Research and Prevention Practice of Debris Flows During the Development of Hydropower in the Downstream of Jinsha River, China

Wudongde, Baihetan, Xiluodu and Xiangjiaba are four cascade hydropower stations in the downstream of Jinsha River, China, with a total installed capacity of 46460 MW and annual energy output of 190 billion kWh, which is the largest hydropower base in China. The region is located in the Hengduan Mountains transiting from Qinghai-Tibet Plateau and Yunnan-Guizhou Plateau to Sichuan basin, and is one of the areas with the strongest neotectonics and modern crust activity in the world; therefore, there are many large-scale and widespread debris flows. The debris flow trench is distributed approximately per 1.8 km along the trunk stream, which is the crucial factors affecting the safety of hydropower construction and operation in the downstream of Jinsha River. During the development of hydropower in the downstream of Jinsha River, based upon the a series of scientific research and engineering practice organized by China Three Gorges Corporation, a set of systematical experience combining scientific research, engineering treatment and management measures for prevention and control of debris flows has been accomplished. In the aspect of scientific research, integration of general investigation and detailed examination of debris flows in important areas and development mechanism of key objects has been adopted. In the aspect of engineering practice, the experience of “slope and bedrock stabilization, combination of drainage and retaining” has been widely used. In the aspect of management measures, the combination of “avoidance and prevention, dynamic evaluation and risk control” has been fully considered. These experience and measures provide important guarantee for the safe construction and operation of cascade hydropower stations in the downstream of Jinsha River, which can also be effective reference for the prevention and control of debris flows in similar environments.