Study On Conventional Pollution Transport In Drainage Ditch Of Qingtongxia Irrigation Area And Its Contribution Rate To Drainage Ditch

Qingtongxia irrigated area is one of the large irrigated areas in China.It is of great significance to construct the model of pollutant migration in typical drainage ditches and study the non-point source pollution and contribution rate of drainage ditches.In this paper,based on the performance characteristics of non-point source pollution in agriculture,the pollution monitoring and testing work,and to investigate in ningxia qingtongxia irrigation district collection to understand the key parameters,such as irrigation of crops,fertilizer application,on the basis of the related parameters for sorting,analysis and calculation,the irrigation area is obtained,the results of the output of the agricultural nonpoint source pollution load,etc.Aiming at the characteristics of the migration and change of agricultural non-point source pollutants,MIKE11 model was used to analyze the movement and change rules of related pollutants.According to the movement and migration characteristics of typical pollutants,such as COD,NH3-N and TP,MIKE11 AD water quality model was used to simulate and calculate the drainage channels.The simulation results of the MIKE11 hydrodynamic and water quality model show that the absolute error Re of drainage flow is 5.6%,the correlation coefficient R2 is 0.98,and the nash-suttcliffe coefficient Ens is 0.988.The simulation errors of total COD,ammonia nitrogen and phosphorus are 9.45%to 18.65%,7.02%to 18.90%and 8.12%to 16.12%respectively.According to the hydrodynamic and water quality models,the flux of pollutants into the river and the contribution rate of major pollutants into the river to the drainage ditch were calculated,and the impact of agricultural non-point source pollution on the drainage ditch was analyzed.The order of contribution rate of COD pollution load in the drainage ditch in the research area is:agricultural pollution>livestock and poultry breeding>rural life;The order of contribution rate of ammonia nitrogen pollution load is:agricultural pollution>livestock and poultry breeding>rural life;The order of contribution rate of total phosphorus pollution load is:livestock breeding>agricultural pollution>rural life.Therefore,this paper believes that the pollution sources of agricultural non-point source pollution in this research area are mainly agricultural pollution and pollution caused by livestock and poultry breeding in this area,which provides Suggestions and references for the prevention and control of major pollution sources and environmental treatment and protection work in this area.