in the back part of the
military outpost.
Site 6: Downstream of the first four springs are others; the spring 06 (Figure
29a) joins the right branch that emanates from the small dam. On the
other hand, the spring 07 (Figure 29b) supplies less water and both are channeled
by small canals, covered by rocks, with traces and little defined sections,
in the form of ditches. The lining of the canals is deteriorated, both
in the bottom and in the walls, because they were manually removed at the
35
a) Artificial canal bed formed by sands and sma ll b) Artificial canal bed formed by angular gravels.
grave ls.
Figure 27. Bed covered with sediments formed by angular grave ls.
a) Interior of the masonry chamber with pipes and
gate valves.
b) Pipe that extends towards the military outpost and
passes by a side of the canal excavated by the bofedal.
Figure 28. Water conveyance chamber and pipe .
172
sides or because they have been turned obstructing the flow. Instead, other
rocks have been fractured by the repetitive changes in temperature. There is
no sediment transport or displacement, since the flows and slopes are very low.
Consequently, the efforts that the current generates on the bottom do not exceed
the capacity of resistance to the displacement of sediments.
Site 7: The junction of the main collector canals 01 to 07 occurs at the confluence
shown in the photograph of Figure 30a. In this photograph we can see a
construction of canals covered with rock and protected to avoid the collapse of
its walls.
Site 8: On this site there is a triangular weir (Figure 30b), which is entered by
two main canals excavated artificially, since in these canals almost vertical cuts
are observed in the walls; both its alignment and slope have a constant line,
without bifurcations, floods or overflows. This weir is geographically located
at the coordinates E 0603030 m, N 7565889 m, with an altitude of 4,412 meters
above sea level (UTM System WGS1984).
36
a) Collector canal of springs 01 to 06. b) Collector canal of spring 07.
Figure 29. Spring water conveyance canals.
a) Unio n of collector canals of springs01 to 07. b) Weir 1 in t he Sout h Bofedal.
Figure 30. Ancient artificial union of canals ard current outlet to measure the flow.
173
From the Weir 1 downwards a concentrated runoff can be distinguished in a
main canal, which has a wide section excavated in the soil type of the bofedal,
as shown in Figure 29 and in the following up to Figure 30b. The margins and
floors near the canal remain moist, with green areas and water streams with
vegetation. In contrast, those high areas of the margins of the bofedal, which
probably have reached humidity, were drained by artificial pipes. These drained
areas were dry and now sandy soils with brave straw predominate that occur
sporadically (see Figure 31). The sands are the product of disintegration due
to sudden changes in temperature, since there are no sediment displacement
processes.
The description made in the previous paragraph indicates that these sectors accumulated
water at some time, similar to a flooding or water-logging. However,
at present only small areas of bofedal are observed, as shown in Figure 32.
Site 9: In the upper part of the South Bofedal, several reaches of canals excavated
in natural soil without water flow were found (Figure 32a); their lines
are rectilinear and they are directed towards a larger main canal. These canals
could initially be useful to collect only the waters of the wetlands, since on the
south side of the same bofedal there are no springs on the surface.
Site 10: On the right flank of the middle part of the South Bofedal there are
large wetlands, and on the left flank no water is visible (Figure 32b), although
in some sections there are very dry soils, containing paja brava (Stipa ichu – tall
Altiplano grass) (see Figure 32).
Site 11: Weir 2 is located in this place, whose coordinates are E 602792 m, N
7565804 m, altitude 4,440 (UTM System WGS1984). These hydraulic structures
were installed since August of 2017; they have the purpose of measuring
the flows in the installed points. Therefore, at this point the waters of a large
part of the upper South Bofedal converge and before following the flow to the
intermediate bofedal area, it narrows and in this sector the flows of the springs
01 to 20 are measured; and what is collected from the bofedales along the collecting
canals (Figure 34b), although in some reaches they are dry and in their
place there is paja brava (Stipa ichu) (see Figure 32).
37
a) Natural sector of the South Bofedal, seen upwards. b) Natural sector of the South Bofedal, seen
dow nwards.
Figure 31. South Bofedal after the extraction of water through drainage actions.
174
Site 12: Here we have a water storage tank (see Figure 33), it is located at
coordinates E 602752 m and N 7565797 m (UTM System WGS1984). The
photograph shows a provision of the water conveyance pipe that feeds this deposit
that was recently built in order to provide water to ten houses (at present,
said storage tank is not in operation because there are no inhabitants occupying
the aforementioned houses). The configuration of the terrain shows that it was
flooded with water and/or snow, and currently a completely dry bofedal is observed.
See the left flank of Figure 33.
Site 13: downstream from the triangular weir No. 2, a native bofedal species
was found. See Figure 34.
38
CHARACTERIZATION AND EFFIOENCY OF THE HYDRAULIC WORKS BUILT AND INSTAlllD IN THE SIIAIA SECTOR
a) M argin o f the South Bofedal without
vegetation.
b) Natural sector of t he South Bofedal w it hout
w ater with a view towards t he southwest. I
Figur-e 32. Dry sectors in the South Bofedal.
Figure 33. Storage tank.
175
Site 14: In this sector there is an appreciable decrease of the South Bofedal,
since the ground narrows in a rocky formation and there is an increase in the
slope, as seen in the chapter on hydraulic modeling. Between the slopes there
is an approximate space of 20 meters; the left slope has rock formation and the
other has sand that covers the total surface. Subsequently, the water follows
its movement through a reach of artificial canal until the narrowing, whereby
it flows naturally through another short reach without canalization, see Figure
35a.
The bed is made up of sands with gravels and in certain reaches there is aquatic
vegetation typical of the Andean high wetland (Figure 35b). The margins are
composed of bofedal peat (see Figure 35a). However, in some reaches there
are walls protected by well-arranged and jointed rocks in the form of a lining.
Site 15: In the site presented in Figure 38, we can see traces of a road; there
is an access in the form of a ditch that is located at the end of the bofedal. The
flow that passes through this point is with a very small tie-rod and downwards
we can see more vegetation with an approximate width of 8 meters and a short
39
Figure 34. Native sp ecies (toad).
h) Flow 1t-!nd1 co111pri~i11g n hufe d al lhnl hns 1101
IJt>t'II int t'IVt:lit:cJ .
Fiew ... :i~. Cliru;u l ;.,1h.1it:, of Iii;.,, c:;mHI ;uul i.ur ... d ... l .-IIOlll ld 'v\l'pir 3.
176
length; then it narrows and goes through the artificial canal. This site is located
at the geographic coordinates of E 602543 m, N 7565784 m and altitude 4,408
meters above sea level (UTM System WGS1984).
Site 16: The canal returns to be restored by the right flank after the passage of
the ditch (see Figure 37a) and on its left margin there are surfaces of smaller
bofedales (see Figure 37b). In addition, the canalized reach appears with little
rock protection (see Figure 37a).
Site 17: In this place we can see a spring (see Figure 38a) on the right margin
of the canal, in a reach found within ravine and with very little water contribution.
This reach seems to flow in natural conditions, although it is not possible
to observe it easily due to the large size of the grasslands (see Figure 38b). This
sector is geographically located at the coordinates E 602392 m, 7565824 m and
altitude 4,399 meters above sea level (UTM System WGS1984).
40
Figure 36. Ditch for vehicular crossing through a piped reach of the bofedal.
a) Canal with view upstream. b) Left flank with reduced bofedal.
Figure 37. Bofedal that narrows and canal excavated by the bofedal.
177
Site 18: In this sector there is a reach of unlined canal (little protection is seen,
as shown in Figure 39a); although the canal is part of an artificial drainage, this
watercourse is channeled and the flow presents upwelling waters on the right
flank. We can also see rocks with slightly worn edges, which show that at some
time there was movement of sediments and that caused the wear of the rocks
at the margin of the canal (Figure 39b). There is also movement of water in the
area that narrows, it changes in slope increasing the velocity and generating a
slight turbulence. However, the wetlands that cover it extend from one end of
the slope to the other. These slopes are made of rock and have almost vertical
cuts (Figure 39c and d). This sector is geographically located at the coordinates
E 602212 m, N 7565869 m and altitude 4,398 meters above sea level (UTM
System WGS1984).
Site 19: The sector is located in front of the Silala Military Outpost in Bolivia.
The other spring is located in this reach. In the sector of the canal it is seen that
there was an intervention with protection of embankments and rock walls. It is
located at the coordinates E 601804 m, N 7566061 m and altitude 4,390 meters
above sea level (UTM System WGS1984). The reach is flooded, which shows
evidence that the bofedal is saturated, mainly on the left margin (Figure 39a).
In the same reach there is a fish project consisting of two types of ponds, one
made by rocks and the other by a group of reinforced concrete. Both fish ponds
are abandoned.
Site 20: Regarding the water channeling, from the fish sector downwards there
is a rectilinear channeling, which shows that this reach was intervened artificially,
since they have also sporadically protected the walls of the canals with
some rocks. (Figure 39a and b).
41
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTAUED IN THE SILALA SECTOR
a) Spring 21. b) Scrubland on the left flank.
Figure 38. Canal covered by very developed scrubland.
178
Site 21: A reach with short natural channeling is presented, whose flow passes
through a rocky opening (Figure 40a). However, another reach drains through
a saturated wetland (Figure 40b).
Site 22: Weir 3 (see Figure 41a) is located in this place, with the coordinates
E 601473 m, N 7566264 m, 4378 m (UTM System WGS1984). The reach
downstream of the weir is intervened by means of canalization in natural soil
(bofedal peat), see Figure 41b. There also are protections on the sides of the
canal.
42
a) Intervened canal with a view upstream. b) canal with flow, seen from upst ream.
Figure 39. canal in the reach of the Silala Military Outpost.
bj Canal narro·.. v inP, do·,;,.,n, seen from dowmtre:im
:=1gurc40, Norro·..-.·1n.g ::,t the coool'~ rcoc>1 with nJrural How.
179
Site 23: In this sector there is an opening in the reach found within the ravine
and in the same way there is a difference in the terrain’s profile, producing a
fall of water with an approximate height of 5 meters. The site is geographically
located at the coordinates E 601267 m, N 7566267 m and 4,383 meters above
sea level (UTM System WGS1984), see Figure 42a. In the greater narrowing
there is a very strong slope change.
Downwards there is a flow through the bofedal, where its wet condition is
maintained. However, it is possible to appreciate a channeling, where the flow
develops on both sides and then expands throughout the water course, occupying
the entire width of the reach found within the ravine (see Figure 42b). The
reach does not have a defined course, but has a dispersed flow through
the bofedales.
In the presence of the drainage works seen in the upper part of the South
Bofedal, it is noted that the flow has been channeled; being that in its natural
condition, the flow through the bofedales is very much reduced. This assertion
is based on the observation of artificially constructed drainage sections, since
the altered reaches are those in which canals have been excavated and in
43
a) Location of Weir 3. b) Reach canalized after Weir 3.
Figure 41. Reach of the natural canal and the intervened canal in proximity of\Veir 3.
a) Wat erfall at the end of the narrow reach. b) Reach of the bofedal afterthe waterlall
Figure 42. Waterall and reach of t he bofedal h t he canal's zone - South Bofedal.
180
which rocks have been placed for protection. On the other hand, in other reaches,
the porous medium of the bofedales that maintain their natural characteristics
presents slow flows or that are flooded. The reach does not show a typical
section with natural terraces, but in the middle there is an excavated canal with
overflow or deviated flow, which covers the entire width.
Site 24: The reach of this site (Figure 43a) is found within a ravine with semivertical
walls. The flow in this reach is natural.
Figure 43b and c show an intervened reach of the flow, which is excavated on
the bofedal and is protected with stone masonry. The geographical location of
this sector is E 600859 m, N 7566029 m, 4,350 meters above sea level (UTM
System WGS1984).
Site 25: In the reach, there is a rock canal (Figure 43c) that has been intervened
with the construction of a stone masonry. The reach is rectangular, although in
the reach a narrow rocky geomorphology is observed, as seen in Figure 43d.
The site is located at the coordinates E 600843 m, 7565986 m and 4,347 meters
above sea level (UTM System WGS1984).
44
a) Reach found within a ravine of the South Bofedal.
c) Canal protection at the beginning of the reach
found within the ravine.
b) Reach canalized in the South Bofedal.
d) The bofedal and canal ends and starts a fall through
rock with nat ural flow.
Figure 43. Reach found within the ravine and canalization near the end point of the South Bofedal.
181
Site 26: A reach completely found within the ravine is presented and below
is the confluence of the canals of the North and South Bofedales (Figure 44).
The confluence is geographically located at the coordinates E 600652 m, N
7565908 m and 4,323 meters above sea level (UTM System WGS1984).
The sector found within the ravine has the following characteristics:
- The slope is greater in the rocky reach, reason why the runoff develops naturally
between rocky walls that contain the flows.
- Upwelling waters have been observed in the rocky outcrops. This situation
is not visible in the upper reaches. The slopes have vertical cuts and in their
base it is possible to observe formations caused by abrupt waterfalls.
- At the exit of the reach found within the ravine there is a change of the slope
to a low slope, restoring the flow back through an excavated and lined canal.
45
a) The South Bofedal ends and a fall begins along" "a n
uneven reach found within the ravine.
b) Fall through rock with flow and a canalized reach
after it.
Figure 44. Reach found within the ravine and canalization at the end point of the South Bofedal.
182
5.2.2 REACHES OF CANALIZATION IN ROCK
As a result of the topographic survey, between the progressive 2+060 to 2+462
and 2+618 to 2+800 that constitutes a predominantly rocky reach, there is evidence
of sections that have a fairly regular geometric shape, showing sections
of the rectangular and trapezoidal type. Although there are no documents that
claim that the rock has been carved in this reach, however, the regular geometric
layout shown gives strong indications that there have been rock carving
works, to form the canals in this reach. Table 3 presents a detail of the rock
canal longitudes.
The detailed physical characterization of the reaches of rock canals is presented
in Annex 1; Figure 45 shows the indicated reach. It is necessary to clarify that
the classification adopted as “canalization in rock” refers to two cases; rock
canals with presence of peat and canals only in rock.
46
Table 3. Classification by reaches according to a slope range. Detailed physical characterization of the reach with rocky outcrop,
South Bofedal.
PROGRESSIVE LONGITUDE REACH SLOPE
START END (m} (%}
REACH 1 2+060 2+092 32 5.5-6.6
REACH 2 2+092 2+310 218 2.5-4.5
REACH 3 2+310 2+377 67 9.09
REACH 4 2+377 2+462 85 4.95
REACH 5 2+618 2+710 92 1-33
REACH 6 2+710 2+800 90 1-30
TOTAL= 584
183
47
,- ~ '
E tl,
"X.
- -----
fOM:I>
·JCII
BOFEDALSUR
fo./l l00
IQ<,;,' CS'1l -
~
I
.~
~u IC./. ~ j
PERFIL LOAGITUDINAL DEL TRAMO SIN CANALIZAR PROGRESIVA 2+o60 A 2+462 y 2+618 a2+800 - BOFEDAL SUR
TAAMOl IIIMlll
~l'a_lnt_:5._S!l_•EAI_I _-_l'to_'d_lnl_!!ll_H,9_" ___ ,lR.A.M_laM l llllpl1'RW.IMlm04u ill
~
IJoUl
+l!IJ'
4J10
- "'J+• -, - ,- ·- 2+i!GP
001ll-07UI OIU!I O&U!I
~1111
4!5UI
~DO
4'1ilUI
~
04U3
111Kl5 lllWO&
~PMldllltdl-• aq.11••1ura-•
21e11 •
4:IWT
\f:KIID{RO C-5
----...___ Sla1ion=2Hl6LJ7
~ elev a 4318.62g
2+1ir
W1ll
~rt!"
mul
MM
4t1UII
Figure 45. Location of stone-lined reaches in the South Bofedal. Source: Own elaboration based on data from
DIREMAR, GOOGLE EARTH
184
5.2.3 SUMMARY OF THE WORKS OF THE SOUTH BOFEDAL
In the South Bofedal the following aspects are distinguished:
•The drainage canals start from the water collection works built on the upwelling
springs.
•There is a predominance of canals built without coating, with excavations
in natural soil, in this case being understood as “natural soil”, that which
corresponds to the body of the bofedal, i.e. a combination of soil, water and
organic material.
•In the upper part of the bofedal there is a main canal with secondary canals,
these are composed of two secondary canals of considerable longitude and
small branch canals of the reach.
•The geometrical arrangement of the uncoated canals maintains a trapezoidal
rectangular shape. There is no fall of lateral material, so that the conformation
is practically regular.
•As the progressive increases, the main canal adopts a masonry coating, until
the place where the runoff develops on rocks.
•In the upper reach, the slopes are low and as it approaches the channelized
reach it increases until it leaves the rocky sector.
•The horizontal alignment of the canals has predominantly a rectilinear conformation.
The changes of direction are not gradual, so there is no transitional
curvature.
•The main canal of the South [Bofedal] has an average slope of 3.1% from the
top of the ravine up to the confluence with the North Bofedal canal.
•As for the canal dimensions in the South Bofedal reach, the widths vary from
0.71 to 3.2 m; and the depths from 0.19 to 0.50 m.
A summary of the canal types, their longitudes, material type and total length
is presented in Table 4 below. It can be seen that the largest number of canals
built are main and uncoated.
48
Table 4. Summary of longitude of canals in the South Bofedal (measured in met ers).
TYPE OF CANAL WITHOUT COATING WITH MASONRY CANALS
TOTALS
EXCAVATED IN NATURAL SOIL COATING IN ROCK
MAIN 1826.0 461.0 584.0 2871.0
SECONDARY 764.67 49.8 - 814.5
185
5.3 WORKS IN THE NORTH BOFEDAL
Site 27: In Figure 46 there is a panoramic view of the upper area of the North
Bofedal. The soil is constituted by loose fine sands, with remains of rocks
deposited and disintegrated due to weathering and wind erosion.
There is no presence of water or any indication of slope erosion or soil washing
by surface runoff (laminar erosion), much less in gullies, which shows that
there are no floods in the region, as occurs in river basins.
In addition, Figure 46 shows an overview of the type of soil of hillsides and
slopes near the bofedales and the flow of water through them. In general, the
slope cover is typical of arid basins with many areas covered with bare soil.
On the other hand, the sediments of the surface are granular materials that are
produced by abrupt changes of temperature and wind erosion, but not by water
erosion.
In addition, at lower elevations it can be seen that the topography of the terrain
is depressed and the outcrop of fissured rock on both flanks is observed. Further
down, accumulations of fine granular sediment are observed, which come from
the bofedal and also the emerging of springs that are channeled by small canals
to another main collector canal.
Site 28: Figure 47 shows jointed rock, with rock blocks and pieces of broken
rock. Among other configurations, disaggregated rock fragments can be seen
on the rock massif. In general, it is observed that the soil is bear with tenuous
paja brava (Stipa ichu) on the surface of slopes and in scattered clusters (thin
coverage).
49
Figure 46. Upper part of the North Bofedal.
186
Site 29: In the site with the coordinates E 601045 m, N 7566380 m, 4,390 meters
above sea level (UTM System WGS1984) there is an observation well or
piezometer (Figure 49a). Figure 49b shows that there is no erosion on this site.
50
a) Upper reach of the North Bofedal b) Right slope in the South Bofedal
Figure 47. Jointed rocks on the slopes of the North Bofedal.
a) Observat ion well in the North Bofedal. b) Surface without erosion.
---.-1,-~'-....... -;;;. c) First spring in the North Bofedal. d) First water upwelling in the North Bofedal.
Figure 48. Upper Sector of the North Bofedal.
187
Site 30: The first spring in the North Bofedal is located at the foot of a rocky
massif. Humid soil with little flow can be seen on the site, see Figure 48c.
Figure 49d shows minimal flow upwelling water emanating from the subsoil.
Site 31: The first canal is observed in the upper part of the bofedal (Figure 50a).
The characteristics of the canal are the following:
- Its alignment is straight, which implies intervention.
-The canal material is excavated in natural soil (bofedal) and the sediment
from the excavation has been deposited on the right margin.
- The canal has no lining.
Site 32: Figure 49b shows how the flow originates from a spring, then
it is channeled by canalization in natural soil, protected by rocks like
a vault, and the flow is delivered to another main dirt canal of a larger
51
a) Channeling of water from the first spring through b) Union of canals (confluence) for the channeling of
the art ificial canalization at the North Bofedal. water from springs.
Figure 49. Upper reach of the drainage canal in the North Bofedal.
a) Flow in the canal without sediment transport. b) Joints in the North Bofedal.
Figure SO. Canal bottom and slope in the North Bofedal.
188
Site 33: Figure 50a shows a canal with the characteristics described as most
artificially constructed conduits, in which there is no evidence of sediment
transport, such as boulder and pebbles. On the other hand, Figure 50b shows a
jointed rock formation in the north slope.
Site 34: In the photograph of Figure 51 a ditch built for vehicular traffic is
shown, which shows that there was already an access route to the springs, surely
with the purpose of maintenance and inspection of the water abstraction hydraulic
works. This work is located at the coordinates E 600925 m, N 7566322
m, 4,367 meters above sea level (UTM System WGS1984).
In addition, there is a pipe below the speed bump, which extends perpendicular
to the road. This work has the function of driving the spring water from its upper
part and extracting the water from the bofedal, since the pipe has perforations
on its upper side. The length of the pipe cannot be estimated because it is
covered with vegetated peat.
Site 35: The bofedal of the photographs shown in Figure 51a is close to the
springs, and is located at the coordinates E 600890 m, N 7566319 m, 4,361
meters above sea level (UTM System WGS1984). The sector is a typical area
of bofedales where the surface of the soil is not uniform, but protuberances and
depressions appear on the sides of the canal (see Figure 51b). The protuberances
are formed by material from the bofedal (slime-sandy peat) of green color
and with vegetation. In contrast, the depressions have sands and contain wetland
and retained water. The difference in elevations between the flooded area.
Site 36: The photographs in Figure 52 show sediment promontories with characteristics
similar to peat from bofedales; we can even see vegetation formed
in clusters that protrude from the natural surface of the surroundings. It is probable
that this material has been extracted from the excavation carried out in
order to form artificial canals. The appreciation of soil promontories is from
both sides of the canals, similarly, they run parallel to these.
52
a) Speed bump for vehicle crossing. b) Flow throughout the bofedals.
Figure 51. Ditch for vehicular passage and pipe for water flow.
189
A particular feature of this site is the reticulated trace of canals with lateral
drains, those that collect water from the springs in secondary canals that are
almost parallel. The water contribution from springs is carried out in series, that
is to say, as progress is made in the route towards the border, a greater flow is
collected through the main canal. Finally, the water collections of each spring
are added longitudinally and converge until reaching a confluence canal in the
South Bofedal canal.
Site 37: The photograph in Figure 53a shows the bofedales with high humidity
retention and the direction of flow is not observed, so it is considered that this is
a flooded zone. This bofedal configuration is seen in the mid-west sector of the
North Bofedal, it is also seen that in the sector there are no canalization works,
reason why there is accumulation of water among the vegetation clusters. It is
believed that this bofedal configuration is the natural condition of a bofedal in
the region, as can be seen in other photographs that are described in the chapter
that describes wetlands in natural conditions.
Figure 53b shows a view of the main canal to the north, in which the
alignment line of the canal and its relationship with the natural slope
of the bofedal can be seen, this means that the main canal has been traced
in such a way that it runs through the lowest topographic levels, in
53
a) Collector canal with accumulated sediments on t he
s ides.
a) Canal lined with rocks.
b) Secondary canal with sediment clusters on tt
sides.
b) Spring with rock protection.
Figure 52. Reach of minor canalizations (secondary canals).
190
such a way that the water from the springs can be easily abstracted and drain
the water from the bofedales to channel it through the secondary canals.
Site 38: In Figure 54a a perforated transverse pipe is observed, which has the
function of channeling the spring water located at the top, to then deliver it to
a secondary canal that collects water from other springs. Also, it is shown that
the pipe is covered with natural dirt and protected with rocks, which is justified
because this space was built for vehicular traffic above such channeling.
Site 39: The photographs presented in Figure 54b show a spring in the North
Bofedal. It is located at the coordinates E 600831 m, N 7566275 m, 4,359
meters above sea level (UTM System WGS1984), next to the access road to
the area. There is a protection of rock that surrounds the spring and its exit is
achieved towards a small canal covered with rocks. In this spring there is a flow
somewhat higher than the others located in higher elevations, probably because
here there is a greater hydraulic gradient or the fissures in the jointed rocks are
in greater number or size.
54
a) North Bofedal with a downward view. b) North Bofedal and drainage canals with an upward
view.
Figure 53. Flooded zone in the North Bofedal.
a) Perforated pipe. b) Spring.
Figure 54. Abstraction of springs through pipes and canals of accommodated rock.
191
Site 40: In the photograph of Figure 55a, seen upwards, there is a lateral canal
that flows along the left flank. This is located at the coordinates E 600821 m, N
7566267 m, 4,361 meters above sea level (UTM System WGS1984).
Site 41: In the photograph of Figure 57b, another canal can be seen going
down the right flank and dislodging a small flow through a pipeline and merging
with a secondary canal, just at the confluence with another canal. Additionally,
it can be observed that this canal has been protected with rocks in its upper
part, forming a chamber-shaped canal.
Site 42: Figure 56 shows the water that is conveyed through small canals excavated
in the soil of the bofedal; these small canals then enter the main collector
canal.
55
a) Spring Protection. b) Confluence of secondary canals.
Figure 55. Spring protection and dome channeling
a) Input of collector canal. b) Flow in the secondary collector canal.
Figure 56. Collection of water from springs.
192
Site 43: The photograph of Figure 57 shows a spring that emerges at a relatively
high level with respect to the main collector canal. The flow is appreciable
since its inception. The intervention is very noticeable since it has rock canals
that have been carefully placed, in such a way that the flow has a regular wall.
In its lower part, it enters into another canal in line with the slope; in addition,
its section is more or less constant and comprises canals that collect water from
other springs. This sector is geographically located at the coordinates E 600768
m, N 7566308 m (UTM System WGS1984).
In the panoramic view of the North Bofedal (Figure 58 and Figure 59) the following
aspects are observed:
a) From the geo-morphological point of view, it can be distinguished that two
deep valleys have been formed, originated by fluvial-glacial processes that
have given rise to a characteristic geological configuration, with slopes in
both Silala bofedals.
b) The north flank has a moderate slope with loose soil that gives it the shape
of a hillside valley with very sparse vegetation, mainly straw. The opposite
flank is a cliff of high slope formed by rocks. On both flanks there is no
evidence of surface runoff by slope or effects of laminar erosion.
c) The bofedal extends to the south in which a series of artificial canals with
well-defined tracings and slopes that join a larger main collector canal can
be seen from the top.
d) Upwelling waters that occur in the valley are linked to the process of deposition
of loose and disintegrated material, which have allowed the bofedal
to develop throughout the valley, but with greater incidence on the northern
flank.
56
F.ig ure 57• View of spring SO.
193
The configuration of secondary collector canals has a trace in the shape of a
fishbone, which consists of the construction of almost parallel canals that enter
in series to a main conveyance canal. This form of drainage clearly demonstrates
that the springs are being channeled from its upwelling to the confluence
with a larger canal. In turn, another quantity of water is collected from the
bofedales, since these are drained longitudinally until achieving the delivery of
water in the main canal.
57
Figure 58. Panoramic view 1 of the network of canals in the North Bofedal.
Figure 59. Panoramic view 2 of the network of canals in the North Bofedal.
