Transboundary Lakes and Reservoirs: Status and Trends

Volume two focuses on a global-scale assessment of transboundary lake and reservoir basins, which considers their unique defining features, the stresses on their life-supporting ecosystem goods and services, and the assessment and management implications of their inter-linkages with other water systems. It was prepared by the International Lake Environment Committee (ILEC), in cooperation with The Meadows Center for Water and the Environment, Texas State University; Research Centre for Sustainability and Environment (RCSE), Shiga University; Corazón de la Tierra, Guadalajara, Mexico; and International Environmental Management Services (IEMS), Waukesha, Wisconsin USA.

The activities for preparation of the assessment included : (1) collection and dissemination of information and data on environmental aspects of lakes; (2) promotion of technical and management training and workshops on the lake environment; and (3) collaboration with governmental agencies, research institutes and NGOs throughout the world, particularly in developing countries, on environmentally-sound lake management directed to the sustainable use of life -supporting lake ecosystem goods and services.

The transboundary analysis of lakes clearly indicated that ranking lakes in regard to the nature and magnitude of the threats facing them is not simply a number-crunching exercise. Rather, it requires a detailed case-by-case assessment that considers a range of interlinked factors, including their current in-lake status, their geographic location, their linkages with other flowing and pooled water systems in their basins, the range of defining institutional, policy and socio-economic issues, the adequacy of the governance framework under which they are managed, and the magnitude of the threats to the sustainable use of their ecosystem services.  Identifying the ‘worst’ transboundary lake in a given region is also problematic because the very definition of degradation in a given case, whatever its cause, is a function not only of the lake itself, but also of the perspective of those using the ranking results and the factors they consider most important in regard to the rankings.

Consideration of the context is fundamental to optimizing the meaning and significance of the transboundary lake threat rankings, and the responsibility for identifying the appropriate context rests with the user(s) of the ranks, being fundamentally important for maximizing their value and meaning.  The Scenario Analysis Program developed for compiling, analyzing and computing the transboundary lake threat scores, in combination with the integrated assessment and management approach encompassed within ILEC’s Integrated Lake Basin Management (ILBM) provides a means of facilitating such considerations.  As a complement to the widely-used Integrated Water Resources Management (IWRM) approach, the ILBM Platform process represents a virtual framework for identifying and assessing the many complicated interacting factors influencing effective lake basin management, particularly as related to sustainable lake ecosystem services.  It represents a means of considering the significantly different assessment and management needs of lakes and other lentic water systems that comprise the vast majority of the readily-available liquid surface freshwater of the planet.

Transboundary Lake Basins & Reservoirs : Key Messages

1. Lack of uniform lake data makes it difficult to accurately assess the status and trends of transboundary lakes on a global scale. Lakes and other lentic (pooled) water systems contain more than 90 per cent of the liquid freshwater on the surface of our planet, and provide the widest range of life-supporting ecosystem goods and services.  However, there is a serious lack of Lake Basin data on a global scale, seriously hindering our ability to make accurate assessments or realistic comparisons of the status and trends of transboundary lakes.  The international water community must undertake significant development of knowledge bases focusing on lakes, their basins and other lentic water systems in order to address this serious deficiency.
2. Based on their basin characteristics, the African transboundary lakes as a group exhibited the greatest (Adjusted) Human Water Security threats, following by lakes in Asia and South America.  Transboundary lakes in the developed countries exhibited the greatest Incident Biodiversity threats, with those in developing countries exhibiting comparatively better conditions. Accurate assessment of the type and magnitude of transboundary lake threats requires an agreed set of indicators that can be translated into contextually-determined weighted scores, based on the factors and preconditions most important to the user of the ranking results. The TWAP transboundary lakes threats were based on their basin characteristics expressed as 24 basin indicators (drivers) categorized in four thematic subject areas, and complimented by expert opinion and scenario analyses.  Subsequent TWAP-scale assessments that include in-lake information and data will provide more definitive conclusions regarding the transboundary lake threats. As for any prioritization decision-making process, however, it is difficult to identify a unilaterally-agreed list of transboundary lake basins requiring priority management interventions within the TWAP framework.
3. Integrated Water Resource Management (IWRM) can best manage lakes and other lentic water systems for sustainable ecosystem services within the context of an Integrated Lake Basin Management (ILBM) framework for lake basins, their inflowing and outflowing rivers and other lotic waters. IWRM has facilitated water resources policy reforms in many countries, but does not adequately consider the defining characteristics of lakes and other lentic water systems or their ecosystem goods and services, which require longer-term, incremental lake basin governance improvements directed to their sustainable use and conservation. Lakes are also usually linked hydrologically to upstream and downstream water systems.  Infusing ILBM with IWRM offers an effective means of sustainably managing lakes and reservoirs and their interlinked water systems, through gradual, continuous improvement of basin governance, including institutions, policies, stakeholder participation, scientific and traditional knowledge, technical possibilities, and funding constraints.  It also provides a standardized analysis process for enhancing the GEF TDA/SAP process for catalysing transboundary water management interventions, including being a framework for bi- and multi-lateral actions and programs. Further, Integrated Lentic-Lotic Basin Management (ILLBM), as an extension of the ILBM framework, provides a virtual framework for strengthening river-lake-coastal basin governance.

Lakes Website: http://www.ilec.or.jp/en/twap