Impacts of cascade hydropower development on aquatic environment in middle and lower reaches of Jinsha River, China: a review.

The middle and lower reaches of the Jinsha River, which is the upper reach of the Yangtze River in China, play crucial roles in the water security of people living in the middle and lower reaches of the Yangtze River. The construction of 11 dams in this region has significantly altered the aquatic environment. Although researchers have investigated the effects of cascade hydropower station development in the middle and lower reaches of the Jinsha River based on factors such as flow, sediment, and fish, the overall impact of this station on the aquatic environment remains unclear. Therefore, the purpose of this study is to comprehensively investigate the effects of cascade hydropower station development on the aquatic environment based on three factors: river, aquatic organism, and ecosystem factors. In terms of river factors, the development of cascade hydropower stations increases runoff in the dry season and decreases it in the flood season, leading to sediment deposition and water temperature stratification in cascade reservoirs, and changes in water quality. In terms of aquatic organism factors, cascade hydropower development not only changes the species composition but also reduces biodiversity. Effects of ecosystem factors including the ecological flow, value, and landscape as well as sustainability are summarized, with results indicating positive and negative impacts on river ecosystems. Finally, recommendations for future research on the effects of cascade hydropower development on the aquatic environment of rivers are provided.