Abstract: After the impoundment of Three Gorges dam, which caused the radical change of sand conditions and boundary conditions at the perennial backwater area, the variation rule of the reach’s sediment deposition, cross-sections and thalweg, etc., were analyzed and its development trend was also forecasted, combing with the coming water and sediment conditions of Tangtuba Reach at perennial backwater area before and after impoundment as well as the river bed topography prototype observation data.

Key words: hydraulic engineering;water storage, river bed evolution, Tangtuba, evolution trend

摘要： 在三峡大坝蓄水引起常年回水区水沙条件、边界条件发生重大变化的前提下，结合蓄水前后常年回水区塘土坝河段的来水来沙及河床地形的原型观测资料 ，分析了该河段的泥沙淤积、横断面和深泓线等的变化规律，并预测其发展趋势。

关键词: 水利工程, 蓄水, 河床演变, 塘土坝, 演变趋势