Impacts of the South-To-North Water Diversion Projects (Middle Route) on the Water Environment of the Middle and Lower Reaches of the Hanjiang River

In this paper, according to the rule of unbalanced sediment transport and the analysis of field data, different water diversion schemes were theoretically studied, including the erosion and sedimentation trend as well as their impacts on the environment of the middle and lower reaches of the Hanjiang River. The results showed that the 95×10^8m^3 water diversion scheme will cause less erosion and water level decrease than the 15×10^8m^3 water diversion scheme. Using a water diversion scheme of 95×10^8m^3, the decrease of water quantity can impact the river hydrodynamic regime substantially and the environments of the middle and lower reaches of the Hanjiang River will be greatly affected. It is therefore necessary to develop new water resources or build projects to meet the need of the environment and the needs for navigation.