An estimated 3.6 billion people face inadequate access to water at least a month per year – a figure expected to increase to more than 5 billion by 2050.  According to WMO, over 50% of global catchment areas and reservoirs displayed deviations from normal conditions in 2022, of which the majority were drier than usual. Amid intensifying droughts and floods, as well as record breaking temperatures that have put 2023 on track to be the warmest year ever, water is among the principal means through which climate change impacts and acute resource use challenges are being felt worldwide. 

To help tackle these issues, over a hundred countries, the United Nations, international partners and water experts, have stressed the urgent need to better connect groundwater and surface water management, both at national level and in shared basins. 

With water resources under increasing stress and as governments seek to meet competing needs such as irrigation, drinking water and sanitation, energy production needs and ecosystem protection, groundwater is the subject of rising attention. Groundwater, which accounts for 25% of total freshwater withdrawal worldwide, represents a strategic resource for many countries, especially as it is less vulnerable to climate change impacts than surface water.  

However, discussions in Geneva in the framework of the UN Convention on the Protection and Use of Transboundary Watercourses and International Lakes (UN Water Convention) have warned that to ensure sustainable water use, holistic joint water resource management approaches encompassing both groundwater and surface water will be needed. Reinforced cooperation between neighbouring states must underpin these efforts, as 153 nations share water resources with their neighbours, which include some 592 identified transboundary aquifers (groundwater reserves). Among priorities, experts also called for concerted efforts and increased investment to monitor the quantity and quality of groundwater reserves and their complex interactions with surface water resources. 

Learning from experience in shared basins 

Different types of water resources are often managed in isolation. Through a more “joined up” approach known as conjunctive water management, surface water, groundwater and other components of the water cycle can be managed as one single resource, maximizing benefits and streamlining their use. 

The workshop brought together some 200 experts from different contexts around the world to showcase such approaches both in national and transboundary settings, covering a wide variety of technical and policy tools. These included the use of isotope tracers and water balance modelling to increase knowledge on groundwater bodies, as well as legal instruments such as the Draft Articles on the Law of Transboundary Aquifers developed by the International Law Commission and the Model Provisions on Transboundary Groundwaters developed under the Water Convention. 

Examples shared highlighted: 

• The role of Managed Aquifer Recharge in enhancing cooperation over the Genevese Aquifer shared by France and Switzerland, which experienced significant decreases in groundwater levels between 1960 and 1980. 

• Experiences of conjunctive water management projects in the transboundary Shire and Pungwe River basins in Southern Africa. 

• The critical need for data and knowledge in identifying the potential of conjunctive water management between the La Plata River Basin and the Guarani Aquifer System in South America. 

• Building national capacity in six Mediterranean countries (Albania, Lebanon, Libya, Montenegro, Morocco, Tunisia) through national dialogues and training on Conjunctive Water Management. 

• The aim to advance surface water and groundwater management through better cooperation in the Senegalo-Mauritanian Aquifer Basin, including with support from the Water Convention. 

Joined-up approaches pay off 

Experience in the Niger Basin (shared by Benin, Burkina Faso, Cameroon, Cote d’Ivoire, Guinea, Mali, Niger, Nigeria and Chad) and the Iullemeden-Taloudeni/Tanezrouft Aquifer System (shared by Algeria, Benin, Burkina Faso, Mali, Mauritania, Niger and Nigeria) highlighted the importance of modelling the groundwater and surface water interactions to identify opportunities for Conjunctive Water Management.  

The Nile Basin Initiative introduced a project (2020-2025) to support Conjunctive Water Management, focusing on three major transboundary aquifers: Kagera, Mount Elgon and Gedaref Adegrat. Demonstrating the importance of a unified regional approach involving all stakeholders, a project board including relevant ministries has been set-up to oversee the project, with national focal points and a technical advisory committee. 

The Karavanke transboundary groundwater body shared by Slovenia and Austria was presented as an example of successful cooperation, supporting data sharing and breaching political gaps. It highlighted that Conjunctive Water Management is not only about efficient water usage but it is crucial for water protection and underpins sustainable development in shared basins. 

Insights from the Guarani Aquifer System highlighted the need for regional, national and local engagement, agreements connected to action plans, a working organizational framework and capacity building in implementing conjunctive water management from a national to a transboundary setting.  

Discussions also shared insights from Albania, Nigeria, the Gambia, Finland, UNDP (South America), and SADC-GMI (Southern Africa). 

Key outcomes of the exchanges included the need to increase awareness of the benefits of Conjunctive Water Management, especially for climate change adaptation, to move from spontaneous to planned Conjunctive Water Management, and to create enablers and frameworks for Conjunctive Water Management in national and transboundary settings. This will continue to shape countries’ cooperation for sustainable water management under the Water Convention, which can serve as a platform for building capacity, exchanging experience and providing guidance on the topic. 

The Global Workshop on Conjunctive Management of Surface Water and Groundwater: National to Transboundary Level was organized under the leadership of the Ministry of Climate of Estonia, the Ministry of Natural Resources and Spatial Planning of the Republic of Slovenia and UNECE and in partnership with the United Nations Educational, Scientific and Cultural Organization (UNESCO), the United Nations Economic and Social Commission for Western Asia (UNESCWA), the International Atomic Energy Agency (IAEA), the Finnish Environment Institute (SYKE), the International Groundwater Resources Assessment Centre (IGRAC), the Transboundary Aquifers Commission of the International Association of Hydrogeologists (IAH), the Regional Centre for Groundwater Management in Latin America and the Caribbean (CeReGAS), the Sahara and Sahel Observatory (OSS), the Environment Agency Austria (UBA), GEF IW:LEARN and other organizations. The Global Workshop was funded by the governments of Finland, Sweden and Switzerland as well as GEF IW:LEARN. It served as a GEF IW:LEARN global dialogue on conjunctive management of surface water and groundwater.