Analysis Of Water Diversion Scheme And Its Influence On Downstream Water Regime Situation Of Water Supply Project In The West Of Jilin

The western part of Jilin Province belongs to the semi-arid climate area of northern China.The land in the area is fertile,with lakes and wetlands all over the place.However,with the change of global climates,the problems of decreasing rainfall,decreasing groundwater level,shrinking wetlands,land salinization,and soil desertification are becoming increasing serious in this area.It has threatened the ecological security of the region.Through the connection of water system to increase regional lakes,wetland areas,to give full play to the function of flood diversion and flood detention in pool,it can effectively supplement the ground water,control the water and soil loss and restore the ecological environment.However,there are many uncertain factors in the development and utilization of water resources in the basin.Considering that the main purpose of this project is to restore and improve the regional ecological environment,it may bring some unfavorable factors to the downstream hydrological situation and water ecology while bringing ecological benefits.Therefore,this paper analyzes the flood diversion scheme and flood diversion control condition through comprehensive evaluation and other statistical analysis.By establishing the index system for evaluating the water supply priority of the lake and wetland,the water supply target priority is analyzed,and the dispatching operation scheme is discussed.Through the adjustment and calculation of the long series hydrological data,this paper analyzes the influence of water regime in the lower reaches after water diversion.The main research contents and conclusions are as follows:(1)It analyzed the total amount of water resources and the present situation of development and utilization in the study area,predicted the water demand in the study area so as to analyze supply and demand of water resources.Determine the rural ecology as the main water supply object.(2)According to the characteristics of incoming water and flood of the main diversion rivers,it determined the flood diversion plan,and boundary conditions for each diversion scheme with comprehensive analysis as well as the discriminant condition of flood diversion,finally,And the diversion operation scheduling scheme is studied.(3)According to the statistical analysis of the cross-section data of the main rivers of the hydrological stations,it adjusts and calculates by monthly series of data.From aspects of main water level elements such as flow,water level and velocity,it carries out analysis on the hydrological situation in the lower reaches of each main diversion river in the case of flood diversio,it concludes that after the flood diversion and replenishment of the project,the flow and water level of each section after diversion of each section of the downstream section were reduced but the lower range is smaller.It has little effect on the change of hydrological situation in the lower reaches.It helps to alleviate the flood control pressure of downstream rivers..