利用三峡枢纽下泄"清水"改善洞庭湖和荆江的防洪局面

随着三峡水库蓄水，上游金沙江大型水电枢纽陆续建成，三峡水库将长期下泄含沙量较小的“清水”。含沙量的大量减小使长江中游实质上已成为一务新的冲积河流。“清水”大幅度地冲刷荆江河段，将对荆江堤防、河势、航道和防洪形势产生重大的影响。另一方面，三峡水库长期下泄的“清水”具有可观的冲刷能力，是一笔宝贵的财富，善加利用可以改善长江中游的防洪形势。本文建议：增加引“清水”入洞庭湖的水量，一方面避免“清水”对荆江河道的过度冲刷；另一方面可以冲刷洞庭湖的一些关键部位，改善湖区的防洪形势、并促进城陵矾以下长江河道的冲刷。

Improvement of flood control over Dongting Lake & Jingjiang stretch by clean water from TGP

With impoundment of the Three Gorges reservoir and subsequent construction of major hydro projects on the Jinsha River, the Three Gorges reservoir will discharge clean water with less sediment over a long period of time, which implies the middle reach of the Yangtze River will become essentially a new alluvial stream. Heavily scouring of the Jingjiang stretch resulting from the clean water could have significant impact on the levees, river morphology, navigation course and flood defense along the Jingjiang stretch. By proper usage, however, this clean water having powerful scouring force could also improve the flood control situation of the middle and downstream reaches of the Yangtze River. A recommendation is made in this paper, i. e. , increase in clean water diverted from the Yangtze River to the Dongting Lake, which could avoid excessively sourcing the Jingjiang stretch and on the other hand, could scour such key locations along the Lake that flood control conditions in the lake area can be improved and enhance scouring of the Yangtze River downstream of Chenglingji.