Hydrological Response Simulation Of Yunyan River Basin Based On Vegetation Restoration

Severe soil erosion in the Loess Plateau has always attracted attention.With the advancement of ecological projects such as returning farmland to forest and grassland,the vegetation in the area has been restored,which has changed the original underlying surface and climatic conditions in the region.The regional eco-hydrological process has had a profound impact.This paper takes the typical vegetation restoration watershed in the Loess Plateau region of the Yunyan River Basin as the research object.Based on the underlying surface of the basin and meteorological and hydrological data,the SWAT model is used to analyze the response characteristics of the hydrological process of the Yunyan River Basin to the ecological restoration of vegetation.It has certain theoretical and practical significance for the future ecological restoration of vegetation in the Yunyan River Basin.The main conclusions are as follows:(1)Using the land use data in 2000,2007,2013 and 2018,the trend of land use change in the watershed was analyzed,and the response of the ecological and hydrological process of the watershed to land use change was explored.Through simulation,it is found that as the land use type of the watershed changes,the evapotranspiration of the watershed first increases and then decreases,the soil moisture content first decreases,then increases,and then decreases,and the surface runoff decreases first and then increases.The reason for this trend is the change in the area of woodland and grassland.When the area of woodland and grassland increases,the evapotranspiration of the watershed will increase,the surface runoff will decrease,and the soil water content will also decrease.(2)By comparing the hydrological processes of various vegetation cover types and simulating the ecological hydrological response under extreme land use scenarios,it is concluded that the evapotranspiration capacity of forest land,grassland,and cultivated land decreases successively,and the surface runoff formed by cultivated land is larger than that of grassland.Forest land,and grassland has a greater capacity to hold water sources than cultivated land and woodland.(3)Analyzing the change trend of precipitation and temperature in the basin from 2000 to2017,it is found that the precipitation in the basin increased at a rate of 9.85mm/a,and the average temperature decreased at a rate of 0.13?/10 a.On this basis,the climate scenarios of the basin are assumed.Through simulation,it is found that under the set climate scenarios,the runoff of the basin increases,and the impact of precipitation changes on runoff is more significant.