194
5.3.1 SUMMARY OF THE WORKS OF THE NORTH BOFEDAL
In the North Bofedal the following aspects are distinguished:
• The conformation of the North Bofedal differs from the South Bofedal, in
its geometric arrangement. The North Bofedal along the movement of water
through the canals is developed on the bofedals and not on channelized bedrock
as evidenced in the South Bofedal.
• The number of springs of the North Bofedal is higher than that of the South
Bofedal. This situation means that the number of water catchments per
spring is greater and therefore the number of secondary canals is greater.
The disposition of the drainage network –that is to say of the network of
canals of the North Bofedal– is of the “fishbone” type, that is to say there
is a main canal and the secondary canals generate the indicated geometric
disposition.
• Only part of the main canal –specifically the upper part– is uncoated on
natural soil. Making an abstraction of this reach, practically all the canals
(main and secondary) have stone masonry coating without binder material.
In some sectors the use of stone is “denser” as is the case of the main canal.
• In the North Bofedal, the presence of pipes as secondary canals has been
evidenced. The canals operate at free flow, that is, they do not work under
pressure.
• The drainage density of secondary canals is higher than in the South Bofedal,
which shows a much higher degree of intervention.
• The use of stone masonry without binder material greatly helps lateral drainage
along the canals. So the process of collecting water is not only located
at the outlet of the springs but also along the entire canal.
• The secondary canals were protected with dry masonry both in the walls and
in their upper part, forming canals in the form of a vault.
• In the reach before the confluence with the canal coming from the South
Bofedal it is observed that the use of stone masonry is accompanied by a
stone drilling in the sole (the bottom of the canal).
• The plan layout of the primary and secondary canals is rectilinear. The horizontal
alignment of the canals is rectilinear, with no gradual curvature in the
direction changes.
• The main canal of the North [Bofedal] has an average slope of 6.4%, from
the upper part to the confluence with the South Bofedal canal.
• The dimensions of the North bofedal canal vary from 0.40 to 0.48 m, at its
base, and from 0.22 to 0.55 m in depth.
Table 5 presents a summary of the longitudes of canals, types and materials
that are found in the North Bofedal reach. It is observed that there is a greater
predominance of secondary canals, a situation that can be clearly noted by the
existence of a greater number of springs.
58
195
5.4 CONFLUENCE REACH CANAL
5.4.1. DETAILED DESCRIPTION
Site 44: The confluence of the drainage canals in the South and North Bofedales
of Silala occurs at the coordinates E 600650 m, 7565900 m. The entry canals
are straight and fully lined with masonry walls, see Figure 60. There is no sediment
transport and the flow is turbulent.
Before the confluence there are two metallic triangular weirs that monitor the
flow with level sensors.
The main feature at the confluence of the channels of the South and North
Bofedales is that on both sides there is stone masonry canalization with some
type of binder (at bare sight, it has not been possible to establish with precession
the type of binder that might have been employed in said section). The
masonry shows conditions of high resistance to the velocities of the flow (the
magnitudes of the speeds are presented in the chapter corresponding to the hydraulic
modeling).
Site 45: After the confluence of the south and north canals, the collected water
is delivered to a main collector canal, constructed of totally artificial stone
masonry, which
59
Table 5. Summary of canal longitude in the North Bofedal (measured in meters).
TYPE OF CANAL WITHOUT COATING
WITH MASONRY COATING
CANALS
TOTALS
EXCAVATED IN NATURAL SOIL IN ROCK
MAIN 170.0 518.0 - 688.0
SECONDARY - 1112.0 - 1112.0
Hg.urP i'iO. 'J'jpw nt thP r.onilui=nr.P nt r..=in;;I,;, ot tl-P South ;inrl rJorth nnh=-r.;ilP-..
196
channels the volume of water of all the springs and the drainage of bofedales,
as can be seen in Figure 61.
The main characteristic of this canalized reach, from the collection – desiltation
work up to the border (see Figure 62) – is its artificial alignment, which has
been generated from a typical drainage project.
First, Figure 61a shows a canal reach in straight line. Secondly, in the same
alignment of the canal, a rock slope with an almost vertical cut can be seen in
the background. Therefore, the drainage has been diverted, as shown in Figure
61b.
60
a) Straight reach. b) Curved reach.
Figure 61. View of the masonry canal towards the border with Chile.
Figure 62. Intake works, desilting chamber and load chamber near the border.
197
Site 46: Finally, Figure 63 shows a view of the exit canal towards the border
with the Chilean territory. In this figure we can see the line of canals that were
aligned according to the topography of the terrain.
5.4.2. SUMMARY OF THE WORKS OF THE CONFLUENCE
REACH
In the confluence reach the following aspects are distinguished:
• Once the North and South Bofedal canals converge, the channeling canal
carries water from both bodies of water to the border.
• The canal is of greater capacity and its disposition obeys to the configuration
of the ravine. The canal has been built by the central part of the ravine where
it has been shown that the intervention has been developed on a natural
body.
• The canal has been built in stone masonry on the walls and stone treads on
the sole.
• In this reach is located the largest water abstraction work carried out in the
area, consisting of a desiltation chamber and a loading chamber. At present,
this work is in disuse.
• The horizontal alignment of the main canal of the confluence reach is quite
straight and the curves in the direction changes are not gradual.
• The slope is uniform, with an average value of 5.6%.
• The cross section of the almost constant canal. Its mean dimensions are 0.80
meters wide by 0.65 meters deep.
61
Figure 63. Panoramic view of the exit canal towards the border
198
Below, Table 6 provides information about the longitudes of the canals in the
confluence reach. In addition, the characteristics of these and their material are
indicated.
62
Table 6. Summary of the longitude of canals in the Confluence Reach (measured in meters).
TYPE OF CANAL WITHOUT COATING WITH MASONRY CANALS
TOTALS
EXCAVATED IN NATURAL SOIL COATING IN ROCK
MAIN 0.0 706.0 - 706.0
SECONDARY - 238.0 - 238.0
199
6 DESCRIPTION AND CLASSIFICATION OF WATER COLLECTION
WORKS
6.1 WATER COLLECTION WORKS
6.1.1. CLASSIFICATION
For purposes of accuracy it is necessary to differentiate between two types of
water collection, as they are addressed in this work:
• Specific catchment
• Longitudinal catchment
The specific catchment is understood as the works executed to collect the waters
at the exit of each spring, while the longitudinal catchment is understood
as the capture of waters along the drainage canals.
In turn, the specific catchment differs between smaller and larger catchments,
the smaller catchments are those that, due to their volume of work, are located
at the exit of each spring, whereas a greater catchment is the one that is in the
confluence reach, where the works are bigger and where the objective is to collect
the water that flows to that point coming from the north and south canals.
6.1.2 MINOR SPECIFIC CATCHMENTS
Based on the methodological approach of this study, 138 springs are accounted
for (SENAMHI-DIREMAR, 2018).
In order to achieve greater efficiency in collecting the entire flow of each
spring, especially those with greater water contribution, small hydraulic collection
structures have been built consisting of concrete walls or stone masonry.
At the exit of these small catchments, there are the secondary canals of the
drainage network. These water catchment works in turn fulfill the objective of
channeling the emerging water.
63
f.,
a) Catchment work wit out protection o co e
water from the spring.
b) Catchment work with protection to collect water from
the spring.
Figure 64. Collection of water from springs.
200
According to the field inspections, the water collection or abstraction works in
the springs are practically equivalent to the number of existing water eyes with
the greatest contribution, and according to the observations made, it is distinguished
that said works are adequately protected. In the photograph of Figure
64a it shows a work of unprotected catchment in the spring 47; however, Figure
64b presents a more elaborated protection. The difference is that the greatest
protection is for the highest flow springs.
6.1.3 LONGITUDINAL ABSTRACTION WORKS
The canals have been built with dry stone masonry or have been simply excavated
in natural soil in order to form cross sections in an almost rectangular
shape. The dimensions of the canals vary, as described above.
It is possible to characterize the canals in terms of their conformation and their
dimensions, the widths of the canals are highly variable, in both the South and
North bofedals (see Figure 65a and Figure 66a and b respectively), similarly,
their depths are diverse.
The canals in the North and South Bofedales have different characteristics. The
main characteristic is that it has reaches with lining and others without lining.
Figure 65 and Figure 66 present canals of both bofedales with similar interventions.
The first shows the non-lined canal, while the second shows the canal
lined with dry stone masonry. The canals do not present any concrete or binder
that might make the rock assembly impermeable.
64
a) Average canal without lining in the South Bofedal. b) Average Cana l with lining in the North Bofedal.
Figure 65. Longitudinal abstraction stone-lined canals
201
According to what has been indicated, it has been demonstrated that the longitudinal
collection works capture the water longitudinally along its entire length,
as can be seen in Figure 67, the same one that develops through the permeable
walls. This is a way of lowering the originally upwelling water table (see
Figure 68), this descent channels a flow of the bofedals towards the canals; in
this way it is possible to drain the bodies of water located in the bofedals (see
similar canals from Figure 70 to Figure 72).
The drainage of the waterbodies is manifested both in the main canals and the
secondary canals.
65
a) Ave rage canal wit hout lining in the North Bofedal. b) Average canal with lining in the North Bofedal.
Figure 66. Average canals in the North Bofedal.
t A A !
EscurrlmlenlO
Superficial dlfuso
Nisei F reabco
aj ~
Figure 67. Wetland waterbodies a) natural and b) intervened.
202
The main channels collect the waters that are delivered from the secondary
channels, in addition, these have a trace that runs through the lowest points of
the land, since when superimposing them with the topography of the land it is
verified that they travel in linear lines and with slopes regulated by the same
terrain, as drainage projects are carried out on roads or agricultural lands. These
assertions were studied and verified in the topographic plans, therefore, the
construction shows that not only the springs have been drained, but also the
bofedales have been drained.
66
Nivel de agua para un bofedal saludable
¥· --=-1-~:. ·~ ·-=-d - ~ - ·-"' - ·-=;,· .. .:"'--=-- , -=;: · -=-~ -=-··· ~ - ~ - . ~ .. ~
- ·~ 4 "':a:-: .- ~ . - - ·--= - :=-- · - - . -·. - . - - · -. ~ ~· ~· ~ ·. -:'" "' ~ ~ · ~~ ~· ~ .. ~ "" ~· : .. ~· ~ --v. ~ . ~
·:¾ -. _..,,- -..... _ .. - ~ - -..... - ._..,-=-· ~ · --= -~--= -.:a,. - _.. ... -
·-. ~ - . - ·- -· - . -=- ·, .7" - . --= ~ -=- j:-=-.
- ···-=- . . .
4-' ··~ ·-"'~
~ · ~- ~ ~· ~ ~ , ~ • ~ - ~
-
Suelo compuesto de Turba-limos y Arenas
a)
Abatim iento del nivel de agua
-=- -=-
N ivel del agua poste rior al drenaje del bofedal
b)
Figure 68. Water abstraction in the bofedales, a) before the canals were built and b) after canal construction
203
67
Seconda1y Canal
Figure 69. Characteristics of the layout of main and secondary canals in the North Bofedal.
a) Main canal in the South Bofedal. b) Secondary canal in the South Bofedal.
Figure 70. Main and secondary canals in the South Bofedal.
204
68
a) Main canal in the North Bofedal. b) Secondary canal in the North Bofedal.
Figure 71. Main and secondary canals in the North Bofedal .
. .
. . ~ -~ ~ '~ .<t .... ti,-~
Figure 72. Panoramic view in which the main canal of the North Bofedal can be seen.
205
6.1.4 GREATER SPECIFIC CATCHMENT
The largest specific water catchment work is at the beginning of the confluence
reach, which is composed of concrete masonry works. Its objective has been to
collect the water flow from the main confluence canal. It consists of collector
canals and a chamber that acts as a loading chamber for the abduction of steel
pipes.
The water intake work is located a few meters below the confluence point of the
South Bofedal and North Bofedal canals; see Figure 73. This work also has the
purpose of retaining fine sediments, since its configuration and structure is designed
for it, which makes us suppose that at some time, with the canalization
works, sediment transport of certain characteristics was presented. However,
at present it is not possible to establish accurate criteria for its functionality
due to the scarce information and, mainly because in the upper part there is no
evidence of sediment transport.
The water intake work and the desiltation chamber (Figure 74a) also fulfill the
function of loading chamber (as it is observed in the Figure 74b), because at
the exit of the same two steel pipes were connected that started from inside the
work.
As mentioned, the intake works at the border, collects water from a canal on the
left bank, the water is collected by raising the water level, then passing through
several slopes with the function of depositing the solid particles and then divert
them to a tank that connects to two pipes with diameters of 10” and 12”.
Currently, the outlet canal of the intake work, located on the left bank, is in
disuse and buried.
69
Figure 73. Water intake work, desiltation chamber and loading chamber near the border.
206
6.1.5 ADDUCTION
Although drainage canals fulfill the function of collecting and channeling water,
in the present analysis they are not considered as adduction works. The adduction
in the past context refers to the pipes that came out of the larger work.
The adduction consists of three types: 1) the one that is drawn from the springs,
in order to channel the water towards the main canals in the bofedals; 2) the
one that corresponds to the main canals that collect the water drained from the
bofedals and 3) the one that carries out the final collector or exit canal towards
the border.
70
a) Desiltation chamber and loading chamber
near the Border with Chile.
b) Dimensions of elements of the water intake work.
Figure 74. Water Intake Work (Source: OIREMAR).
207
7 DESCRIPTION OF THE SEDIMENT TRANSPORT PROCESS
This analysis of sediment transport is not based on field measurements made
to evaluate the bottom trawl transport, since this transport does not occur in the
Silala canals with the measured flows.
The description of the sediment transport process is based on the field evidences
and also on the results of the water quality analysis elaborated by DIREMAR.
The field inspections consider two main aspects:
• Processes related to laminar erosion.
• Transport of sediments in the canals.
7.1 PROCESSES RELATED TO LAMINAR EROSION
The entire basin has been covered in order to find some evidence to indicate
the existence of signs of laminar erosion caused by an atmospheric agent, precipitation
or wind.
The field inspection shows that although there is topographic relief and surface
highly vulnerable to water erosion; that the precipitation is snow-like and
there is no erosion by water action, despite the fact that the surface of the basin
has disintegrated soils with high potential to generate erosion and movement
of sediments. Described in other terms it can be explained that there are no
traces of runoff caused by precipitation as it occurs in a basin where runoff is
caused by an excess of precipitation and saturation of soils, that is, there are
no courses that could show the concentration of flow in a drainage network.
In conclusion, there is no surface runoff that can cause laminar erosion (see
Figure 75).
71
Figure 75. Hillside of the North Bofedal without signs of erosion.
208
7.2 TRANSPORT OF SEDIMENTS IN THE CANALS
From the field inspection it is observed that there is no bottom transport in
the canals as can be seen in the photographs of Figure 76. This situation is
corroborated with the daily flow records of the period between December-2017
and March-2018, which shows a limnogram of measurements in which it is
clearly distinguished that extreme events do not occur, that is, no events that
are related to a storm are observed. The limnogram of the aforementioned
Figure 77 shows that there are no spikes that indicate a hydrological response
to precipitation. In this way, it has been demonstrated that bottom transport
does not exist due to seasonal variations.
According to the inquiries made to the hydrometric technicians of SENAMHI
that carry out measurement work and flow gauging on a monthly basis, they
indicate that sediment retention exists in the anterior part of some weirs.
72
a) Canal in the North Bofedal with sediments in the
bottom without movement.
a) Sediments on slopes of the South Bofedal (Site
2, Dm = 0.2 cm)
b) Canal in the South Bofedal with sediments in total
rest.
b) Sediments in the upper zone of the South Bofedal
canal (Site 1, Dm = 0.3 cm)
Figure 76. Sediments in the canals and hillside in the upper area of the bofedals.
209
Along the canals it is observed that the particles located in the bottom of the
canals do not show a configuration that allows assuring the presence of spherical
particles, cobbles or boulders as it happens in the fluvial canals.
It is recommended to carry out an evaluation or specific studies based on
measurements with sediment traps. Consequently, under the current state of
information about sediments, it is not possible to draw definitive conclusions.
However, there is material that is transported in suspension. This is verified
with the water quality sheets taken in different campaigns, which are attached
in Annex 3.
The results of the water quality analysis show very low concentrations of
suspended solids, even null in some measuring points, with an average of 2.9
mg/l..
73
60
Va ores Diaries d e I Nive I de I A ua - Bof e d a I Sur v Bofe da I Norte
- - 50
E u .. 40
0 ·.c.: ' c.. 30 GI .. - .0. 20 > - ~ ,_
10
0 ....... 01) 01) 01) 01) 01) 01) 01) 01) 01)
---
...
---
...
---
...
---
...
---
...
---
...
---
...
---
...
---
...
N --- ... ... ... ... N N "' "' "' "' ~ ~ ~ ~ ~ ~ ~ ~ ~ -..-.- 0 0 0 ~
,,.. ... ... ... ...
"' ... N "' ... 0 ... N "'
- Cl_Bofedal Sur - c2 Bofedal Sur
- c4 Bofedal Sur - cs Bofedal Sur
Figure 77. Water levels In the weirs Cl to C6 for the period Oecember-2017 to March-2018.
210
8 SURFACE FLOW HYDRAULIC MODEL IN HEC-GEORAS
8.1 SPECIFIC OBJECTIVE
The objective of the present hydraulic analysis is to evaluate the hydrodynamic
conditions of the flow or surface runoff of water in the Silala canal water system
and to evaluate the influence of the artificial interventions (canalization
introduced to abstract and convey the water)—which alter the surface and subsurface
natural water regime—on the bofedal outflows.
8.2 HYDRAULIC MODEL
In the system surveyed, in which canals predominate a mathematical model has
been completed with the HEC – RAS Model (HEC-GeoRAS), in its unidimensional
and bi- dimensional hydraulic simulation modules, which provide the
hydrodynamic elements, or variables of the system in order to characterize the
flow regime, velocity, water depths, Froude number, Energy Line, etc.
The HEC-RAS mathematically determines the hydraulic profiles by means of
the relations of classical hydrodynamics. Its application requires the definition
of the land surface to be modeled and flow data for hydrological events
or regimes. The geometrical and hydrometrical data are used to calculate the
hydraulic profile of a gradually varied flow from calculations of energy losses.
HEC-RAS is able to model a complete network of canals, dendritic systems, or
a simple river course (depending on how detailed the information available is,
the decision can be made to idealize the system). The HEC-RAS requires the
introduction of geometric data to represent a canal network, data on the crosssections
Since the introduction of its 2.0. version, the HEC-RAS allows the use
of three-dimensional geometry to describe flow networks and cross-sections,
and its latest versions allow the extraction of the geometry of a digital terrain
model by means of an interface, or extension into Geographic Information Systems
(ARCGIS).
The model uses cross-section geometric data to characterize the channel’s
transport capacity (effective hydraulic area) and geomorphological characteristics.
The following parameters must be inserted:
• The Canal’s Morphometry, which will represent the surface and its location in
the section to be modeled (Reach). This geometry is taken by means of crosssections
perpendicular to the flow direction of the main canal (cross-section
data). The portions of the main canal (canal) axis are defined with those of
the edge of the flood area (banks), helping define the flow’s hydraulic loading
capacity.
• Distances longitudinal to the channel between cross-sections (Reach lengths),
allowing to determine the energy loss that takes place in each reach in-between
sections. These distances must be taken from the left and right edges, or margins,
and from the main channel axis.
• Roughness coefficients (“n” Manning), which are taken into consideration for
the calculation of the energy losses produced by friction between the surface of
the bed and margins with water, this is given for each reach in-between sections
and by type of material present in the bed and canal walls. This coefficient is
usually represented by the “Manning” coefficient.
74
211
• Shrinkage and expansion coefficients, which depend on the characteristics
and the changes produced in the canals.
The HEC-RAS model (River Analysis System) can calculate the hydraulic parameters
of a river by simulating its behavior with the existing structures.
For the present case, where the temporal evolution is not a factor to be taken
into account and the flow is eminently one-dimensional, this model is sufficient,
although it has been modeled two-dimensionally. These model types are
based on relatively simple but effective numerical schemes. The fundamental
equation in mathematical modeling is the preservation of energy between two
sections, although the preservation of movement amounts for local phenomena,
such as regime changes, can also be used, as well as other more or less empirical
equations for other local effects.
8.3 METHODOLOGY
The hydrodynamic flow analysis of the canal system by modeling and mathematical
simulation requires the following steps to be followed:
• Collection of detailed topographical (Planialtimetric) data, satellite imagery
and digital aerophotography provided by DIREMAR, in dwg format for CIVIL
3D as a surface model and for Autocad with detail of contours and planimeters,
such as canals, bofedal areas, infrastructures, flumes, roads, etc.
• Collection and revision of previous referential documentation for the area
surveyed, or similar water systems.
• Topographical survey with stationary total stations for each relevant point or
gauging section.
• Based on the detailed topography, digital elevation or terrain models (DEM)
were generated in Geographic Information Systems (ARCGIS) in Grid and
TIN format; for the model to best describe the terrain’s surface configuration,
the model has a resolution of 20x20 cm.
• Setting up of the geometry of the canal system in HEC Geo RAS, which
works in an interface in ARCGIS and creates the geometry to be exported from
a DEM, to then be exported to HEC- RAS. Cross-sections were defined every
10 meters to achieve a better detail of the hydraulic conditions by sections.
• Parameterization and estimation of hydraulic parameters (slopes, Manning
roughness coefficients) on basis of hydrometric information provided by SENAMHI
through DIREMAR to for its processing and management (calibration
curves).
• Definition of the hydrological scenario (flowrate) on basis of the available hydrometric
information of drainage (levels and gauges) provided by SENAMHI
through DIREMAR.
• Parameterization of the simulated hydraulic conditions, by sections, nodes or
confluences.
• Refining the information to achieve an optimal simulation of the mathematical
model for the Silala drainage system in HEC-RAS.
• Hydraulic simulation for the baseline scenario.
• Presentation of results and evaluation.
75
212
8.4 GEOMETRY OF THE WATER SYSTEM
The configuration and length of the system is defined by the influence of the
inflows and main water sources in the bofedal areas at the headwaters and
springs.
A detailed topographic map with level curves was prepared, see Figure 78.
76
Figure 78. Topographic Survey Map with Level Curves every 1 meter and every 20 cm. (Source: Own elaboration, based on
the topography provided by DIREMAR)
213
Subsequently, a digital terrain model was constructed (Figure 79), a three-dimensional
surface of the hydraulic system was generated, for processing in
ARCGIS HEC-GEORAS and subsequent importation to HEC-RAS.
77
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based on the topography provided by DIREMAR).
214
Figure 80 shows the geometry of the HEC RAS Model with its cross sections
and results of the run of the hydraulic simulation. Figure 81 then shows the network
of channels in perspective and the 3D model in the HEC-RAS program,
with the location of the cross sections. The system has been divided into three
axes or sections:
• South Silala. Longer branch, which develops predominantly from east to west.
• North Silala. Short branch, it develops predominantly from northeast to southwest.
• Silala Confluence Section. Confluence of the North and South Branches, it
develops predominantly from northeast to the south west.
78
215
79
OiARACTERIZATION AND EHIOENCY OF THE HYDRAULIC WORKS BUILT AND INSTAU.ED IN THE SHALA SECTOR
Figure 80. Geometry in the HEC-RAS Model {Digital Elevation Model {DEM), Electrode Emplacement Points, CrossSections).
(Source: Own elaboration, based on the topoeraphy provided by DIREMAR).
216
Annex 2 presents the detailed geometry of the three reached mentioned (North,
South and Confluence).
80
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Figure 81. Geometry in the HEC-RAS Model (Perspective, cross-Sections). (Source: Own elaboration)
217
8.5 DRAINAGE SYSTEM GRADIENT
The gradient is decisive in the hydraulic conditions inasmuch as it determines
the flow regime in the canal, where the critical, subcritical and supercritical
flows are defined. The gradient can be extracted from the geometric model,
from the topography or from the digital elevation model.
The system’s gentlest gradients are presented in the highest part (electrode emplacement
points 3+600 m-a 1+600 m) of the South branch of the Silala system,
and increase as the course develops, south branch (electrode emplacement
points 1+600 m to 0+00 m), particularly the north branch and the confluence
sections [sic]. The slope varies from 0.012 to 0.062 m/m.
81
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218
A detail of the longitudinal and hydraulic profiles is presented for the three
reaches (i.e. the North, South and Confluence reaches) is presented as Annex
2 hereto.
8.6 MANNING COEFFICIENT (n)
This coefficient provides the degree of resistance to the flow generated by the
canal contour and is related to its surface and the formation of materials.
The predominant material in the system of canals that are not stone-lined are
peats, high-altitude materials, and saturated areas; and in the system of stonelined
canals are rigid, rough, and solid [materials] in which the variation of the
water level is small, reason why a slow flow is estimated (subcritical regime).
Under these characteristics, the roughness coefficient is high, and varies between
0.06 and 0.25.
Table 7. Referential Manning roughness coefficient values. (Source: Ven Te Chow)
Tipo de can.al y descri;>cioo J>,finimo Nomul Mi'<imo
Excav•do o dnpdo
a. En tie.rra, recto y Ullllorme
I. Limpio~ recie.ntemente termin3do 0.016 0.018 0.020
2. Limpio, despues de e:q>OSici.on a la intemperie 0.018 0.022 0 .025
3. Coo gnvas, secciOo Wlllorme, limpio 0.022 0.025 0.030
4. Coo pi.stos cortos, a~ m.a.Je.z;as 0.022 0.027 0.033
b. En lien., S"'Jl-eante y lento
I. Sin vegetaci6n 0.023 0.025 0.030
2. Pis:tos, ~gun.as Ill31e.zas 0.025 0,030 0.033
3. Malezas dens1s o pl.antis acuiticu en cm.ales 0.030 0.035 0.040
profundos
4. F ondo en tierr.a con la dos e.n piedra 0.028 0.030 0.035
5. F oa.do pedregoso y bane as coo malezas 0.025 0.035 0.040
6. F ondo en cmtos rO<bdos y udos limpios 0.030 0.040 0.050
c. Excavado con pala. drag.ado
I. Sin vegetaci6n 0.025 0.028 0.033
2. Matorrales lireros e.n las bancas 0.035 0.050 0.060
d. C.ortes en roca
I. Li.sos y uni.fonnes 0.025 0.035 0.040
2. Afilados • irreguures 0.0356 0.040 0.050
e. Cm,!es wi maotenimwlto, nwezas y m.atorrales
sin cortar
I. Malezas dens.as, ran alt.ls como la. profundid.ad 0.050 0.0S0 0.120
de ilujo
2. Fondo limpio, matonales en los bdos 0.040 0.0 50 0.0S0
3. lgu.al nfrel mttimo de Oujo 0.045 0.070 0.110
4. Matornle:s de.osos, uivel alto 0.0S0 0.100 0.140
Conieotes naturales
1- Corriente> muores (aocho superlicial enninl
crec.i.e .ote 100 < pies) Corrie.ntes e.n pla.nicies
I. Limpi.a.s, rectn, m.iximo Divel, si.o monticulos 0.025 0.030 0.033
oi pozos profundos
2. Jg,ul al antuior, pero coo mas piedns y 0.030 0.035 0.040
malezas
3. Limpio serpentea.nte, alrunos pozos y bmcos 0.033 0.040 0.045
de arena
4. igiul al anterior, pero coo a.lgunos matoru.les 0.035 0.045 0.050
ypiedns
5. Jgual al .nterior, D.inles b,jos, peodientes y 0.040 0.04S 0.055
secciones mas ine£icientes
6. Jg,ul al 4, pero con m.as pieclns 0.045 0.050 0.060
7. Tn.m.os lentos, con mllle.za.s pozos profwldos 0.050 0.0 70 0.0S0
8. Tramos coo. muW maleza, pozos profundos o 0.075 0.100 0.150
cam.les de crecientes con much.os uboles con
m;iton.i.le.s bajos,
219
8.7 HYDROLOGICAL SCENARIO OF THE SYSTEM
The hydrological scenario of the system to be used for the hydraulic analysis
and evaluation of surface flow involves the analysis and processing of hydrometric
information (limnimetric levels and gauging in canals) to obtain a series
of values of simulation flowrates and average monthly values (see Table 9,
Table 10 and Figure 83). The hydrological regime establishes that the monthly
and seasonal variability is not significant, that is to say, that the oscillations and
magnitudes do not respond to the rain and drought seasons, but remain rather
stable throughout the year with very small range variations.
