UNESCO/OAS ISARM-Americas Programme - Transboundary Aquifers of the Americas


The ISARM-Americas Programme was launched at the global “Internationally Shared Aquifer Resources Management - ISARM Programme”, during the 14th Session of UNESCO IHP Intergovernmental Council, in June 2000, in cooperation with several other international organizations, notably the United Nations Food and Agriculture Organization (FAO), the Economic Commission for Europe (UNECE), the United Nations Economic and Social Commission for Western Asia (UNESCWA), and the International Association of Hydrogeologists (IAH).  It aims to promote the recognition and understanding of transboundary groundwater resources, and foster collaboration among the countries sharing the same resource to achieve consensus on legal, institutional, socio-economic, scientific, and environmental aspects.  Another important objective of the ISARM-Americas Programme is the identification of case-studies of particular interest.  The Programme operates through a joint coordination committee of experts from UNESCO-IHP, IAH, FAO, and UNECE.


One of the most important objectives of the ISARM Americas Programme is to create a comprehensive Inventory of Transboundary Aquifers of the Americas, a collection of data regarding the hydro-geological characteristics, the actual use of the shared groundwater, and relevant legal and institutional aspects.  This work has, inter alia, the potential for interfecundation of successful concepts and solutions devised for/by countries of different subregions in the Hemisphere.


From the start of the activities in 2003, the Programme has assessed the prevalence of transboundary aquifers in the Western Hemisphere, with the contributions of a network of National Coordinators which represent 24 countries of the Americas. The questionnaires were designed to cover all fundamental aspects of both Legal and Institutional frameworks of each country’s water management systems. They highlight international treaties, conventions and declarations between countries sharing surface-and groundwater resources, and request separate data for state/provinces and federal governments, where applicable.  The answers have been systematized and classified, with tentative conclusions suggested.  Four previous Coordination Workshops were held in Montevideo, Uruguay, on September 24th - 25th, 2003; El Paso, Mexico, November 10th-12th, 2004, São Paulo, Brazil, November 30th – December 2nd, 2005, and San Salvador, El Salvador, November 20th – 22nd, 2006. Up to January 2006, 68 transboundary aquifers were identified: 29 in South America, 18 in Central America, 17 in North America, and 4 in the Caribbean.


During the Montevideo Workshop the countries proposed nine transboundary aquifers as possible case studies for project implementation with the ISARM approach. They are located in areas of particular concern in the Americas: arid and semi-arid regions; areas vulnerable to natural hazards and to climatic variability due to climate change; areas with severe land/water degradation due to increased urbanization and industrialization, extensive agriculture and deforestation, which impact entire ecosystems; and areas of potential water use conflict, with high levels of poverty and health uncertainty.


In 2004 the ISARM-Americas Steering Committee identified three priority case-studies of transboundary aquifers: the Artibonito and Masacre ones in the Hispaniola Island (Haiti – Dominican Rep.)  as an example of inter-mountainous and coastal transboundary aquifers in small islands developing states; the Yrenda-Toba-Tarijeno aquifer system in the Gran Chaco Americano (Argentina-Bolivia-Paraguay), representing transboundary aquifers in semi-arid zones of South America; and the Hueco Bolson aquifer (Mexico-USA), as an example of transboundary aquifer system in urban areas.


The Committee found that deforestation in the Artibonito basin impacted ecosystems and made them vulnerable to climatic fluctuations. Under the auspices of the UNESCO/OAS ISARM-Americas Programme, the Dominican Republic and Haiti agreed on cooperative work “to sustainably manage the aquifers“. The project will identify technical, legal, scientific and governance gaps and strengthens the institutions responsible for water resource management. It will focus on schemes for managed groundwater recharge, to mitigate the vulnerability of these two countries to extreme climatic conditions, such as hurricanes, high rainfall periods that alternate with extended droughts.


