HYDROLOGICAL CHANGES IN THE MEKONG RIVER BASIN UNDER FUTURE HYDROPOWER DEVELOPMENT AND RESERVOIR OPERATIONS

抄録

 Hydropower is an important development opportunity for the Mekong River Basin (MRB) and its member countries. However, the rapid development of hydropower projects in the last decades has threatened the natural flow regimes of the basin. When all hydropower projects are completed, they will put more pressure on the hydrology of the basin. Due to the unavailability of the detailed hydropower operation rules, especially for the future development, we first estimated the general patterns of dam operations by maximizing the hydropower generation based on the proposed and existing storage volumes and turbine flow capacities. Then we propose a simple storage model representing the hydropower dam operations in this river basin. For the hydrological assessment, we used a distributed hydrologic model, Rainfall-Runoff-Inundation (RRI) model. The simulation was conducted from 2010 to 2016. The results suggest that the RRI model incorporated with our proposed model can reproduce the discharge hydrograph of the MRB. The hydropower developments would increase the dry seasonal flow while decreasing the wet seasonal flow. The impact can be seen as far as downstream of the Lower Mekong Basin (LMB). The impacts of future hydropower development on the LMB are significantly larger than the present hydropower development. On the monthly scale, under the future hydropower development scenario, the discharge changes range from -17% to +40% at Chiang Saen, and -16% to +100% at Kratie. In the dry season, the discharge at Kratie was significantly increased up to 40%. While in the wet season, the discharge was decreased by 15%. This study provides important information for reservoir operators and policymakers for the sustainable development of the basin.