三峡蓄水后白沙～茅草街双向水流河段航道的变化

Navigation channel changes in bidirectional flow from Baisha to Maocaojie after operation of Three Gorges Reservoir

根据实测资料分析了白沙～茅草街双向水流河段水沙特性以及该河段碍航成因，得到蓄水前南咀输入该河段的沙量太大是导致枯水期碍航的主要原因．在此基础上，利用三口分流的最新研究成果，计算了蓄水20a后进入该河段水沙的变化，得到了蓄水20a后南咀站沙量减少将会导致该河段在枯期碍航的情况得到改善的结论．且水库凋蓄作用导致白沙～茅草街河段在4、10、11月份水位下降，但仍满足通航要求，12月至次年3月份枯水期水位略有增加，且低于设计水位的天数有一定的减小，因此通航条件将会有一定的改善，5、6月份水位增加，也均满足通航条件．总之，蓄水20a后白沙～茅草街河段通航条件将会得到改善．

According to the field data, the flow and sediment characters from Baisha to Maocaojie in Dongting Lake are analyzed; the cause is that the sediment discharge at Nanzui Station is too much before the operation of Three Gorges Reservoir. Based on this, and using the latest research achievement about the flow of the three diversions, the changes in the flow and sediment characters about this river after the Three Gorges Reservoir being built 20 years, are analyzed. The results show that, the sediment discharge at Nanzui Station will reduce, which lead to the conditions of the navigation channel improving; the more uniform discharge processes will lead to the water level dropping in April, October and November, but meeting the navigation requirements; from December to March next year, the water level increases slightly; and the navigation requirements will become a certain improvement; the water level increases in May and June so as to meet the navigation conditions. So the navigation requirements will become a certain improvement after the Three Gorges Reservoir being built 20 years.