Scientists from the Environmental CrossRoads Research Group contribute to report assessing risks to the world’s shared river basins

The first global assessment of threats and risks to transboundary river basins has been released by a consortium of institutions* led by the UNEP-DHI Center for Water and Environment and including the Environmental CrossRoads Research Group of the CUNY Advanced Science Research Center’s Environmental Sciences Initiative.

Around the world, there are 286 transboundary river basins, which cross international borders and are shared by two or more countries. Together, these basins span 151 countries and include 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.

The goal of this Transboundary Waters Assessment Programme (TWAP), initiated by the Global Environment Facility (GEF) and coordinated by the United Nations Environment Programme (UNEP), was to create a baseline assessment of all the transboundary water resources on Earth. Of particular interest was five transboundary system components: (i) Groundwater, (ii) Lake Basins, (iii) River Basins, (iv) Large Marine Ecosystems (LMEs), and (v) Open Ocean.

Scientists from the Environmental CrossRoads Research Group served as lead and contributing authors on several chapters of this report, including those related to water quantity (Chapter 3.2) and ecosystems (Chapter 3.4). They also developed 4 of the 15 core indicators used to assess River Basins as part of these chapters:

  • A Human Water Stress indicator to identify water availability measured per capita and water use compared to water availability
  • An indicator to identify the impacts of dams on ecosystems, including dam density and river flow disruption
  • An indicator to identify threats to fish, including from fishing pressure and non-native species
  • An indicator of wetland disconnectivity, which highlights the impacts and losses to ecosystem functionality from wetland disturbance and loss, such as draining of wetlands, levee construction and altering river courses

This work, outlined in Chapter 3.2, emphasized the importance of addressing water security needs for humans in river basins that are already or projected to be prone to water stresses, such as drought.

It also highlighted in Chapter 3.4 the importance of making decisions about where dams are located and how dams are designed and operated in order to maximize human benefits and minimize negative impacts to ecosystems. This is especially important in transboundary areas, where dams may be located in countries that are upstream of where their impacts may be felt.

Some of the key findings from the overall report 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 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.

More information on transboundary river basins can be found at the TWAP River Basins Component website, which includes links to the Final Technical Report, Summary for Policy Makers, and an Interactive Results Portal with global maps of assessment results and indicator metadata sheets. All assessment results, analyses and supplementary datasets can be freely downloaded.


  • 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-Advanced Science Research Center (CUNY ASRC), Environmental Sciences Initiative/Environmental CrossRoads Research Group, 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
  • 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