| Climate change and human activities(mainly considering the change of Land Use/Land Cover Change)have become important factors affecting the hydrological and water resources evolution in the Tao’er River Basin.Due to its location on the Northern edge of the East Asian monsoon climate zone,combined with the mountain effect,the hydrological and meteorological processes in the basin are complex.Sexuality,uneven spatial and temporal distribution of rainfall,and the social factors of rapid agricultural development in recent years have made water shortages,droughts and floods frequently become a serious challenge for the basin.The Tao’er River Basin has become one of the more prominent areas of water use in the Nenjiang River Basin.With the implementation of the national food security strategy,the demand for water resources in the future will further increase.Based on the above situation,the SWAT model is applied to the hydrological simulation of the Tao’er River Basin,and the impacts of land use change and climate scenarios on the hydrology and water resources of the basin are analyzed,which has important reference significance for the development,utilization and management of water resources in the basin.This paper mainly carried out the following research work:(1)Hydrological model construction and parameter determination of the Tao’er River Basin.The SWAT model spatial database is constructed based on the natural geospatial spatial data of the Tao’er River Basin,and the sub-basin and hydrological response unit(HRU)of the Tao’er River Basin is completed.The Tao’er River Basin is divided into 25 sub-basins and 268 HRUs;For the SWAT model 22 main parameters were used for sensitivity analysis,and the most sensitive first 11parameters were selected as key parameters.On this basis,the SUFI-2 algorithm was used to optimize the key model parameters to the Tao’er River Basin,based on the historical measured daily runoff process of the stations(Heidimiao,Chaersen,and Wuchagou),the simulation accuracy of the runoff process in the Tao’er River Basin was evaluated.The results show that the goodness of fit R~2 of Heidimiao,Chaersen and Wuchagou Stations are 0.88,0.87 and 0.84,respectively,and the simulation effect is better.It is concluded that the SWAT model has good applicability in the study area.(2)Analysis of the impact of land types on the hydrology and water resources of the Tao’er River.The main land use types in the Tao’er River Basin were determined,and the trends of various land use types in different periods were analyzed.The land use types in different periods were used to simulate the runoff process of three hydrological stations in the basin.The changes of runoff processes in the upstream,middle and downstream of the basin in 1995,2005 and 2015;The six types of extreme land use in the basin were assumed,and the effects of different land use types on the hydrological processes of the basin were analyzed and compared.The total amount of surface water resources at different frequencies in the basin under the land use change scenario shows that the amount of surface water resources in Tao’er River Basin varies with different land use types.(3)Analysis of climate characteristics and hydrologic and water resource response of the Tao’er River Basin under climate scenarios.The future(2020-2050)precipitation and temperature distribution characteristics of RCP4.5 and RCP8.5 are analyzed.The results show that the annual variation of annual precipitation in the basin under the two scenarios of RCP4.5 and RCP8.5 shows an overall downward trend;the interannual variation of temperature in both scenarios shows an overall upward trend.Under the RCP4.5 scenario,the year’s average temperature rise is1.58°C compared with the baseline period.Under the RCP8.5 scenario,the average temperature rise is more significant,and the temperature increase is 2°C.The future runoff of Wuchagou station in the upstream and Chaersen station in the middle reaches shows a decreasing trend under the RCP4.5 and RCP8.5 scenarios.According to the future trend of precipitation and temperature to assume the climate scenario model,the future runoff of the three hydrological stations in the Tao’er River Basin is decreasing.The average annual measured runoff of the basin export hydrological control station(Heidimiao)was 1.697 billion m~3.Under the RCP4.5 scenario,the average annual runoff of Heidimiao was 1.709 billion m~3,which is 0.12 billion m~3larger than the measured annual runoff.Under the RCP8.5 scenario,the average annual runoff was 1.72 billion m~3,which is 0.23 billion m~3 larger than the measured annual runoff.Under the assumed climate scenario,the average annual runoff is 1.454billion m~3,which is 2.43 billion m~3 less than the measured annual runoff. |
