三峡工程对坝下长江流量影响研究

根据长江水情的具体特点，采用Ｐｒｅｉｓｍａｎｎ隐式格式，建立了一个描述长江情的水动力学数值模式。以最佳拟合历史水文资料，重演历史水文过程为原则，率定数值模式中的各参数；并运行率定后的模式，进行三峡工程对坝下长江若干断面处流量影响的模拟预测。

The Impacts of The Three Gorges Project on its Downflow Discharge of The Changjiang River

According to the regime of the Changjiang River.this paper sets up a numerical dynamlcs model of applying Preismann implicit difference method for difference treating of Saint Venant equations. Based on the best-imitating historical hydrologic data and recurring historical hydrologic process, each parameter in the differential equation is rated. The rated model is used to study the impacts of the Three Gorges Project on the discharge, in dry and rain seasons respectively, at certain stations along the Changjiang River. The results are as follows. (1) The impacts of the increased/decreased sluicing discharge from the Three Gorges Dam will reduce relatively with the distance of calculating section from Yichang Station after the Three Gorges Project operated. The relative reducing rate is about 0. 5 during rain season, and about 0. 67 during dry season in Datong section of the river. The reason is that the distance of calculating section from Yichang to Datong is not only longer, but also wider,and the capacity of river regulating is greater. (2) Because of greater roughness of the river basing during dry season (0. 036 0 - 0. 0365)than that of rain season(0. 026 0- 0. 026 5), the damping effect of the river section during dry season is stronger than that of rain season,and the the impacts of the Three Gorges Project on discharge along its down flow of the Changjiang River during dry season are greater than that of rain season. The rate of the impact value between rain season and dry season is 1. 0-0. 75.when the sluicing discharge from the Three Gorges Project increases/decreases relatively after the Three Gorges Project operated.