Effects of hydropower development on aquatic eco-environment and adaptive managements

Eco-environmental conservation has been a long challenge and even bottleneck for sustainable hydropower development. This study comprehensively reviewed the advances of researches on river damming impacts on biogeochemical cycling and thereby the aquatic eco-environment effects, zoobenthos habitat, fish habitat and migration routes, as well as structure and non-structure conservation measures. It analyzed the current challenges in fundamental researches and engineering applications as well as the underlying reasons, and highlighted the core aspects for future investigations. These include:① Long-term in-situ monitoring to discover the interception, transformation and transport processes of biogenic elements, and reveal the associated mechanism as well as the accumulated eco-environmental impacts; ② Reservoir induced changes in effective accumulated temperature regime for fish gonadal development and critical temperature regime for fish spawning, and consequently their joint effects on fish reproduction. In particular, the study pointed out the irrationality of some mandatory measures for indigenous fish conservation at present, and proposed the options such as ecological flow and tributary habitat compensation for high dams, and finally it provided some novel technologies to quantitatively assess the efficiency of conservation measures.