Environmental Protection and Sustainable Development of the Guaraní Aquifer System

The Guaraní Aquifer System (GAS) is a groundwater reservoir. The water is found in the pores and fissures of sandstones, formed during the geological times of the Mesozoic Ages (130-200 million years ago), which are typically covered by thick layers of basalts that confined them.

The GAS constitutes one of the largest reservoirs of groundwater in the world, with current water storage of approximately 37.000 km3 and a natural recharge of 166 km3 per year. The water in the sandstones can be found at depths ranging from 50m to 1500m, with temperatures that vary between 33°C and 65°C. This broad thermal range offers possibilities for diverse geothermic applications.

The GAS is located in eastern and mid-southern South America and underlies in some areas of Argentina, Brazil, Paraguay and Uruguay. It is estimated that the total surface of the GAS is 1,190,000 km2 with 225,000 km2 in Argentina, 850,000 km2 in Brazil, 70,000 km2 in Paraguay and 45,000 km2 in Uruguay.

Approximately 24 million people live in the area delimited by the boundaries of the aquifer and a total of 70 million people live in areas that directly or indirectly influence it. The main use of the aquifer is for drinking water supply, but there are also industrial, agricultural irrigation and thermal tourism uses.


The Project is organized in seven interrelated “components”, which are designed to aid in a better understanding of the morphology and behavior of the GAS, its use and conservation, and its relationship with communities and institutions. This knowledge will inform the development of systems and tools for coordinated management of the waters in the GAS. Specific components of the GAS project are:

  1. Expansion and consolidation of the current scientific and technical knowledge Base of the Guaraní Aquifer System
  2. Joint development and implementation of the Guaraní Aquifer System management framework, based on an agreed Strategic Action Plan
  3. Promotion of public participation, social communication and environmental education
  4. Project monitoring and evaluation, and dissemination of projects results
  5. Development of groundwater management measures and mitigation measures within identified critical areas (“Hot Spots”)
  6. Assessment of geothermal energy potential use, “clean energy”, from the GAS
  7. Project coordination and management
Project Goals

The Environmental Protection and Sustainable Development of the Guaraní Aquifer System (GAS) Project was developed to support Argentina, Brazil, Paraguay and Uruguay in the elaboration and implementation of a shared institutional, legal and technical framework to preserve and manage the GAS for the current and future generations.

The long term objective of this Project is the sustainable management and use of the GAS in Argentina, Brazil, Paraguay and Uruguay, through an adequate and functional management framework, based on appropriate technical, scientific, institutional, legal, economical and environmental guidance. More explicit objectives of the project are:

  • To enhance and enlarge the technical knowledge of the Guaraní Aquifer System.
  • To implement a permanent Well Monitoring Network and an Information System for the whole GAS.
  • To elaborate the Strategic Action Plan (SAP) and the Transboundary Diagnostic Analysis (TDA).
  • To develop a proposal for a coordinated management framework, which would seek to harmonize water policies and management tools among the four participating countries and reduce future qualitative and quantitative threats to the GAS.
Location of the Project

Global Environment Facility (GEF)
World Bank (WB)
Organization of the American States (OAS)
Netherlands and German Governments
International Atomic Energy Agency ( IAEA)

News & Events

November 13-19 2011. Medellin, Colombia. Seventh Inter-American Dialogue on Water Management (D7)


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