83
Table 8. Referential Manning roughness coefficient values (Continued). (Source: Ven Te Chow)
Tioo de canal v descriocion Minimo Normal Maximo
b. Corrientes montaiiosas, sin vegetaci6n en el canal,
bancas usualmente empinadas, :i!boles y mato!T'3les a lo
largo de las bancas sumergidas en niveles altos
1. Foudo: Gravas, cantos rodados y algunas 0.030 0.040 0.050
rocas
2. Foudo: Cantos rodados con rocas grandes 0.040 0.050 0.070
2- Planicies de inundaci6n
a. Pastizales, sin matorrales
1. Pasto corto 0.025 0.030 0.035
2. Pasto alto 0.030 0.035 0.050
b. Areas cultivadas
1. Sin cultivo 0.020 0.030 0.040
2. Cultivos en linea maduros 0.025 0.035 0.045
3. Campos de cultivo maduros 0.030 0.040 0.050
C. Mato!T'3les
I. Mato!T'3les disperses, mucha maleza 0.035 0.050 0.070
2. Pocos matorrales y :i!boles, en inv-ierno 0.035 0.050 0.060
3. Pocos mato!T'3les y :i!boles, en verano 0.040 0.060 0.080
4. Matorrales medios a densos, en inviemo 0.045 0.070 0.110
5. Matomles medios a densos, en verano 0.070 0.100 0.160
d. Arboles
1. Sauces densos, rectos yen verauo 0.110 0.150 0.200
2. Terreuo limpio, con troncos sin retofios 0.030 0.040 0.050
3. Igual al anterior, pero con una gran cantidad 0.050 0.060 0.080
de retoi'ios
4. gran cantidad de arboles, alguuos troncos 0.080 0.10 0.120
caidos, con poco crecimiento de matomles, nivel
de! agua por debajo de las ramas.
5. Igual al anterior, pero con nivel de crecieute 0.100 0.120 0.160
por encima de las ramas
3- Corrieutes mayores (ancho superficial en nivel
creciente > 100 pies). El valor den es menor que el
correspoudiente a corrientes menores con descripci6n
similar, debido a que las bancas ofrecen resistencia menos
efectiva.
a. Secci6n regular, sin cantos rodados ni matorrales 0.025 - 0.060
b. Secci6n irrei!Ular y rugosa 0.035 - 0.100
220
The flowrate in the system determines the flow depth necessary for a determined
flow, in addition to other hydrodynamic parameters of the environment
in which the water flows.
In the present study, the surface flow of the system under the baseline averageflow
hydrological scenario was simulated for the period with available data,
determined on basis of the information provided by SENAMHI through
DIREMAR and the processing and analysis of said data.
Figure 83 shows the spatial distribution of continuous gauging points
monitored by SENAMH; the scheme shows the gauging points from which the
incremental flows where obtained. Table 10 presents the incremental flows and
their calculation for the application of modeling scenarios by reaches.
84
Table 9. Point average flows measured in Continuous Gauging Sites "C:'. (Source: Own elaboration, based on information
from SENAMHI)
Codigo CAUDAL
Punto Punto de Aforo
11 1s I [m3 /s]
C1 Abra en el punb C-1 canal sur 26.25 0.0263
C2 Abra en el punb C-2 canal sur 33.94 0.0339
C3 Abra en el punb C-3 canal sur 34.14 0.0341
C4 Abra en el punb C-4 canal sur 52.09 0.0521
C5 Abra en el punb C-5 canal sur 94.20 0.0942
C6 Abra en el punb C-6 canal narte 52.06 0.0521
C7 Abra en el punb C-7 canal principal 134.31 0.1343
Table 10. Incremental average flows in Continuous Gauging Points "C''. (Source: Own elaboration, based on information
from SENAMHI)
POINT INCREMENT AL FLOW FLOW
CODE PER REACH
I II s I I m3 ts I
C1 Qc1 26.25 0.0263
C2 A Qc2 = Q c2 - Q c1 7.69 00077
C3 dQc3=Qc3-Qc2 0.20 0.0002
C4 dQc4 = Qc4 - Qc3 17.95 0.0180
C5 dQc5=Qc5-Qc4 42.11 0.0421
C6 Qc6 52 06 0.0521
C7 A Qc7 = Q c7 - Q c6 - Qc5 -11.95 -0 0120
221
85
7~"' ~ ;;\ .t,!
!
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0
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Figure 83. Hydraulic System of Silala and continuous Gauging Points monitored by SENAMHI.
222
8.8 HYDRAULIC REGIME OF THE FLOW
The hydraulic regime of the flow was calculated with the Froude number, which
defines whether the regime is Subcritical, Supercritical or Critical (Fr <1, Fr>
1, Fr = 1), through the HEC-RAS surface flow simulation program. The Froude
number was calculated for each point and the results are reflected in Annex 1.
This reach has a predominant Subcritical regime.
8.8.1. Gauging campaign of April 2018
The objective of the gauging campaign was to determine the referential roughness
coefficients and geometric and hydraulic parameters to calibrate the model.
Gauging has been carried out in 21 cross sections of the network of channels,
in correspondence with the gauging points of the SENAMHI.
Table 11 shows the results of the 21 measurements; 18 points correspond to the
main canal and 3 points correspond to secondary canals.
86
Table 11. Hydraulic characteristics at t he measurement points of the April 2018 campaign.
Main canal Main Seco
Depth
Water
Gradient Velocity
Manning
Flow
Froude
Flow
Horizontal
Area
denomination Canal nd ary
(m)
mirror
(m2) (m/m) (m/s)
Roughnes
(m3/s)
Number
type
alignment of the
Canal (m) ' canal in point
Cl 0.18 0.81 0.140 0.0246 0.264 0.148 0.037 0.20 Subcritical Straight canal
Sl 0 .165 0.60 0.096 0.0123 0.302 0.084 0.029 0.24 Subcritical Straight canal
S2 0.15 LlO 0.147 0.0143 0.259 0.105 0.038 0.21 Subcritical Straight canal
C2 0.09 0.90 0.088 0.0430 OA43 0.086 0.039 OA7 Subcritical Straight canal
S6 0.13 L20 0.138 0.0098 0.333 0.063 0.046 0.30 Subcritical Straight canal
C3 0.17 0.94 0.141 0.0325 0.298 0.144 0.042 0.23 Subcritical Straight canal
South
drainage
S7 0.11 LOO 0.101 0.0420 0.366 0.108 0.037 0.35 Subcritical Straight canal
canal S8 0.14 L 62 0.222 0.0224 0.206 0.175 0.046 0.18 Subcritical Straight canal
C4 0.12 0.90 0.100 0.0224 0.521 0.058 0.052 0.48 Subcritical Straight canal
Subcritical
Flow on rock with
S10 0.25 LOO 0.222 0.0624 0.509 0.142 0.113 0.33
soft curve
Subcritical
Flow on rock
S11 0.29 0.96 0.246 0.0624 0.519 0.150 0.128 0.31
with soft curve
cs 0.19 0.60 0.096 0.0624 1.013 0.057 0.097 0.61
Flow on rock
Subcritical
with soft curve
S18 0.07 0.36 0.024 0.103 0.002 0.12 Subcritical Straight canal
S17 0.09 OAS 0.036 0.915 0.033 0.97 Critical Straight canal
North S16 0.12 OA4 0.046 0.0520 0.255 0.156 0.012 0.24 Subcritical Straight canal
d,ainage S15 0.10 0.60 0.049 0.0520 0.756 0.055 0.037 0.76 Subcritical Straight canal
canal S13 0.12 0.60 0.081 0.786 0.064 0.72 Subcritical Straight canal
S12 0.15 0.55 0.074 0.0520 0.854 0.056 0.063 0.70 Subcritical Straight canal
CG 0.11 0.85 0.095 0.0624 0.635 0.078 0.061 0.74 Subcritical Straight canal
Confluence Desilting 0.09 LOO 0.090 1.726 0.155 L 84 Subcritical Straight canal
d,ainage chamber
canal
C7 030 0.90 0.251 0.0624 0.748 0.104 0.187 0.44 Subcritical Straight canal
S19 0.33 0.85 0.266 0.0624 0.815 0.099 0.217 OAS Subcritical Straight canal
223
8.9 HYDRAULIC SIMULATION OF THE SURFACE FLOW IN HECRAS
Simulation outputs are presented graphically for:
• Hydraulic profiles by reach
• Velocity profiles throughout the reach
• Longitudinal profile of the Froude number throughout the reach
• Longitudinal profile of the gradient throughout the reach
• Longitudinal profile of the hydraulic depths throughout the reach
The HEC-RAS program uses abbreviated parameters for its edition; those that
are of interest for the present project are listed below:
Q Total: Total Flow
Min Ch El: Minimum altitude in the main canal
Q Total: Total Flow
Min Ch El: Minimum altitude in the main canal
W.S. Elev: Water film elevation
Crit W.S: Water film elevation in a critical regime.
E.G. Elev: Elevation of the Energy line
E.G. Slope: Gradient of the power line
Vel Chnl: Velocity in the main canal
Flow Area: Hydraulic area
Top Width: Width of the water film
Froude # Chl: Froude Number
Vel Head: Energy of velocity
Wetted Per: Wet perimeter
Hydr. Depth: Hydraulic depth
Avg. Vel.: Average velocity
Annex 2 presents in detail the hydraulic profiles and simulated cross sections
for the hydrological base scenario, and the geometric and morphological
conditions described, for the three sections (North, South and confluence).
Figure 84 shows the results in Ras Mapper of Hec-Ras of the simulation, with
the DEM digital elevation model and the surface of the water film in light blue.
87
224
88
Figure 84. Present ation o f the Hydraulic Simulation in RAS Mapper (Silala).
225
8.10 Hydraulic Model Results
From the presented results, in both graphs and tables (annexes), concerning
the hydraulic simulation of the surface flow in the Silala System, it can be
concluded:
• Based on the topography provided by DIREMAR, it has been possible
to construct a DEM Digital Terrain Model with a 20x20 cm resolution detail,
which properly represents the Silala system with the detail required to obtain a
geometric model for a hydraulic simulation in HEC- RAS.
• The hydraulic parameters defined for the simulation (Manning roughness
coefficient and gradient) represent the conditions of the Silala hydraulic system.
• The hydraulic profile shows that there are slight depressions where a certain
amount of water accumulates (in these sections the depth is greater than the
average and the water flows out of the main canal).
• The velocity profile shows that speeds between 0.4 m/s predominate and
that velocities vary from a minimum of 0.2 m/s to a maximum of 1.0 m/s,
approximately. This also happens in the reaches with both gentle and greater
slopes, respectively.
• The predominant flow regime is subcritical, of the Froude Number profile,
in which values of Fr <1 predominate; however, there are areas of steeper
gradients (slope profile), which implies a higher speed and a Fr> 1 over 1.5,
approximately. This happens only at certain points.
• Average or predominant depth are less than 0.2 m, some stretches or points
of greater tension accumulate water or there are certain conditions that raise the
water flow depth.
89
226
9 CONCLUSIONS
9.1 NATURAL CONDITIONS
a) Bofedal category
The natural conditions of the waters of the Silala must be understood from a
physical- biological category defined by a water–soil–biotope unit. Trying to
explain the development of the water in isolation entails destroying the existing
link between the elements mentioned and the environment.
Within this framework, the waters of the Silala are fully integrated to the high
mountain wetlands, independent of the extension, gradient, and vegetation
and flow characteristics. Therefore, the water moves within this category [of
wetlands].
Although there is a short section in the southern branch where, due to the
geological conditions, the movement is superficial over a channel in the rock, the
body of water assumes again its status as a bofedal category at the confluence.
b) Water source
• There is no contribution from surface runoff in the basin.
The absence of surface runoff in the basin, as a result of the hydrological
response of precipitation, is demonstrated by two aspects:
■ The flow regime in each of the monitoring points does not vary in terms
of time; its behavior is practically constant throughout the whole year, i.e.
there is no seasonal variation.
■ Throughout the contribution basin it is not possible to find signs of laminar
runoff. There are no traces, even at the micro basin scale, of a drainage
network. In concrete terms, there are no fluvial processes in the basin due
to the absence of surplus precipitation. Surface flow is absent in the basin.
• The water source of the bofedals comes from groundwater inflows.
The waters that upwell along the bofedales are manifested as springs, which
deliver the water in the form of groundwater inflows to the bofedals; otherwise
it would not be possible to explain their existence.
The behavior of the flows in the different water control points, taking into account
the study period from May 2017 to March 2018, indicates that the only source of
inflows to the water bodies, defined by the bofedals and transition zones, originates
from groundwater. This hypothesis is also founded in the fact that the estimated
variation of the flows at the monthly level for the same water control point
90
227
(gauging points) does not show significant variations with respect to the average
flows.
c) Water movement
• Combination of movement in porous medium and surface flow that does
not concentrate in the bofedal.
The movement of water in the bodies of water of the Silala is governed by
gravity, however, it is necessary to differentiate this movement in the following
categories:
■ The movement of water through the bodies of bofedales develops slowly and
at a very slow pace, depending on the characteristics of the permeability, porosity,
content of organic matter, hydraulic gradient and flowrates.
■ The movement of water on the bofedals, under natural conditions,
without artificial intervention, has been developed in a micro-surface fashion
through unconcentrated branches where it is not possible to define a channel or
watercourse, properly speaking.
From a technical point of view, the natural movement of the Silala through the
Silala bofedals does not respond to the technical definition of a river, i.e. “a
large-scale water stream that drains a basin in a natural way”.
Although the term “of large dimensions” can be subjective in relation to the
magnitude of flow, however, it is distinguished that the contributions of the
body of the Silala are in the approximate order of 160 l/s, a comparatively low
value with other courses that originate in the Andean Cordillera.
In the Silala basin, there is no surface drainage because there is no contribution
of surface water that has the capacity to generate the mentioned flow.
9.2 STATE OF INTERVENTION ON BODIES OF WATER
The following conclusions have been reached in relation to the interventions
introduced in the waterbodies of Silala, through the implementation of hydraulic
works:
• Hydraulic system
The interventions introduced in the Silala waterbodies account for a hydraulic
system, these are not isolated works, but rather respond to a set of works, from
the abstraction works to outside the Bolivian territory.
• Purpose of these interventions
91
228
The main objective of the hydraulic works has been to improve the hydraulic
efficiency of abstraction and conveyance, by means of the intake works of the
springs and the drainage of water bodies through the channels.
The construction of unlined channels, channels with dry stone lining and perforated
pipes in the bofedales has caused a remarkable modification of the
original water regime. It has even caused the reduction of the flow that fed the
bofedales and in some cases the water supply has been interrupted to a great
extent, causing the desiccation of the bofedales.
• First intervention
Intake works
The intake works on the section of the confluence, according to the current
dimensions, had the capacity to capture and convey all the contribution of the
waters. The intake work was built in concrete.
Water conveyance works
The purpose of the conveyance works was to drive all the water collected in
the confluence, within Bolivian territory, to Chilean territory connecting a load
chamber to the intake.
• Second intervention
Specific intake works
The second intervention in the field of hydraulic works does not respond, as in
the case of the first intervention, to isolated actions, but to a global intervention,
composed of a set of collection or intake works in each of the springs that have
a higher flow. Its objective is to operate on the source of water right where it
originates, trying to reduce water losses as much as possible.
Longitudinal water conveyance works (conveyance canals)
The conveyance canals do not respond to the category of waterproofed pipes
designed “only” to direct the flow to lower areas, but are in themselves “drainage
canals”, whose objective is also to collect the water “laterally”, that is to
say through the depletion of the water table to increase the flow rate already
abstracted from each spring; hence these conveyance works are considered longitudinal
conveyance works.
• General characteristics of the hydraulic works
The introduction of the works in the Silala waterbodies have had characteristics
of significant “aggressiveness” to the environment, not only for its effects on
the water regime, but on the biotic environment. The drainage of the phreatic
level in the wetlands has caused the disappearance of healthy wetlands both in
the north and south bofedals.
92
229
The results of the hydraulic modeling performed for this survey show that the
water movement conditions in the Silala waterbodies have been modified significantly.
The incorporation of hydraulic works has changed the natural conditions
of water movement in porous medium and has turned an unconcentrated
surface flow into a free surface flow in the drainage canals implemented.
The modifications to the hydraulic behavior of the natural state of the bofedals
are striking in their impact on the velocities of the predominant water movement
in the porous medium, which is in the order of 2.3 x 10-9 cm/s in the
North bofedal and 6.5 x 10-9 cm/s in the south bofedal in its prior condition,
but then intervention reaches speeds of up to 0.4 m / s with extremes that vary
between 0.2 m/s and 1.0 m/s, approximately. The predominant flow regime is
sub-critical (Froude Number inferior to one), there are drops or inclined slope
areas with sub-critical regime (Froude Number inferior than one). In average,
the predominant depths are inferior to 0.2 m.
• Lengths and Types of Material of the Canals in Silala
The adduction systems in the South and North Bofedals, as well as in the confluence
canal are constructed with different materials and different lengths.
Among the most repetitive criteria for the construction of canals it has been
identified the canals excavated in natural soil, similarly, it has been identified
canals lined with dry masonry, masonry canals with binder and stone canals.
The length of the main and secondary canals in the South bofedal is of 3,685.5
m, while that comprising the main and secondary canals of the North bofedal
is of 1,800.0 m. The length of the main and secondary canals at the confluence
reach, on the other hand, is of 944.0 m.
The total length of main channels in the north, south and confluence bofedales
reaches 4,265 m, while the secondary lengths reach a length of 2,114.4 m. The
total length of channels built is 6,379 m.
Table 12 presents a summary of the lengths of the main and secondary canals
of the South and North Bofedals, and the confluence reach.
93
Table 12. Hydraulic characteristics at the measurement points during the April 2018 campaign.
Canal loneth, (m)
Sector Main Canal Secondary Canal Sub-Total
South bofedal 2871,0 8 14,5 3685,5
Nort h bofeda I 688,0 1112,0 1800,0
Confluence reach 706,0 238,0 944,0
Total 4265,0 2164,5 6429,5
230
9.3. SUMMARY
For all that has been verified and explained in the above chapters, it can thus
be concluded that the degree of intervention in the Silala bofedals, due to the
magnitude of the hydraulic works built, as well as the high level of efficiency
of water abstraction and channeling, has been demonstrated. The length of the
canals built exceeds 6 kilometers and the catchments in the major contribution
springs reach almost a hundred works. The flow with very low velocities –in its
natural state– has reached comparatively much higher values, due to the water
channeling through the built canals.
The interventions have not only affected the natural water supply of the springs
to the bofedals, but they have also affected the body of the bofedales themselves,
causing the drainage of these by means of the implementation of permeable
canals.
The hydraulic works have caused a strong impact on the natural environment,
since the initial condition of these bodies of water has not been respected as
natural reservoirs and regulators of the soil–water–biotope system.
The conservation of water bodies has been subordinated to a vision of intervention
with the basic principle of increase the amount of water abstraction for use
purposes.
In short, the main objective has been to drain the bodies of water from the
springs and bofedals.
94
231
REFERENCES
García, E. y Otto, M. 2015. 2, Lima : s.n., 2015, Ecol.apl., Vol. 14 Caracterización ecohidrológica
de humedales alto andinos usando imágenes de satélite multitemporales en la cabecera
de cuenca del Río Santa, Ancash, Perú. García, E. y Otto, M. 2015. 2, Lima : s.n., 2015,
Ecol.apl., Vol. 14.
CNCH. 1992. Modifica Artículos 58 y 63 del Código de Aguas. Legislación Chilena. s.l. :
Biblioteca Nacional del Congreso Nacional de Chile, 1992.
COFADENA. 2017. Estudio geofísico mediante tomografías eléctricas resistivas - ERT - del
área del Silala, Provincia Sud Lipez, Departamento de Potosí - Bolivia. Coorporación de las
Fuerzas Armadas para el Desarrollo Nacional (COFADENA), Dirección de Reinvindicación
Marítima, Silala y Recursos Hídricos Internacionales (DIREMAR). La Paz, Bolivia : Unidad
de Explotación de Recursos Hídricos (Ü.E.R.H.), 2017.
Technical Consultants, 2018. GEORREFERENCATION STUDY, TOPOGRAPHICAL
SURVEY AND DETERMINATION OF INFILTRATION CAPACITY IN THE FACE OF A
POSSIBLE SURFACE RUN OFF IN THE AREA OF THE SILALA SPRINGS. DIREMAR.
La Paz: s.n., 2018. Consultancy Report.
DIREMAR. 2017. Characterization of the Soils of the Silala Bofedals and surrounding areas.
DIREMAR. La Paz: PLURINATIONAL STATE OF BOLIVIA, 2017. p. 135, Consulting Report.
Fox, Robert H. 1922. The Waterworks Department of the Antofagasta (Chili) & Bolivia Railway
Company. Johannesburg : South African Journal of Science, 1922.
Gómez-García, R. 1997. Recursos Hídricos Transfronterizos entre las Repúblicas de Bolivia y
Chile. Unidad de Análisis de Política Exterior (UDAPEX), Ministerio de Relaciones Exteriores
y Culto de la República de Bolivia. La Paz, Bolivia : Corporación Andina de Fomento, 1997.
Hydrologic Engineering Center. 2011. HEC-GeoRAS GIS Tools for support of HEC-RAS
using ArcGIS User´s Manual. Version 4.3.93, Febreary. [ed.] Institute for Water Resources US
Army Corps of Engineers. Davis : s.n., 2011.
IGM. 2016. Ubicación georreferenciada, Aguas del Silala . Instituto Geográfico Militar. s.l. :
Agosto, 2016.
Jackson, C. Rhett, Thompson, James A. y Kolka, Randall K. 2014. Wetland soils, hydrology
and geomorphology. [aut. libro] D. Batzer y R., Sharitz. [ed.] University of California Press.
Ecology of freshwater and estuarine wetlands. Berkeley : s.n., 2014, págs. 23-60, Chapter 2.
Ramsar Convention of Wetlands. 1971. Acta final de la Conferencia Internacional sobre la
Conservación de los Humedales y las Aves Acuaticas. Ramsar, Irán : s.n., 1971. Acta de Conferencia
del 30 de enero al 3 de febrero de 1971.
—. 2016. Introducción a la Convención sobre los Humedales,. Subserie I Manual de la Convención
de RAMSAR. Gland, Suiza : Secretaria de la Convención de Ramsar, 2016. Manual 1.
—. 2010.
Manual de Lineamientos Ramsar en relación con el agua. Gland, Suiza : Secretaría de la
Convención de Ramsa, 2010.
Sangueza, Abel. 2016. Estudio de Prospección Geofísica por el Método de Tomografía Eléctrica
en el Sudoeste del Departamento de Potosí - Municipio de San Pablo de Lipez. [ed.]
MINISTERIO DE MEDIO AMBIENTE Y AGUA. [recopil.] VICEMINISTERIO DE AGUA
POTABLE Y SANEAMIENTO BASICO. La Paz, Bolivia : s.n., Julio de 2016.
SENAMHI. 2014. Servicio Nacional de Meteorología e Hidrología de Bolivia. http://www.
senamhi.gob.bo/. [En línea] 2014. [Citado el: 20 de 6 de 2014.] http://www.senamhi.gob.bo/.
232
95
SENAMHI-DIREMAR. 2018. Informe de Medición de Caudales en la Región de los Manantiales
del Silala. Ministerio de Medio Ambiente y Agua. La Paz : s.n., 2018.
SERGEOMIN. 2017. Mapeo geológico estructural del área circundante a los manantiales del
SILALA. Servicio Geológico Minero, DIREMAR. 2017.
The Antofagasta (Chili) & Bolivia Railway Company Ltd. 1928. New Intake Chambers,
etc. Siloli Chilean Section Estimates Nos. 1440/41. [Documento]. 29 de June de 1928. No 165.
—. 1928. Proposed open channel from Siloli Springs “Orientales” and “Cajon” to intake of
Siloli Pipe Line. 27 de January de 1928. No 143.
WMO. 2012. International Glossary of Hydrology. [ed.] United Nations Educational, Scientific
and Cultural Organization World Meteorological Organization. Geneva : s.n., 2012. No.
385.
96
233
97
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
lOANNEXES
ANNEX 1: DETAILED CHARACTERIZATION OF THE CANALS OF THE SOUTH,
NORTH AND CONFLUENCE BOFEDALS
UMSA-IHH
1. LOCATION
START
END
DESCRIPTION OF THE PHYSICAL CHARACTERISTICS OF THE SOUTH BOFEDAL
- PROGRESSIVE 0+000 - 0+099.04
WATER SYSTEM: SILALA SPRNGS I DIREMAR
EVALUATION SHEET OF CANALIZED REACH
DEPARTAMENT POTOSI MUNICIPALITY SAN PABLO DE LIPEZ
PROVINCE SOUTH LIPEZ CANTON QUETENA CHICO
WATER SYSTEM SI LALA SPRINGS
COMPONENT SOUTH CANAL
COORDINATES ELEVATION
PROGRESSIVE
ESTE NORTE (m.a.s.l)
0+000 603122.247 7565884.6 4406.98
0+099.04 603033.528 7565891.227 4404.45
2. MORPHOLOGICAL CHARACTERISTICS OF THE REACH
LONGITUDINAL PROFILE
PROFILE SHAPE REACH OF UNIFORM SLOPE WITH ALTERNATING REACHES WITH
CROSSES WITH DIVERSION CANALS
SLOPE RANGE% 2.3 I
DOMINANT LONGITUDINAL SLOPE % 2.3 I
CROSS SECTIONS IN THE REACH
PROGRESSIVE 0+010 PROGRESSIVE 0+080
Width(m) 1.40 Depth (m) I 0.1s Width(m) 1.20 I Depth (m) I o.3o
lo+oso oo I
10+010.00 I 4406 -~ 0O"N' -- 4406 ci ~
om .,.:..:~ ON w..,
cic.ci f:2::,.:
4407 -~ .,.:..: ~ -~ 4407 11'1 "--w 1ff w.., en .. 4405 - od - 4405
~ I
"--> 11f "--w
o d I
4406 4406 -1 1
-1 0 1
THE REACH IS MADE UP OF BOFEDAL PEAT MATERIAL. NO
MORPHOLOGY EROSION PROCESSES ARE OBSERVED. THE TERRAIN IS UNIFORM
WITH SLIGHT SLOPE DOWNWARDS
PLANT
CURVILINEAR IN THE FIRST THIRD OF THE REACH AND
FORM OF ALIGNMENT STRAIGHT IN THE MIDDLE AND FINAL PART OF THE REACH.
