上游来水来沙变化及对重庆河段泥沙淤积的影响

Impact of incoming runoff and sediment on sediment deposition along the Chongqing reach

三峡水库按175 m方案正常蓄水运行后,处于回水变动区的重庆河段将具有水库和天然河道的双重特性,随着水库运行时间的增长,该河段将呈现累积性泥沙淤积趋势.根据长江寸滩站和嘉陵江北碚站长系列水文观测资料分析,近年来三峡入库泥沙明显减少,而随着金沙江和嘉陵江上游梯级开发的逐步实施,上游大型水库拦沙效益将逐步显现,重庆河段的来沙量将进一步减少,可有效减缓重庆河段泥沙淤积速率,减少淤积总量和边滩淤积,增加三峡水库的兴利库容利用率,有利于重庆河段岸线及水资源综合利用.

When the Three Gorges Reservoir operates at the normal water level of 175 m, the Chongqing reach which is at the fluctuating backwater area will have the dual characteristics of reservoir and natural river. They will present a trend of cumulative sedimentation with the lapse of operating time. According to the statistic analysis of the long term hydrological observation data from Cuntan Station in the Yangtze River and Beibei Station in Jialing River, the sediment transported into the Three Gorges Reservoir has reduced significantly in recent years. At the same time, with the implementation of the cascade development plan of the Jinsha River and the upper reaches of Jialing River, the effect of sediment-retention of large-scale reservoirs in the upstream will appear gradually, and the sediment from the Chongqing reach will also be further reduced. All of this will lessen the sedimentary rate and deposition amount of the Chongqing reach, and reduce their side bar deposition. Meanwhile, it will increase the availability of the storage capacity of the Three Gorges Reservoir and benefit the comprehensive exploitation of the shoreline and water resources of the Chongqing reach.