While ecosystem services provided by these systems support the socioeconomic development and wellbeing of much of the world’s population, these basins continue to be impacted and degraded by multiple and complex human-induced and natural stresses. Further, management of transboundary waters is increasingly becoming constrained by limited availability of funds, resulting in the need for better prioritization of the allocations of limited financial resources. One of the major constraints to the effective management of transboundary waters is the lack of a systematic, periodic global comparative assessment of their changing conditions in response to changing stresses.
About TWAP River Basins Component
The TWAP contains one component for each of the five water systems: (i) Groundwater, (ii) Lake Basins, (iii) River Basins, (iv) Large Marine Ecosystems (LMEs), and (v) Open Ocean. This website hosts the results of the assessment work of the TWAP River Basins component.
The TWAP River Basins (TWAP RB) component is a global assessment of 286 transboundary river basins, aimed at enabling the prioritisation of funds for basins at risk from a variety of issues, covering water quantity, water quality, ecosystems, governance and socio-economics. The TWAP RB assessment also covers risks to deltas from threats of a transboundary nature, and considers the relative influence of lakes on these river basins. TWAP RB is an indicator–based assessment, allowing for an analysis of basins, based on risks to both societies and ecosystems. It also includes provisional outlook projections to 2030 and 2050 for a limited number of indicators.
The methodology of TWAP RB builds on existing datasets and decades of assessment work. Importantly, it involves well-established partnerships between institutions that have a history of working together, as well as bringing in other institutions that add value and expertise and broaden the scope of the network. Formalizing these partnerships under the framework of the TWAP has created a sound basis for a sustainable process.
The Global Transboundary River Basins
The world’s transboundary river basins span 151 countries, include more than 2.8 billion people (around 42 % of the world’s population), cover 62 million km2 (42 % of the total land area of the Earth), and produce around 22 000 km3 of river discharge each year (roughly 54 % of the global river discharge).
The delineation of the 286 global transboundary river basins has been one of the key outputs of the TWAP RB component. The TWAP RB component was able to improve existing account and delineations of the global transboundary river basins, thereby creating an update from the latest known list of 276 transboundary basins within the Transboundary Freshwater Dispute Database (TFDD) maintained by Oregon State University.
From earlier known transboundary river basin delineations ( 214 transboundary basins identified by UNDESA (1978), 261 by Oregon State University (1999), 263 by OSU (2002), 276 by OSU (2012)) the number has thus risen to 286. The increase in number of transboundary river basins over the years have been a factor of improved global Digital Elevation Models (DEMs) and breaking up of countries. The latest basin delineations are based on HydroBASINS (Lehner and Grill 2013), which is an update of HydroSHEDS, using a 90m DEM. The global map of the 286 transboundary basins can be seen below and explored in further detail in the TWAP RB Data Portal. More information on methodology of the updated delineation can be found here.
Additional five indicators were included to assess the linkages with other water systems. Lakes are important in providing buffering and storage capacity within transboundary river basins, thus directly influencing water quantity and quality within a given basin. The Lake Influence Indicator aims to highlight these important interactions and interdependencies, focusing on lake buffering and storage capacity within TWAP river basins.
Many river basins assessed under TWAP RB include deltas, occurring where a river flows into a lake or the sea. The physical geography of deltas often differs markedly from that in the neighbouring parts of the basin, in terms of relief, subsurface characteristics and hydrology. At the same time, many deltas are centres of large populations, agricultural production and economic activity, while maintaining direct connections to the health of the respective river basins. Deltas are therefore given special attention in the TWAP RB, and four Delta Vulnerability indicators were included for a selected number of deltas.
An full overview of the TWAP RB indicators can be seen below.
This assessment categorises relative levels of risk to transboundary basins across a range of issues, including water stress (over-exploited and degraded water resources) and threats to ecosystems, and considers the socio-economic and governance capacity to address these risks.
The principle of relative risk is used since the assessment is intended to be not a detailed basin-by-basin study but an overarching assessment which allows for the direct comparison of the situation between basins. Risk here refers to the risk to either humans or ecosystems for the particular issue the indicator represents, within the transboundary basin context.