CHANNEL WIDTH VARIABILITY WITH NARROWING AND WIDENING
234
98
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
3. DESCRIPTION OF THE REACH
THE MATERIAL OF THE ANALYZED REACH IS OF NATURAL SOIL WITHOUT COATING. THE REACH PRESENTS A
UNIFORM SLOPE OF 2.3%. THE HORIZONTAL ALIGNMENT OF THE DRAINAGE CANAL IS CURVED IN THE FIRST THIRD
OF THE REACH AND STRAIGHT IN THE MIDDLE AND FINAL PART OF THE REACH. THE REACH IS MADE UP OF
BOFEDAL PEAT MATERIAL. NO EROSION PROCESSES ARE OBSERVED. THE TERRAIN IS UNIFORM WITH SLIGHT SLOPE
DOWNWARDS.
THE CIRCULAR SHAPE OF THE FIRSTTHIRD OF THE REACH AND THE SOUTHEAST TO NORTHWEST DIRECTION OF THE
STRAIGHT REACH HAS A HIGHLY EFFICIENT WATER COLLECTION FUNCTION.
- REACH OF THE PROGRESSIVE 0+000. COLLECTION OF WATER WITH SMALL CANALS FROM THE SPRINGS TO THE
MAIN CANAL.
- REACH OF THE FIRST THIRD. THE CIRCULAR SHAPE OF THE REACH AVOIDS THE MOVEMENT OF THE REMAINING
WATER FLOW FROM THE WATER EYES TOWARDS THE SOUTHEAST (CURRENTLYTHE SALINE BOFEDAL).
- MIDDLE AND FINAL REACH. THE STRAIGHT SECTION OF APPROXIMATELY 70 METERS AVOIDS THE REMAINING
FLOW OF THE WATER EYES TOWARDS THE SOUTHEAST (SALINE BOFEDAL) AND TOWARDS THE WEST (SOUTH
BOFEDAL AFTER THIS REACH).
THE IMPACT OF THE EFFICIENT UPTAKE OF WATER IN THIS REACH IS OBSERVED IN THE SOUTHEASTERN BOFEDAL,
WHICH IS TOTALLY DEGRADED (CURRENTLY THE SALINE BOFEDAL) AND THE SOUTH BOFEDAL AFTER THIS REACH
(DEGRADED BOFEDAL).
4. PHOTOGRAPHS
BOFEDAL SOUTHEAST OF THE ANALYZED REACH. THE MOVEMENT OF WATER TOWARDS THIS BOFEDAL HAS BEEN
TOTALLY ANNULLED, ATTHE MOMENT IT IS A DEGRADED SALINE BOFEDAL
235
99
7565900
7565850
7565800
602800
602800
4410
4408-
4406·
440- ·
440r-<
4400
43'JIH
PROCR!_SIVA
K:OTA 1£RREN<l
SOUTH CANAL - PROGRESSIVE 0+170 - 0+288.08 - SLOPE 1.4 %
602850 602900
602850 602900 602950 603000 603050
1~ ROGRESIVA 0+170- 0- 28808 - CANAL MAMPOSTERIA OE p EOR!,_l
Longitud 118.08 m - pie 1.4 %
--- - -------- ···--- ·---- ·-•-- .....,........-. ·---•--- ·---·· - .. - - ____ ,,
1
603100
7565900
7565850
=r:J 7565800
603100
()+160 0+170 0+180
J40J 95 440182 440370
()+200
4403.49
0+220 (}+ ?"1
url~m
0+260
440289
Ot 280 Ot 288. 08 Ot 300 I
440328 4402 67 4402.54 4402 46 I
LEYENDA DE SIM BOLOS CONVENOONALES
.........._ EJC AlOGRESf'M TtJ8ERlA'S: _.,,,.,,-- CMIAl.U. RIO$ Y OUf.£tRADA$ OOFB)Jl.ES M QJOSDEAGuAVYAtWfflAi.CS CURVAOE NIVEl C#(JA. tm
Figure 86. Plant and Longitudinal Profile of the South canal Reach between the progressives Of-170 and Of-288.08 - South Bofedal of the Sllala Springs. (Source: Own elaboration
based on data provided by DIRE MAR)
236
100
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
DESCRIPTION OF THE PHYSICAL CHARACTERISTICS OF THE SOUTH CANAL -
PROGRESSIVE 0+170 - 0+288.08
UMSA-IHH WATER SYSTEM: SILALA SPRNGS I DIREMAR
EVALUATION SHEET OF CANALIZED REACH
1. LOCATION
MUNICIPAL!
DEPARTAMENT POTOSI TY SAN PABLO DE LIPEZ
PROVINCE SOUTH LIPEZ CANTON QUETENA CHICO
WATER SYSTEM SI LALA SPRINGS
COMPONENT SOUTH CANAL
PROGRESSIVE
COORDINATES ELEVATION
EAST NORTH (m.a.s.l)
START 0+170 602963 756S891 4403.95
END 0+288.08 602850 7565860 4402.58
2. MORPHOLOGICAL CHARACTERISTICS OF THE REACH
LONGITUDINAL PROFILE
PROFILE SHAPE UNIFORM PROFILE WITH FAIRLY ALIGNED
CANALIZATION.
SLOPE RANGE% 1.4
DOMINANT LONGITUDINAL SLOPE% 1.4
CROSS SECTIONS IN THE REACH
PROGRESSIVE O+ 180 PROGRESSIVE 0+270
Width(ml I o.95 Depth (ml I 0.28 Width(ml I L55 I Depth (ml I 0.24
Io+ 210.00 I
Io+ 1so.oo I 4404 -,- D ro - - 4404
4405 + + 4405 D,....
DD c:iN
D,.... cirri ~,.:..;.::~ ~~
W ,q- u_ w il'--1 1!f ~> 4403 - I"---... D d - 4403
4404 - "- w D d tr~ 4404 I I I
I -1 0 1 -1 0 1
MORPHOLOGY
IN BOTH MARGINS THERE ARE BOFEDALS AND THE
CONFIGURATION OF BOTH FLANKS IS UNIFORM
PLANT
FORM OF ALIGNMENT STRAIGHT REACH
CHANNEL WIDTH VARIABILITY WITH NARROWING AND WIDENING
237
101
3. DESCRIPTION OF THE REACH
The material of the analyzed reached is of stone masonry. The reach presents a uniform slope. In both margins
there are bofedals and the configuration of both flanks is uniform. The reach does not present lateral water
income.
The rectilinear alignment and the masonry material prevent losses of water from the canal towards the bofedal.
The impact of the efficient water channeling of the analyzed reach (and the efficient abstraction and channeling of
the reaches upstream) can be seen in the difference in groundwater levels from the progressive 0+000 to 0+280.
The water table in the vicinity of the progressive 0+000 is 0.20 meters below the surface of the terrain, while the
water table in the progressive 0+250 is 0.45 meters below the surface (Orzag, 2017).
238
102
CHARACTERIZATION ANO EFFICI.ENCY OF THE HYDRAULIC \VORKS BUILT ANO INSTALLED IN THE SI LALA SECTOR
SOUTH CANAL - PROGRESSIVE 0+170 - 0+288.08 - SLOPE 1.4 %
755590n I 1~~zc:
7565850
7565800
602800 602850 602900 602950 603000 603050
4410 -
4408 - PROGRESIVA 0+170- 0+ 288.08 - CANAL MAMPOSTERIA DE PIEDRA
4406 - Longitud 118.08 m - p\e 1.4 %
4404 L I
4402 -
4400
4398 - T T T r T T
I I I I I
PR0GRESIVA 0+160 0+170 0+180 0+700 0+220 n+?4 0+ 60 0+2H0 0+288.08
A 44n_•;,gs 4403.82 4403.70 44 .49 44 .2R rn n 4402.89 4407 67 4407 ."i4
LEYENDA DE SIMBOLOS CONVENCIONALES
-...... E..E - FROGRESIVA ............ TUBERIPS ---- CPNAI..ES. RIOSYQUEEIRAOAS e BOFB>,.._ES ¥ OJOSOEAGUAYw>.NANTIAI.ES
7565900
7565850
7565800
603100
T
0+300
4402.46
Figure 86. Pla nt and Longitu dina l Profile of the Sout h Ca n al Reach between the p rogressives 0+170 and 0+288.08 - South Bofedal of the Sil ala Springs. (Source: Own e laboration
based o n d at a provided b y D IRE MAR)
239
103
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AN D INSTALLED IN THE SILALA
SECTOR
DESCRIPTION OF THE PHYSICAL CHARACTERISTICS OF THE SOUTH CANAL -
PROGRESSIVE 1+760 TO 1+783.66
UMSA-IHH WATER SYSTEM: SILALA SPRNGS I DIREMAR
EVALUATION SHEET OF CANALIZED REACH
1. LOCATION
MUNICIPALI
DEPARTAMENT POTOSI TY SAN PABLO DE LIPEZ
PROVINCE SOUTH LIPEZ CANTON QUETENA CHICO
WATER SYSTEM SI LALA SPRINGS
COMPONENT SOUTH CANAL
COORDINATES ELEVATION
PROGRESSIVE
EAST NORTH (m.a.s.l)
START 1+760 601576 7565242 4376.61
END 1+783.66 601555 7565252 4376.23
2. MORPHOLOGICAL CHARACTERISTICS OF THE REACH
LONGITUDINAL PROFILE
PROFILE SHAPE UNIFORM SLOPE OF 1.6%
SLOPE RANGE% 1.6
DOMINANT LONGITUDINAL SLOPE% 1.6
CROSS SECTIONS IN THE REACH
PROGRESSIVE 1+760 PROGRESSIVE 1 + 780
Width(m) 12.10 Depth (m) I 0.24 Width(m) I 3.20 I Depth (m) I 0.19 "'" L 1:-i~~ A'""
4378
11t180.001
4378
8:el
4377 ~I;, 4377
4377 ~ ~ 4377 ..... t;~ ~
4376 I I I I I I I 4376
4376 _1 O 1 4376 I I I I I I I
-2 -1 0 1
THE RIGHT FLANK OF THE REACH IS LOOSE GRANULAR
MORPHOLOGY MATERIAL AND THE LEFT FLANK IS ROCKY MATERIAL
WITH EXPOSURE TO WIND EROSION PROCESSES
PLANT
FORM OF ALIGNMENT CURVILINEAR
CHANNEL WIDTH VARIABILITY WITH NARROWING AND WIDENING
240
104
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
3. DESCRIPTION OF THE REACH
THE MATERIAL OF THE ANALYZED REACH IS OF STONE MASONRY. THE REACH PRESENTS A UNIFORM SLOPE. THE
RIGHT FLANK OF THE REACH IS LOOSE GRANULAR MATERIAL AND THE LEFT FLANK IS ROCKY MATERIAL WITH
EXPOSURE TO WIND EROSION PROCESSES. THE WIDTH FROM THE PROGRESSIVE 1+630 TO THE PROGRESSIVE
1+740 IS WIDE, IT VARIES BETWEEN 3 TO 4.5 METERS AND THE DEPTH VARIES BETWEEN 0.2 TO 0.4 METERS. IN THE
ANALYZED REACH THERE IS A SLIGHT NARROWING OF THE WIDTH TO 2.1 METERS. THE STONE MASONRY
MATERIAL OF THE ANALVZED REACH PROTECTS THE CURVE OF THE CANAL FROM THE EROSION OF THE FLOW,
WITH THE FLOW IN THE REACH OF 0.05 M3/S.
241
105
7566250
7566200
601450 601500
PROTECTION OF THE CHANNEL IN THE
CURVE WITH STONE MASONRY TO AVOID
EROSION OF THE FLOW
601450 601500
601550
601550
601600
601600
601650
CUTS IN THE NATURAL TERRAIN
TO OBTAIN THE UNIFORM SLOPE
IN THE CANAL
601650
438l
4380
PROGRESIVA 1+760-1+783.66
CANAL DE MAMPOSTERIA DE PIEDRA
Long. 23.66 m - PTE 1.6 %
601700
,:,,_
601700
4378t .........
4376 = CT--... .. -.......................... , ............. ............ 1
!.±.UQ. 1+740 1+760 +783-7 1±_8~ Li8.1Q. 1±_8.1Q.
4~ 4376.77 4376.61 ~376.V 4375.98 437~.80 437~43
LE'l'ENOA_QE S1MB_QLOS_C<lNIIE1"C10_1'l~LES
7566250
7566200
' EJE • RIOGREStVA T\ftRIAS ~ CN4ALES, .R..IOS YOVB3AADAS OOFED,,11.ES ~ OJOSOEK'JJA Y MNWfrtAl.fS CUltVAOE.NfVEl. (:AOA 11'1'1
Figure 87. Plant and Longitudinal Profile of Reach between the progressives 1+783 and 1+783.66 - South Bofedal of the Silala Springs. (Source: Own elaboration based on data
provided by DI REMAR)
242
106
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
DESCRIPTION OF THE PHYSICAL CHARACTERISTICS OF THE SOUTH BOFEDAL - REACH
1
UMSA-IHH WATER SYSTEM: SILALA SPRNGS I DIREMAR
EVALUATION SHEET OF THE NATURAL SECTION CANAL
1. LOCATION
MUNICIPAL!
DEPARTAMENT POTOSI TY SAN PABLO DE LIPEZ
PROVINCE SOUTH LIPEZ CANTON QUETENA CHICO
WATER SYSTEM SI LALA SPRINGS
COMPONENT SOUTH SPRING
PROGRESSIVE
COORDINATES ELEVATION
EAST NORTH (m.a.s.l)
START 2+060 601302.667 7566271.441 4371.21
END 2+092 601252.916 7566276.059 4366.16
2. MORPHOLOGICAL CHARACTERISTICS OF THE REACH
LONGITUDINAL PROFILE
VARIABLE AT SHORT AND MEDIUM DISTANCES.
PROFILE SHAPE INTERNAL REACHES OF VARIED SLOPES TO SUBHORIZONTAL
SLOPE RANGE% 5.S-6.6
DOMINANT LONGITUDINAL SLOPE% 5.75
CROSS SECTION TYPE - CANAL (ST)
FORM OF THE SECTION IRREGULAR TRAPEZOIDAL
AVERAGE WIDTH IN THE BED (A) [ml 1.15
DEPTH OF THE SECTION (H) [ml 0.21
RIGHT BANK SLOPE (STd) % 144.90
LEFT BANK SLOPE ($Ti)% 268.75
MORPHOLOGY
STEEP FLANKS DUE TO EROSION OR ANTHROPOGENIC
EFFECT
CROSS SECTION TYPE - FLANK (SF)
RIGHT FLANK SLOPE (SFd) % 250.87
LEFT FLANK SLOPE (SFI) % 52.83
AVERAGE DEPTH OF THE FLANKS (H) [ml 12.92
PLANT
FORM OF ALIGNMENT CURVILINEAR WITH THREE MAIN CURVES
CHANNEL WIDTH VARIABILITY WITH NARROWING AND WIDENING
243
107
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
3. DESCRIPTION OF THE REACH
THE DOMINANT LITHOLOGY OF THE BED IN THE ANALYZED REACH HAS SANDS AND ROCK, WITH DISPERSED
ORGANIC MATERIAL. IN THE CURVED PARTS OF THE ALIGNMENT OF THE CHANNEL THE PRESENCE OF BOFEDALS
STANDS OUT WHERE THE FLOW HAS A DIFFUSE BEHAVIOR. THE CROSS SECTIONS OF THE REACH HAVE HIGH SLOPE
FLANKS WITH A MINIMUM HEIGHT OF 16 METERS.
4. REPRESENTATIVE CROSS SECTION
a) FLANK b) CANAL
12+090.00 I
1 2+090.00 I
4380 Sfda81B51
_,,
4380
4370 mo 4370 T~=14&.5ir,,
4370
1"- H~l07
4360 4360 ,\, I 1;
4340
- 20 -10 0 10 20
4340 nl-''-la.~~l
4360 10 5 0 5
4360
244
108
~
le
TRAMO l • RANGO DIPINDIINTE S.S-6.,o/. • PROGRISIV A 2+il35.30-2-Hl9l9'
601300 6 01280 601260
---------- --~-:_t=--=-- ----:7/.~~·~• 1/,· ~~11
;,,---~~ ~~-"' -~':_~ - : . ;?= <-;,--;; 0 __ ..~. .._,_ )\ ;::; (
. -~ ~ . ..t:.
~ - ./ ~- '
'::;:;;- ....---~ ~- (
·~ I \ ~~
t "'l "~ ,/': ;f/', '-"'-~-'--~.:8:==-1 ~. -,~->, "-~~~~ ~ ~~- "" ~~
601300 601280 601260
-1- 4J72-: ~ 5.Ml%
E
5.75% S!
..;
4.368-: - - . .62% I
l i - - 1 4.364.-=- - . TRAMO 1 - :- Rqo Ptrdtra: 5.5% - 8.8".4 4.360- -- ' -~ ~
•U56.= --
ii !g ,~ ti !i ,~ i 'II! ,; ~; -1 ~·8 ~
Ii i~ ii ii ,~ ·-~lit ,..S ii;; ii •-llll 5"1'5
LEYENDA DE S-..tBOLOS CONVENCIOHA LES
......_ &.IE- PIIDOIUBIIM Til■a.i,;e: .,,,,,,,,-,- CJulM..E,JU)SYQIISIII.M.118 "!.. a) I SIALBE li,t O,l08.EK>"IJAY •~·.Alr'T1AL~
Figure 88. Plant and longitudinal Profile of Reach 1, between the progressives 2+o60 and 2+092 - South Bofedal o f the Sllala Springs. (Source: Own elaboration based on data
provided by DIREMAR)
245
109
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
DESCRIPTION OF THE PHYSICAL CHARACTERISTICS OF THE SOUTH CANAL - REACH 2
UMSA-IHH WATER SYSTEM: SI LALA SPRNGS I DIREMAR
EVALUATION SHEET OF THE NATURAL SECTION CANAL
1. LOCATION
MUNICIPAL!
DEPARTAMENT POTOSI TY SAN PABLO DE LIPEZ
PROVINCE SOUTH LIPEZ CANTON QUETENA CHICO
WATER SYSTEM SI LALA SPRINGS
COMPONENT SOUTH SPRING
PROGRESSIVE
COORDINATES ELEVATION
EAST NORTH (m. a.s. l)
START 2+092 601253.175 7566268.023 4363.61
END 2+310 601067.271 7566199.469 4357.68
2. MORPHOLOGICAL CHARACTERISTICS OF THE REACH
LONGITUDINAL PROFILE
PROFILE SHAPE
VARIABLE AT MEDIUM AND LONG DISTANCES. REACHES
WITH LOW SLOPES TO SUB-HORIZONTAL.
SLOPE RANGE% 2.5 -4.5
DOMINANT LONGITUDINAL SLOPE% 3.36
CROSS SECTION TYPE - CANAL (ST)
FORM OF THE SECTION IRREGULAR TRAPEZOIDAL
AVERAGE WIDTH IN THE BED (A) [m] 0.90
DEPTH OF THE SECTION (H) [m] 0.40
RIGHT BANK SLOPE (STd) % 716.67
LEFT BANK SLOPE ($Ti)% 400
MORPHOLOGY
STEEP FLANKS DUE TO EROSION OR ANTHROPOGENIC
EFFECT
CROSS SECTION TYPE - FLANK (SF) .I
RIGHT FLANK SLOPE (SFd) % 50.22
LEFT FLANK SLOPE (SFI) % 84.80
AVERAGE DEPTH OF THE FLANKS (H) [m] 9.38
PLANT
FORM OF ALIGNMENT CURVILINEAR WITH ONE MAIN CURVE
CHANNEL WIDTH VARIABILITY WITH CONSTANT SECTION, NARROWING AND WIDENING
3. DESCRIPTION OF THE REACH
THIS SECTION PRESENTS A TOPOGRAPHIC DIFFERENCE OF 5 METERS. ITS MAIN CHARACTERISTIC IS THE
CONCENTRATED FLOW THROUGH A CHANNELIZED REACH WITH ROCK FORMATION. THROUGHOUTTHIS REACH THERE
IS NO FLOW CANALIZATION, PROBABLY BECAUSE THE FLOW IS FORCED TO PASS THROUGH THE NARROWING AND THE
CONTOUR FORMED OF APPARENTLY HEALTHY ROCK.
246
110
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
4. REPRESENTATIVE CROSS SECTION
a) FLANK b) CANAL
I 2+120.00 I 12+ 120.00 I
4390 4390 4365 4365
4380 Sfdal1.85ll SFF$,81~
4380 4364 4364
~ / -A=UO nr ,L
4370 ~ ~ ~~ 4370 436J - 1 .___..., ,L ,...... 436l
.£._A_ 7J .,n
~ 4360 ~ , .. •\,JO~- 4360 4362 ~ ~ 4362
i I s ,llll.~~
4350 4350 4361 4361
ST<F\C<!.IH
4340 - O - 0 10 b 4340 4360 4360 - 1
I 2+230.00 I I 2+230.00 I
4390 4390
4362 4362
4380 4380
SFd=51.76% SFi-92.50% --H=0.80m
4361 >=Fli\..1 - e== 4361
4370 ll" -!•1J25m-/
4370
4360 .:i ~ ~ 4360 4360 71' IT1'i155 55 ~ C ,-.•,:BO ~ 4360
:l ,(I od " ~ 4J59 STd•1I 0.7 ,. 4J59
4350 4350
43511 4J5B
4340 4340 -1
-20 -to 0 10 20
247
111
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
4. REPRESENTATIVE CROSS SECTION
a) FLANK b) CANAL
2+ 290.00
12+290.001
4380 4380
IJ60
~ -ml Sf~.81111
4370 4370
4359
4360 4360
ll58
4350 4350
ll57
4340 4340
4J56
4330
-20 -10 10 20
4330
5. FOTOGRAFfA
248
112
'IRillO 1-RilGO DI PDIDIDl'D ~ -ft.OCDSWA~-Z~
7566200
la
li'I
.1.B..
....
81
OI
00
0
0
~
Is
§
~
0 ....
~ ; . ~ - ..,,
§!
t::l lo
601250 601200 7006200 601100 7 006200 60104)
l"RIW02 -
P~ .2.Sti-4.6%
11 ll
ii II
LEYENOAOE Slt.lBOLDS CONVENCIONALES
.,...,....., ,,,,,.-- C )JIA.LSS, 1'.IOS Y Q 1111 E■aMJIIIB IOfEt.AL.16' ~ O.0SDl!!JIIIIO.AVUAll-"-TIIU..B!!!t ~ Cl■R."'°'OE■l'Ula,. CMA'WI
Figure 89. Plant and Longitudinal Profile of Reach 2, between the progressives 2+o92 and 2+310 - South Bofedal of the Silala Springs. (Source: Own elaboration based on data
provided by DIREMAR, GOOGLE EARTH)
249
113
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
DESCRIPTION OF THE PHYSICAL CHARACTERISTICS OF THE SOUTH CANAL - REACH 3
UMSA-IHH WATER SYSTEM: SI LALA SPRNGS I DIREMAR
EVALUATION SHEET OF THE NATURAL SECTION CANAL
1. LOCATION
MUNICIPAL!
DEPARTAMENT POTOSI TY SAN PABLO DE LIPEZ
PROVINCE SOUTH LIPEZ CANTON QUETENA CHICO
WATER SYSTEM SI LALA SPRINGS
COMPONENT SOUTH SPRING
PROGRESSIVE
COORDINATES ELEVATION
EAST NORTH (m.a.s. l)
START 2+310 601067.271 7566199.469 4357.68
END 2+377 601000.401 7566163.514 4351.60
2. MORPHOLOGICAL CHARACTERISTICS OF THE REACH
LONGITUDINAL PROFILE
PROFILE SHAPE CONSTANT WITH LOW SLOPES.
SLOPE RANGE% 9.09
DOMINANT LONGITUDINAL SLOPE% 9.09
CROSS SECTION TYPE - CANAL (ST)
FORM OF THE SECTION IRREGULAR TRAPEZOIDAL
AVERAGE WIDTH IN THE BED (A) [m) 1.23
DEPTH OF THE SECTION (H) [m) 0.50
RIGHT BANK SLOPE (STd) % 172.41
LEFT BANK SLOPE (STi)% 175
MORPHOLOGY
STEEP FLANKS DUE TO EROSION OR ANTHROPOGENIC
EFFECT
CROSS SECTION TYPE - FLANK (SF) I
RIGHT FLANK SLOPE (SFd) % 43.37
LEFT FLANK SLOPE (SFI) % 79.46
AVERAGE DEPTH OF THE FLANKS (H) [m) 14.69
PLANT
FORM OF ALIGNMENT STRAIGHT AND CURVILINEAR WITH ONE MAIN CURVE
CHANNEL WIDTH VARIABILITY WITH CONSTANT SECTION
3. DESCRIPTION OF THE REACH
THIS REACH HAS A NATURAL COURSE WITH ROCK PROTECTIONS ON THE WALLS, THE SLOPES ARE SMOOTH AND THE
FLOW IS SLIGHTLY TURBULENT. THERE IS NO SEDIMENT TRANSPORT AND NO SEDIMENTATION PROCESSES ARE
OBSERVED.
250
114
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
4. REPRESENTATIVE CROSS SECTION
b) FLANK b) CANAL
2+370.00
12+370.00 I
4380 4380
4354 4354
4370 Sfd=4S.SHII 4370
~
SF~l\l.~ !I
4353 mJ
4360 4360
4352 4352
4350 4350
~
0 4351 4351
II
4340 :c: 4340
4350 4350
4330
5. FOTOGRAFIA
251
115
TR,U,I05-RANGODIPINDIINTB1%-33%-PROGR181VA 1+611-.2+710
600840
600B00 600760 600720
LEYENDADE SIMBOLOS CONVENCIONALES
' EJE- PROGRESIIIA TIJBERIAS ---- CANP.LES. ROSVOUEBR"-OAS IIOFEOAlES ~ OJOS DEAGUI\ V ll'1lAIITII\LES
gj
!
i Q
CURVAOENIVEL CADA Im
Figure 92. Plant and Longitudinal Profile of Reach 5, progressive 2+618 to 2+ 710 - South Bofedal of the Silala Springs. Source: Own elaboration based on data provided by
DIREMAR, GOOGLE EARTH.
252
116
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
DESCRIPTION OF THE PHYSICAL CHARACTERISTICS OF THE SOUTH CANAL - REACH 4
UMSA-IHH WATER SYSTEM: SI LALA SPRNGS I DIREMAR
EVALUATION SHEET OF THE NATURAL SECTION CANAL
1. LOCATION
MUNICIPAL!
DEPARTAMENT POTOSI TY SAN PABLO DE LIPEZ
PROVINCE SOUTH LIPEZ CANTON QUETENA CHICO
WATER SYSTEM SI LALA SPRINGS
COMPONENT SOUTH SPRING
PROGRESSIVE
COORDINATES ELEVATION
EAST NORTH (m.a.s. l)
START 2+377 601001.015 7566163.683 4351.56
END 2+462 600839.034 7565964.318 4337.57
2. MORPHOLOGICAL CHARACTERISTICS OF THE REACH
LONGITUDINAL PROFILE
PROFILE SHAPE CONSTANTS WITH LOW SLOPES.
