Optimization Of Monitoring Points And Model Simulation Of Non-point Source Pollution In Hetao Irrigation Area

The migration,transformation and prevention and control of agricultural non-point source pollutants is one of the hot research in the field of environmental science and engineering,and it is of great significance in ensuring the water ecological security of the basin.Hetao irrigation area is an important national commodity grain and oil production base.Its agricultural non-point source pollution prevention and control is directly related to the ecological protection and high-quality development of the Yellow River Basin in Inner Mongolia.Taking Hetao irrigation area as the research area,this paper analyzes the temporal and spatial distribution characteristics of pollutants in surface water,groundwater and soil in Hetao irrigation area through sampling and actual measurement,constructs Hetao Irrigation Area SWAT model,simulates and analyzes the output characteristics of non-point source pollutants TN and TP in Hetao Irrigation Area Based on the calibrated SWAT model,and identifies the key output source areas.In addition,according to the field sampling results of surface water,groundwater and soil,the existing sampling points are optimized by cluster analysis method,and preliminary countermeasures and suggestions are put forward for the control of non-point source pollution in Hetao irrigation area.The main research results are as follows:1.Non point source pollution is the main cause of Eco-environmental pollution in Hetao irrigation area.The non-point source pollution of surface water,soil and groundwater in Hetao irrigation area is mainly concentrated in Wulanbuhe irrigation area,Jiefangzha irrigation area and Yichang irrigation area.2.The SWAT model of Hetao irrigation area is constructed in this study.Sufi-2 in swat-cup is used to calibrate the simulation data.The results show that the fitting degree of measured data and simulation data is high,which proves that SWAT model has good adaptability in Hetao irrigation area.3.This study uses the data of the calibrated SWAT model to analyze the characteristics of non-point source pollution in Hetao irrigation area.It shows that TN is the main non-point source pollutant in Hetao irrigation area,and the output of nitrogen and phosphorus from non-point source pollution in Hetao irrigation area shows obvious seasonal characteristics,which is much higher in summer than in the other three seasons.According to the higher area proportion of pollutant output,it is found that Wulanbuhe irrigation area,Jiefangzha irrigation area and Yichang irrigation area are the key source areas of non-point source pollution in Hetao irrigation area.Precipitation,planting structure and livestock breeding are the main factors leading to non-point source pollution.4.Cluster analysis is used to optimize the monitoring points in Hetao irrigation area.After analysis,the number of soil sampling points in Hetao irrigation area is optimized from 24 to 10,the number of groundwater sampling points is optimized from 25 to 12,and the number of surface water sampling points is optimized from 36 to 19.The research results of this paper can provide some theoretical basis and technical support for the optimization of non-point source pollution monitoring points and pollution prevention and control in Hetao irrigation area.