Abstract: Through the analysis on Tangtuba upstream volumetric coming water and sediment conditions，it is showed tat this reach is the part of the typical mountainous river; the banks are of relative rigid composition; the riverbed deformation is mainly the mass movement of traction load; and the annual coming water and sediment volume of the reach has little change．Combination of the change of water and sediment condition and the field terrain materials after Three Gorges dam water storage，the riverbed evolution law of Tangtuba reach is analyzed thoroughly，and the bottomland evolution tendency is also forecasted，which provides theorectic basis for the channel maintenance and management．

Key words: water and sediment condition, riverbed evolution, evolution trend

摘要： 分析了塘土坝上游来水来沙条件，结果表明: 该河段为典型山区河流，河岸组成较为坚硬，河床变形以推移质运动为主，河段年际间来水来沙变化不大。结合三峡大坝蓄水运行后该河段水沙条件的变化及实测地形资料，深入分析了塘土坝河段河床演变规律，并预测了洲滩演变趋势。为该河段航道维护和治理提供了理论依据。

关键词: 水沙条件, 河床演变, 演变趋势