三峡成库后重庆段运行水位流场模拟

基于圣维南方程组，采用隐式差分格式求解，建立了一维流场模型，计算了三峡库区重庆段，从寸滩断面到市域出口共500余km长江干流江段整体水流特征．对三峡成库后2个典型蓄水位条件下重庆段水流状态进行了模拟预测．预测结果表明：三峡水库蓄水后，坝前156m水位条件下，回水区水面宽度是建库前的3倍左右，断面平均流速仅为建库前的1／3左右；坝前175m水位条件下，回水区水面宽度是建库前的3．5倍左右，断面平均流速仅为建库前的1／4左右．模拟结果反映了建库前后长江干流一维流场的变化特点．它为分析三峡水库在不同水位运行时对重庆段水流状态及生态环境的影响范围及程度提供了参考．

One-dimensional Water Flow Modeling for Chongqing Region at Two Typical Storage Levels in the Three-Gorges Reservoir

The one-dimensional flow model based on Saint-Venant equation is developed.Then,it is applied to calculate the holistic hydraulic characteristics in the natural condition of the Three Gorges Reservoir in Chongqing region,which is the 500 km-long mainstream beginning at Cuntan and ending at the boundary of Chongqing.Further,the model is applied to predict the hydraulic characteristics of the calculating zone at the time of the second stage of the dam construction(156 m storage level at the dam) and the completion of the project(175 m storage level at the dam).When the reservoir is operated at the storage level of 156m,the river-width of most corss-section increasing 2 times and the cross-section average velocity is reduced by 2/3 compared with these in the natural condition.When the reservoir is operated at the storage level of 175 m,the river-width of most cross-section increasing 2.5 times and the cross-section average velocity is reduced by 3/4 compared with these in the natural condition.The validating result indicates that the model properly reflectes the holistic hydraulic characteristics.This model is an effective tool for the assessment of the environmental impacts of the Three Gorges operated at the different storage level.