World Water Day 2022 featured an exchange on experiences with transboundary groundwater management across three continents: Africa, Europe, and South America.
The joint management of transboundary water resources is very rare: more than 500 transboundary aquifers exist, but there are only six functional transboundary groundwater agreements worldwide.
For this reason, the United Nations Economic Commission for Europe (UNECE) together with the Geneva Water Hub (GWH) organised a comparative exchange focusing on the Senegalo-Mauritanian Aquifer, the Genevois Aquifer and the Guarani Aquifer.
UNECE chief of transboundary cooperation, Francesca Bernardini, highlighted the importance of sharing experiences between the few cases of transboundary groundwater management that exist. For transboundary water management, she noted, trust can be built between parties fueled by transparent access to data.
Prof Mark Zeitoun of the GWH highlighted the vulnerability of groundwater resources and noted that it is through the exchange of knowledge on the subject that joint groundwater management can be advanced.
In the case of the Senegalo-Mauritanian Aquifer it was the extensive institutional capacity and long experience of the Senegal River Development Organisation (OMVS) and the Gambia River Development Organisation (OMVG) which enabled the countries involved to embark on the process of managing the transboundary aquifer. It has taken two years to develop a programme of action for the aquifer, which is essential as the Senegal basin provides 80% of the water for Senegal, Gambia, Mauritania and Guinea Bissau, and the aquifer is critical resource which enhances resilience to climate change.
Close to urban areas, there are indications that the aquifer is being overused, and there is the threat of quality loss through the infiltration of pollution from the surface as well as saltwater ingress in coastal areas. In 2021 the GWH supported a dialogue on the aquifer in Geneva which led to a declaration of intent by the four ministers involved to work on a joint set of rules for cooperation.
The Aquifer du Genevois is shared by France and Switzerland. The city of Geneva sources some 80% of its drinking water from Lake Leman (a/k/a Lake Geneva) but the remaining 20% is nevertheless crucial.
The lake and the aquifer have been exploited since the 19th century. Overexploitation in the 1960s and 1970’s led to studies of the resource and the development of legal structures to manage the water across the Swiss-French border. Discussions between the two countries took eight years.
Eventually an agreement was signed in 1977 involving the exchange of information as well as agreement on the terms under which artificial recharge of the groundwater table would be implemented. Since then, the groundwater table has been restored, underlining the importance of the intervention at that time.
The Guarani Aquifer covers more than 1 million km ² mainly underlying the Paraná River basin and is shared by Brazil, Paraguay, Uruguay and Argentina. Brazil uses the larger part of the water of the aquifer, and of the joint use of the waster of the aquifer, 80% is used for public water supply, approximately 15% is used for industrial purposes and 5% is used for geothermal application.
The aquifer is vulnerable to pollution from extensive changes to land use activities in its recharge areas, and initiatives have been underway since 1995 to bring government and civil society parties into a joint agreement on the aquifer.
An influential research project in 2003-2009 entitled the Environmental Protection and Sustainable Development of the Guarani Aquifer System Project has noted no conflicts over the resource but has stimulated exchanges of information, leading ultimately to the signing of the agreement on the aquifer by the four countries in 2010.