The relative risk categories were assigned using thresholds defined on an indicator-by-indicator basis, using science-based thresholds where available and statistical categorisation approaches where no such thresholds could be identified.
The individual approaches to assigning these thresholds are discussed in the indicator descriptions in Chapter 3 of the final TWAP RB Technical Report. For detailed information on the individual indicator calculations and data sources, see metadata sheets available on TWAP RB Data portal, as well as Annex IX of the final technical report.
The River Basins working group is made up of nine partners, with UNEP-DHI as the coordinator of the assessment.
Partnership: Centre on Water and Environment (component
coordinator). UNEP-DHI draws on more than three
decades of experience in water resource management, policy and
modelling and has been involved in a number of global, regional and
local assessments for the UN and other bodies (e.g. UN-Water World
Water Development Reports (WWDRs), UNEP Global Environment Outlooks
(GEOs)). UNEP-DHI is familiar with GEF and UNEP processes and has a
broad network including river basin organisations, private
companies, research institutions and UN organisations, and is
therefore well placed to coordinate the River Basins component. It
is also responsible for the Wastewater Pollution and Enabling
• Stockholm International Water Institute (SIWI). Transboundary Water Management is one of SIWI’s main work areas and SIWI expertise in water governance and socioeconomic aspects of water is an essential component of TWAP. Within the TWAP RB, SIWI is responsible for the Legal Framework Indicator, the cross-cutting governance assessment, and supporting component coordination. SIWI also contributes to the sustainability aspects of the assessment.
• International Union for the Conservation of Nature (IUCN). IUCN is a leading provider of biodiversity knowledge, and its products (e.g. Red List Index) have already contributed to valuable global assessments and reporting (e.g. Millennium Ecosystem Assessment, Convention on Biological Diversity (CBD) Aichi Targets). IUCN also has experience in defining ways to improve livelihoods and enhance human wellbeing while conserving the integrity and health of water ecosystems and their services. IUCN is responsible for supporting component coordination including harmonisation of the adopted basin delineation layer and review of reporting on ecosystem indicators, and the Extinction Risk indicator.
• CUNY Environmental CrossRoads Initiative, City College of New York, is an internationally recognised centre for environmental research, and a unique meeting ground for science and policy experts. CUNY CrossRoads employs regional to global scale hydrology models (WBMplus) to assess how humans are embedded into the basic character of the water cycle through water abstraction and flow diversion, land-cover change, pollution, destruction of aquatic biodiversity, and climate change. Within TWAP RB, CUNY is responsible for the following indicators: Human Water Stress (current status and projected stress), Wetland Disconnectivity, Ecosystem Impacts from Dams, and Threat to Fish.
• Centre for Environmental Systems Research (CESR), University of Kassel, with the WaterGAP (Water - Global Analysis and Prognosis) model, has broad experience in modelling and assessing global water resources, i.e. current and future water availability and sectoral water uses. CESR supports the TWAP by providing its latest datasets and modelling capability and is responsible for the following indicators: Environmental Water Stress (current status and projected stress), Agricultural Water Stress, and Lake Influence.
• Oregon State University (OSU), Program in Water Conflict Management and Transformation (PWCMT). The PWCMT creates and hosts the largest online database on international freshwater treaties and has undertaken a large number of projects to analyse the performance of transboundary institutions under diverse stressors. It also serves as a training, resource and information hub for students, citizens, officials, and business leaders across the United States and internationally, facilitating dialogue on critical water issues across diverse values and perspectives. It is responsible for the indicator Risk of Potential Hydropolitical Tensions due to Basin Development in Absence of Adequate Institutional Capacity (current and projected).
• International Geosphere-Biosphere Programme (IGBP). IGBP projects develop comprehensive science plans through a process of discussion and consultation with the global scientific community, involving hundreds of scientists from all continents. This ensures the development of truly international research frameworks and fosters international and interdisciplinary networks within national and regional research efforts. IGBP, with its Global Nutrient Export from WaterSheds 2 (Global NEWS 2), is responsible for the Nutrient Pollution (baseline and projected) Indicators.
