Effects of upstream reservoir regulation on the hydrological regime and fish habitats of the Lijiang River, China

Dam construction may alter the hydrological regime of rivers, and thus may cause profound and accumulative impacts on a river ecosystem. Therefore, research on hydrological and ecological response to river regulation has received increasing interest. This research, takes the middle reach of the Lijiang River as a case and an indigenous cyprinid fish Spinibarbus hollandi (S. hollandi) as a target species for the development of an integrated hydro-environmental-habitat model. In contrast to previous studies focusing only on habitat suitability, this research takes into account habitat quality such as habitat fragmentation. The model analyses the effects of flow regime changes due to upstream reservoir operation on habitats for juvenile fish. Unregulated flow (UF) and regulated flow (RF) were simulated, and the corresponding effects on habitat of S. hollandi were analysed and discussed. Using the developed model, an ecologically-based flow regime was derived ensuring several conservation levels for S. hollandi habitats. Based on the recommended ecological flow regime, rules for reservoir operation are suggested.