Analysis on water environment impacts of cascade hydropower development in Chongqing Reach of Wujiang Basin

• 1、College of Hydrology and Water Resources, Hohai University, Nanjing 210098

Abstract：Cascade hydropower development is attached great importance to the national hydroelectric energy development. However, because of the cascade hydropower development, the natural rivers and the ecosystem change a lot in the basin even the unsuitable management can destroy the sustainable development. Past researches pays close attention to the impact on technical economy and seldom discuss the function in the ecosystem. In the paper, cascade hydropower in Chongqing Reach of Wujiang Basin is studied by combining the quantitative and qualitative methods to get the influence on water ecological environment factors, such as water temperature, water quality and hydrology situations. Those impacts can be excluded by three aspects: (1) Runoff in high-water period is decreasing, while the runoff in low-water period is increasing. That is to say, the cascade hydropower changes the annual distribution of water quantity. (2) In comparison with natural rivers, owing to regulation, warm flood is stored in summer and autumn, which cause water temperature rise in autumn and winter. On the contrary, cool water is stored in winter, and then makes downstream water cooler. (3) In consequence of upstream incomings of water and pollutants, water quality in some subareas is bad in the reservoir and it causes decreasing water quality in Chongqing Reach of Wujiang Basin and the influence is small.

Keywords： water environment, analysis on impacts, Chongqing Reach of Wujiang Basin