Response Of Eco-hydrology Evolution To Changing Environment In Grassland Watershed Of Plateau Inland River

The interactive relationships between hydrological and meteorological elements and the environment are dynamic,as evidenced by the fact that changes in temperature,precipitation,and runoff usually drive the evolution of ecosystems.Investigations on the changing properties of temperature and precipitation and fluctuations in river runoff are of great importance in view of the significant impacts of climate variations and human activities on the hydrological cycle and ecological environment.Studing Xilin River Basin and balaguer River Basin located in the same climatic zone as the research objects,this paper uses climate tendency method,Mann-Kendall test method,Kriging difference method,correlation analysis method and normalized difference vegetation index etc.in order to systematically study the differences between human activities,meteorological and hydrological factors and ecological environment evolution in the two places.Artificial precipitation is used to simulate and study the runoff yield and concentration characteristics of the plateau inland river grassland basin and the influence of changing environment on the surface runoff coefficient.SWAT model is applied to simulate runoff and analyze the attribution of runoff changes in Xilin and balaguer river basins,aiming at providing basic basis for ecological environment protection and ecological hydrological change analysis,and having certain practical significance for understanding and understanding the evolution law of ecological environment in river basins under the change of hydrological and meteorological factors.The results show that:1.From the late 1980s to the first 10 years of the 21st century,the temperature in the study area increased significantly,precipitation and runoff decreased sharply,population and GDP increased,NDVI index decreased,resulting in deterioration of ecological environment and worsening of meteorological drought.2.The distribution of soil types in the upper reaches of the balaguer River Basin is mainly sandy loam and loamy sandy soil.The grass weight decreases from south to north and from east to west.The grass root weight is mainly distributed in 200-300g areas.3.Runoff coefficient is greatly influenced by rainfall intensity.The change rate of runoff coefficient caused by changing environment before mutation is 23.58%,that caused by changing environment after mutation is 53.07%,(?)and that caused by changing environment after mutation is 2.25 times of that before mutation.4.The sensitivity levels of runoff curve and soil evaporation compensation coefficient in the upper reaches of Xilin River Basin and balaguer River Basin are very high,and Ens and R2 are relatively high,which all meet the SWAT simulation accuracy requirements.5.Runoff changes in the upper reaches of Xilin River Basin and the upper reaches of balaguer River Basin are mainly affected by climate change,with contribution rates of about 77%and 80%,respectively,while human activities have less impact,with contribution rates of about 23%and 20%,respectively.