Author(s): Jianguo Chen, Anjun Deng, Haihua Hu
Keywords: Annual average sedimentation loss rates of reservoirs; Capacity/sediment ratios; Operation modes; Water and sediment conditions; Influencing factors;
Abstract: The annual average sedimentation loss rates of reservoirs are important indicators which reflect the annual average sedimentation loss degrees of the reservoirs during certain periods of time. It is closely related to the capacity/sediment ratios (total reservoir capacity/annual average sediment inflow), as well as the reservoir operation modes, water and sediment inflow processes, and reservoir operation stages. It has been found that under normal circumstances, the larger the capacity/sediment ratio is, the smaller the proportion of siltation in the reservoir capacity will be, and the smaller the annual average sedimentation loss rates of the reservoirs will be. Methods which are favorable for sediment discharge are normally adopted in reservoirs. Therefore, the sedimentation volumes of the reservoirs will be less, and the annual average sedimentation loss rates will also be small. It has been observed that under favorable conditions of water and sediment, the annual average sedimentation loss rates tend to be minimal. When comparing the early and later periods of reservoir operations, it was determined that due to the sediment transporting capacities of the water flow processes were low. Therefore, the sediment had not been easily discharged in the downstream areas, and the annual average sedimentation loss rates of the reservoirs had increased. However, it was found that reductions in the annual average sedimentation loss rates of reservoirs could be achieved by increasing the capacity/sediment ratios; using reservoir operation modes which were advantageous to sediment discharge; optimizing the water and sediment inflow processes; and other comprehensive measures.