SLOPE RANGE% 4.95
DOMINANT LONGITUDINAL SLOPE% 4.95
CROSS SECTION TYPE - CANAL (ST)
FORM OF THE SECTION IRREGULAR TRAPEZOIDAL
AVERAGE WIDTH IN THE BED (A) [m) 1
DEPTH OF THE SECTION (H) [m) 0.30
RIGHT BANK SLOPE (STd) % 143.75
LEFT BANK SLOPE (STi)% 384.64
MORPHOLOGY
STEEP FLANKS DUE TO EROSION OR ANTHROPOGENIC
EFFECT
CROSS SECTION TYPE - FLANK (SF)
RIGHT FLANK SLOPE (SFd) % 13.72
LEFT FLANK SLOPE (SFI) % 51.85
AVERAGE DEPTH OF THE FLANKS (H) [m] 68.81
PLANT
FORM OF ALIGNMENT STRAIGHT AND CURVILINEAR WITH THREE MAIN CURVES
WITH CONSTANT SECTION AND NARROWING OF THE
CHANNEL WIDTH VARIABILITY CHANNEL
3. DESCRIPTION OF THE REACH
THIS REACH HAS CHARACTERISTICS SIMILAR TO THE IMMEDIATELY SUPERIOR REACH, HOWEVER IT IS SEEN THAT THE
TURBULENCE IS SMALLER AND THE SLOPE DECREASES WITH RESPECT TO THE PREVIOUS ONE. THE PRESENCE OF
GREATER FLOW IS ALSO APPRECIATED, BUT NO SPRINGS ARE OBSERVED WITH THE NAKED EYE.
253
117
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
4. REPRESENTATIVE CROSS SECTION
a) FLANK b) CANAL
I 2+s60.oo I
I 2+s60.oo I
4370 4370
4345 4J45
4360 4360
Sfd=51.85!1 4344 4344
4350 4350
434J 4343
4340 ~ ,0. , 4340 Sli 384 1'1i
0 4342 4J42 II Sli 143. Sib
:,:
4330 4330
4341 4J41
4320
-20 - 10 0 10 20
4320
5. FOTOGRAFIA
254
118
CHARACTERIZATION AN IJ EFFICIENCY OF THE HYIJRAULJC WORKS BUILT ANIJ INSTALLEU IN THE SILALA SECTOR
'J:RAM04 -:RANGO DI PEIU)llffl4~-PROGIIS1VA ,+377-l+.!Q
I
II
LEYENDADE SIM BOLDS CONIIENCIONALES
llJIBU'G ,,,,....,.., CA.IIAUB,RQSYQ IIEI IIADIC3 .,
{) IOfEMUB ~ 0J:>8D EJOUAYMAIIAITWJB ~ CII R~ DE I IVEL CAOA.tm
Figure 91. Plant and Longitudinal Profile of Reach 4, between the progressives 2+380 and 2+462 -South Bofedal of the Silala
Springs. (Source: Own elaboration based on data provided by DIREMAR, GOOGLE EARTH)
255
119
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
DESCRIPTION OF THE PHYSICAL CHARACTERISTICS OF THE SOUTH BOFEDAL - REACH
5
UMSA-IHH WATER SYSTEM: SI LALA SPRNGS I DIREMAR
EVALUATION SHEET OF THE NATURAL SECTION CANAL
1. LOCATION
MUNICIPAL!
DEPARTAMENT POTOSI TY SAN PABLO DE LIPEZ
PROVINCE SOUTH LIPEZ CANTON QUETENA CHICO
WATER SYSTEM SI LALA SPRINGS
COMPONENT SOUTH SPRING
PROGRESSIVE
COORDINATES ELEVATION
EAST NORTH (m.a.s. l)
START 2+618 600839.034 7565964.318 4339.20
END 2+710 600737.348 7565914.940 4329.10
2. MORPHOLOGICAL CHARACTERISTICS OF THE REACH
LONGITUDINAL PROFILE
VARIABLE AT SHORT AND MEDIUM DISTANCES.
PROFILE SHAPE INTERNAL REACHES OF VARIED SLOPES TO SUBHORIZONTAL.
SLOPE RANGE% 1-33 I
DOMINANT LONGITUDINAL SLOPE% 15.76
CROSS SECTION TYPE - CANAL (ST)
FORM OF THE SECTION IRREGULAR TRAPEZOIDAL
AVERAGE WIDTH IN THE BED (A) [ml 1.62
DEPTH OF THE SECTION (H) [ml 1.15
RIGHT BANK SLOPE (STd) % VERTICAL
LEFT BANK SLOPE (STi) % VERTICAL
MORPHOLOGY
STEEP FLANKS DUE TO EROSION OR ANTHROPOGENIC
EFFECT
CROSS SECTION TYPE - FLANK (SF)
RIGHT FLANK SLOPE (SFd) % 477.87
LEFT FLANK SLOPE (SFI) % 110.05
AVERAGE DEPTH OF THE FLANKS (H) [m] 25.16
PLANT
STRAIGHT AND CURVILINEAR WITH THREE MAIN
FORM OF ALIGNMENT CURVES
WITH CONSTANT SECTION AND NARROWING OF THE
CHANNEL WIDTH VARIABILITY CHANNEL
3. DESCRIPTION OF THE REACH
THE LAST REACH OF THIS CHANNELIZED AREA HAS A TYPICAL CHARACTERISTIC OF FLOW THROUGH CHANNELS,
BECAUSE THERE IS NO CLEAR ALIGNMENT AND TOTALLY IRREGULAR SECTION DUE TO THE ROCK FORMATION.
THE FLOW DEVELOPS WITH TOTAL TURBULENCE AND THE VELOCITIES ARE VERY HIGH.
I
256
120
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
4. REPRESENTATIVE CROSS SECTION
a) FLANK b) CANAL
4370
4360
4350
4340
4330
4320
1 2+6so.oo I
d
I
:i::
4370
4360
4350
4340
4330
4320
4310 -20 -10 0 10 20 4310
4J80
4370
4J60
4350
4340
JO
J20
1 2+690.00 I
431Kl
1,170
4J6()
4350
mo
4330
+JZO
12+6so.oo 1
2+690.00
257
121
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
5. FOTOGRAFIA
258
122
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA SECTOR
TRAMO S - RANGO DK PKNDIBNTK 1%-33% - PROGRI181VA 1+618 -.2+710
600800 600760 600720
~
Ul~ ------~~
I I
"'-- EJE-PR0GRESh/A TUBER~ ,,,,,,...--, CA W:-.LES, ROSVQUEIIRAOAS BO FEOALES ~ OJOS OE AGUo. V Uo.NAtlTLO.LES
ill
§
..... I
CURVA DE NWEL CADA Im
Figure 92. Plant and Longitudina l Profile of Reach 5, progressive 2+618 to 2+710 -South Bofedal of the Si lala Springs. Source: Own elaboration based on data provided by
DIREMAR, GOOGLE EARTH.
259
123
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
DESCRIPTION OF THE PHYSICAL CHARACTERISTICS OF THE SOUTH CANAL - REACH 6
UMSA-IHH WATER SYSTEM: SI LALA SPRNGS I DIREMAR
EVALUATION SHEET OF THE NATURAL SECTION CANAL
1. LOCATION
MUNICIPAL!
DEPARTAMENT POTOSI lY SAN PABLO DE LIPEZ
PROVINCE SOUTH LIPEZ CANTON QUETENA CHICO
WATER SYSTEM SI LALA SPRINGS
COMPONENT SOUTH SPRING
PROGRESSIVE
COORDINATES ELEVATION
EAST NORTH (m.a.s.l)
START 2+710 600737.348 7565914.940 4329.10
END 2+800 600737.348 7565914.940 4329.18
2. MORPHOLOGICAL CHARACTERISTICS OF THE REACH
LONGITUDINAL PROFILE
VARIABLE AT SHORT AND MEDIUM DISTANCES.
PROFILE SHAPE INTERNAL REACHES OF VARIED SLOPES TO SUBHORIZONTAL.
SLOPE RANGE% 1-30
DOMINANT LONGITUDINAL SLOPE% 15.76
CROSS SECTION TYPE - CANAL (ST)
FORM OF THE SECTION IRREGULAR TRAPEZOIDAL
AVERAGE WIDTH IN THE BED (A) [ml 2.72
DEPTH OF THE SECTION (H) [ml 2.68
RIGHT BANK SLOPE (STd) % 294.44
LEFT BANK SLOPE (STi) % VERTICAL
MORPHOLOGY
STEEP FLANKS DUE TO EROSION OR ANTHROPOGENIC
EFFECT
CROSS SECTION TYPE - FLANK (SF)
RIGHT FLANK SLOPE (SFd) % 77.06
LEFT FLANK SLOPE (SFI) % 278.23
AVERAGE DEPTH OF THE FLANKS (H) [ml 23.18
PLANT
STRAIGHT AND CURVILINEAR WITH THREE MAIN
FORM OF ALIGNMENT CURVES
WITH CONSTANT SECTION AND NARROWING OF THE
CHANNEL WIDTH VARIABILITY CHANNEL
3. DESCRIPTION OF THE REACH
THE LAST REACH OF THIS CHANNELIZED AREA HAS A lYPICAL CHARACTERISTIC OF FLOW THROUGH CHANNELS,
BECAUSE THERE IS NO CLEAR ALIGNMENT AND TOTALLY IRREGULAR SECTION DUE TO THE ROCK FORMATION.
THE FLOW DEVELOPS WITH TOTAL TURBULENCE AND THE VELOCITIES ARE VERY HIGH.
ALMOST AT THE END OF THE REACH A DECREASE IN THE SLOPE IS OBSERVED AND THERE ARE TWO DISSIPATING
MATTRESSES THAT CUSHION THE ABRASIVE EFFECT OF WATER.
AFTER A CHANGE IN THE SLOPE, THE FLOW IS SLOWER AND FINALLY LEAVES THE SOUTH BOFEDAL CANAL TO
JOIN THE NORTH BOFEDAL CANAL.
260
124
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
4. REPRESENTATIVE CROSS SECTION
a) FLANK b) CANAL
12+ no.oo I
12+ no.oo I
4370 mo
4360 4360 IJJ2 •2.72 43J2
lft,lJIJ.11 4350 4J50 ~ I ! 43J\
4340 4J40 IJJO 7 43JO
4330 4JJ() IJZI ms
:l!
4320 IJ2a 4328 ol 4320 :,:
4310 4310 IJ27 4327
IJ26 4326
4300 -20 - 10 10 20
4JO()
12+ 760.00 I I 2+ 760.00 I
4J29 4.11!1
4.170 mo
ma ()2&
4.360 Sf"1t~IH 4J60
lJ27 ()27
4350 4J50
4326 4326
4J40 mo
lJ25 ()25
mo 4J.lO
132! 4324
4320 4320
I lJ2J 4l23 :,:
4310 4310
1322 ()22
4300 - 20 -10 0 10 20
4JOO
4321 4321
261
125
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
262
126
TIW,{O, -RARGO DI:~ l ~-PROGRDIVA l+110-2-+9Xl
I
I
I 6Xl!IO) C0071:0
I] I ,.18 J!...ua VERlEDERO C-5
, TIW,f0$ ~ Sto11on-2+86U7
RlsngoPIIDlk11'- 30f. I elev -1316.62S
1.26
Ii l: 11~ ~.
LEYENDA DE SIMBCT.OS CO\IVENCIONALES
"'- EJC • PROORESIVA TVBERIAS ,--- CANALES.RIOSYOUEBRAOAS BOFE'DALES ~ OJOS DE AGtlA Y MAN:.~NTlAl.ES CURVAOEHN"E-L CM>A1m
Figure 93. Plant and Longitudinal Profile of Reach 6, progressive 0+710 to 2+800 - South Bofedal of the Silala Springs. Source: Own elaboration based on data provided by
DIREMAR.
263
127
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AN D INSTALLED IN THE SILALA
SECTOR
DESCRIPTION OF THE PHYSICAL CHARACTERISTICS OF THE NORTH CANAL -
PROGRESSIVE 0+260 - 0+360
UMSA-IHH I I DIREMAR
I WATER SYSTEM: SILALA SPRNGS I
EVALUATION SHEET OF THE CANALIZED REACH
1. LOCATION
MUNICIPALI
DEPARTAMENT POTOSI TY SAN PABLO DE LIPEZ
PROVINCE SOUTH LIPEZ CANTON QUETENA CHICO
WATER SYSTEM SI LALA SPRINGS
COMPONENT NORTH CANAL
PROGRESSIVE
COORDINATES ELEVATION
EAST NORTH (m.a.s.l)
0+260 (NORTH
START CANAL) 600704.1 7566211.1 4347.92
0+360 (NORTH
END CANAL) 600792.7 7566256.7 4343.61
2. MORPHOLOGICAL CHARACTERISTICS OF THE REACH
LONGITUDINAL PROFILE
PROFILE SHAPE REACH WITH VARIABLE SLOPE BETWEEN 3.2 TO 5.9%
WITH TENDENCY TO INCREASE THE SLOPE DOWNWARDS
SLOPE RANGE% 3.2- 5.9
DOMINANT LONGITUDINAL SLOPE% 4.5
CROSS SECTIONS IN THE REACH
PROGRESSIVE 0+260 PROGRESSIVE 0+360
Width(m) 10.40 Depth (m) I 0.22 Width(m) 10.ss I Depth (m) 10.32
10+260.00 1
4345 - 1 o+36o.oo 1 ~ 4345
8~
4349 - ON 4349 =-nk om or-:
i:-: ;:!; 4344 - ~ 4344
-i- , .. Ji____,- ~
4348 I I T I I 4348 I I I I I 4343 -1 0 1
4343
-1 0 1
I The start of the reach is the exit of the ravine. Rocky material is found on both sides of the cana l.
MORPHOLOGY
The protection material of the walls improves downwards, thus the jointing of the masonry
contains binder material. The width of the canal is extended from 0.40 to 0.60 meters.
PLANT
I FORM OF ALIGNMENT STRAIGHT REACH
CHANNEL WIDTH VARIABILITY WITH NARROWING AND WIDENING
264
128
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
3. DESCRIPTION OF THE REACH
THE MATERIAL OF THE REACH ANALYZED IS OF STONE MASONRY. THE REACH HAS A VARIABLE SLOPE OF
3.2 TO 5.9%. THE WIDTH OF THE CANAL 15 EXTENDED FROM 0.40 TO 0.60 METERS. THE START OF THE
REACH IS THE EXIT OF THE RAVINE. ROCKY MATERIAL IS FOUND ON BOTH SIDES OF THE CANAL. THE
PROTECTION MATERIAL OF THE WALLS OF THE CANAL IMPROVES DOWNWARDS, THE JOINTING OF THE
MASONRY IS OBSERVED WITH BINDER MATERIAL.
PHYSICAL CHARACTERISTICS OF THE REACH, ITS HYDRAULIC IMPLICATION AND ENVIRONMENTAL
IMPACT
THE RECTILINEAR LINE OF THE CANAL IN A STEEP TERRAIN LEADS TO STEEP SLOPES IN THE CANAL. DUE TO STEEP
SLOPES, THE VELOCITIES IN THE CANAL ARE GREATER THAN 0.7 M/5 (VELOCITIES THAT INCREASE
DOWNSTREAM). DUE TO THE NEED TO PROTECT THE WALLS AND THE SCREED OF THE CHANNEL
AGAINST THE EROSIVE EFFECT OF HIGH SPEEDS, THESE HAVE BEEN WELDED WITH A VERY SPECIAL
BINDER MATERIAL WITH HIGH RESISTANCE TO EROSION.
THE WATER ABSTRACTION WITH THE FISHBONE SYSTEM IN THE SECONDARY CANALS FROM THE
PROGRESSIVE O + 000 TOO+ 360, EROSION PROTECTION OF THE WALLS AND FLOOR OF THE CANAL TO
THE EROSION OF THE STRONG VELOCITIES AND WATERPROOFING OF THE MAIN NORTH CANAL, MAKES
THE WATER ABSTRACTION AND CHANNELING SYSTEM HIGHLY EFFICIENT.
THE ENVIRONMENTAL IMPACT EXEMPLIFIED IN THE WATER TABLE VARIABLE SHOWS THE DESCENT OF
THE WATER TABLE IN A SHORT REACH OF THE ANALYSIS AREA. POINT 600833 EAST, 7566295 NORTH,
WATER TABLE 0.10 METERS BELOW THE SURFACE OF THE TERRAIN, POINT 600775 EAST, 7566269
NORTH, 0.4 METERS BELOW THE SURFACE OF THE TERRAIN, DISTANCE BETWEEN THE TWO POINTS 62
METERS (ORZAG, 2017).
265
129
NORTH CANAL - PROGRESSIVE O + 260 - 0 + 360- SLOPE 4 .5%
600700 600750 600800
75662so I I ~
4548-.=-
!44-
4 }14- ~
4l4H-
4
PROGRt:SIVA
COlA IERRE~O
CANAL NORTE (se tomo 100 m) PROGRESIVA 0+260-0+360
CANAL DE MAMPOSTERIA DE PIEDRA - pendiente 3.2 o
~
o+280 0+340
4 347.29 4344.79
5.9 %
-l
·--------~-- ---~---
LEYEN0A OE SIM BOLOS COtlVENCIONALES
.........._ E.1E - PROGRESNA -.. __,--,- CNMl.£SRIOSV0U1:BR,\[)JIS B:JFED,lt_ES M OJOSOEN:AJAYMN.&NtTIALES
7566250
0.JRVADE Hl"II@. CADA 1""
Figure 94. Plant and Longitudinal Profile of the North canal of the reach between the progressive o + 260 too+ 360 - North Bofedal of the Silala Springs. (source: Own
e laboration based on data provided by DIREMAR, GOOGLE EARTH)
266
130
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
DESCRIPTION OF THE PHYSICAL CHARACTERISTICS OF THE CONFLUENCE
CANAL - PROGRESSIVE 2 + 920 TO 2 + 970
UMSA-IHH I WATER SYSTEM: SILALA SPRNGS DIREMAR
EVALUATION SHEET OF THE CANALIZED REACH
1. LOCATION
MUNICIPAL!
DEPARTAMENT POTOSI TY SAN PABLO DE LIPEZ
PROVINCE SOUTH LIPEZ CANTON QUETENA CHICO
WATER SYSTEM SI LALA SPRINGS
COMPONENT CONFLUENCE CANAL
PROGRESSIVE
COORDINATES ELEVATION
EAST NORTH (m. a.s.l)
2+920
(CONFLUENCE
START CANAL) 6000618.4 7565870.5 4316.08
2+970
(CONFLUENCE
END CANAL) 600586.87 7565832.3 4311.96
2. MORPHOLOGICAL CHARACTERISTICS OF THE REACH
LONGITUDINAL PROFILE
PROFILE SHAPE VARIABLE AT SHORT AND MEDIUM DISTANCES. THE
PREDOMINANT SLOPE IS 5.9%
SLOPE RANGE% 3.2- 5.9
DOMINANT LONGITUDINAL SLOPE% 5.9
CROSS SECTIONS IN THE REACH
PROGRESSIVE 2+920 PROGRESSIVE 2+970
Width(m) 0.80 Depth (m) I 0.82 Width(m) I o.68 I Depth (m) I o.65
I 2+920.00 I I 2+910.00 I
O<O on 4317 _,_ 00 ci<.O --: - 4317 4313 -- o en -- 4313
.-,.......J ~t--'.-;'.n .! e~ ~ ~ -, ~; f c- ~ w
0---" \ ~d
4316
l w
4316 4312 4312
I 11
-1 0 1 - I 0 I
THE CONFLUENCE REACH IS LINED AT THE BEGINNING. THE CONFLUENCE REACH
CANALS IN THE CONFLUENCE REACH ARE THE DEEPEST OF THE ENTIRE DRAINAGE
SYSTEM. THE CONDITIONS OF THE PIPELINE FROM THE INTAKE WORK UP TO THE
PROGRESSIVE 3 + 000 IS DIVERSE, THERE ARE REACHES IN GOOD CONDITION AND IN
MORPHOLOGY POOR CONDITION, WITH MOST OF THE REACHES IN GOOD CONDITION.
PLANT
I FORM OF ALIGNMENT STRAIGHT REACH
CHANNEL WIDTH VARIABILITY WITH NARROWING AND WIDENING
267
131
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
3. DESCRIPTION OF THE REACH
THE CANAL REACH ANALYZED AND THE ENTIRE REACH OF THE CONFLUENCE CANAL ARE BUILT WITH STONE
MASONRY; THE BINDER OF THIS COATING MATERIAL IS A MIXTURE OF LIME AND SOME TYPE OF POZZOLAN THAT
PRODUCES A RESISTANT AND APPARENTLY DURABLE MIXTURE. THE SLOPE IN THE ANALYZED REACH IS VARIABLE
WITH AN AVERAGE OF 5.9%. THE CANALS IN THE CONFLUENCE REACH ARE THE DEEPEST OF THE ENTIRE DRAINAGE
SYSTEM. THE CONDITIONS OF THE PIPELINE FROM THE INTAKE WORK UP TO THE PROGRESSIVE 3 + 000 IS DIVERSE,
THERE ARE REACHES IN GOOD CONDITION AND IN POOR CONDITION, WITH MOST OF THE REACHES IN GOOD
CONDITION.
THE CHARACTERISTICS OF A STEEP SLOPE IN THE CONFLUENCE REACH (WHOSE SLOPE IS SLIGHTLY GREATER THAN
THE NORTH CANAL) INDICATE THE SAME CONDITIONS OF SLOPE FLOW AND CANAL PROTECTION OF THE NORTH
CANAL.
THE RECTILINEAR LINE OF THE CANAL IN A STEEP TERRAIN LEADS TO STRONG SLOPES OF AROUND 6% AND HIGH
VELOCITIES GREATER THAN 0.75 M/S (VELOCITIES THAT INCREASE DOWNSTREAM). THE PROTECTION OF THE
WALLS AND THE FLOOR OF THE CANAL AGAINST THE EROSIVE EFFECT OF THE HIGH VELOCITIES HAS BEEN MADE
WITH A VERY SPECIAL BINDER MATERIAL WITH HIGH RESISTANCE TO EROSION.
DESPITE THE EXISTENCE OF SOME REACHES IN POOR CONDITION OF THE CONFLUENCE CANAL, THE HYDRAULIC
CHANNELLING IS EFFICIENT REFLECTED IN THE DEGRADATION OF THE SLOPING BOFEDAL OF THE CONFLUENCE
REACH.
4. PHOTOGRAPHS
Confluence Canal.
268
132
7565850
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INST ALL ED IN THE SI LALA SECTOR
600550
CONFLUENCE CANAL - PROGRESSIVE 2+920 - 2+970 - SLOPE 4.S %
600600
CANAL CONFLUENCIA (SE TOMA 100 m) PROGRESIVA 2+920-2+970
CANAL DE MAMPOSTERIA DE PIEDRA - pendiente 5.9 %
~ 1
2+920 2+:940 2+960 2+970 2+980
4316.06 431J95 4312.80 431 1.96 43U .13
LEYENDA DE S IM BOLOS CONVENCIONALES
......._ EJE-ffiOGRESIVA ............. TU8£RIAS --- C ..... AI..ES,RIOSYQUEBRADAS a BOFEDPI..ES ~ OJOSDEAGUAYMANANTIALES
600650
3+:ooo
43Q9.73
7565850
Figure 95. Plant and Longitudinal Profile of the Confluence Canal Reach between the progressive 2 + 920 to 2 + 2970- Confluence Bofedal of the Silala Springs. (Source: Own
elaboration based on data provided by DIREMAR)
269
133
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
ANNEX 2: CHARACTERIZATION OF THE CANALS OF THE SOUTH BOFEDAL
HYDRAULIC MODELING WITH HEC GEO RAS HYDRAULIC SYSTEM INCLUDING THE BOFEDALS AND
CANALS
Figure 96. Detail of the hydraulic model for the North Branch of Silala in HEC-RAS. (Source: prepared by the authors)
270
134
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
Figure 97. Detail of the hydraulic model for the South Branch of the Silala in HEC-RAS
271
135
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
COUFL_C5
S11.ALA_CONFLU
Figure 98. Detail of the hydraulic model for the Confluence Branch of the Silala in HEC-RAS
272
136
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
Figure 99. Detail of the Hydraulic Model of the Confluence Reach of the Silala in HEC-RAS
273
137
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
,,, ,,, ,,,
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fil fil fil ~ :, :,a :,a
a a a
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f- __). ' al
' " 0
~ ! ~ ~ ~ ~ ~ ~ ~ ~ ~ ! ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
I w) "'!l'"l l
Figure 100. Hydraulic profile in the North Branch Silala in HEC-RAS
274
138
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SLALA_lopo Aan: simulac0n1 02/06/2018
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275
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CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AN D INSTALLED IN THE SILALA
SECTOR
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g_ 8 r-+ \ ~
; I ~I--+----+----+----+----+-----,,+---+---+---+---+
:s ...J '~ ~
~ \-1- ~
\. ~ -+----+----+----+--+----+-___."..,--+--+----+---+ ~
---+---+------+---+-----+----------l-.,+----+--+--+
~
--+----+----+----+----+----+---+",,._---+----+---+ ~
~ ~ --+----+----+----+----+----+---+---.,~ --+----+---+ ~
-+----+----+----+--+----+----+-½,--+-----+---+
\ §
-+----+----+----+--+----+----+--+-'-, ---+---+
\ ~
'
M . .
(w) UO!j!?h8J3
Figure 102. Hydraulic profile of the Confluence Branch of the Silala in HEC-RAS
276
140
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
:'3 .;_
~ el m
"8 ::,
0 0 ! ~ w
::s
0 0 e :§
:l! ~ -- -- -- ~
-~ !§
---== ~
I - t ~
- <(-- lri ---~ !)!
----- :,. :ii
I .;c- :); - 1-------_ ~
§
L__ ~
= I- ~ ; -------
r------ ~
<'! - "--. = ~
§ - <::: i------ ~
·13
f ~ ."1 llil
.~ g !J -=--i---" ~
"' ~ +-- ;:i;
0: 0 0 1"l !i ii -~ g a r~ ~
I--, ~
~ ~ .,.,--- !'l
f r ---- ~
---------- - ~ - ~
~ ~ - - -=- -
~ cl
<°'" §
I g
55
"
-1---- cl
0
:" ~ ~ :; ~ :g ;; ~ ~ ;:; ~
(S/W) 1u6 18 ,, A '( S/ w) IUUJ l'A ·1~ w) va1 ,, A
Figure 103. Hydraulic Profile of the velocities in the North Branch of the Silala in HEC-RAS
s
1i
iJl
i5
l!
~
~
277
141
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AN D INSTALLED IN THE SILALA
SECTOR
':5 .;_ §
~
C> ~
~ z
"!! ':!l ; ~
j ,6a3 :", ~
0 0 ~ '.§ I
:j! :j! >:
i I ~-1 ~
~
~ ...Jc(...J<( ~"'"' ~ ),,~..,: ~b "' ~
~
T ~
I=
"' ' el "3-=' ' ~ ~ u,
"' ~
~I
N 1-
I l~ --+ 1---=, ~
I I -,__~ - I §
i gl -=-' ~
-"' ~ .~ -=' §
f"r. 3u, §
ill 8. -=' = ~ ..___, i[ - ~
- - !'!
0
C
l I -~ §
~ =
§
I= Pe;--- f?
g; '
~' I-,;-- §
; §
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~
~ f-----., N
--- -- §
~ ....1<(....1 <( <n .=.>a:: ~1-a:: ~ u; ~ .;o - ci, ,c ;'; ci ~ ~ 0 ci 0 0 0 0
[S/ w[ "6'~ I' A '(S/ w) IU48 l'A '(S/ w) »•11• A
Figure 104. Hydraulic Profile of the velocities in the South Branch of the Silala in HEC-RAS
i:
~
lJl
0
"l!
