Study On Lake Water Level Regulation And Water Quality Response Mechanism And Its Application

Lake is an important water resource storage area.With the development of urbanization,lake pollution is becoming more and more serious.The source of lake water pollution control is to take measures to cut down the amount of pollutants into the lake,supplemented by dredging,ecological restoration,form control and other means to improve water quality.This paper studies the influence of water level regulation on water quality in order to provide a measure to improve water quality in lakes.Different lake functions,such as runoff regulation,agricultural irrigation and water supply,have different requirements on lake water level,and changes in lake water level will cause changes in hydrodynamic conditions,thus affecting the transport,mixing and transformation of pollutants in the water.From the point of view of the water environment capacity of a lake,the larger the water volume of a lake,the larger the total amount of pollutants that can be accommodated.Therefore,the lake management department can take the initiative to regulate the water level of the lake according to the pollution of the lake to improve the water quality of the lake.In this paper,Huangjia Lake in Wuhan was taken as the research object,combined with the actual situation of the lake basin,through the establishment of a two-dimensional hydrodynamic water quality model of the lake,the water level regulation and water quality change response mechanism of Huangjia Lake were studied,and the water level regulation scheme based on water quality management objectives was proposed.The main work contents and achievements of this paper are as follows:(1)Analyze the current water quality of Huangjia Lake and its inter-annual change trend.By 2019,the water quality of Huangjia Lake does not meet the requirements of Class III water quality management goals,showing a moderate eutrophication state.Chemical oxygen demand(COD),total phosphorus(TP),and total nitrogen(TN)are the main pollutants exceeding the standard in Huangjia Lake.Based on the measured data and collected data,assess the pollutant structure of Huangjia Lake into the lake,and evaluate the water environmental quality of Huangjia Lake.(2)Construct a two-dimensional hydrodynamic water quality model of Huangjia Lake.Construct a two-dimensional hydrodynamic water quality model of the Huangjia Lake basin based on Huangjia Lake underwater topographic data,lake surface wind field,rainfall runoff and other data to simulate the lake’s lake movement state,hydrodynamic condition change and water quality change proces,and use the 2018 measured water quality data to determine the rationality of the model Perform verification and calibrate related parameters.(3)Correlation analysis of Huangjia Lake water level regulation and water quality changes.Based on the morphological characteristics of the Huangjia Lake lake and the pollutant diffusion situation obtained by water quality simulation,the concentration of various pollutants at the designated initial water level of Huangjia Lake is obtained,and the Spearman correlation analysis method is used to analyze the correlation between the water level and water quality indicators.It is found that the COD concentration of Huangjia Lake in the flood season has a strong negative correlation with the water level.It is more obvious to raise the water level of the lake between 17.0m and 19.0m to improve the water quality.However,in the non-flood season,the correlation between the main pollutants and the water level is not strong and should be passed Take other water ecological restoration measures to improve lake water quality.Finally,a technical plan for water quality and water level scheduling that meets the conditions of Huangjia Lake is proposed.