The Yrenda – Toba – Tarijeño Transboundary Aquifer System – SAYTT covers approximately 350.000 km2 of Bolivia, Argentina and Paraguay, in the Gran Chaco, where water scarcity is rampant. This study will be addressed within the context of the Project “Framework for the Management of the Water Resources of the La Plata River Basin”, carried out by  Argentina, Bolivia, Brazil, Paraguay and Uruguay, in coordination with the Plata Basin Intergovernmental Commission - and supported by UNEP, OAS, and GEF. La Plata Project will seek to identify joint water management priorities and establish a framework to adapt to increasing risks of major floods and droughts, as well as to prevent contamination from sediment loads in the Plata estuary. The Yrenda-Toba-Tarijeño project is being developed with a fund from Italy. UNESCO-IHP is coordinating and supporting member states in the development and/or update of the water balance, water use, and demand in the La Plata Basin. The SAYTT pilot-project will provide a comprehensive understanding of the aquifer system and its function in supporting human needs and environmental sustainability, as well as a guidance for the actions to be taken in other aquifers in the La Plata Basin to establish more sustainable management mechanisms.


Thanks to the contribution of the UNESCO-OAS ISARM Americas Programme in understanding the groundwater resources of the Amazon [1], it is now possible to have a comprehensive approach to the protection and management of the invaluable freshwater resources contained in the Amazonas Transboundary Aquifer System. Following the ISARM Americas Coordination Workshops, the basin countries, and their regional organization ATCO, have in fact come to recognize the need for the integrated, conjunctive management of surface and groundwater, from the overall Amazon basin level down to the single micro-basins or flood plain areas. A better understanding of the ATAS is however necessary to move towards a management framework that would ensure that the strategic roles of groundwater in (i) providing high quality water for human consumption, (ii) sustaining ecosystems, and (iii) mitigating the impacts of climatic fluctuations and change, are taken into full consideration and preserved. This diagnostic reconnaissance of the Amazonas Transboundary Aquifer System will be carried out within the framework of the GEF-UNEP-OAS-ATCO project “Integrated and Sustainable Management of Transboundary Water Resources in the Amazon River Basin”


The Hueco-Bolsón Transboundary Aquifer is shared by Mexico and the U.S.A. and represents an example of urban aquifer in an arid area. It is located to the East and South of the El Paso, and Ciudad Juarez, and bisected by the Rio Bravo.  El Paso and Ciudad Juarez apply a program for the exploitation and protection of the aquifer.. A source of artificial recharge is the Hueco Bolson Recharge Project. Approximately 10 million gallons per day of raw wastewater is treated to potable water standards. Half that amount is then injected into the aquifer. The Hueco Bolson Transboundary Aquifer was designated as an ISARM Americas advanced case study.


In 2005 in Sao Paulo, during the 3rd. Coordination Workshop (final report Spa Eng ) countries validated the templates with the information of each aquifer and the structure and contents of the I Vol. of the ISARM Americas Series “Transboundary Aquifer of the Americas Preliminary Assessment” were agreed on.


The 4th Workshop was held in 2006 in San Salvador, El Salvador  (final report Spa Eng)  The legal and institutional water framework from each country was presented and analyzed, and agreement was reached on the structure of the II Volume of the ISARM Americas Series “Transboundary Aquifer of the Americas Preliminary Assessment”, the first of 3 volumes to be published by the UNESCO/OAS ISARM Americas Programme by 2008. It represents the main outcome of the first phase of the Programme activities and will provide hydrogeological baseline information, gathered during the first three years of activities of the Programme with valuable efforts by the American Member States. It includes synoptic tables for each sub-region, a compilation of geological and hydrogeological information, as well as present use groundwater, expected demand and future scenarios, and sketch-maps for transboundary aquifer systems, together with a geological or hydrogeological section or model, when provided by the countries. It also includes recommendations on sustainable management of the transboundary aquifers of the Americas.


Other three priority case-studies have been selected during these workshops: the Pantanal transboundary aquifer system, shared by Bolivia, Brazil and Paraguay, the Ostua-Metapan, between El Salvador and Guatemala and the Rio Negro transboundary aquifer system, between Honduras and Nicaragua.


In 2007 the host city for our 5th Workshop was Montreal, Canada (Final Report). During this event the 1st book of the series UNESCO/OAS ISARM Americas “Preliminary Assessment: Transboundary Aquifer Systems in the Americas” was delivered to the ISARM Focal Points ( 1st. Book in Spanish).


The 6th Coordination Workshop UNESCO/OAS ISARM Americas took place in Santo Domingo, Dominican Republic at the beginning 3-5 of December 2008. During this workshop the National Coordinators and the ISARM Steering Committee decided the structure of the III book “Socio-economical and environmental aspects in transboundary aquifers”, reviewing and giving their approval. This third publication is expected to be edited at the beginning of 2009 and be published by March of the same year.





This page was last updated on Tuesday February 03, 2009.