Simulation Of The Runoff And Sediment Response To Climate And Land Use Change Based On SWAT Model

Due to the influence of natural factors such as terrain and topography and human activities,soil erosion is the main ecological problem.Through the simulation of hydrological process,watershed hydrological process is forecast,and Simulation of the Runoff and Sediment Response to climate and land use change based on hydrological Model.Based on the research of the runoff and sediment yield,which is beneficial to the reasonable development and management of river basin water resources,to ensure the safety of the Three Gorges Project and even the Yangtze River Basin Ecological security.It is of great application value to realize the sustainable use of water and soil resources.This paper selects the Longxi River tributary of the Yangtze River basin.In this paper,the SWAT model is used to model the water sub module and the soil erosion sub module.Longxi River Basin DEM digital elevation map is input to the model,through the digital elevation map it can generated river network and sub basins,add reservoir,and calculate the parameters of sub basin.Then the SWAT model is used to reclassify and then overlay analyze the land use,the soil grid map and the slope of the watershed.Then,according to the results of superposition analysis,the watershed is divided into 342 hydrological response units.Meteorological data has a great influence on runoff and sediment,and the meteorological data in the basin are loaded into the SWAT model.The simulation is based on the input data to simulate the runoff and sediment.According to the simulation results,the parameters need to be adjusted.In this paper,SWATCUP is used to calibrate and validate the model.In this paper,three evaluation indexes are used to evaluate the applicability of the model.According to the results of calibration and verification,the average monthly measured values are 0.64 and the correlation coefficient was up to 0.71 Nash-Suttcliffe in 2003-2008.In 2009-2014,the simulated and measured values of Nash-Suttcliffe were 0.74,and the correlation coefficient was up to 0.79.In 2003-2008,the average monthly sediment load was 0.75,the correlation coefficient was Nash-Suttcliffe,and the correlation coefficient was up to 0.83.In 2009-2014,the simulation value and the measured value of Nash-Suttcliffe was 0.71 and the correlation coefficient was up to 0.83.From the results of the evaluation index,the model is applicable to the study of Longxi River basin.Climate change and land use planning change is objective existence,by setting 25 kinds of climate change,by using 25 kinds of meteorological environment changes,the article simulate of runoff and sediment,and then analyze and conclude that the influence of precipitation on runoff and sediment yield are positively correlated and sensitive,and the influence of temperature on runoff with the amount of sediment is negative and weak.The influence of land use change on runoff and sediment is another important part of hydrological simulation.In recent years,by reason of the serious soil erosion,Chongqing has also implemented the plan of returning farmland to forest and grassland.From the analysis of the change of time,on the basis of land use spatial data in 2000,2005,2010 on the runoff and sediment simulation,simulation results show that in land use,the more the farmland is,the larger the amount of runoff and sediment is.When there is more woodland and less farmland,the amount of runoff and sediment is relatively small.It indicates that the land use planning is beneficial to conserve water and soil conservation.On the spatial variation,based on the land use spatial data in 2005,according to the plan of returning farmland to forest and grassland in different slope,three kinds of land use were set up.According to the three kinds of land use,the hydrological data in the basin are simulated and the simulation results are obtained.The effects of different slope on the runoff and sediment were different.The practical implementation of the policy of returning farmland to forest and grassland in the future is of practical significance.