三峡水库建成后对长江河床演变影响的预测与对策

本文重点讨论了长江三峡水利枢纽建成后,水动力条件大大改变,必然会引起水库上、中、下游河床发生一系列的变化。如注入水库的各条支流,由于河流基准面被大大抬高,都会形成河口拦门沙和水下三角洲。分析了因入库河流基准面抬高,自然会引起水库上游河床的摆动变形。以及水库蓄水后,由于波浪、水流对库岸的侵蚀塑造作用和水库运营调蓄时,会产生动水压力和静水压力的变化,以及风浪的侵蚀、掏蚀,必然会大大引起库岸变形;对水库库区附近淹没、侵没和渗漏的影响;水库建成后,水库运营清水下泄时,由于含沙量大大减少,水的动能加大,任何水库都会引起其下游河道冲刷及河床变形,河床会发生演变,所以,三峡水库的河床也会有一个新的调整周期。

Influence of the Three-Gorges Reservoir on Evolution of Yangtze River bed

After the completion of the Three-Gorges reservoir,a series of changes in fluvial processes of the upper,middle and lower reaches of the reservoir will inevitably occur, causing changes in Yangtze River bed. Firstly, river mouth bars and subaqueous deltas will be formed because of the elevated base level of the tributaries at river mouths where the tributaries flow into the reservoir and its downstream area. Secondly,swing and deformation of the riverbed will occur in the upper reaches near the reservoir and banks along the reservoir when the reservoir begins to store water. Thirdly, riverbed scouring and channel deformation will happen at the downstream of the reservoir because of unmixed water flows when the reservoir sluices, which will influence seriously Wuhan city and Jinjiang, the reach of Yangtze River from Yichang city to Wuhan city.These processes in Hubei province and Chongqing municipality should be studied and calculated as soon as possible so that the countermeasures can be made promptly.