Modelling the Mekong: hydrological simulation for environmental impact studies

The Mekong, with a basin area of almost 800,000 km(2) and a length of 4500 km, is one of the most important rivers of the world. The many lakes and we tlands along the river, including Cambodia's Tonle Sap (Grand Lac), are maj or sources of fish for the riparian peoples and form an important part of t he regional economy. This resource may be affected by proposed developments in the basin. Using climatic, topographic and land cover data from the Int ernet, the semi-distributed land-use runoff process (SLURP) hydrological mo del was used to simulate the complete hydrological cycle of the Mekong and its tributaries. Information on dam locations and reservoir characteristics were obtained from local sources. The model was verified by comparing simu lated flows with recorded daily flows for the Mekong River and by comparing simulated levels of the Tonle Sap lake with recorded daily levels. The dai ly computed levels of the Tonle Sap lake were then converted into flooded a reas for each land cover around the lake which were then used in a fish pro duction model to evaluate the possible impacts of basin development on the fisheries. Model outputs may also be used to investigate issues such as wat er allocations and the effects of land use change or climate change on wate r resources and the aquatic and riparian environments. (C) 2001 Elsevier Sc ience B.V. All rights reserved.