Abstract: The reservoir area of Gongzui has basically reached the erosion-deposition balance. The influence of clear water scour from new large reservoir on sedimentation of Gongzui reservoir is discussed. The changes of reservoir capacity, sediment composition and reservoir section before and after scour are analyzed, combined with measured data. The results show that there is obvious scour in reservoir section, and the sediment is pushed forward to dam in the form of mound, which indicates that scour is beneficial to the recovery of reservoir capacity. But the recovery of reservoir capacity has a certain lag. Besides, the moving and coarsening of reservoir sediment would lead to an increase in the size of sediment over dam and generator set, which would aggravate the erosion on overflow surface and turbine.

Key words: erosion-deposition balance, clear water scour, coarsening of sediment

摘要： 龚嘴水库已基本达到冲淤平衡，但在上游新建大型水电站清水下泄冲刷下，根据实测资料分析了冲刷前后的库容、床沙组成、库区断面的变化，表明龚嘴水库库区断面出现明显的冲刷，水库泥沙呈堆丘式向坝前推移，冲刷作用对水库库容的恢复是有利的，但库容恢复相对下泄清水时间有一定的滞后。此外，水库泥沙的推移和床沙的粗化将导致过坝、过机泥沙粒径的增加，从而加剧对过流面的冲刷和对水轮机的磨蚀破坏。

关键词: 冲淤平衡, 清水冲刷, 泥沙粗化