Research On The Coupling Of SWAT And WASP Models Of Watershed Non-point Source Pollution And Water Environment Capacity

Yanghe River Basin is a typical river,which explores its non-point source pollution control problem,and proposes a water quality simulation of this type and estimating environmental capacity,development and application of exploratory modeling on this type of river.The decision has a key help.This paper uses SWAT and WASP model to couple non-point source pollution in Yanghe River Basin.The water environment capacity is calculated,and the specific research content and results are as follows:（1）Build a SWAT basic database,complete the non-point source pollutant simulation,parameter sensitivity analysis of the Yanghe Basin,and the model parameters are regulated.Through the verification of runoff runoff of the 24th basin,the periodic R² is 0.89,E_ns is 0.80,and the verification period R² is 0.96,and the verification period E_ns is 0.95.The model is proved to apply to the non-point source simulation of Yanghe River Basin.The simulation results show that the spatial distribution of pollutants in the study is similar.The sub-basin of the study area produces large pollution is No.4,No.16,No.17,and No.18.All of these sub-watershed are located at the exit of the basin,and the organic contaminants migrated by the Yanghe River are aggregated here,and they are also positively correlated with agricultural activities in these sub-basin.（2）The simulation results of the SWAT model are used as the boundary condition of the WASP model,and the entire basin pollutant distribution is calculated through WASP.Complete river isolation,hydrological boundary and model parameters,eventually divided into 27 river sections,using the No.13 river section NH3-N month mean,using NH3-N,2013 The average value verifies that the relative error of the final rate period and the verification period is 10%,8.19%,respectively.The model finally simulates the spatial distribution of the average monthly ammonia nitrogen,total phosphorus and total nitrogen in Yanghe River Basin.For polluting load space distribution,the river distribution of the three types of pollutants in Yanghe River Basin is consistent,of which the pollution of total phosphorus is relatively serious.（3）Through the coupling model,90%hydrological warranty ratio is completed,the calculation of water environment capacity of Yanghe River Basin is:the calculation results are:Yanghe Basin River section ammonia hydrogen environment capacity is882.52 t/a,total nitrogen water environment capacity is 2679.19 t/a,total phosphorus environment capacity is 352.42 t/a.