The most comprehensive assessment of the world’s 286 transboundary river basins identifies hotspots at risk from a variety of issues, with risks in some regions projected to increase

Press Release

The world’s 286 transboundary river basins span 151 countries, including more than 40% of the Earth’s population and land area. They support the socioeconomic development and wellbeing of humanity and are home to a high proportion of the world’s biodiversity. Transboundary river basins cross international borders and are shared by two or more countries, which often makes managing them more challenging.

The Transboundary Waters Assessment Programme (TWAP) was initiated by the Global Environment Facility (GEF) to create a baseline assessment of all the transboundary water resources on Earth. The programme, coordinated by UNEP, consists of five transboundary water systems components, which are:
(i) Groundwater,
(ii) Lake Basins,
(iii) River Basins,
(iv) Large Marine Ecosystems (LMEs), and
(v) Open Ocean.

The UNEP-DHI Partnership, in collaboration with 8 internationally recognized organizations and research institutes, leads the transboundary river basins assessment*. The assessment is the first of its kind in scope and ambition.

A selection of key findings and recommendations include:

  1. The threat to freshwater biodiversity is global. Extinction risks are moderate to very high in 70% of the area of transboundary river basins. However, local-level, tailored solutions are needed to address risks of species extinction.
  2. The construction of dams and water diversions is in progress or planned in many transboundary river basins, often without adequate international water cooperation instruments. While many transboundary agreements exist, more effort is needed to update them to reflect modern principles of transboundary water management. This includes the obligation to not cause significant harm to the river and the areas surrounding it, and the commitment to principles of cooperation and information exchange.
  3. Risks are projected to increase in the next 15-30 years, particularly in four hotspot regions: the Middle East, Central Asia, the Ganges-Brahmaputra-Meghna basin, and the Orange and Limpopo basins in Southern Africa. Action should be taken now to reduce future impacts and subsequent costs.

To set the 2010 baseline, we have used 15 core indicators in the assessment, covering water quantity, water quality, ecosystems, governance and socioeconomics. Five of these indicators are projected to 2030 and 2050. The assessment also covers risks in 26 deltas.

The assessment serves a number of purposes. This includes identification of river basins at risk from a variety of issues, encouraging knowledge exchange and increasing awareness of the importance of the transboundary waters and their current state.

The final report, interactive results portal and other associated products are to be launched at the GEF International Waters Conference (IWC-8) May 9-13, Sri Lanka, at the second session of the United Nations Environmental Assembly (UNEA-2), May 23-27, Kenya, and at other events during 2016 (TBC). This marks the culmination of a six-year process to produce a baseline assessment of the river basins. We hope that the assessment will be periodically repeated to track the impacts of interventions over time.

More information on transboundary river basins can be found at The website also includes links to the following resources:

  1. Final Technical Report
  2. Summary for Policy Makers
  3. Interactive Results Portal with global maps of assessment results and indicator metadata sheets

All assessment results, analyses and supplementary datasets can be freely downloaded.

* Partners:

  • Center for Environmental Systems Research (CESR), University of Kassel, Germany;
  • Center for International Earth Science Information Network (CIESIN), Columbia University, USA;
  • City University of New York (CUNY), Environmental CrossRoads Initiative, USA;
  • Delta Alliance (primarily Alterra Wageningen and Deltares)
  • International Union for the Conservation of Nature (IUCN);
  • International Geosphere-Biosphere Program (IGBP);
  • Oregon State University (OSU), USA;
  • Stockholm International Water Institute (SIWI), Sweden; and
  • UNEP-DHI Partnership: Centre on Water and Environment.

Supporting partners:

  • Australian Rivers Institute, Griffith University, Australia.
  • Centro de Estudios Avanzados en Zonas Aridas
  • University of Washington, USA
  • Wageningen UR

Each partner contributed their expertise, datasets, models and assessment tools to undertake this extensive global assessment.