• Center for International Earth Science Information Network (CIESIN), Columbia University, works at the intersection of the social, natural, and information sciences, and specialises in on-line data and information management, spatial data integration and training, and interdisciplinary research related to human interactions in the environment. Within TWAP RB, CIESIN contributes significant experience and data with respect to global population datasets, and is responsible for the indicators for Economic Dependence on Water Resources, Societal Wellbeing, Exposure to Floods and Droughts, and projected Change in Population Density, as well as contributing the global population datasets for the whole of the TWAP.
• Delta Alliance (primarily Alterra and Deltares, Netherlands) is an international knowledge-driven network organisation with the mission of improving the resilience of the world’s deltas. Under TWAP RB, DA is responsible for the Delta Vulnerability indicators for a selection of significant transboundary deltas, drawing on methodologies developed for projects previously realized by the DA.
- Australian Rivers Institute, Griffith University
Explore Assessment Results
Data and results may be viewed in a number of different ways and functionalities available include:
- Indicator risk maps at basin level
- Indicator risk maps at Basin Country Unit (BCU) level
- Results sheets and metadata description sheets can be downloaded for each indicator.
- River basin factsheets can also be downloaded for each basin. These contain the background information relevant to each basin, as well as an overview of the assessment results for all indicators in the basin.
The challenges faced by basins and deltas include a mixture of threats which can be mitigated to some degree, but also unique geophysical, climatic and socioeconomic parameters which set the bounds for applying management responses. Ultimately, successful outcomes will only be achieved with a mixture of political will, resources and adequate governance capacity at both national and transboundary scales.
See links to full assessment report and the Summary for Policy Makers in the Publications and Press section.
Sustainability of TWAP RB
TWAP RB consortium partners are currently in discussion with a number of organisations (including UNECE, WWF, GRID-Arendal, WWAP, CI, basin organisations and others) to identify potential collaboration opportunities to make best use of the existing assessment results, and to further develop the assessment methodology to better suit the needs of various organisations and global, as well as local uses.
Further description of these collaboration opportunities are included in the Sustaining Mechanisms Report.
Publications and Press
Status and Trends
The final technical report of the TWAP RB assessment (March 2016). Contains results and results maps for all assessment indicators, as well as integrated analysis accross indicators. The technical report is accompanied by Summary for Policy Makers.
TWAP RB Technical Assessment Report:
- Technical Report without Annexes (high-res166 MB)
- Technical Report without Annexes (low-res 22.7 MB)
Summary for Policy Makers:
- Summary for Policy Makers (high-res 14 MB) (Spanish) (Russian) (French) (Arabic) (Chinese)
- Summary for Policy
Makers (low-res 2.5MB)
Table of Contents (high-res 3.9MB) (low-res
Chapter 1: Introduction (high-res 5MB) (low-res 1.5MB)
Chapter 2: Assessment approach and methods (high-res 3.1MB) (low-res 1.1MB)
Chapter 3: Transboundary river basins Indicator assessment (high-res 97.2MB) (low-res 10.5MB)
Chapter 4: Integrated indicator analysis (high-res 15MB) (low-res 3.6MB)
Chapter 5: Water systems links (high-res 9MB) (low-res 1.4MB)
Chapter 6: Conclusions (high-res 7.4MB) (low-res 1.2MB)
Table of transboundary river basins and their countries (169KB)
TWAP in Press
- Al Jazeera interview with TWAP RB PM Paul Glennie
- Journal Article: A Comparative Analysis of Water Governance, Water Management, and Environmental Performance in River Basins. Christian Knieper and Claudia Pahl-Wostl, Water Resources Management, March 2016, pp 1-17.
Links and Contacts
TWAP Full Size Project website: www.geftwap.org and Data Portal: http://www.geftwap.org/data-portal
TWAP Groundwater: http://www.isarm.org/publications/438
TWAP Lakes and Reservoirs: http://icws.meadowscenter.txstate.edu/TWAP.html
TWAP Large Marine Ecosystems: http://www.unesco.org/new/en/twap-lme
TWAP Open Ocean: http://www.geftwap.org/water-systems/open-ocean
For enquiries regarding TWAP RB please contact:
Paul Glennie, UNEP-DHI or Maija Bertule, UNEP-DHI.
Last update: 06.04.2016.