三峡工程变动回水区泥沙淤积的改善对策

Sedimentation Improvements in the Backwater Variation Zone of Three Gorges Reservoir

三峡工程变动回水区的泥沙淤积及其对航道港口等通航设施的影响，一直是人们关注的重大技术问题。本文分析了长江上游金沙江和支流嘉陵江上建库拦沙，可使进入变动回水区的悬移质泥沙数量减少５０％以上，这样，就能从根本上改善三峡工程变动回水区悬移质泥沙的淤积问题。采取设置库中库的拦沙措施，则可以较好地解决推移质泥沙在变动回水区航槽中的堆积。

One of the technological problems suspected to occur after Three Gorges Reservoir's being put into operation is the sedimentation in the back water variation zone, and its influence on the navigation channels and the harbor terminals. This paper analyses the contributions of the dams to be constructed on the upstream of Changjiang River, Jinsha, and on its tributary river, Jialing, to reducing the silt transfer, which may account for 50% of the total amount in natural conditions. Nevertheless, the remaining part of silt, together with the silt scoured from the downstream riverbed by the clear waters the reservoirs spill out, is still very harmful for navigation if the silt deposits in the backwater variation zone along which harbors are situated. The paper puts forward a proposal that an underwater dam, or simply a reservior, be constructed between Jinsha dam and the harbors to retain the silt before it reaches the backwater variation zone.