Runoff Simulation Using SWAT Model In The Tai Ping Basin

Surface runoff simulation is a very important technique and link in many research fields,such as sediment yield,non-point source pollution,surface water balance and so on.Water is the carrier of sediment and pollutant transport.When precipitation removes the loss of surface runoff,sediment,pollutants and other substances flow into the river with water.When surface runoff happened,sediment,pollutants and other substances flew into the river with water.Therefore,the study of runoff is a key step in the study of sediment yield and non-point source pollution.This paper selected the upstream in Taiping River as the study area,with supported by ArcGIS,the surface runoff was simulated by Arc SWAT.First,using the DEM of study area as the basic in order to divide hydrological response unit of watershed;extracted of land use type map based on remote sensing Image by ENVI;through the operation of extracting soil parameters by using SPAW software,the soil database in the study area was established.According to the meteorological data in the study area,the weather generator was constructed,the database of weather was follow constructed.Using the dates from 2005-2009 to corrected the model,the dates from 2010-2015 were used to test and verify the model.The main contents and achievements of this paper are as follows:(1)Building spatial database.Using GIS,ENVI and other software.By cutting,reclassifying,etc.,the spatial data such as DEM,land use classification and soil map of the research area were obtained under the same basis of unified coordinate system.(2)Completion of the establishment of attribute database.Localization of SWAT model soil database through data searching,soil particle size conversion and other operations.Meanwhile,using the measured meteorological data of Dutou Hydrological Station in the research area,using Swat Weather.exe software to calculated the data which was the basic when weather generator was constructed.On the basis of this,the meteorological database of Taiping River was constructed too.(3)Calibration and validation of model parameters.Using the data from 2005-2010 in study area to calibrate the model,data from 2011-2015 to validate the model.Adjusted SCS model runoff curve,soil available water,saturated soil water conductivity,retention time of groundwater recharge,base flow decline coefficient,soil evaporation recharge coefficient,etc were calculated by SWAT_CUP.In multiple superposition calculations.(4)Constructing SWAT Model of Taiping River Basin.The daily runoff,monthly runoff,annual rainfall and annual runoff were simulated by SWAT model.Analyzing by Excel,the absolute values of the relative errors in the correction period and the verification period were less than 15,and the determination coefficients R2 were all great er than 0.85.The simulation efficiency coefficient Ens of Nash Sutcliffe was more than 0.70.The simulation effect of monthly runoff simulation was better than that of daily average runoff.The SWAT model has good applicability in Taiping River,.Besides,this model can be used in other watersheds like Taiping River,which are lack of measured data.(5)With the same meteorological,soil types and other features,the land use type from 2005 to 2015 was set as the land use scene,and the runoff simulation results of the watershed were analyzed.The results shown that the relationship between the sum of bare land area & building land area and the runoff of the study area was highly correlation.