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Transboundary Waters Assessment Programme (TWAP) – Lakes Component

General Information


TWAP - Introduction

Lakes: The Mirrors of the Earth


Lakes contain large volumes of freshwater readily accessible for human uses. As such, lakes, whether natural or artificial (reservoirs) are dramatic and highly-visible features of the global landscape. They also provide a wide range of life-supporting and economically-important ecosystem goods and services. Our planet contains an estimated 27 million natural lakes with surface areas greater than 1 ha, with the 17 largest natural lakes covering an area of about 100 million ha (1 million km2). There are an additional half million artificial lakes (reservoirs) with surface areas exceeding 1 ha. These water bodies collectively contain more than 90% of the liquid freshwater on the surface of our planet at any given instant. Being major lentic water systems easily accessible to human exploitation, lakes are used for a wider range of human purposes than any other type of freshwater system, which also makes them more susceptible to water use conflicts. Lakes exhibit several defining characteristics, including, (1) a long water residence time, (2) an integrating nature for all inflowing water and material inputs, and (3) non-linear responses to human interventions (so-called hysteresis property), all of which complicate their accurate assessment and effective management. In fact, being integrating ‘sinks’ for inflowing waters and the materials carried in them, lakes represent valuable barometers of the impacts of human activities within their drainage basins, with their degradation often being a trigger for freshwater management interventions.


What’s TWAP?

The TWAP (Transboundary Waters Assessment Programme) is an international project funded by the Global Environment Facility (GEF) to conduct a global-scale assessment of five major types of transboundary water systems (Lakes, Rivers, Groundwater, Large Marine Ecosystems, Open Oceans) (Figures) for the purpose of ranking them, in their respective types, in regard to their degree of vulnerability to human impacts. The results of this global assessment will provide the GEF with a means of establishing priorities in regard to the most effective funding allocations within its International Waters portfolio.


TWAP-Lake Group Activities

After completing an initial TWAP medium-size project focusing on the development of assessment methodologies, and in collaboration with the United Nations Environment Programme (UNEP), the International Lake Environment Committee Foundation (ILEC) initiated a TWAP-FSP (Full-Size Project) to rank transboundary lakes and reservoirs, utilizing a GIS-based spatial and analytical methodology with relevant indicators. This project is being pursued in collaboration with the Research Center for Sustainability and Environment (Shiga University, Japan) and the Meadows Center for Water and the Environment (Texas State University, USA).

Activities and Resources


ILEC has established a Lakes Working Group to undertake the primary lake and reservoir component of TWAP. To date, the group has organized and convened nine Lakes Expert Group Meetings, as follows:


(1) Project Inception Meeting (May 13-16, 2013, ILEC Headquarters, Japan);

(2) East/Southeast Asia Expert Group Meeting (July 8-11, 2013, Kuala Lumpur, Malaysia, supported by NAHRIM);

(3) East Africa/Europe/Central Asia Expert Group Meeting (September 19-22, 2013, Perugia, Italy);

(4) Consultative Meeting for Central Asia (November 5, 2013, ILEC Headquarters, Japan);

(5) Central America Expert Group Meeting (December 2013, Guanajuato, Mexico);

(6) South America Expert Group Meeting (December 2013, Rio de Janeiro, Brazil);

(7) South Asia Expert Group Meeting (January 2014, Delhi, India, in collaboration with Chilika Development Authority); 

(8) Africa Expert Group Meeting (February 2014, Nairobi, Kenya); and

(9) Consultative Meeting with South Asia and Southeast LME Group (March 2014, Manila, Philippines)


Additional Lakes Expert Group Meetings are being scheduled in the coming few months, including Central/West Asia Expert Group Meeting and West African Sub Region Expert Group Meeting.


Activities and Progress

The Lakes Working Group has been conducting the following three major activities:


(1) Activity-1: Identifying priorities for transboundary lake basins

- Delineation of the areal boundaries of approximately 160 GEF-eligible and 50 non-GEF-eligible transboundary lake and reservoir basins, using GIS-based technique, combined with remote sensing data and a digital elevation model;

- Identification of indicators, with relevant data collection, GIS analysis, and evaluation, to rank the lake and reservoir basins in regard to their vulnerability to human activities. Determining the relative importance of these indicators is a continuing activity being conducted on a sub-continental/regional basis.


(2) Activity-2: Identifying and characterizing sub-continental/regional issues and challenges

- Preparation of sub-continental/regional GIS overlay maps on a global scale to illustrate the hydrologic linkages between the focused transboundary lake and reservoir basins and their nearby transboundary river basins, groundwater aquifers and large marine ecosystems;

- Collecting data of biodiversity hotspots, land degradation, and land uses and overlapping them onto these sub-continental/regional maps to highlight water-related issues and characterize each sub-continental/regional area


(3) Activity-3: Developing frameworks and methodologies to assess the status and management needs of lake and reservoir basins and to rank and prioritize transboundary lakes

- An integration of the causal framework “Driver Forces – Pressures – States – Impacts – Responses” (DPSIR) with the interface framework of “Provisioning/Cultural/Regulating/Supporting Ecosystem Services” in ecosystem management into a new assessment framework “Stress – Impairment – Impacts”;

- An application of the analytical approach “Analytic Hierarchy Process” (AHP) and the operational approach “Multi-criteria Analysis” (MCA) in decision-making science to the above integration; and

- An implementation of the technique of “Questionnaire Survey” (data format as interval scale scores), in addition to the computer-based techniques “Geographical Information System” (GIS) and “Remote Sensing” (RS) (data format as criteria indicator values), to enhance the effectiveness of the overall assessment.



General information on the TWAP project is available on the TWAP project website, while more detailed information regarding the transboundary lakes and reservoirs component of TWAP is available on both the ILEC website and the website of The Meadows Center for Water and the Environment at Texas State University.




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