Applying physical habitat model of zoobenthos in typical reaches of the Yangtze River

The physical habitat model considering the habitat demand of aquatic organisms is considered to be one of the most popular method to evaluate the impact of the flow change on river ecosystem. In this study, the Jianli river section of the main stream of the Yangtze River with islands and floodplain is selected as an example to establish the physical habitat model for different macrozoobenthos groups, calculate the time series of the suitable habitat area under the changing flow to make the ecological flow decision accordingly. The results show that the most sensitive environmental parameter of macrozoobenthos is velocity, and the suitable range is 0 ~ 0.2 m/s. The second is water depth, and the suitable range is 0 ~ 6 m. Considering the sensitive environmental parameters, the best ecological flow of macrozoobenthos is 20 000 m3/s in wet period and 4000 m3/s in dry period. After impounding the Three Gorges dam, the low value of weighted usable area in dry period and normal period decreases, while increases in wet period. In order to protect the habitat of benthic animals, it is suggested that the Three gorges dam can take into account the ecological flow demand of benthic animals while flood control and water storage, increase the flow in the dry period and the normal period in the dry year, increase the flow in the dry period in the normal year, and reduce the flow in the wet period in the wet year. The results of this study can be used as a reference for the ecological flow decision-making and ecological restoration scheme design of different target species in other reaches of the Yangtze River. © 2020, China Water Power Press. All right reserved.