Assessment Of Future Water Resources In The Naoli River Basin Based On Surface-subsurface Simulation

The growth of population and the development of economy in China make the problem of water shortage more prominent,threatening the safety of the ecological environment.Therefore,the rational allocation of water resources has become become an urgent need for the development and planning of water conservancy in China.Sanjiang Plain is a national grain base and an important distribution area of wetland in China.However,the contradiction between water supply and demand has been increasingly intensified in recent years.Understanding the evolution characteristics of regional water resources in the future is very important to ensure the agriculture and wetland water.Therefore,a case study of Naoli River Basin in Sanjiang Plain is analysed,where the mismatch between supply and demand for water is greatest.Surface water model and groundwater model were used to simulate the hydrological process of the basin,to scientifically understand the law and mechanism of water cycle evolution in changing environment.Moreover,the applicability of climate models was evaluated,and the climate changes under different future scenarios were predicted based on the correction of climate models,so as to predict the future water resources in the basin.The main conclusions are as follows:(1)In order to simulate the water cycle in the basin,the VIC distributed hydrological model is applied to the Naoli River Basin,and the model parameters are calibrated by the random autostart simplex method,the simulation results are evaluated on the mo nthly scale with the Nash coefficient and coefficient of determination,the results show that the VIC model can well reflect the month of flexure river basin runoff process.Visual Modflow software was used to build a groundwater model in the plain area of Naolihe River Basin.The water level of the observed wells calculated by the identified model was the same as the actual water level trend,indicating that the model was set reasonably and could be applied to hydrological prediction of Naolihe River Basin under future climate change.(2)To evaluate the applicability of climate models,the ability of the nine climate models of CMIP6 to simulate the spatiotemporal precipitation during the historical operation was evaluated.The results of the comprehensive evaluation of nine climate models show that the three climate models that are better simulated in Songliao basin are Can ESM5,GISS-E2-1-G and GISS-E2-1-H.Different climate models have different simulation capabilities in different indicators.(3)Based on the CANESM5 climate model and ISI-MIP correction method,the precipitation,maximum and minimum temperature in the Naolihe River Basin under three future scenarios are predicted,and the future runoff and groundwater level in the study area are predicted by VIC model and groundwater model.The results showed that the correction of the climate models improved the accuracy of the data,and the precipitation in the future flood season will increase under the three scenarios,and the annual temperature increased.In addition,the annual average runoff decreases to different degrees.Compared with the baseline period,the average runoff of Kaizuzi Station in 2021-2050 decreases by 107 million m~3 under SSP1-2.6 scenarios,by 59 million m~3 under SSP2-4.5 scenarios,and by 42 million m~3 under SSP5-8.5 scenarios.The annual spring flood runoff decreases.Under the current exploitation condition,the groundwater level also shows a decreasing trend.