Zoning and classification of ecological flow velocity thresholds required by river fish during sensitivity spawning periods
The reasonable formulation of sensitive ecological flow targets is a challenging issue in ecological flow management in China.To address the existing problems of complicated calculation methods and lack of key parame-ters in the establishment of sensitive ecological flow targets,this paper focuses on the fish spawning period and propo-ses a method for calculating ecological flow velocity and flow volume during sensitive periods in river segments catego-rized by region.Different threshold values for ecological flow velocity during sensitive periods are established for dif-ferent regions(Northeast,Huang-Huai-Hai,Southwest,Middle and lower Yangtze River,South-East coastal are-as,and Northwest regions)and different types of rivers(by catchment area,mountain reach,plain reach,etc.).The results indicate that the recommended average flow velocity for all categorized regions is 0.66 m/s,with moun-tainous large stations averaging 0.94 m/s,mountainous small stations averaging 0.62 m/s,plain large stations aver-aging 0.63 m/s,and plain small stations averaging 0.46 m/s.Based on this thresholds,ecological flow targets dur-ing sensitive periods are calculated for 217 river segments designated for fish spawning habitat protection nationwide.An analysis of the rationality and adaptability of the thresholds is conducted in conjunction with results from wetted perimeter method for certain sections.The verification results demonstrate that the applicable thresholds and meth-odology are suitable for diverse river types and scales,thereby offering valuable insights for managing and control-ling sensitive ecological flow in Chinese rivers.
万方数据
维普
