| Water shortage has become the main factor restricting the sustainable development of economy and society.SWAT software of distributed hydrological model was selected.The research area was Yanqi Basin in arid northwest Xinjiang,SWAT model for Yanqi Basin was established by collecting DEM digital elevation map,land use data,soil data and meteorological data from 1961 to 2007.The specific steps were as follows: firstly,the spatial transformation of soil and meteorological data was carried out in Yanqi basin;secondly,the SWAT model was established in the basin and its applicability in Yanqi basin was studied;and then,the sensitivity of SWAT model parameters was analyzed;finally,the hydrological changes of wetlands in Yanqi basin were analyzed.The main conclusions of this study were as follows:(1)The annual temperature in Yanqi Basin presented a significant upward trend,the average relative humidity presented a weak upward trend,the sunshine hours decreased significantly,and the wind speed presented a significant downward trend before 1990,and then an upward trend;the annual variation trend of evapotranspiration in Yanqi Basin was bounded by 1989,and the annual variation trend of evapotranspiration in Yanqi Basin decreased significantly between 1961 and 1989 at a rate of 15.22 mm/a,and showed a significant downward trend.The trend of decrease was contrary to that of increase in temperature,but increased significantly after 1989 at a rate of 15.09mm/a.The overall trend of evapotranspiration was consistent with that of wind speed.(2)Based on DEM map,land use map,soil type map and meteorological data of hydrological stations in Yanqi basin,SWAT model of Yanqi basin was constructed.The annual and monthly runoff processes were simulated by using the runoff data in the study area.The results showed that the simulated annual and monthly runoff values of the model were larger than the measured values.The determination coefficients were between 0.64-0.92,the relative errors were between 9.67% and 13.56%,and the Nash coefficients were between 0.70-0.85.The fitting effect was very good.Therefore,SWAT model could simulate the annual and monthly runoff process of Yanqi Basin well and was suitable for the study of Yanqi Basin.(3)The water level of Bosten Lake showed a significant downward-upward-downward trend during 1959-2015.The area of Bosten Lake showed a decreasing-increasing-decreasing trend during 1958-2015.(4)For annual runoff forecasting,after 2050,the trend of runoff forecasting under the two climate scenarios is basically similar,and the range of fluctuation rising and falling was the same.In the other years,the trend of runoff forecasting under the two future climate scenarios was different.For monthly runoff forecasting,the monthly mean runoff trend under the two climatic scenarios was basically the same,in other words,the runoff in spring and summer increased first and then decreased with time,decreased at any time in autumn,and basically remains unchanged in winter.There was a difference that in RCP 8.5 scenario,the maximum runoff in spring and summer occurred at 2050 s.In RCP 4.5 scenario,the maximum runoff in spring occurs at 2080 s,runoff in summer was at 2020 s.(5)In the next two climate models,the water level showed a slight upward trend from 2020 to 2100,and the water level under RCP 8.5 scenario fallen more than that under RCP 4.5 scenario.RCP 8.5 scenario reached the lowest water level in 2040 and 2090,which was 0.08% lower than the current year;RCP 4.5 scenario reached the lowest water level in 2084,which was 0.09% lower than the current year. |
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