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Water crossing borders: 64% of the world’s countries share Transboundary Aquifers with their neighbours

Water crossing borders: 64% of the world’s countries share Transboundary Aquifers with their neighbours

Foz do Iguacu by Stefan Siepman

In celebration of World Water Day 2016, IGRAC analysed how many countries share significant groundwater resources with their neighbouring countries. The analysis which is based on the 2015 edition of the Map of Transboundary Aquifers of the World shows that at least 145 countries share an aquifer with neighbouring countries.  

There are now 592 identified transboundary aquifers (including 226 transboundary groundwater bodies as defined in the European Union Water Framework Directive). Over 64% of the world’s countries share such transboundary aquifers. When strictly focusing on mainland countries, so excluding islands, this percentage is even 91%. 

From all 592 transboundary aquifers and groundwater bodies that have been identified, some are shared by as much as 6 countries:

  • Nakhichevan/Larijan and Djebrail Aquifer, shared by Azerbaijan, Armenia, Georgia, Iran, Turkey and Russia
  • Amazonas, shared by Bolivia, Brazil, Colombia, Ecuador, Peru and Venezuela        
  • Nakhichevan/Larijan and Djebrail Aquifer, shared by Azerbaijan, Armenia, Georgia, Iran, Turkey and Russia
  • Lake Chad Basin, shared by Chad, Niger, Nigeria, Cameroon, Central African Republic and Algeria

IGRAC and Transboundary Groundwater

Political, institutional, socio-economic, cultural and other differences among countries make the assessment, management and governance of internationally shared aquifers challenging. As a United Nations’ Centre, IGRAC provides independent content and process support to the assessment of transboundary aquifers. 

IGRAC’s activities related to transboundary aquifers are carried out in the framework of the ISARM programme (led by UNESCO-IHP) and projects supported by international donors like the Transboundary Waters Assessment Programme (TWAP) supported by the Global Environment Facility (GEF), the Groundwater Resources Governance in Transboundary Aquifers (GGRETA) project supported by the Swiss Agency for Development and Cooperation (SDC) and the Ramotswa project supported by RESILIM/USAID

Important contributions to the knowledge on transboundary aquifers are also provided through regional assessments led by regional organisations such as UNECE, ESCWA, OAS, OSS and SADC. The outcomes of transboundary aquifers assessments and mapping projects are compiled by IGRAC into the map of Transboundary Aquifers of the World (IGRAC & UNESCO-IHP). The map is updated on a regular basis. Recently, IGRAC and UNESCO-IHP also published a methodology for the Multi-Disciplinary Assessment of Transboundary Aquifers.