Study On Surface Runoff And Non-point Source Pollution In Haoping River Basin Based On SWMM

Water resources are an indispensable part of human life and survival.Having a good water environment is a necessary condition for our Chinese children and girls to have a good life.However,China is a country with a shortage of water resources,and its per capita water occupancy is far less than the world level.At the same time,with the development and utilization of nature,people even destroy it.The rivers,lakes and reservoirs in China have been affected and polluted to varying degrees.Protecting water environment and controlling pollution have become an urgent task.Therefore,each region should detect the water quality problems,reasonably analyze the non-point source pollution in each region,determine the impact of different factors on the regional pollution,and put forward the control strategy of the non-point source pollution,which has a great guiding role in practical application.In this paper,SWMM,Arc-GIS and AutoCAD software are used together to model the Haoping River Basin,simulate the change of runoff and the migration of pollutants under different rainfall intensities,and study the runoff,runoff quality,river water quality and the runoff depth under different rainfall recurrence periods in the sub-catchment area of the Haoping River Basin.The changes of degree and concentration of pollutants were studied.The main research results are as follows:(1)Rainfall intensity of eight recurrence periods in the Haoping River Basin was generated by combining the rainfall pattern generator with the rainstorm intensity formula of Ankang City,and the curve of rainfall intensity varying with time was drawn.The impermeability and permeability rate of underlying surface types in the Haoping River Basin were determined.(2)Runoff is related to many factors.Under the same conditions of rainstorm intensity,slope and area,the larger the impermeability,the worse the infiltration capacity,the larger the runoff generated;and when the slope is different and other conditions are the same,the larger the slope,the larger the runoff generated.(3)Through the study of the variation law of pollutant concentration,it is concluded thatwith the increase of rainfall intensity,the concentration of pollutants in surface runoff decreases and increases,and the concentration of pollutants in upstream river is higher than that in downstream river.(4)Through the trial algorithm,it is concluded that in the Haoping River Basin,the use intensity of chemical fertilizer is controlled within 220 kg/ha,all surface runoff meets the requirements of class III water body and will not pollute rivers;when the use intensity of chemical fertilizer is greater than 220 kg/ha,the water body near the outlet of cultivated land in the basin can not be guaranteed not to be polluted.By combining with relevant national policies,the feasibility of using chemical fertilizer index in Haoping River Basin was judged,and the control measures of non-point source pollution were put forward according to the actual situation of Haoping River Basin.