| Due to its specific geographical location and climatic conditions,the Huaihe River Basin has caused droughts and floods frequently.In order to reduce disasters,it is necessary to imply effective actions to manage it.Besides,it is also necessary to establish accurate runoff simulation model to prevent and cope with possible disadvantageous conditions may occur in time.Climate change affects the intensity of water circulation and the increasing uncertainty of future hydrological conditions directly,and affects regional social progress and economic development.Therefore,Researching of the runoff response under climate change is of great significance to understand the change law of drought and flood mechanisms,and to designate regional climate change adaptation strategies.In this research,taken the catchment area in the upper of Wujiadu station as the research area,and used statistical analysis,hydrological simulation,climate simulation and water resources utilization analysis methods to analyze the evolution trend and regular characteristics of hydrological elements in this area,and established hydrological models and predicted water resources in future.Runoff changes climate scenarios and analysis of water utilization in Bengbu City in future.The main conclusions are showed as below:(1)Based on historical observation data from 1979 to 2013,the interannual variation trend of precipitation,temperature and runoff,and the distribution characteristics and periodicity of precipitation,temperature and runoff are researched by non-parametric MK(Mann-Kendall)test and Morlet wavelet transform.The research concluded that the annual precipitation in the research area showed an insignificant decrease trend,and the sudden change points appeared in 2009.The annual maximum and minimum temperatures showed a notable increasing trend,with mutations respectively in 1990 and 1987.The annual runoff showed a non-significant reducing trend,and the runoff was unevenly distributed during the year,especially from July to August,which as the main flood season of the Huaihe River,while in winter and spring,the runoff increased sharply,drought was prone to occur,which may bring some pressure to flood-relief.Runoff and precipitation both show a decreasing trend,and there is a common cycle of 11a.(2)Based on the ArcGIS software platform,the SWAT model was established based on the spatial and attribute databases of terrain,soil,and water system.The SWAT-CUP software was used to calibrate and validate the model,which made the model suitable for runoff simulation in the survey area.The research results showed that the model had the best simulation effect when the sub-basin was divided into number 43.The rate of the Nash efficiency coefficient,the determination coefficient and the percentage deviation were 0.79,0.79 and 1.1%,and the verification periods are 0.72,0.72 and 6.4%,respectively.The model's simulation effect wss evaluated as "very good",and the model had higher runoff simulation accuracy in the area.(3)Based on the CMIP5 model,the climate model which has great ability of simulation in the research area was screened by Taylor graph method.The research showed that the 5-model combination average was better than the single mode significantly.The multi-mode set average can improve the simulation ability of the model significantly,and reduce the influence of the uncertainty of the single mode on the simulation results;the future runoff showed the decreasing trend which compared with the baseline period.RCP4.5 and RCP8.5 of the runoff reductions in the two scenarios respectively decreased to 24.26%and 33.35%,indicating a higher probability of drought in the future research area.(4)Analyzed the supply and demand of water resources in Bengbu City,based on the results of future runoff prediction.Grey correlation analysis was used to screen the main influencing factors of water demand.BP neural network was used to predict water demand.At the same time,the accuracy of water demand prediction is verified by quota method and multiple regression method.The future water resource availability can be calculated according to the runoff frequency curve.The supply and demand of water resources in Bengbu were analyzed and the benefits were put forward.The research concluded that the water shortage in 2022 is larger in the RCP4.5 scenario,and the water shortage in 2025 is smaller,while the water shortage in 2027 is greater in the RCP8.5 scenario,and the water shortage in 2022 is smaller.Different water supply and demand shows differences,which indicates that the climate change has a major impact on water resources change in different scenarios.Aiming at water shortage periods,it can be alleviated by enabling Tianhe emergency water source and appropriate over-exploitation groundwater.Meanwhile,by means of "South-to-North Water Transfer" and "Leading Water from Yangtze to Huaihe River",the external water transfer of the project can also alleviate the shortage of water resources. |
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