Hydrology And Water Environment Research Based On Climate Change And Human Activity Scenarios In Kaidu River

Inland rivers and lakes in arid and semi-arid regions are important water resources for maintaining local production and ecological balance of the watershed.Under the combined effect of climate change and human activities,inland river basin ecosystems and water resources based on ice and snow melt water supply will become more vulnerable and sensitive.With the increase of population and human production levels in arid and semi-arid regions,the oasis area continues to expand,water consumption continues to increase,and a large amount of pollutants are discharged into the surface water system,resulting in tight water supply and deterioration of the water environment,which has severely restricted the sustainable development of the arid and semi-arid regions of China.Accurately analyze the impact mechanism of climate change and human activity scenarios on hydrological processes and water environment changes,quantitatively analyze the impact of different scenarios on hydrology and water quality,are having important significance for the sustainable use and effective management of water resources in arid and semi-arid regions.Aiming at the challenges in the study of hydrological processes and water quality change prediction in arid and semi-arid regions,this study takes the Kaidu River Basin as the research object,and the future meteorological data of dynamic downscaling(RegCM4,HadGEM3-RA and SUN-MM5)and statistical downscaling(GCMS aggregate averaging)were extracted and coupled with the constructed SWAT model.Then the future changes in water resources were predicted in the Kaidu River Basin.Next,the point source and non-point source pollution database of the downstream irrigation area were established,and the numerical simulation of the water environment in the downstream irrigation area of the basin was carried out.Then,based on the upstream predicted water resources changes and the future development of agricultural production,six different climate change and human activity scenarios were set up to simulate the future hydrological and water environment trends in the downstream irrigation districts.Finally,the causes of water environment change in Kaidu River irrigation area under different situations are analyzed,and corresponding treatment measures are proposed accordingly.This study mainly draws the following conclusions:(1)By the middle of this century,the temperature in the Kaidu River Basin will be 1.1 to 2.4? higher than the annual average temperature from 1990 to 1999,and the precipitation will increase by 13.6 to 38.4%.With the increase of temperature and the increase of evapotranspiration,the water supply in the Kaidu River Basin is likely to decrease by 2.1 to 22.3%.(2)The loss of non-point source pollutants in Kaidu irrigation area has strong spatial heterogeneity.The loss of fertilizer is an important source of pollutants such as nitrogen and phosphorus in the lake.From 2010 to 2014,the average amount of water,TN and TP entering the Bosten lake through the farmland drainage channel are 4.21×10~8 m~3,773.74 t and 15.49 t,accounting for 15.71%,24.81%and 61.98%of the total amount of the lake,respectively.(3)The simulation results of water environment in different climate scenarios show that the emission of non-point source pollutants is closely related to the change of precipitation.For example,in the case of a 10%reduction in runoff in the Kaidu River and a 20%increase in precipitation,the emissions of TN and TP will increase by 9.56%and 35.65%,respectively.In the scenario of adjustment of agricultural production mode,20%reduction in fertilization and 17%improvement in irrigation efficiency can reduce TN and TP by 14.49%and 16.03%,and increase farmland drainage by 4.77%.The results of the scenario simulation show that under the dual effects of climate change and human activities,the future water supply in the Kaidu River irrigation area will decrease,and the discharge of non-point source pollutants will increase.However,by improving agricultural production methods,the water environment in the irrigation area can still be effectively controlled.