375 / 2024-02-29 22:55:46

Research on the Reservoir Sedimentation during Design of Hydroelectric Stations

Qingyukou reservoir; sediment deposition; mathematical model; the normal water level

Abstract: The sediment accumulation in the reservoir area directly affects the reservoir lifespan and the safety of dam. During the planning and design of the project, the study on the sediment deposition in the reservoir area can provide reliable technical support for the construction of water conservancy project. Taking Qingyukou Reservoir in Sichuan Province as an example, a one-dimensional water and sediment mathematical model was applied to simulate the sedimentation process in the Reservoir of three design schemes, the normal water levels of the three schemes are 397m (Scheme 1), 400m (Scheme 2), and 402m (Scheme 3). The results show that: (1) the lower the normal wate level, the smaller the total amount of sediment accumulation in the reservoir area. When the reservoir is used for 100 years, the total amount of sediment accumulation in scheme 3 is 0.5201×10⁸m³; (2) the sediment deposition body in the reservoir area of each scheme is in the form of delta. The lower the normal water level, the faster the sediment deposition body advances to the dam. When the reservoir is operated to the end of 80 years, the delta sediment in scheme 1 has moved to the front of the dam; (3) the lower the normal water level, the higher the average sediment elevation in front of the dam. The average sediment elevation in front of the dam in scheme 1 is 375.51m; (4) the higher the normal water level, the smaller the remaining reservoir capacity below 402m, and the remaining reservoir capacity ratio in scheme 3 is reduced to 61.9%. From the perspective of engineering economy and the sediment accumulation in the reservoir area, scheme 2 is recommended.