!
I
278
142
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AN D INSTALLED IN THE SILALA
SECTOR
~ ~ .t.
00 00 ~ ~ m'"
"E :s
!' ~ ~ " 0 "' ~ 0
1§ ·"' 3 0 0:
~ ~ ~
~
f I l:l "' f ,~ ~
----- r-,_ ;l;
f -=:::: ~ ~
§
f ~
f ~
--+ - - p ,ii; I
' f'--.___ ~ -- §
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ro
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~ > § ~
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0:: <ii i5
=> \...__ ,.__ ~ 11
8. 15 ~
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~ ~ "'
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--+ ,::,,.__- !!!
..:;:: ~ ~
f -I- +-- ~ ===- ;:;:
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--+ ---- i-----.-.._ §'
~
I~ ~ !'l
f _.;, :a
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f ----+ ------ a' ~
f -1-~ i::::__ 1"
~ = N ~ = ci ci ci ~ ci ;; ci ci ci ci ~ ~ ~
I s1w) 14 61 H 10 A 'I S/ w) 1u4J l' A 'I S/ w) 101 10 A
Figure 105. Hydraulic Profile of the velocities in the Confluence Branch of the Silala at HEC-RAS
279
143
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AN D INSTALLED IN THE SILALA
SECTOR
~ :'§ ,;!
~ ::,; ~ ~
] ~ Cw "C ! 103 0" ' "0
~ :§
a: ~ ~ g
-~
0
ci
Figure 106. Hydraulic Profile of the Froude Number and Velocities in the North Branch of the Silala in HEC-RAS
280
144
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Legend ·11'I "1 "TTTrt'"1I I 1
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100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1000 2000 2100 2200 2300 2400 2500 2600 2700 2800 2000
Main Channel Distaoce (m)
v~ Chnl QMED l{NSUl'l
Vel LeftQ MED MENSUl'l
CritDepM t.ED MENSUAL
Vel R~htQ t.ED t.ENSUl'l
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SILALA_topo Aan: smu~cion1 02/06/2018
l<---------------------SLALA_CONFLUS ILALA_CON A.lt---------------------al
1.2+,----.- ~ ,--.-,- ~-~L_eg_e_rll~-~
1.1
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Vel Chnl QMED MENSUAL I~• Channel a MEO MENSUAI
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roude #Chia MEO MENSUAl
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+-i-+--+-l------+---+-+-+---+-1------+---+-+---+---+-+--+-+---+---+-+--+-1------+---+-+--+-1------+---t- +--l'c-+---+1-----+--+-+-I Vet R~htQ MEO MENSUAL
j_
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20 40 60 80 100 120 140 160 160 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700
MainChannelDistance(m)
Vet LeltQMED MENSUAL
<"l
~
!;:
<"l
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282
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CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
<-,-..__ -->- ~ =j=j=j=j===!=!=t=t===tj=j:jS-~L~:-!~ ~!~t~tj~ S7 §
--+-+--t--+---t--+-+--t---+--t--+-+----+-+-~ t--+---+
----l---l---l------l----l------l---l---l------l---l------l---l----''--...--1-~..-i.,=1------1-----l-~ / - 2P.. ~ f!1111tt11tt~<._ ~r=t==..,t.ti~
.,c::::;::_r____ i<...._,-.._7
+- '
-+--lf-+--lf-----+-+----+-+---+----+-+----+-=---=-==r~-'1.- -+--+-+~
-+--lf-+--lf-----+-+----+-+---+----+-+--;ic-~---"''9-'a:g..: -+ '=-+--+-+~
r--+----+-+--+---+----+-+--+--+--1-+--c-!-----c::--:;,,,--.:_ :+:,, --I--+--+--+~ =---- ---I-> § L__-t--+-f--t---f--t--t--f---t--f--+-----=--Cf-=--=----1s-=l:'ccc_.f--+----+
-=1=tj=t==t=t1=t==tj~-;-~~~=l:~/j:tj=j- L / ~
y -
.--+-+-t--+---t--+-+-t---+-t--+-+---,+=+sct--+---+=--::~
I
Figure 109. Profile of the Gradient, Energy Line, and Depth in the North Branch of the Silala in HEC-RAS
283
147
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
I I I
(!)::::>q::: % --,1<--,1< c.n:::;,ct:: <Dt-a::;:::'!:'r'/
0 0
·--,_.- ~
--~ f ~
--==~=~-~= -= ~ :-.? ~
~~-.:.::=::;-- g
.> ~
~
Figure 110. Profile of the Gradient, Energy Line, and Depth in the South Branch of the Silala in HEC-RAS
284
148
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
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:::,,, ___
I
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j ~-+--+---+-r---+--+-+--+---;-+--+--+--+--+-_,._ _-_+ ~-----~1 -__- +---+-7r<--+--+~ ·! ~I -+--+---+-r---+--+-+--+---i-+--+--+--+--+---+-r-~-t----,,+--+--<c+/ --+ M !
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Figure 111, Profile of the Gradient, Energy Line, and Depth in the Confluence Branch of the Silala in HEC-RAS
285
149
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
S @Plan 01
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Figure 112. Hydraulic Simulation in Ras Mapper for the North Branch of the Silala in HEC-RAS
286
150
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
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8 0 Te,r.,;ns
!-.~Terrain
Figure 113. Hydraulic Simulation in Ras Mapper for the South Branch of the Silala in HEC-RAS
287
151
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Flfllte 11,. Hydraulic Slmulwtlon In llas Mapptt for the Conffutntt Branch of the Sllata In KEC•MS
288
152
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
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Figure 115. Cross-sections of the North Branch of the Silala in HEC-RAS
289
153
'
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
--------------+-,,-,---,!
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/
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Figure 116. Cross-sections of the South Branch of the Silala in HEC-RAS
290
154
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
SLALA_topo Pl;:,n: •ffll,lacioo1 02106120 1A
RMr • SLJU.._SUR R .. Oll•SM.11.,\_SUR_TRW R$•1"90 - .165-+--------------
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Figure 117. Cross-sections of the South Branch of the Silala in HEC-RAS (Continued)
291
155
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
$ LAI..A_tepo Ran: Sl'N.l illck>n 1 02/005/20 16
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Figure 118. Cross-sections of the Confluence Branch of the Silala in HEC-RAS
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292
156
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
SIMULACION HIDRAUUCA DE FLUJO SUPERFICIAL DELSISTEMA SI LALA
River Reach RiverSta Profile
QTotal MinChEI W.S. Elev CritW.S. E.G.Elev E.G.Slope VelChnl Flow Area Top Width
Froude#Chl
(m3/s) 1ml Im) Im) Im) (m/m) Im/,) (m2) (m)
SILALA SIIALA_SUR """ QMEO 0.03 440<i2 440<i2 44!<2 44!<.2 0.474 0.28 0.10 8.02 0.81
SILALA SILALA_SUR 2850 QMEO 0.03 4405.6 440'9 4405.9 0.001 0.08 0.34 1.75 0.06
SILALA SILALA_SUR 2840 QMEO 0.03 440'8 440'9 4405.9 0.007 0.09 0.28 4.95 0.12
SILALA SIIALA_SUR 2&30 QMED 0.03 4405.6 440'6 44056 4405.6 0.613 0.43 0.06 3.14 1.00
SIL.ALA SILALA_SUR 2820 QMEO 0.03 440'4 440'5 4405.S 0.001 0.03 0.85 19.43 0.05
SIL.ALA SILALA_SUR 2810 QMEO 0.03 4405.4 440'4 4405.4 0.007 0.05 0.54 26.93 0.11
SIL.ALA SILALA_SUR 21<Xl QMEO 0.03 4405.2 440'2 4405.2 4405.2 0.147 0.23 0.11 5.20 0.50
SIL.ALA SILALA_SUR 2790 QMEO 0.03 4404.8 4404.9 4404.9 a.cm 0.13 0.20 2.03 0.13
SIL.ALA SILALA_SUR 278JJ QMEO 0.03 4404.8 4404.9 4404.9 0.012 0.10 0.26 6.20 0.16
SILALA SIL.ALA SUR 2770 QMEO 0.03 4404.6 44047 4404.7 0.009 0.19 0.14 1.35 0.19
SIL.ALA SILALA_SUR 27<ll QMEO 0.03 4404.4 4404.5 4404.S 4404.6 0.074 0.27 0.10 2.58 0.45
SIL.ALA SILALA_SUR 2750 QMEO 0.03 4404.4 4404.5 4404.5 0.(03 0.07 0.40 8.73 0.10
SILALA SILALA_SUR 2740 QMEO 0.03 4404.2 4404.4 4404.4 0.006 0.07 0.38 12.63 0.13
SILALA SILALA_SUR 2730 QMED 0.03 4404.2 4404.2 4404.2 0.110 0.24 0.11 5.12 0.51
5ILALA SILALA_SUR 2720 QMEO 0.03 4404.0 44041 4404.1 o.cm 0.10 0.25 2.87 0.11
5ILALA SILALA_SUR 2710 QMEO 0.03 4404.0 4404.0 4404.0 4404.0 0.379 0.32 0.08 5.84 0.88
SILALA SILALA_SUR 2700 QMEO 0.03 44018 440'9 4403.9 0.003 0.07 0.39 7.89 0.10
SILALA SILALA_SUR 2680 QMEO 0.03 4403.8 44018 4403.8 0.010 0.07 0.38 18.71 0.15
SILALA SILALA_SUR 2680 QMEO 0.03 4403.6 44018 4403.8 0.004 0.14 0.19 1.33 0.12
SILALA SILALA SUR 2670 QMEO 0.03 44016 440'7 4403.7 0.101 0.37 O.D7 1.55 0.55
SILALA SILALA_SUR 265D QMED 0.03 44014 44016 4403.6 0.003 0.13 0.20 1"1 0.12
SILALA SILALA_SUR 2650 QMEO 0.03 4403.4 440'5 4403.5 0.111 0.37 0.07 164 0.57
SILALA SILALA_SUR 2640 QMEO 0.03 44012 44013 4403.3 0.004 0.12 0.21 2.04 0.12
SILALA SILALA_SUR 26]() QMED 0.03 44011 44013 4403.3 0.039 0.26 0.10 l.7S 0.34
SILALA SILALA_SUR 2620 QMEO 0.03 4403.0 44012 4403.2 0.004 0.14 0.18 144 0.13
SILALA SILALA_SUR 2610 QMEO 0.03 44010 44011 4403.1 0.010 0.16 0.16 2.04 0.18
SILALA SILALA_SUR 200'.l QMED 0.03 4402.8 440>9 4402.9 0.117 0.37 O.D7 1.69 0.58
SILALA SILALA_SUR 2590 QMEO 0.03 4402.6 44028 4402.8 0.003 0.10 0.27 3.18 0.10
SILALA SILALA_SUR 25'0 QMEO 0.03 44026 440V 4402.7 0.003 0.12 0.22 1.92 0.11
SILALA SILALA SUR 2570 QMED 0.03 4402.6 440V 4402.7 0.011 0.14 0.18 304 0.18
SILALA SILALA_SUR 25"1 QMEO 0.03 4402.4 440L4 4402.4 0.108 0.28 0.09 3.25 0.53
SILALA SILALA_SUR 2550 QMEO 0.03 440L1 440L1 4402.2 0.011 0.14 0.19 3.29 0.19
SILALA SILALA_SUR 2>00 QMEO 0.03 44020 440L1 4402.1 0.005 0.12 0.22 2.76 0.14
SILALA SILALA_SUR 2530 QMED 0.03 4402.0 44020 4402.0 0.122 0.27 0.10 4.06 0.54
SILALA SILALA_SUR_TRM2 2520 QMEO 0.03 4401.6 44018 4401.7 4401.8 0.009 0.11 0.32 7.09 0.16
SILALA SILALA_SUR_TRM2 2510 QMEO 0.03 44015 44015 4401.5 4401.5 0.219 0.49 O.D7 1.93 0.82
SILALA SILALA_SUR_TRM2 2,X, QMED 0.03 4401.2 44013 4401.3 0.006 0.09 0.36 8.51 0.14
SILALA SILALA_SUR_TRM2 24"1 QMEO 0.03 4401.1 44011 4401.1 4401.1 0.173 0.29 0.12 5.77 0.86
SILALA SILALA_SUR_TRM2 2480 QMEO 0.03 44008 44009 4400.9 0.008 0.14 0.25 3.iO 0.17
SILALA SILALA SUR TRM2 2470 QMED 0.03 44006 44006 4400.6 4400.7 0.251 0.49 O.D7 2.07 0.86
SILALA SILALA_SUR_TRM2 24(,0 QMEO 0.03 44003 44004 4400.4 0.007 0.12 0.29 5.31 0.16
SILALA SILALA_SUR_TRM2 2450 QMEO 0.03 44002 44003 4400.l 0.053 0.24 0.14 4.02 0.40
SILALA SILALA_SUR_TRM2 2440 QMEO 0.03 4399.8 4399.9 4399.9 4399.9 0.024 0.25 0.14 1.97 0.30
SILALA SILALA_SUR_TRM2 2430 QMEO 0.03 4399.6 4399.7 4399.7 0.028 0.19 0.18 4.52 0.30
SILALA SILALA_SUR_TRM2 2420 QMEO 0.03 4399.4 4399.6 4399.6 0.001 0.05 0.65 6."1 0.05
SILALA SILALA_SUR_TRM2 2410 QMEO 0.03 4399.6 4399.6 4399.6 4399.6 0.525 0.28 0.12 14.43 0.99
SILALA SILALA_SUR_TRM2 2400 QMED 0.03 4399.2 4399.3 4399.3 0.003 0.07 O.Sl 9.99 0.09
SILALA SILALA_SUR_TRM2 2390 QMEO 0.03 4399.2 4399.2 4399.2 4399.2 0.289 0.30 0.11 8.31 0.80
SILALA SILALA_SUR_TRM2 2380 QMEO 0.03 4398.9 4399.0 4399.0 0.007 0.10 0.34 7.85 0.15
SILALA SILALA SUR TRM2 2370 QMEO 0.03 4398.8 4398.8 4398.8 0.026 0.1S 0.22 7.03 0.27
SILALA SILALA_SUR_TRM2 2360 QMEO 0.03 4398.7 4398.8 4398.8 0.005 0.08 0.44 11.65 0.13
SILALA SILALA_SUR_TRM2 2350 QMEO 0.03 4398.6 4398.6 4398.6 0.071 0.16 0.21 13.25 0.41
SILALA SILALA_SUR_TRM2 2340 QMED 0.03 4398.S 4398.S 4398.S 0.004 0.07 0.46 11.12 0.11
SILALA SILALA_SUR_TRM2 2330 QMEO 0.03 4398.4 4398.4 4398.4 0.035 0.14 0.25 11.47 0.30
SILALA SILALA_SUR_TRM2 2320 QMEO 0.03 4398.2 4398.3 4398.3 0.005 0.09 0.37 7.79 0.13
SILALA SILALA_SUR_TRM2 2310 QMED 0.03 4398.0 4398.2 4398.2 0.020 0.11 030 11.82 0.23
SILALA SILALA_SUR_TRM2 2»:J QMEO 0.03 4398.0 4398.0 4398.0 0.018 0.12 0.28 9.32 0.23
SILALA SILALA_SUR_TRM2 2290 QMEO 0.03 4397.8 4397.9 4397.9 0.012 0.14 0.24 4.63 0.20
SILALA SILALA_SUR_TRM2 22ll0 QMEO 0.03 4397.6 4397.7 4397.7 0.021 0.29 0.12 1.18 0.29
SILALA SILALA SUR TRM2 2270 QMED 0.03 4397.4 4397.5 4397.5 0.022 0.28 0.12 1.39 0.30
SILALA SILALA_SUR_TRM2 22<,J QMEO 0.03 4397.2 4397.3 4397.3 0.014 0.23 0.14 146 0.24
SILALA SILALA_SUR_TRM2 2250 QMEO 0.03 4397.0 4397.2 4397.2 0.023 0.27 0.12 1.46 0.30
SILALA SILALA_SUR_TRM2 2240 QMEO 0.03 4396.8 4397.0 4396.9 4397.0 0.012 0.10 0.33 10.05 0.18
SILALA SILALA_SUR_TRM2 2230 QMEO 0.03 4396.6 4396.6 4396.6 4396.7 0.381 0.52 0.06 2.44 1.02
SILALA SILALA_SUR_TRM2 2220 QMEO 0.03 4396.2 4396.4 4396.4 0.003 0.10 0.34 4.16 0.11
SILALA SILALA_SUR_TRM2 2210 QMED 0.03 4396.2 4396.3 4396.3 4396.3 0.012 0.12 0.28 7.24 0.20
SILALA SILALA_SUR_TRM2 ""' QMEO 0.03 4396.0 4396.0 4396.0 4396.0 0.164 0.33 0.10 4.20 0.86
SILALA SILALA_SUR_TRM2 2190 QMEO 0.03 4395.6 4395.7 4395.7 0.006 0.08 0.41 10.03 0.13
SILALA SILALA_SUR_TRM2 21ll0 QMEO 0.03 4395.4 4395.5 4395.5 4395.5 0.299 0.61 0.06 1.36 0.97
SILALA SILALA SUR TRM2 2170 QMEO 0.03 4395.0 4395.1 4395.1 0.004 0.10 0.35 5.24 0.12
293
157
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
SIMULACl6N HloR.4.UUCA DE FLUJO SUPERFICIAL DELSISTEMA SILAlA
River Reach RiverSta Profi le
QTotal MinChEI W.S.Elev CritW.S. E.G.Elev E.G.Slope VelChnl Flow Area TopWidth
Froude#Chl
(m3/s) 1ml (ml (ml (ml (m/m) {m/s) (m2) (ml
SILALA SILALA_SUR_TRM2 "''' QMEO 0.03 4395.0 4395.0 4395.0 0.014 0.12 0.29 8.73 0.20
SILALA SILALA_SUR_TRM2 2150 QMEO 0.03 4394.6 4394.6 4394.6 4394.6 0.475 0.43 0.08 4.00 1.06
SILALA SILALA_SUR_TRM2 2140 QMEO 0.03 4394.4 4394.5 4394.5 0.002 0.07 0.51 7.10 0.08
SILALA SILALA_SUR_TRM2 11.lO QMEO 0.03 4394.4 4394.4 4394.4 0.014 0.13 0.27 706 0.21
SILALA SILALA_SUR_TRM2 2120 QMEO 0.03 4394.0 4394.1 4394.1 0.111 0.39 0.09 2.01 0.60
SILALA SILALA_SUR_TRM2 2110 QMEO 0.03 4393.6 4393.7 4393.7 0.016 0.24 0.14 1.60 0.26
SILALA SILALA_SUR_TRM2 1100 QMEO 0.03 4393.4 4393.5 4393.5 0.036 0.28 0.12 1.93 0.36
SILALA SILALA_SUR_TRM2 2(00 QMEO 0.03 4393.2 4393.3 4393.3 4393.3 0.009 0.17 0.21 2.82 0.19
SILALA SILALA_SUR_TRM2 2060 QMEO 0.03 4393.0 4393.1 4393.1 0.157 0.46 O.D7 1.68 0.71
SILALA SIL.ALA SUR TRM2 2070 QMEO 0.03 4392.6 4392.7 4392.6 4392.7 0.020 0.18 0.19 3.82 0.26
SILALA SILALA_SUR_TRM2 2060 QMEO 0.03 4392.4 4392.4 4392.4 4392.4 0.023 0.15 0.22 6.35 0.26
SILALA SILALA_SUR_TRM2 "''' QMEO 0.03 4392.0 4392.1 4392.1 0.054 0.18 0.19 8.26 0.38
SIL.ALA SILALA_SUR_TRM2 2040 QMED 0.03 4391.S 43915 4391.S 0.1S3 0.43 0.08 2.04 0.69
SILALA SILALA_SUR_TRM2 2030 QMEO 0.03 4391.0 43911 4391.1 0.020 0.24 0.14 1.73 0.28
SILALA SILALA_SUR_TRM2 2020 QMEO 0.03 4390.8 4390.9 43~.9 0.027 0.27 0.13 1.77 0.32
SIL.ALA SILALA_SUR_TRM3 2010 QMEO 0.03 4390.6 4390.8 43~.8 0.008 0.13 0.26 2.2S 0.12
SIL.ALA SILALA_SUR_TRM3 2000 QMEO 0.03 4390.6 4390.6 43~.6 0.018 0.09 0.36 9.58 0.16
SILALA SILALA_SUR_TRM3 1990 QMEO 0.03 4390.4 4390.4 43~.4 0.024 0.10 0.34 9.93 0.18
SILALA SILALA_SUR_TRM3 1980 QMEO 0.03 439()2 4390.2 43~.2 43~.2 O.D15 0.10 0.36 8.24 0.15
SIL.ALA SIL.ALA SUR TRM3 1970 QMEO 0.03 4390.0 43900 43~.o 0.027 0.12 0.29 7.79 0.19
SILALA SILALA_SUR_TRM3 1960 QMEO 0.03 4389.7 4389.7 4389.7 0.039 0.16 0.21 4.46 0.24
SILALA SILALA_SUR_TRM3 1950 QMEO 0.03 4389.4 4389.5 4389.5 0.014 0.13 0.27 3.79 0.15
SILALA SILALA_SUR_TRM3 1""' QMEO 0.03 4389.2 4389.3 4389.3 0.071 0.22 0.16 3.31 0.32
SIL.ALA SILALA_SUR_TRM3 1930 QMEO 0.03 4388.9 4389.0 4389.0 0.012 0.11 0.31 4.84 0.14
SILALA SILALA_SUR_TRM3 1920 QMEO 0.03 4388.6 438&7 4388.8 0.087 0.32 0.11 1.49 0.37
SILALA SILALA_SUR_TRM3 1910 QMEO 0.03 438&4 438&5 4388.5 0.011 0.13 0.25 2.71 0.14
SIL.ALA SILALA_SUR_TRM3 19)) QMEO 0.03 4388.2 438&3 4388.3 0.077 0.26 0.13 2.24 0.34
SILALA SILALA_SUR_TRM3 1890 QMEO 0.03 4387.8 4387.9 4387.9 0.018 0.18 0.19 1.86 0.18
SILALA SILALA_SUR_TRM3 1880 QMEO 0.03 4387.6 4387.7 4387.7 0.059 0.19 0.18 4.13 0.29
Sil.ALA SIL.ALA SUR TRM3 1870 QMEO 0.03 4387.2 4387.3 4387.3 0.022 0.16 0.22 2.99 0.19
SIL.ALA SILALA_SUR_TRM3 1960 QMEO 0.03 4387.0 4387.1 4387.1 0.013 0.13 0.26 3.34 0.lS
SILALA SILALA_SUR_TRM3 1850 QMEO 0.03 4386.8 438.9 4386.9 0.050 0.19 0.18 3.63 0.27
SIL.ALA SILALA_SUR_TRM3 1840 QMED 0.03 4386.6 438S8 4386.8 o.oo; 0.11 0.31 2.93 0.11
SIL.ALA SILALA_SUR_TRM3 1880 QMEO 0.03 4386.5 438&6 4386.6 4386.6 0.744 0.41 0.08 4.04 0.90
SILALA SILALA_SUR_TRM3 1820 QMEO 0.03 4386.2 438•3 4386.3 0.008 0.08 0.40 7.07 0.11
SILALA SILALA_SUR_TRM3 1810 QMEO 0.03 438SO 438Sl 4386.1 0.069 0.21 0.17 3.66 0.31
SIL.ALA SILALA_SUR_TRM3 lll)J QMEO 0.03 4385.8 438'9 4385.9 0.010 0.09 0.40 7.68 0.12
SILALA SILALA_SUR_TRM3 1790 QMEO 0.03 4385.6 438'7 4385.7 0.111 0.21 0.16 4.00 0.38
SILALA SILALA_SUR_TRM3 llllO QMEO 0.03 438'4 438'5 4385.5 0.009 0.08 0.41 7.57 0.11
SIL.ALA SIL.ALA SUR_TRM3 1770 QMED 0.03 4385.2 43853 438S.3 0.037 0.21 0.16 2.23 0.25
SILALA SILALA_SUR_TRM3 17'0 QMEO 0.03 4384.8 438'1 4385.1 0.011 0.17 0.21 1.50 0.14
