Improvement of river environment in the downstream reaches of dams

댐하류의 하천환경 개선

I introduce the Flexible Dam Operation (FDO) and some of sediment control techniques In dams which are implemented as trials to avoid or reduce environmental impact of dams on the downstream reaches. The FDO is a dam management method to improve river environment in the downstream reaches by means of the flushing flow, the maintenance flow and so on utilizing a vacant portion of capacity for flood control without interrupting prime flood control function during the rainy/typhoon season. It Is suggested by the guideline of the FDO that EDO should be implemented regularly after the trial for about three years. The basic conception of the FDO is described here. The example of excavation of deposited sediments in check dams and placement of sand ana gravel immediately downstream of the dams and the example of coordinated sediment flushing are described as some of sediment control techniques in dams. Now they are at the stage of experiment and trial. Therefore, it is important to increase examples and establish the technical methodology and the environmental evaluation method for them.