Adapting to Climate Change: Assessing the World Bank Group ...

CHAPTER 3CLIMATE VARIABILITYBox 3-1. Managing Water Resources in the Mekong River BasinThe Mekong River Basin illustrates the challenges of transboundary integrated water resourcesmanagement and the inextricability of climate change and development planning.The lower basin riparians—Cambodia, Lao Peoples Democratic Republic, Thailand, and Vietnam—began discussing basin management in 1957 and formed the Mekong River Commission (MRC) in 1995.The MRC’s mission is “To promote and coordinate sustainable management and development of waterand related resources for the countries’ mutual benefit and the people’s well-being.” This is a technicallyand politically challenging task. The lower basin alone has 60 million inhabitants and there are complexinterconnections among the many water uses. The river’s annual cycle of ebb and flood sustain the richfisheries and distinctive ecology of the Tonle Sap Great Lake and regulate water and nutrient flows tothe fertile irrigated fields of the Mekong Delta. Development of the basin’s immense hydropowerpotential can bring income and carbon-free energy, but it also affects water and sediment flows, as wellas the river’s unique aquatic biodiversity. Sorting out development plans would be difficult enoughwithin a single country, let alone among four nations with a history of conflict.The GEF-funded, Bank-executed Water Utilization Project (WUP) addressed both the technical andpolitical challenges. The core idea was to build confidence, trust, and data sharing through theconstruction of a hydrological model of the basin—the Decision Support Framework (DSF). The DSFwould then be used to determine minimum allowable values for water flow and water quality.Agreement on these “rules” would define a “Development Opportunity Space” that could be used todetermine the acceptability of proposed plans for development. A similar approach was successfullyused, over a long period in the negotiation of European treaties on transboundary air pollution. Riverbasin modeling activities were also included in the Bank-executed portion of the Nile Basin Initiative.Results to date have been mixed. Progress was made on adopting procedural guidelines, including thoserelated to prior consultation on projects that affect the Mekong mainstream. The DSF was constructedand the process has contributed to capacity building and data-sharing. However, the MRC countrieshave so far been unable to agree on the critical parameters defining water quality and quantity. Soinstead of starting with criteria for water quality and quantity and using them to assess developmentscenarios, the MRC has proceeded in the opposite direction. It has defined some development scenariosand used the DSF to assess their impact on water quality and quantity, together with otherenvironmental and economic impacts.The DSF has been used to explore the implications of development and climate change for the Basin. Inthe absence of further development, climate change would tend to increase both high and low flows.However, a development scenario (including ongoing construction of storage reservoirs in China), tendsto even out the annual flow cycle, especially upstream in the Lower Basin, counteracting climate impactsduring the rainy season and reinforcing them during the dry season. The DSF can assess some of thecosts and benefits of these changes, including impacts on the Tonle Sap and on the Mekong Delta,though it does not well represent sediment flows or fish migration.The Bank is increasingly engaged in analytic and project work on integrated water resourcemanagement in large river basins (both national and transboundary), including the Amu Daurya, Niger,Shire (Malawi), Tana and Beles (Ethiopia) and Zambezi,. As in the case of the Mekong, much of thiswork relies heavily on hydrological modeling to explore the economic and environmental impacts ofalternative development and climate scenarios. A lesson from the WUP is the desirability of using opensourcemodeling. The WUP uses, in part, a proprietary model. This inhibits wider distribution andindependent review of model structure and performance, undermining capacity building andcredibility.Source: IEG mission; (Mekong River Commission 2010)35