SILALA SILALA_SUR_TRM3 1750 QMEO 0.03 438<8 43849 4384.9 0.045 0.27 0.13 1.29 0.28
SIL.ALA SILALA_SUR_TRM3 1740 QMEO 0.03 4384.6 4384.8 4384.8 0.008 0.14 0.24 1.66 0.12
SIL.ALA SILALA_SUR_TRM3 1730 QMEO 0.03 4384.6 43847 4384.7 0.013 0.09 0.40 9.58 0.13
SILALA SILALA_SUR_TRM3 rno QMEO 0.03 43844 43845 4384.5 0.022 O.C>J 0.36 11.45 0.17
SIL.ALA SILALA_SUR_TRM3 1710 QMEO 0.03 4384.2 4384.3 4384.3 0.012 0.16 0.22 1.88 0.15
SIL.ALA SILALA_SUR_TRM3 1100 QMEO 0.03 4384.1 43842 4384.2 0.024 0.12 0.29 7.03 0.18
SILALA SILALA_SUR_TRM3 """ QMEO 0.03 4384.0 4384.1 4384.1 0.008 0.07 0.47 10.27 0.11
SILALA SILALA_SUR_TRM3 1680 QMEO 0.03 43818 43818 4383.8 4383.8 0.256 0.25 0.14 6.34 0.53
SIL.ALA SIL.ALA SUR TRM3 1670 QMEO 0.03 43814 438'7 4383.7 0.000 0.03 1.25 8.91 0.02
SIL.ALA SILALA_SUR_TRM3 1660 QMEO 0.03 4383.6 438'7 4383.7 0.005 0.08 0.42 5.75 0.09
SILALA SILALA_SUR_TRM3 1650 QMEO 0.03 4383.6 438'6 4383.6 0.007 0.06 0.58 15.66 0.10
SIL.ALA SILALA_SUR_TRM3 1640 QMEO 0.03 43814 43814 4383.4 43814 0.883 0.40 0.09 4.83 0.96
SIL.ALA SILALA_SUR_TRM3 HilO QMEO 0.03 4382.9 438'1 4383.1 0.000 0.02 1.94 12.26 0.01
SILALA SILALA_SUR_TRM3 1620 QMEO 0.03 4383.0 438'1 4383.1 0.001 0.04 0.90 7.38 0.03
SILALA SILALA_SUR_TRM3 1610 QMEO 0.03 43810 438'1 4383.1 0.003 0.07 0.46 4.39 0.07
SIL.ALA SILALA_SUR_TRM3 160) QMEO 0.03 43810 43810 4383.0 4383.0 0.894 0.31 0.11 9.19 0.90
SILALA SILALA_SUR_TRM3 1590 QMEO 0.03 4382.8 43829 4382.9 0.003 0.05 0.74 13.43 0.06
SILALA SILALA_SUR_TRM3 1580 QMEO 0.03 43827 43828 4382.8 4382.8 0.007 0.05 0.65 20.31 0.C>J
SIL.ALA SIL.ALA SUR TRM3 1570 QMED 0.03 4382.6 438>6 4382.6 0.282 0.19 0.18 13.22 0.52
SILALA SILALA_SUR_TRM3 1960 QMEO 0.03 4382.4 43825 4382.5 0.004 0.07 0.51 7.81 0.08
SILALA SILALA_SUR_TRM3 1550 QMEO 0.03 43822 43824 4382.4 o.oo; 0.06 0.59 14.67 0.C>J
SIL.ALA SILALA_SUR_TRM3 1540 QMED 0.03 4382.2 43823 4382.3 0.030 0.22 0.16 1.74 0.23
SIL.ALA SILALA_SUR_TRM3 1530 QMEO 0.03 4382.0 43821 4382.1 0.011 0.15 0.22 1.83 0.14
SILALA SILALA_SUR_TRM3 1520 QMEO 0.03 43820 43821 4382.1 0.007 0.06 0.55 12.91 0.10
SIL.ALA SILALA_SUR_TRM3 1510 QMED 0.03 4381.8 43819 4381.9 0.026 0.22 0.16 1.S2 0.22
SIL.ALA SILALA_SUR_TRM3 19)) QMEO 0.03 4381.6 43818 4381.8 0.008 0.13 0.27 2.55 0.12
SILALA SILALA_SUR_TRM3 1490 QMEO 0.03 43816 43817 4381.6 4381.7 0.009 0.12 0.29 3.11 0.12
SIL.ALA SILALA_SUR_TRM3 ""' QMEO 0.03 4381.4 43814 4381.4 4381.4 0.614 0.43 0.08 3.11 0.85
SIL.ALA SIL.ALA SUR TRM3 1470 QMEO 0.03 4381.0 43811 4381.1 0.002 0.07 0.47 3.75 O.Q7
294
158
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
SIMULACl6N HloR.4.UUCA DE FLUJO SUPERFIC IAL DELSISTEMA SILAlA
River Reach RiverSta Profi le
QTotal MinChEI W.S.Elev CritW.S. E.G.Elev E.G.Slope VelChnl Flow Area TopWidth
Froude#Chl
(m3/s) 1ml (ml (ml (ml (m/m) {m/s) (m2) (ml
SILALA SILALA_SUR_TRM3 14(,() QMEO 0.03 4l810 4l811 4381.1 0.008 0.11 0.32 3.79 0.12
SILALA SILALA_SUR_TRM3 1450 QMEO 0.03 4380.8 4l809 4380.9 0.154 0.31 0.11 2.39 0.47
SILALA SILALA_SUR_TRM3 1440 QMEO 0.03 43806 43808 4380.8 0.002 0.07 0.51 4.89 0.07
SILALA SILALA_SUR_TRM3 1430 QMEO 0.03 4380.6 4l808 4380.8 0.003 0.09 0.37 144 O.Ol
SILALA SILALA_SUR_TRM3 1420 QMEO 0.03 4380.6 4l806 4380.6 4380.7 0.650 0.58 0.06 1.52 0.93
SILALA SILALA_SUR_TRM3 1410 QMEO 0.03 43802 43805 4380.5 0.004 0.13 0.26 1.34 0.00
SILALA SILALA_SUR_TRM3 1400 QMEO 0.03 4l802 4l804 4380.4 0.012 0.10 0.34 5.96 0.13
SILALA SILALA_SUR_TRM3 ll90 QMEO 0.03 4380.2 4l80l 4380.3 0.016 0.10 0.35 8.05 0.15
SILALA SILALA_SUR_TRM3 llllO QMEO 0.03 43800 43801 4380.1 0.021 0.18 0.19 2.04 0.19
SILALA SIL.ALA SUR TRM3 1370 QMEO 0.03 4379.7 4379.9 4379.9 0.025 0.19 0.18 1.96 0.20
SILALA SILALA_SUR_TRM3 13(,() QMEO 0.03 4379.6 4379.8 4379.8 0.008 0.14 0.24 1.86 0.13
SILALA SILALA_SUR_TRM3 1350 QMEO 0.03 4379.4 4379.6 4379.6 0.065 0.28 0.12 1.54 0.33
SILALA SILALA_SUR_TRM3 1340 QMED 0.03 4379.2 4379.4 4379.4 0.007 0.13 0.25 1.96 0.12
SILALA SILALA_SUR_TRM3 1330 QMEO 0.03 4379.2 4379.3 4379.3 0.034 0.16 0.22 4.35 0.22
SILALA SILALA_SUR_TRM3 1320 QMEO 0.03 4378.9 4379.0 4379.0 0.017 0.15 0.23 3.01 0.17
SILALA SILALA_SUR_TRM3 1310 QMEO 0.03 4378.8 4378.9 4378.9 0.008 0.11 0.30 3.17 0.12
SILALA SILALA_SUR_TRM3 B>J QMEO 0.03 437&6 4378.9 4378.9 OOOJ 0.05 0.75 3.59 0.03
SILALA SILALA_SUR_TRM3 1290 QMEO 0.03 4378.8 4378.9 4378.9 0.010 0.12 0.29 3.51 0.13
SILALA SILALA_SUR_TRM3 1111() QMEO 0.03 4378.6 4378.7 4378.7 0.088 0.27 0.12 2.16 0.36
SILALA SILALA SUR TRM3 1170 QMEO 0.03 4378.4 4378.6 4378.6 0.004 0.10 0.33 2.36 0.09
SILALA SILALA_SUR_TRM3 11(,() QMEO 0.03 4378.4 4378.5 4378.5 0.027 0.17 0.20 1.98 0.21
SILALA SILALA_SUR_TRM3 1250 QMEO 0.03 4378.2 4378.3 4378.3 0.012 0.13 0.26 3.05 0.15
SILALA SILALA_SUR_TRM3 1240 QMEO 0.03 4378.0 4378.1 4378.1 0.044 0.20 0.17 2.72 0.26
SILALA SILALA_SUR_TRM3 1130 QMEO 0.03 4377.8 4378.0 4378.0 0.005 0.09 0.40 '"' 0.09
SILALA SILALA_SUR_TRM3 1220 QMEO 0.03 4377.8 4377.9 4377.9 0.054 0.18 0.19 4.50 0.27
SILALA SILALA_SUR_TRM3 1210 QMEO 0.03 4377.6 4377.7 4377.7 0.005 o.ro 0.38 3.83 0.00
SILALA SILALA_SUR_TRM3 1200 QMED 0.03 4377.6 4377.7 4377.7 0.008 0.09 0.36 5.18 0.11
SILALA SILALA_SUR_TRM3 ll!J0 QMEO 0.03 4377.4 4377.4 4377.4 4377.4 0.421 0.36 0.10 3.65 0.71
SILALA SILALA_SUR_TRM3 1180 QMEO 0.03 4377.2 4377.3 4377.3 0.003 0.08 0.45 l.89 0.07
SILALA SILALA SUR TRM3 1170 QMED 0.03 4377.2 4377.2 4377.2 4377.2 0.551 0.40 0.09 3.46 0.80
SILALA 51LALA_SUR_TRM3 11(,() QMEO 0.03 4377.0 4377.1 4377.1 0.003 0.08 0.44 3.66 0.07
SILALA SILALA_SUR_TRM3 1150 QMEO 0.03 4377.0 4377.1 4377.1 0.077 0.21 0.16 l.79 0.33
SILALA SILALA_SUR_TRM3 1140 QMED 0.03 4376.8 4376.9 4376.9 0.004 0.09 0.38 3.67 0.00
SILALA SILALA_SUR_TRM3 1130 QMEO 0.03 4376.8 4376.9 4376.9 0.023 0.11 0.32 8.72 0.17
SILALA SILALA_SUR_TRM3 1120 QMEO 0.03 4376.3 4376.7 4376.7 0.007 0.07 0.50 9.21 0.00
SILALA SILALA_SUR_TRM3 1110 QMEO 0.03 4376.5 4376.6 4376.6 0.172 0.20 0.17 8.23 0.44
SILALA SILALA_SUR_TRM3 1100 QMEO 0.03 4376.4 4376.5 4376.5 0.003 0.05 0.69 12.00 0.D7
SILALA SILALA_SUR_TRM3 1000 QMEO 0.03 4376.4 4376.4 4376.4 0.028 0.05 0.36 16.Sl 0.15
SILALA SILALA_SUR_TRM3 1000 QMEO 0.03 4376.2 4376.3 4376.3 0.011 0.08 0.40 8.81 0.13
SILALA SILALA SUR_TRM3 1070 QMED 0.03 4376.0 4376.1 4376.1 0.D15 0.17 0.21 1.92 0.16
SILALA SILALA_SUR_TRM3 1(,0 QMEO 0.03 4375.8 4376.0 4376.0 0.006 0.08 0.44 6.29 0.00
SILALA SILALA_SUR_TRM3 !CEO QMEO 0.03 4375.8 4376.0 4376.0 0.D15 0.16 0.21 1.98 0.16
SILALA SILALA_SUR_TRM3 1040 QMEO 0.03 4375.6 4375.8 437S.7 4375.8 0.009 0.08 0.41 780 0.11
SILALA SILALA_SUR_TRM3 1030 QMEO 0.03 4375.5 4375.6 4375.6 0.261 0.48 0.D7 1.18 0.63
SILALA SILALA_SUR_TRM3 1020 QMEO 0.03 4375.4 4375.5 4375.S 0.003 0.07 0.48 5.35 0.08
SILALA SILALA_SUR_TRM4 1010 QMEO 0.05 4375.2 4375.3 4375.3 0.107 0.37 0.14 1.80 0.42
SILALA SILALA_SUR_TRM4 1(00 QMEO 0.05 4375.0 4375.1 4375.1 0.010 0.19 0.28 2.38 0.18
SILALA SILALA_SUR_TRM4 990 QMEO 0.05 4374.9 4375.0 4375.0 0.023 0.16 0.32 6.51 0.23
SILALA SILALA_SUR_TRM4 980 QMEO 0.05 4374.6 4374.7 4374.7 0.033 0.26 0.20 1.56 0.30
SILALA SILALA SUR TRM4 970 QMED 0.05 4374.4 4374.6 4374.6 0.006 0.16 0.32 2.48 0.14
SILALA SILALA_SUR_TRM4 960 QMEO 0.05 4374.4 4374.5 4374.5 0.014 0.16 0.32 4.35 0.19
SILALA SILALA_SUR_TRM4 950 QMEO 0.05 4374.2 4374.3 4374.3 0.030 0.24 0.22 3.00 0.28
SILALA SILALA_SUR_TRM4 940 QMED 0.05 43719 4374.1 4374.1 0.016 0.19 0.28 3.56 0.21
SILALA SILALA_SUR_TRM4 930 QMEO 0.05 43718 4374.0 4374.0 0.006 0.16 0.32 2.24 0.13
SILALA SILALA_SUR_TRM4 920 QMEO 0.05 4373.8 4373.9 4373.9 0.020 0.14 0.22 2.25 0.24
SILALA SILALA_SUR_TRM4 910 QMEO 0.05 4373.6 4373.8 4373.8 0.010 0.19 0.27 2.3S 0.18
SILALA 51LALA_SUR_TRM4 900 QMEO 0.05 4373.5 4373.6 4373.6 0.019 0.18 0.29 4.45 0.22
SILALA SILALA_SUR_TRM4 890 QMEO 0.05 4373.4 4373.5 4373.5 0.010 0.13 0.41 6.37 0.16
SILALA SILALA_SUR_TRM4 880 QMEO 0.05 4373.2 43713 4373.3 0.031 0.31 0.17 1.50 0.30
SILALA SILALA SUR TRM4 870 QMED 0.05 4372.9 4373.2 4373.2 0.006 0.17 0.31 1.84 0.13
SILALA SILALA_SUR_TRM4 860 QMEO 0.05 4373.0 4373.1 4373.1 0.018 0.20 0.26 3.10 0.22
SILALA SILALA_SUR_TRM4 850 QMEO 0.05 43726 43728 4372.8 0.115 0.43 0.12 1.83 0.54
SILALA SILALA_SUR_TRM4 840 QMED 0.05 4372.0 43721 4372.1 0.044 0.27 0.19 184 0.34
SILALA SILALA_SUR_TRM4 830 QMEO 0.05 4370.8 43710 4371.0 4371.1 0.SJS 0.77 0.D7 1.13 1.01
SILALA SILALA_SUR_TRM4 810 QMEO 0.05 4370.2 4370.3 4370.2 4370.3 0.023 0.20 0.26 l.90 0.25
SILALA SILALA_SUR_TRM4 810 QMED 0.05 4369.8 437D.0 4370.0 0.048 0.35 0.15 '"' 0.37
SILALA SILALA_SUR_TRM4 800 QMEO 0.05 4368.8 4368.9 4368.9 4368.9 0.409 0.74 0.D7 1.24 1.00
SILALA SILALA_SUR_TRM4 790 QMEO 0.05 4367.7 4367.7 4367.7 4367.8 0.394 0.72 0.08 1.50 0.98
SILALA SILALA_SUR_TRM4 780 QMEO 0.05 4363.7 4363.8 4363.8 4363.8 0.416 0.65 0.08 1.79 0.98
SILALA SILALA SUR TRM4 770 QMED 0.05 4362.9 4363.2 4363.2 0.00J 0.04 1.48 6.58 0.D2
295
159
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA
SECTOR
SIMULACl6N HloR.4.UUCA DE FLUJO SUPERFICIAL DELSISTEMA SILAlA
River Reach RiverSta Profi le
QTotal MinChEI W.S.Elev CritW.S. E.G.Elev E.G.Slope VelChnl Flow Area TopWidth
Froude#Chl
(m3/s) 1ml (ml (ml (ml (m/m) {m/s) (m2) (ml
SILALA SILALA_SUR_TRM4 7(,() QMEO 0.05 4363.0 436'2 4363.1 4363.2 0.010 0.15 0.34 3.99 0.17
SILALA SILALA_SUR_TRM4 750 QMEO 0.05 4362.8 4362.9 4362.9 4362.9 0.389 0.72 0.07 1.28 0.98
SILALA SILALA_SUR_TRM4 740 QMEO 0.05 43624 4362.7 4362.7 0.001 0.06 0.83 5.99 0.05
SILALA SILALA_SUR_TRM4 730 QMEO 0.05 43626 43627 4362.7 0.021 0.18 0.30 5.06 0.23
SILALA SILALA_SUR_TRM4 720 QMEO 0.05 4362.4 43625 4362.S 0.019 0.16 0.33 rn 0.22
SILALA SILALA_SUR_TRM4 710 QMEO 0.05 43623 4362.4 4362.3 4362.4 0.008 0.10 0.53 10.19 0.14
SILALA SILALA_SUR_TRM4 700 QMEO 0.05 4362.2 4362.2 4362.2 0.036 0.15 0.36 12.15 0.27
SILALA SILALA_SUR_TRM4 '"' QMEO 0.05 4362.0 43621 4362.0 4362.1 0.011 0.11 0.48 10.23 0.16
SILALA SILALA_SUR_TRM4 680 QMEO 0.05 43619 43619 4361.9 0.011 0.12 0.43 7.69 0.17
SILALA SILALA SUR TRM4 670 QMEO 0.05 4361.6 43617 4361.7 0.141 0.36 0.1S 356 0.56
SILALA SILALA_SUR_TRM4 56D QMEO 0.05 4361.2 43613 4361.3 0.016 0.19 0.28 3.37 0.21
SILALA SILALA_SUR_TRM4 650 QMEO 0.05 43610 43611 4361.1 0.024 0.23 0.23 2.92 0.26
SILALA SILALA_SUR_TRM4 640 QMED 0.05 4360.6 4360.9 4360.9 0.016 0.29 0.18 088 0.21
SILALA SILALA_SUR_TRM4 630 QMEO 0.05 43604 4360.7 4360.7 0.057 0.47 0.11 0.71 0.38
SILALA SILALA_SUR_TRM4 620 QMEO 0.05 4360.2 4360.4 4360.4 0.018 0.27 0.20 1.46 0.23
SILALA SILALA_SUR_TRM4 610 QMEO 0.05 43S9.9 4360.1 4360.1 0.046 0.3S O.lS 1.Sl 0.35
SILALA SILALA_SUR_TRM4 (,(X) QMEO 0.05 4359.5 4359.6 4359.6 0.047 0.34 0.16 1.78 0.36
51LALA SILALA_SUR_TRM4 "' QMEO 0.05 4359.0 4359.2 4359.2 0.042 0.38 0.14 1.17 0.35
SILALA SILALA_SUR_TRM4 580 QMEO 0.05 4358.5 4358.7 4358.7 0.052 0.45 0.12 0.77 0.37
SILALA SILALA SUR TRM4 570 QMEO 0.05 43Sao 4358.2 4358.2 0.055 0.42 0.12 1.07 0.40
SILALA SILALA_SUR_TRM4 560 QMEO 0.05 4357.4 4357.6 4357.6 0.066 0.43 0.12 1.23 0.43
SILALA 51LALA_SUR_TRM4 550 QMEO 0.05 4356.7 4356.9 4356.9 0.0!IO 0.44 0.12 1.35 0.47
SILALA SILALA_SUR_TRM4 540 QMEO 0.05 4355.8 4356.0 4355.9 4356.0 0.087 0.55 0.09 0.66 0.47
SILALA SILALA_SUR_TRM4 530 QMEO 0.05 4354.3 4354.5 4354.5 4354.5 0.318 0.&l 0.06 0.79 0 . .,
SILALA SILALA_SUR_TRM4 520 QMEO 0.05 4353.4 4353.6 4353.6 0.044 0.38 0.14 1.19 0.36
SILALA 51LALA_SUR_TRM4 510 QMEO 0.05 4353.0 4353.1 4353.1 0.043 0.35 0.15 1.47 0.35
SILALA SILALA_SUR_TRM4 500 QMED 0.05 4352.0 43S2.1 4352.1 4352.2 0.379 0.89 0.1,; 0.70 0.98
SILALA SILALA_5UR_TRM4 ,., QMEO 0.05 4351.3 43515 4351.5 0.018 0.22 0.23 2.26 0.22
SILALA 51LALA_SUR_TRM4 480 QMEO 0.05 43510 43511 4351.1 0.199 0.55 0.10 1.55 0.71
SILALA SILALA SUR TRM4 470 QMED 0.05 4350.4 43S0.6 4350.6 0.019 0.25 0.21 186 0.24
SILALA SILALA_SUR_TRM4 4(,() QMEO 0.05 4349.8 4350.0 4350.0 0.066 0.48 0.11 0.87 0.43
SILALA SILALA_SUR_TRM4 450 QMEO 0.05 4349.4 4349.7 4349.7 0.020 0.31 0.17 1.03 0.24
SILALA SILALA_SUR_TRM4 440 QMED 0.05 4349.2 4349.3 4349.4 0.066 0.41 0.13 1.35 0.43
SILALA SILALA_SUR_TRM4 430 QMEO 0.05 4348.6 434&8 4348.8 4348.9 0.040 0.38 0.14 1.10 0.34
SILALA SILALA_SUR_TRM4 420 QMEO 0.05 4348.0 434&1 4348.1 0.148 0.59 0.09 1.02 0.63
SILALA 51LALA_SUR_TRM4 410 QMEO 0.05 4347.4 4347.5 4347.5 0.031 0.32 0.16 1.38 0.30
SILALA SILALA_SUR_TRM4 400 QMEO 0.05 4347.0 4347.1 4347.2 0.051 0.41 0.13 1.10 0.38
SILALA SILALA_SUR_TRM4 3., QMEO 0.05 4346.6 434"8 4346.8 0.032 0.20 0.26 5.13 0.28
SILALA SILALA_SUR_TRM4 38-0 QMEO 0.05 434&2 434&3 4346.3 0.055 0.30 0.17 2.56 0.38
SILALA SILALA SUR_TRM4 370 QMED 0.05 4345.7 434'9 4345.9 0.035 0.36 0.15 1.15 0.32
SILALA SILALA_SUR_TRM4 3(,() QMEO 0.05 4345.2 434'4 4345.3 4345.4 0.069 0.35 0.15 196 0.41
SILALA SILALA_SUR_TRM4 350 QMEO 0.05 43448 43449 4344.9 0.035 0.29 0.19 2.38 0.31
SILALA SILALA_SUR_TRM4 340 QMEO 0.05 4344.4 4344.6 4344.6 0.039 0.38 0.14 1.07 0.34
SILALA SILALA_SUR_TRM4 330 QMEO 0.05 43418 4344.0 4344.0 0.097 0.51 0.10 1.03 0.52
SILALA SILALA_SUR_TRM4 320 QMEO 0.05 43414 434,6 4343.6 0.019 0.29 0.18 1.13 0.24
SILALA SILALA_SUR_TRM4 310 QMEO 0.05 4343.2 43414 4343.4 0.034 0.36 0.15 1.13 0.32
SILALA SILALA_SUR_TRM4 300 QMEO 0.05 4342.8 434l0 4343.0 0.050 0.41 0.13 LOS 0.38
SILALA SILALA_SUR_TRM4 2., QMEO 0.05 4342.2 4342.4 4342.4 0.076 0.48 0.11 0.99 0.46
SILALA SILALA_SUR_TRM4 280 QMEO 0.05 43414 43415 4341.6 0.087 0.51 0.10 0.94 0.49
SILALA SILALA SUR TRM4 270 QMED 0.05 43408 43410 4341.0 0.042 0.37 0.14 1.19 0.35
SILALA SILALA_SUR_TRM4 2(,() QMEO 0.05 4340.2 43404 4340.4 0.085 0.50 0.10 0.95 0.49
SILALA SILALA_SUR_TRM4 250 QMEO 0.05 4339.6 4339.7 4339.7 0.053 0.36 0.14 1(,() 0.39
SILALA SILALA_SUR_TRM4 240 QMED 0.05 4339.0 4339.1 4339.1 0.075 0.41 0.13 148 0.45
SILALA SILALA_SUR_TRM4 230 QMEO 0.05 4338.4 4338.5 4338.S 0.043 0.38 0.14 1.25 0.36
SILALA SILALA_SUR_TRM4 220 QMEO 0.05 4338.0 4338.1 4338.1 0.038 0.36 0.15 1.45 0.34
SILALA SILALA_SUR_TRM4 210 QMEO 0.05 4337.1 4337.2 4337.2 4337.2 0.478 0.76 O.D7 1.22 1.02
SILALA SILALA_SUR_TRM4 200 QMEO 0.05 4335.5 4335.8 4335.8 0.035 0.43 0.13 0.81 0.33
SILALA SILALA_SUR_TRM4 1., QMEO 0.05 4334.8 4334.9 4334.9 4335.0 0.373 0.88 0.06 0.73 0.98
SILALA SILALA_SUR_TRM4 180 QMEO 0.05 4334.2 4334.0 4334.0 4334.0 0.566 0.06 0.82 0.00
SILALA SILALA SUR TRM4 170 QMED 0.05 4331.2 43312 4331.2 4331.2 0.411 0.49 0.09 209 0.89
SILALA SILALA_SUR_TRM4 1(,() QMEO 0.05 4329.0 4329.2 4329.2 0.090 0.53 0.11 0.97 0.46
SILALA SILALA_SUR_TRM4 150 QMEO 0.05 4328.8 4329.0 4329.0 0.005 0.20 0.27 1.29 0.14
SILALA SILALA_SUR_TRM4 140 QMED 0.05 4328.8 4328.8 4328.8 4328.9 0.457 0.65 0.09 2.26 1.02
SILALA SILALA_SUR_TRM4 130 QMEO 0.05 4326.8 4327.0 4326.9 4327.0 0.116 0.63 0.09 0.66 0.54
SILALA SILALA_SUR_TRM4 120 QMEO 0.05 4324.9 4325.0 432S.O 4325.1 0.389 0.73 O.D7 1.35 0.98
SILALA SILALA_SUR_TRM4 110 QMED 0.05 4323.6 4323.9 4323.9 O.Q28 0.37 0.14 0(,() 0.24
SILALA SILALA_SUR_TRM4 100 QMEO 0.05 4323.1 4323.2 4323.2 4323.2 0.394 0.85 0.06 0.82 0.99
SILALA SILALA_SUR_TRM4 ., QMEO 0.05 43218 43219 4321.9 4321.9 0.407 0.79 0.07 1.05 1.00
SILALA SILALA_SUR_TRM4 ., QMEO 0.05 4320.4 4320.6 4320.6 0.023 0.33 0.16 084 0.25
SILALA SILALA SUR TRM4 70 QMED 0.05 4320.2 4320.4 4320.4 0.027 0.33 0.16 1.17 0.29
296
160
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SILALA
SECTOR
SIMULACl6N HIOAAUUCA DE FLUJO SUPERFICIAL DELSISTEMA SILAlA
River Reach RiverSta Profi le
QTotal MinChEI W.S.Elev CritW.S. E.G.Elev E.G.Slope VelChnl Flow Area TopWidth
Froude#Chl
(m3/s) (m) (ml (ml (ml (m/m) {m/s) (m2) (ml
SILALA SILALA_SUR_TRM4 "' QMEO 0.05 4320.1 4320.2 4320.2 0.015 0.18 0.33 5.02 0.20
SILALA SILALA_SUR_TRM4 so QMEO 0.05 4319.6 4319.7 4319.7 4319.8 0.378 0.89 0.06 0.71 0.98
SILALA SILALA_SUR_TRM4 ., QMEO 0.05 4319.1 4319.2 4319.2 0.016 0.16 0.33 5.16 0.21
SILALA SILALA_SUR_TRM4 so QMEO 0.05 431&9 4319.1 4319.1 0.020 0.19 0.27 3.99 0.23
SILALA SILALA_SUR_TRMS " QMEO 0.O'J 4318.6 4318.9 4318.9 0.027 0.28 0.34 3.32 0.27
SILALA SILALA_SUR_TRMS 10 QMEO 0.O'J 4318.3 4318.6 4318.6 0.035 0.30 0.31 3.20 0.31
SILALA SILALA_NOR 680 QMEO 0.05 4361.2 43613 4361.3 0.095 0.35 0.15 3.28 0.53
SILALA SILALA_NOR 670 QMEO 0.05 4360.2 4360.3 4360.3 4360.4 0.121 0.62 0.08 0.91 0.65
