Research on Environmental Effects of Large Scale Hydropower Project: A Case Study in Three-Gorge Project

Shao, A.; Wang, S.; Wang, Q., and Liu, Y., 2015. Research on environmental effects of large scale hydropower project: a case study in Three-Gorge Project.

The topography is low and flat in the estuarine region of the Yangtze River where waterlogged and salt-affected soil has been a latent threat to agricultural development for long time. After the Three-Gorge Project is built up, the Three-Gorge Reservoir seasonally adjusted runoff will impact on the dynamic of soil water and salt in the region. The influence of these relationships is very complicated. In spring, it will cause the river water level to increase so that discharge increases which will not favor desalting. At the same time, the mineral levels of the groundwater will decrease which favors of desalting. In autumn and winter, it will make the river water level drop so that the discharge decreases which favors desalting. However, the mineral level of the groundwater will increase and a salty tide invasion will strengthen which will not favor desalting. The initial predicted result of the numerical simulation shows that salification will be bigger in autumn than desalinization in spring. The degree of impact of the project on the regime of soil salt will be gradually weakened along the river up from the estuary. The nearer to the sea, the bigger the impact, and from cross profiles, the nearer to the river, the bigger the impact. It is more probable that soil will produce salification or secondary salinization especially within 4 kilometers of the river.