Hydrologic Simulation And Prediction Based On The SWAT Model

The global warming trend and the increasing human activities have had a profound impact on the terrestrial ecosystem,especially on the grassland ecosystem.The economic development and population growth pressure has led to the shortage of water resources in the watershed.This has intensified the trend of drought and desertification.Therefore,quantifying the effect of climate change and land use change on water resources,it has very important value to the local water resources management and the sustainable development of grassland ecological system and improving the regional environment quality.In this paper,we constructed a SWAT model in the Tabuhe watershed.The calibration and verification were conducted with the monthly average runoff from 2008 to 2016.It could be used to study the hydrological process of Tabuhe watershed.The main results were shown as follow:(1)We analyzed the sensitivity parameters : SCS runoff curve number,base flow alpha factor,aquifer recharge,delay time,into the main channel in the shallow aquifer groundwater level threshold,the groundwater evaporation coefficient,soil evaporation compensation coefficient,average air temperature and melting snow day factor.(2)The calibration and verification results of the SWAT model show that: in the calibration and verification period the relative errors of are-12.6% and 10.6%.The determination coefficient is 0.78,0.73,and Nash-Sutclife is 0.75 and 0.69.(3)We analyzed the trend of precipitation and temperature according to the meteorological data in Tabuhe basin.Temperature showed a trend of rapid increase with the rate of 0.42?/10 a.Precipitation showed that fluctuations of 50%.So we set 14 kinds of climate change scenario.The results show that the change of hydrological factors is positively correlated with rainfall.When the annual rainfall increased by 50%,the annual runoff in Tabuhe increased by a maximum of 97.3%.In addition,when the temperature increased by 2 and the rainfall decreased by 50%,the runoff decreased by a maximum of-90.2%.(4)Comparison of runoff changes under different land-use pattern,average annual runoff,sediment reduction of 10.2% and 9% respectively.Soil water content increased by 15.6%.And the change in evapotranspiration is very small.