SILALA SILALA_NOR 660 QMEO 0.05 4359.2 4359.3 4359.4 0.052 0.44 0.12 1.15 0.44
SILALA SILALA NOR 650 QMEO 0.05 43S8.4 43S8.S 43S8.S 0.149 0.64 0.08 099 0.72
SILALA SILALA_NOR 640 QMEO 0.05 4357.8 43S7.9 43S7.9 0.030 0.3S 0.1S 138 0.34
SILALA SILALA_NOR 630 QMEO 0.05 4357.4 43S7.S 4357.6 0.056 0.27 0.19 4.33 0.41
SILALA SILALA_NOR 620 QMEO 0.05 43S6.9 43S7.0 43S7.0 0.057 0.31 0.17 3.24 0.42
SILALA SILALA_NOR 610 QMEO 0.05 43S6.4 43S6.S 43S6.S 0.046 0.26 0.20 3.94 0.37
SILALA SILALA_NOR 600 QMEO 0.05 43S5.9 43S6.1 43S6.1 0.037 0.36 0.14 1.48 0.37
SILALA SILALA_NOR 5'<l QMEO 0.05 435S.4 43S5.6 435S.6 0.076 0.49 0.11 1.14 O.S2
SILALA SILALA_NOR 580 QMEO 0.0S 43S4.8 43S4.9 4354.9 0.050 0.43 0.12 1.19 0.43
SILALA SILALA_NOR 570 QMEO 0.05 4354.0 43S4.2 4354.2 0.133 0.66 0.08 0.00 0.68
SILALA SILALA_NOR 560 QMEO 0.05 43S3.4 43S3.6 4353.6 0.033 0.«J 0.13 1.00 0.35
SILALA SILALA NOR 550 QMEO 0.05 43S3.0 43S3.1 43S3.2 0.058 0.47 0.11 1.07 0.46
SILALA SILALA_NOR 540 QMEO 0.05 4352.6 43S2.9 4352.9 0.016 0.29 0.18 1.31 0.25
SILALA SILALA_NOR 530 QMEO 0.05 4352.6 43S2.7 4352.7 0.021 0.15 0.34 8.97 0.25
SILALA SILALA_NOR 520 QMEO 0.05 43S18 43S2.0 43S2.0 43S2.0 0.27S 0.89 0.06 0.63 0.93
SILALA SILALA_NOR 510 QMEO 0.05 43514 43S16 4351.6 0.017 0.30 0.18 1.34 0.26
SILALA SILALA_NOR 500 QMEO 0.05 43510 43512 4351.2 0.145 0.70 0.07 0.72 0.70
SILALA SILALA_NOR 4'<l QMEO 0.05 4350.5 4350.7 4350.7 0.027 0.32 0.16 1.55 0.32
SILALA SILALA_NOR 480 QMEO 0.05 43S0.0 43S01 4350.1 0.197 0.6S 0.08 1.22 0.81
SILALA SILALA_NOR 470 QMEO 0.05 4349.2 4349.5 4349.S 0.030 0.38 0.14 0.96 0.32
SILALA SILALA_NOR 460 QMEO 0.05 4349.0 4349.1 4349.1 0.051 0.34 0.15 2.14 0.41
SILALA SILALA NOR 450 QMEO 0.05 4348.6 434&7 4348.7 0.026 0.28 0.18 2.06 0.31
SILALA SILALA_NOR 440 QMEO 0.05 4348.2 434&5 4348.S 0.033 0.26 0.20 3.07 0.33
SILALA SILALA_NOR 430 QMEO 0.05 4348.0 434&2 4348.2 0.014 0.13 0.39 9.03 0.20
SILALA SILALA_NOR 420 QMEO 0.05 4347.8 4347.9 4347.9 4347.9 0.110 0.29 0.18 6.19 0.53
SILALA SILALA_NOR 410 QMEO 0.05 4347.4 4347.S 4347.S 0.022 0.22 0.23 3.44 0.27
SILALA SILALA_NOR 460 QMEO 0.05 4347.0 4347.2 4347.2 0.041 0.31 0.17 2.16 0.36
SILALA SILALA_NOR 3'<) QMEO 0.05 434S6 434S9 4346.9 0.030 0.28 0.19 2.30 0.31
SILALA SILALA_NOR 380 QMEO 0.05 4346.2 434S3 4346.3 0.146 0.43 0.13 3.38 0.65
SILALA SILALA_NOR 370 QMEO 0.05 4345.6 434'7 4345.7 0.033 0.15 0.22 3.52 0.28
SILALA SILALA_NOR 360 QMEO 0.05 434,0 43449 4344.9 0.248 0.O'J 1.73 0.00
SILALA SILALA NOR 350 QMEO 0.05 4344.4 4344.4 4344.3 4344.4 0.023 0.22 2.28 0.00
SILALA SILALA_NOR 340 QMEO 0.05 4344.0 434'9 4343.9 4343.9 0.377 0.08 1.71 0.00
SILALA SILALA_NOR 330 QMEO 0.05 43412 43414 4343.3 4343.4 0.014 0.19 0.27 3.31 0.22
SILALA SILALA_NOR 320 QMEO 0.05 4342.9 43410 4343.0 4343.0 0.318 0.47 0.11 399 0.'<l
SILALA SILALA_NOR 310 QMEO 0.05 4342.0 43421 4342.1 4342.1 0.043 0.28 0.19 3.31 0.37
SILALA SILALA_NOR 300 QMEO 0.05 43412 43413 4341.3 4341.3 0.178 0.64 0.08 1.03 0.73
SILALA SILALA_NOR '"' QMEO 0.05 4340.4 43405 4340.S 0.054 0.25 0.21 5.02 0.39
SILALA SILALA_NOR 280 QMEO 0.05 4339.2 4339.3 4339.3 4339.3 0.34S 0.66 0.08 1.79 1.00
SILALA SILALA_NOR 270 QMEO 0.05 4338.2 4338.3 4338.3 0.048 0.35 0.15 1.96 0.41
SILALA SILALA_NOR 260 QMEO 0.05 4337.5 4337.6 4337.6 0.107 0.45 0.12 2.00 0.59
SILALA SILALA NOR 250 QMEO 0.05 4336.7 4336.8 4336.9 0.060 0.34 0.1S 2.SS 0.44
SILALA SILALA_NOR 2«) QMEO 0.05 4336.0 4336.1 4336.0 4336.1 0.107 0.43 0.12 2.18 0.57
SILALA SILALA_NOR 230 QMEO 0.05 4335.2 4335.4 4335.4 0.048 0.46 0.11 0.92 0.42
SILALA SILALA_NOR 220 QMEO 0.05 4334.S 4334.7 4334.7 0.101 O.S7 0.O'J 099 0.60
SILALA SILALA_NOR 210 QMEO 0.05 4333.6 4333.8 4333.8 0.000 0.58 0.0'J 0.71 0.52
SILALA SILALA_NOR 200 QMEO 0.05 4333.0 4333.2 4333.2 0.043 0.46 0.11 0.73 0.38
SILALA SILALA_NOR l'<l QMEO 0.05 43326 4332.7 4332.7 0.069 0.36 0.15 2.47 0.47
SILALA SILALA_NOR 180 QMEO 0.05 4331.6 4331.7 4331.7 0.149 0.56 0.0'J 1.34 0.68
SILALA SILALA_NOR 170 QMEO 0.05 4330.8 4330.9 4330.9 0.048 0.40 0.13 1.34 0.41
SILALA SILALA_NOR 160 QMEO 0.05 4330.0 4330.1 4330.1 0.153 0.61 0.O'J 1.18 0.72
SILALA SILALA NOR 150 QMEO 0.05 4329.2 4329.3 4329.3 0.048 0.37 0.14 1.78 0.41
SILALA SILALA_NOR l«J QMEO 0.05 4328.6 4328.7 4328.7 0.085 0.46 0.11 1.51 0.54
SILALA SILALA_NOR 130 QMEO 0.05 4328.0 4328.1 4328.1 0.044 0.36 0.14 1.68 0.40
SILALA SILALA_NOR 120 QMEO 0.05 4327.2 4327.4 4327.4 4327.4 0.113 0.44 0.12 208 0.58
SILALA SILALA_NOR 110 QMEO 0.05 4326.6 4326.7 4326.7 0.049 0.36 0.1S 1.86 0.41
SILALA SILALA_NOR 100 QMEO 0.05 4325.8 4325.9 4325.9 0.168 0.68 0.08 0.94 0.76
SILALA SILALA_NOR "' QMEO 0.05 4325.0 4325.2 432S.1 4325.2 0.041 0.36 0.14 1.49 0.37
SILALA SILALA_NOR ., QMEO 0.05 4324.2 4324.3 4324.3 4324.3 0.307 0.72 0.0, 1.2S 0.95
SILALA SILALA_NOR JO QMEO 0.05 4323.4 4323.6 4323.6 0.029 0.33 0.16 1.39 0.31
SILALA SILALA_NOR "' QMEO 0.05 4322.7 4322.8 4322.8 4322.9 0.346 0.79 0.0, 1.04 1.00
SILALA SILALA NOR so QMEO 0.05 4321.6 4321.9 4321.8 4321.9 0.04S 0.47 0.11 0.73 0.39
297
161
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AN D INSTALLED IN THE SILALA
SECTOR
SIMULACl6N HIORAUUCA DE FLUJOSUPERFICIAL DELSISTEMA SILALA
River Reach RiverSta Profi le QTotal MinChEI W.S.Elev CritW.S. E.G.Elev E.G.Slope VelChnl Flow Area Top Width
Froude#Chl
(m3/s) 1ml (ml (ml (ml (m/m) (m/s} (m2) 1ml
SILALA SILALA_NOR 40 QMED 0.05 4321.0 4321.2 4321.2 0.123 0.67 0.00 0.70 0.64
SILALA SILALA_NOR 30 QMED 0.05 4320.4 4320.6 4320.5 4320.6 0.033 0.41 0.13 0.92 0.35
SILALA SILALA_NOR 20 QMED 0.05 4319.9 4320.0 4320.0 4320.1 0.328 0.67 0.00 164 0.98
SILALA SILALA_CONFLU 710 QMED 0.13 4317.8 4318.1 4318.1 0.017 0.25 0.53 3.41 0.21
SILALA SILALA_CONFLU 700 QMED 0.13 4317.4 4317.6 4317.7 0.263 0.78 0.17 1.59 0.76
SILALA SILALA_CONFLU 6'>J QMED 0.13 4316.8 4317.1 4317.1 0.023 0.32 0.41 196 0.23
SILALA SILAIA_CONFLU 680 QMED 0.13 4316.4 4316.9 4316.9 0.023 0.26 o.ss 2.63 0.15
Sil.ALA SILALA_CONFLU 670 QMED 0.13 4316.2 4316.3 4316.3 0.224 0.47 0.28 3.04 0.49
Sil.ALA SILALA_CONFLU "" QMED 0.13 4314.8 4315.2 4315.2 0.073 046 0.29 1.27 0.31
SILALA SILALA CONFLU 650 QMED 0.13 4314.0 4314.2 4314.2 0.118 036 038 3'>J 0.37
SILALA SILALA_CONFLU 640 QMED 0.13 4313.2 4313.5 4313.5 0.051 0.33 0.41 2.10 0.24
SILALA SILALA_CONFLU 630 QMED 0.13 4312.4 4312.7 4312.7 0.139 0.54 0.2S 1.47 0.42
SILALA SILALA_CONFLU 620 QMED 0.13 4311.6 4312.1 4311.8 4312.1 0.038 0.31 0.44 2.23 0.22
SILALA SILALA_CONFLU 610 QMED 0.13 4310.8 4310.9 4310.9 4311.0 0.937 1.07 0.12 1.16 1.05
SILALA SILALA_CONFLU 600 QMED 0.13 4310.0 4310.4 4310.4 0.011 0.21 0.64 2.41 0.13
SILALA SILALA_CONFLU 5'>J QMED 0.13 4309.8 4310.2 4310.2 0.022 0.21 0.6S 404 0.16
SILALA SILALA_CONFLU 580 QMED 0.13 4309.4 4309.5 4309.S 4309.6 0.850 1.02 0.13 1.22 1.00
SILALA SILALA_CONFLU 570 QMED 0.13 4308.4 4308.7 4308.7 0.024 0.18 0.75 6.99 0.17
SILALA SILALA_CONFLU SW QMED 0.13 4307.9 4308.1 4308.1 0.305 0.59 0.23 2.20 0.59
SILALA SILALA CONFLU 550 QMED 0.13 4306.7 4307.0 4307.0 0.054 0.39 0.34 1.65 0.27
SILALA SILALA_CONFLU 540 QMED 0.13 4306.0 4306.4 4306.4 0.069 0.46 0.29 LC< 0.28
SILALA SILALA_CONFLU 530 QMED 0.13 4305.4 4305.8 4305.8 0.057 0.43 0.31 108 0.26
SILALA SILALA_CONFLU 520 QMED 0.13 4304.8 4305.3 4305.0 4305.3 0.047 0.38 0.35 1.47 0.25
SILALA SILALA_CONFLU 510 QMED 0.13 4304.2 4304.4 4304.4 0.195 0.62 0.22 1.41 0.50
SILALA SILALA_CONFLU 500 QMED 0.13 4303.4 4303.9 4303.9 0.026 0.21 0.64 4.64 0.18
SILALA SILALA_CONFLU 4'>'.) QMED 0.13 4303.2 4303.S 4303.S 0.071 0.41 0.33 1.87 0.31
SILALA SILALA_CONFLU 480 QMED 0.13 4302.4 4302.7 4302.7 0.076 0.35 0.38 2.86 0.31
SILALA SILALA_CONFLU 470 QMED 0.13 4301.8 4302.1 4302.1 0.052 0.31 0.43 2.91 0.26
SILALA SILALA_CONFLU 4r,o QMED 0.13 4301.2 4301.S 4301.5 0.068 0.45 030 1.25 0.29
SILALA SILALA CONFLU 450 QMED 0.13 4300.6 4300.9 4300.9 0.048 0.40 0.34 1.31 0.25
SILALA SILALA_CONFLU 440 QMED 0.13 4300.0 4300.4 4300.4 0.073 0.40 0.34 1.87 0.30
SILALA SILALA_CONFLU 430 QMED 0.13 4299.2 4299.8 4299.8 0.051 0.36 0.37 1.71 0.24
SILALA SILALA_CONFLU 420 QMED 0.13 4298.7 4299.2 4299.2 0.065 0.46 0.29 1.01 0.27
SILALA SILALA_CONFLU 410 QMED 0.13 4298.2 4298.6 4298.6 0.047 0.36 0.37 1.63 0.24
SILALA SILALA_CONFLU 400 QMED 0.13 4'297.7 4298.1 4298.1 0.058 0.34 0.39 2.41 0.27
SILALA SILALA_CONFLU 3'>J QMED 0.13 4297.4 4297.7 4297.7 O.Q28 0.23 0.59 409 0.19
SILALA SILALA_CONFLU 380 QMED 0.13 4297.0 4297.3 4297.3 0.073 0.30 0.45 4.46 0.30
SILALA SILALA_CONFLU 370 QMED 0.13 4296.2 4296.6 4296.7 0.057 0.41 0.33 1.38 0.27
SILALA SILALA_CONFLU 360 QMED 0.13 4295.6 4295.9 4295.9 0.095 0.51 0.26 1.18 0.35
SILALA SILALA CONFLU 350 QMED 0.13 4294.7 4295.0 4295.1 0.081 0.50 0.27 109 0.32
SILALA SILALA_CONFLU 340 QMED 0.13 4294.0 4294.3 4294.4 0.061 0.36 0.37 1.98 0.27
SILALA SILALA_CONFLU 330 QMED 0.13 4293.6 4293.9 4293.9 0.040 034 0.39 1.87 0.24
SILALA SILALA_CONFLU 320 QMED 0.13 4293.0 4293.4 4293.4 0.055 0.35 0.39 2.27 0.27
SILALA SILALA_CONFLU 310 QMED 0.13 4'292.4 4292.8 4292.8 0.071 0.45 0.30 1.38 0.31
SILALA SILALA_CONFLU 300 QMED 0.13 4291.8 4292.0 4292.1 0.071 0.41 0.33 ,., 0.31
SILALA SILALA_CONFLU 2'>'.) QMED 0.13 4291.2 4291.5 4291.5 0.047 0.37 0.36 1.65 0.26
SILALA SILALA_CONFLU 280 QMED 0.13 429:l.8 4291.2 4291.2 0.024 0.30 0.44 1.59 0.18
SILALA SILALA_CONFLU 270 QMED 0.13 42~.4 42~.8 42~.8 0.073 0.48 0.28 104 0.29
SILALA SILALA_CONFLU 2r,o QMED 0.13 4289.6 42~.2 42~.2 0.051 0.41 0.33 0.99 0.23
SILALA SILALA CONFLU 250 QMED 0.13 4289.0 4289.4 4289.4 0.124 0.59 0.23 0.92 0.37
SILALA SILALA_CONFLU 240 QMED 0.13 4288.2 4288.8 4288.8 0.036 0.36 0.37 1.03 0.19
SILALA SILALA_CONFLU 230 QMED 0.13 4288.0 4288.4 4288.4 0.049 0.40 0.33 1.23 0.25
SILALA SILALA_CONFLU 220 QMED 0.13 4287.6 4288.0 4288.0 0.031 0.26 0.52 2.98 0.20
SILALA SILALA_CONFLU 210 QMED 0.13 4287.1 4287.5 4287.5 0.095 0.38 0.35 2.61 0.33
SILALA SILALA_CONFLU 200 QMED 0.13 4286.4 4286.9 4286.9 0.038 0.37 0.36 1.14 0.21
SILALA SILALA_CONFLU l'Kl QMED 0.13 4286.0 4286.4 4286.4 0.072 0.46 0.29 1.26 0.30
SILALA SILALA_CONFLU 180 QMED 0.13 4285.4 4285.8 4285.8 0.056 0.43 0.31 1.21 0.27
SILALA SILALA_CONFLU 170 QMED 0.13 4284.8 4285.2 4285.2 0.063 0.45 0.30 1.08 0.28
SILALA SILALA_CONFLU 1r,o QMED 0.13 4284.2 4284.6 4284.6 0.048 0.39 034 134 0.25
SILALA SILALA CONFLU 150 QMED 0.13 4283.8 4284.2 4284.2 0.038 0.33 0.40 1.81 0.23
SILALA SILALA_CONFLU 140 QMED 0.13 4283.4 4283.9 4283.9 0.026 0.25 0.54 2.87 0.19
SILALA SILALA_CONFLU 130 QMED 0.13 4282.9 4283.1 4283.2 0.611 1.01 0.13 0.92 0.84
SILALA SILALA_CONFLU 120 QMED 0.13 4282.0 4282.5 4282.5 0.023 0.24 0.56 2.82 0.17
SILALA SILALA_CONFLU 110 QMED 0.13 4281.8 4282.1 4282.1 0.064 0.45 0.30 1.25 0.29
SILALA SILALA_CONFLU 100 QMED 0.13 4281.2 4281.6 4281.6 0.042 0.39 0.35 1.17 0.23
SILALA SILALA_CONFLU ., QMED 0.13 4280.8 4281.2 4281.2 0.053 0.37 0.36 1.82 0.27
SILALA SILALA_CONFLU 80 QMED 0.13 4280.2 4280.5 4280.5 0.088 0.47 0.28 144 0.34
SILALA SILALA_CONFLU 70 QMED 0.13 4279.6 4280.0 4280.0 0.034 0.32 0.46 240 0.20
SILALA SILALA_CONFLU r,o QMED 0.13 4279.2 4279.5 4279.5 0.076 0.47 0.28 1.23 0.31
SILALA SILALA CONFLU 50 QMED 0.13 4278.2 4278.9 4278.9 0.039 0.34 0.40 1.14 0.18
SILALA SILALA_CONFLU 40 QMED 0.13 4278.2 4278.5 4278.5 0.062 0.39 0.35 2.29 0.29
SILALA SILALA_CONFLU 30 QMED 0.13 4277.4 4277.8 4277.8 O.D78 0.47 0.29 1.33 0.32
SILALA SILALA_CONFLU 20 QMED 0.13 4277.0 4277.3 4277.3 0.030 0.33 0.42 194 0.21
SILALA SILALA_CONFLU 10 QMED 0.13 4276.6 4276.9 4276.7 4276.9 0.062 0.44 0.31 1.26 0.28
298
162
CHARACTERIZATION AND EFFICIENCY OF THE HYDRAULIC WORKS BUILT AND INSTALLED IN THE SI LALA SECTOR
ANNEX 3: WATER QUALITY MEASUREMENT SHEETS IN THE CANALS OF THE SILALA SPRINGS
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•c μSiem mg/L %Sat NTIJ D/DD mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L D/DD D/DD UFC/11D UFC/11D
ml ml
SIT-I TAIKA -P □ ZD HOTEL 6.1 7.34 1893 7.17 1 □ 1. 2 □. □ □ □. □ 177.83 11. □ 6 l □ .52 ID.48 1.33 7.54 9.8 □ □ □□ ID 3.33 2.77 19.83 □.□ 68.47 □.ID □. □6 □.38 5. □ -91.2 -1 □. 5 □
SI-I N □ R TH SPRING B □ FE □A L 14.4 8.25 114.2 5.84 98.3 □.2 3 □.□ ID 6.12 9. □ 4 1.46 9.38 1.82 4.94 7.74 □. □□ 56.62 2.6 □ 1711 3. □ 35.41 □.□7 □. □3 □.23 <2. □ -91.2 -11.66
Sl-2 SOUTH SPRING B □ F E □ AL 14. □ 7.75 246. □ 6. □ I 9 9. □ D.2 □ □. □ 2 31.8 □ 16.31 6.13 19. □ B 2.8 □ 6.14 8.98 □ □□ 142.96 2.22 2 1. □2 □.□ 62.74 □.ID □. □3 □.3 9 <2. □ -95.7 - 12 . □ 3
Sl-3 SOUTH SPRING B □ FE □ AL 14.6 7.41 260. □ 6. □ I ID □.4 □.25 □.□ 237.75 17. □ 4 7. □ 5 19. □ B 3.1 □ 6.61 8.98 □. □□ 145.79 2.32 22 . □ 4 4. □ 7B.57 □. □ 6 □. □3 □.34 <2 . □ -95.6 -12.13
Sl-4 SPRING □ F THE SOU TH B □ FE □ AL 12.2 7.8 □ 22 6. □ 6.48 ID3.7 □. 15 □.□ 2 □8.11 14.61 5.4 □ 18. □ 9 2.8 □ 5.34 7.74 □ □□ 127.39 2.39 2 □.26 2. □ 68.74 □□ B □ □2 □.32 <2. □ - 97. □ -12.18
Sl-5 SOUTH B □ FE □ A L CANAL l □ .9 8.4□ 283. □ 7. □ 6 11 □.□ 2.32 □.□ 261.88 19.57 8.97 19. □ B 3.59 4.74 8.98 □. □□ 165.61 □.Bl 22.21 8. □ 85.79 □.17 □. □3 □.22 2.7 -96.1 -12. □ 9 7. □□ E+□ 2 7. □□ E+□2
Sl-6 SILALA N □ R lH B □ F E □A L 16.3 8.16 115.4 5.89 1 □2.5 □.2 5 □.□ ID2.3□ 8.41 1.51 9.68 1.82 4.54 6.91 □ □□ 55.2 □ 2. □ 5 17.45 2. □ 29.45 □□ B □. □3 □.3□ <2 . □ -9 □. 8 -11.55
Sl-7 N □ R TH B □ FE □ A L CANAL 15.7 8.DI 1 3 9 □ 5.92 IDl.9 □.1 5 □.□ 113.18 9.48 1.95 l □ .68 1.92 5.2 □ 7.46 □. □□ 6 □. 8 6 2.13 17.62 I. □ 31.69 □.19 □. □3 □.25 <2 . □ -92.1 -11.74
Sl-8 SILALA SOUTH B □ FEDA L 14.5 7.59 4 □4. □ 5.4 92.5 D.33 □. I 3597B 32.32 15.81 21.□ 7 5.45 5.47 l □.□B □ □□ 225. □ 5 2. □ 7 31.7B 3 . □ 141.37 D.73 □. □ 5 □.29 2.8 -95.6 -12.26
Sl-9 B □ FEDAL □ F THE N □ R TH CANAL 15.5 B. □ 3 124.7 6.19 ID5.3 □ . 17 □. □ 113.84 8.48 1.56 ID.48 1.92 5. □ 7 7.05 D. D □ 63.69 2.13 16.4 □ □.□ 29.58 □.11 D.03 □.23 •2.D -!11.3 -11.72
SI-ID BDFEDAL □ F THE NORTH CANAL 14.9 8.08 96.3 6.22 1Dl6 0.48 □. □ 84.39 7.52 1.13 7.89 1.82 4.24 6.01 D D □ 43.88 I.Bl 17.59 3 . □ 25.63 0.14 0.04 □ 2 □ •2.D -9 □.I -11.41
SI-II BDFEDAL □ F THE NORTH PIEZDMETER 14.9 8.21 87.7 6.04 99.5 D.25 □.D 75.32 7.50 D.94 7.29 1.92 4.14 5.94 D. D □ 36.80 1.73 17.36 2. □ 24.58 0.12 □.ID D.19 2.1 -90.2 -11.83
Sl-12 SILi.LA NDRlH BDFEDAL 13.8 8.31 173.7 6.41 IDS.I 1.39 □. □ 152.24 12.66 3.73 13.ID 2.51 4.87 6.91 D D □ 89.17 1. 36 18.16 2. □ 48.76 0.12 D. □ 3 0.25 3.6 -92.4 -11.72 D. D □ E+D D D.D □ E+D D
Sl-13 NORTH BDFEDAL CANAL D . D □ E•DD D . D □ E•D D
Sl-14 NORTH B □ FEDA L CANAL 14.8 8.19 121.7 6.22 1 □4.6 0.7 □ □. □ 113.63 9.20 1.83 l □ .18 1.92 4.8 □ 6.63 D D □ 63.69 1.94 16.06 2 . □ 33.21 D □ B D . □ 3 0.25 •2.D -92 . □ -11.58 D. D □ E•D D D.D □ E•D D
Sl-15 SOUTH B □ FEDA L CANAL 12.3 8.44 217.D 6.31 IDl.5 2.55 □. D 201.59 15.87 5.93 IS.ID 2.90 5.20 8.15 D. D □ 123.14 1. 66 18.95 7. □ 66.33 D.12 □.DB D.25 3.8 -93.4 -11.65 I.D □ E+D3 I.D□ E•D3
Si-16 s □ urn B □ FEDA L CANAL 13.4 8.44 302. □ 7.28 11 8.D 0.52 □.I 268.31 22.22 ID.27 19 . □ B 3.88 5.40 6.63 D D □ 168.44 1.17 18.3 □ 4. □ 98.77 0.12 D . □ 5 D.17 l □ .6 l. □□ E+D2 I.D □ E•D2
Sl-17 SDUlH B □ FEOA L 13.5 9.00 248.D 8.18 137.6 D.47 □. D 189.02 17.41 7.20 21.07 3.10 5.74 7.32 20.88 83.51 D.63 18.55 4. □ 74.63 D.18 D.03 0.19 8.2 3.DDE•D2 3.DD E•□2
Sl-18 SDUlH LIPEZPRDVINCE 14.3 8.98 256.D 6.73 113.1 D.33 D.D 205.43 17.12 7.18 18.58 3.15 5.17 6.98 14.62 ID7.57 D.94 20.04 3.0 72.54 D.16 D.07 D.25 3.6 D.DDE•DD D.DDE•DD
LCE-1 LAGUNA COLD.RADA SPRING SOU TH LIPEZ PROV. 14.18.24 957.D 4.97 83.8 0.31 0.4 449.54 9.67 4.42 ID3.78 13.21 174.48 43.17 □ . DD 46.~ 1.83 35.06 4.0 44.35 D.07 0.04 D.44 •2.D -86.D -11. 45
LCS-1 LAG UNA COLD.RADA SPRING SOUTH LIPEZ 16.7 8.35 998.D 4.86 84.6 D.35 0.4 382.32 ID.34 4.81 112.74 13.70 88.07 3986 □ . DD 66.53 I.Bl 33.74 4.0 46.32 D.05 D.04 D.38 13.8
LCMAC-1 LAG UNA CDLDRADA VIEWPOINT IS.I 8.03 Sill □ 5.54 1 □2 .4 D.36 0.2 391.52 8.68 3.22 55.95 9.28 203.17 18.35 □ . DD 45.29 l.7l 35.74 3.0 35.86 D.06 D.03 □.4 3 •2.D -95. 3 -12.58
Annex 23.2
C. Barrón, “Study of Georeferencing, Topographic
survey and determination of the infiltration capacity
in the event of possible surface runoff in the area of
the Silala springs”, May 2018
(English Translation)