The Hydrological Process Simulation Of Kushui River Basin Based On The SWAT Model

Hydrological model is a helpful tool,which can be used to quantitatively and scientifically analyze hydrological factor.Considering the spatial distribution of underlying surface,the distributed hydrological model become very popular in the development of hydrological model.SWAT(Soil and Water Assessment Tool),a Semi-distributed hydrological model associated with GIS technology,has been applied to simulate the hydrological process,improving the calculation efficiency and making the simulation result visual.Based on Digital elevation model,landuse,soil data,climate and hydrological data of Kushui river basin,the SWAT model was been constructed with ArcSWAT2012 module set in the software ArcGIS10.2.After parameter sensitivity analysis,calibration and verification,four landuse scenarios was been designed to analyze the change of runoff,evaporation and soil infiltration under the four landuse scenarios separately.The main conclusion presented as follow:(1)On the basis of DEM of,Kushui river basin was been divided as 16 sub-basins by using the ArcSWAT2012.Landuse,soil map and slope were overlaid,as s result that 371 HRU was produced.(2)By using SWAT-CUP,the model parameter sensitivity,calibration and verification were completed according the monthly runoff data of Guojiaqiao hydrological station.The result showed that groundwater delay time,base flow coefficient,SCS runoff curve number,soil saturated infiltration coefficient,base flow factor were high in sensitivity analysis;over the period of calibration(2000-2008),Nash-Suttcliffe efficiency coefficients the model was 0.756,and the coefficient of determination was 0.609 and 0.735;In the verification stage from(2009-2016),the Nash-Suttcliffe efficiency coefficients was 0.709 with coefficients of determination being 0.766.By counting and analyzing the simulated hydrological eigenvalues of kushuiriver basin,the result showed that runoff,evaporation and soil water infiltration were sensitive to the precipitation that they developed consistently with the precipitation;the simulation result can reflect the practical hydrological situation of kushui river basin,making the simulated hydrological eigenvalues useful in research on the hydrological cycling process of kushui river basin.(3)To explore the landuse variation effect on the hydrologic features of kushui river basin,the another two landuse data were input into the model with landuse type matrix instructed,the main landuse that made big difference on the hydrologic features of the basin was found initially,the result showed that by the forest area increasing,annual average runoff,evaporation were decreasing and soil infiltration was accelerating.To accurtely confirm the effect of landuse and cliamte change on hydrologoc features of kushui river basin,35 climate scenarios and 4 landuse scenarios were designed to explore the evolution process of annual runoff evapotranspiration and annual soil infiltration.The simulation results under landuse scenarios showed that the trend of every hydrology factor under 4 landuse scenarios is same.When the arable land changed into woodland,the change rate of runoff and soil infiltration were higher than that in other landuse scenarios;When the arable land changed into grassland,the evapotranspiration was accelerated.When the bare land changed into woodland and grassland,the runoff and evapotranspiration reduced with soil infiltration increasing and the effect of changing bare land into woodland was better than changing into grassland,revealing that forest planting can be the best choice to restore the bare land.With the precipitation and temperature variation representing the climate changing factor,the climate change scenarios were designed for the SWAT model.The simulation results showed that runoff and soil infiltration changes were positively correlated with precipitation change.Temperature changes were negatively correlated with Runoff and soil infiltration changes and positively correlated with evapotranspiration.The research also showed that precipitation is determinant to evapotranspiration with temperature being driving factor.