输沙量法计算长江宜昌至监利河段河道冲淤量的修正研究

Modifying the channel erosion and deposition amount of Yichang-Jianli reach calculated by sediment discharge method

采用输沙量法计算河道冲淤量时,需考虑水文测验存在的误差,以及河道崩岸、河道采砂、河道分汇流、河段水量不平衡等引起的区间沙量变化。本文利用三峡坝下游宜昌、枝城、沙市和监利等水文站实测悬移质、推移质资料,采用输沙量法分别计算了宜昌至枝城、枝城至沙市和沙市至监利河段2002年11月至2008年10月河道冲淤量。在此基础上,将长江河道采砂调查成果、河道崩岸以及河段取水产生的引沙量以及2006年长江水利委员会水文局临底悬沙观测试验资料应用于输沙量平衡法计算河道冲淤量的修正。将修正前后的河道冲淤量与地形法计算结果作比较可知:对输沙量法计算得到的河道冲淤量进行修正是必要的。

When sediment discharge method is used to calculate the amount of river channel erosion and deposition, measurement errors and sediment amounts caused by bank collapse, sand mining, diversion and conflux, and water imbalance, need to be considered. This study used sediment discharge method to calculate the sediment amounts of river channel erosion and deposition in the reaches of Yichang-Zhicheng, Zhicheng-Shashi, and Shashi-Jianli for the period from Nov. 2002 to Oct. 2008, using measured data of suspended load and bed load at the hydrological stations downstream of the Three Gorges dam, i.e. Yichang, Zhicheng, Shashi, and Jianli. These calculations were then modified with the data of sand mining, bank collapse and sediment diversion in the Yangtze channel and the field observation data of near-bed suspended load collected by Bureau of Hydrology, Changjiang Water Resources Commission （BOH, CWRC） in 2006. Comparison of the calculations and their modifications with the results by topographic method shows the necessary of modification.