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.

The report is available online at http://twap-rivers.org/.