Research On Evaluation And Management Of Yangtze River Ecological Flow Based On Hydrological Ecological Model

At present,there are a large number of gates and dams in the Yangtze River Basin in my country,and strong human activities such as gate and dam construction have obviously changed the hydrological situation of the river,resulting in the variation of river flow,adversely affecting the survival and reproduction of river aquatic organisms,and seriously jeopardizing the ecological health of the river.Therefore,studying the relationship between changes in river flow and ecological response,and evaluating and managing ecological flow have important theoretical and practical significance for maintaining the healthy development of the Yangtze River ecosystem.This article mainly takes the Yangtze River as the research object,selects the measured hydrological data of Pingshan,Yichang,and Datong,takes the representative fish of the Yangtze River as the ecological target,and studies the relationship between fish spawning and water demand;combined with the measured hydrological data,evaluates the ecology of the Yangtze River The ecological flow process of species;finally,an ecological flow management plan is proposed based on the ecological flow process.The main contents and results of the research are as follows:(1)Based on the theory of river ecological health,identify the characteristics of river hydrological regimes and ecological impacts,explain the composition of ecological flow and its ecological impacts,quantitatively analyze the relationship between changes in flow regimes and ecological responses,construct hydrological ecological models,and propose ecological flow management measures for maintenance Provide reference for river ecosystem health.(2)The upper boundary of the low flow process at Pingshan station on the upper reaches of the Yangtze River is 1843 m~3/s,and the upper boundary of the high flow process is 9923 m~3/s;the upper boundary of the low flow process at Yichang station in the middle reaches is 5466 m~3/s,and the next high flow process is 30083 m~3 /s;the upper bound of the low flow process of the downstream Datong station is 18023 m~3/s,and the upper bound of the high flow process is 48133 m~3/s.(3)Using the wet cycle method to calculate the minimum ecological flow of Pingshan,Yichang,and Datong stations were 679 m~3/s,2382 m~3/s,3756 m~3/s,respectively,which accounted for 5.13%,17.58%,12.65% of the multi-year average flow;The suitable ecological flows calculated by the IHA-RVA method are 3510 m~3/s,10937 m~3/s,23052 m~3/s,respectively,accounting for 82.65%,84.62%,83.07% of the multi-year average flow.(4)Analyze the guarantee rate of the minimum and suitable ecological flow.The minimum ecological flow guarantee rate for different level years of Pingshan,Yichang,and Datong are all 100%;the suitable ecological flow guarantee rate of Pingshan,Yichang,and Datong stations in the dry year are 19.05.%,32.35%,25.52%,the suitable ecological flow guarantee rates in normal water years are 57.44%,52.27%,100%,and the suitable ecological flow guarantee rates in wet years are 69.64%,55.39%,96.88%.(5)Manage the river ecological flow from the aspects of joint reservoir dispatching,engineering measures and non-engineering measures.Formulate river ecological flow management steps,put forward some requirements when constructing drainage works,and put forward management opinions on system management,water resources allocation,and supervision and law enforcement.