Analysis And Utilization Of Rain And Flood Resources In Shu River Basin At Rizhao City

As the largest transit river at Rizhao City,Shu River is a important water supply source,the remaining rain flood water of it is insufficent and the exporting water is so huge,caused the shortage of water source of Rizhao City.Therefore,understanding the process of runoff and rain flood resources of Shu River at Rizhao City comprehensively,increase the volume of impound floodwater,Optimize the utilization of rainwater resources in Shu River basin at Rizhao City can give rise to positive effect on reducing water stress and promoting rational allocation of water resources in Rizhao City.Taking Shu River Basin at Rizhao City as a study area,this paper using ArcGIS as the platform and using ArcSWAT as a tool to simulate the runoff,then verify the applicability of the SWAT model in the study area.Combining the validated model to analyze and calculate the rainfall and flood resources in the study area,and based on this,analyze the simplification of river base flow calculation.Finally,the SCS-CN model combined with ArcGIS was used to study the facilities layout scheme for intercepting rainwater floods in the study area,and proposed a reasonable and feasible measure to effectively increase the rainfall and flood storage capacity.The main conclusions are as follows:(1)Using ArcGIS as the platform and using ArcSWAT as a tool to simulate the runoff,the study is eventually divided into 67 subbasins and 240 hydrological response units(HRU).Using the traffic data of Qingfengling Station and Juxian Station from 2011 to 2016,the model parameters of the monthly scale are determined and verified.The correlation coefficient(R~2)of rate period and verification period are0.86 and 0.88,and the Nash-Sutcliffe efficiency coefficient(Ens)are 0.87 and 0.89,respectively in Qingfengling Station.The R~2 of rate period and verification period are0.87 and 0.89,and the Ens are 0.86 and 0.86,respectively in Juxian Station.Judging from the applicability evaluation criteria of the model,the SWAT runoff model can accurately reflect the monthly runoff process in the study area.(2)The SWAT model with good utilization rate is used for the runoff simulation of the flood year,the normal flow year,the drought year,and the special drought year.According to the simulation results,the surface water resources formed by the rainfall Shu River Basin at Rizhao City are calculated.The simulation and calculation results show that:1)the average surface runoff of the Weihe River Basin in Rizhao is 435.99million m~3,and the annual runoff of the flood year,normal flow year,drought year and special drought year is 583.85 million m~3,444.32 million m~3,351.44 million m~3,and 246.39 million m~3,respectively.The annual average rainfall infiltration recharge is 211.33 million m~3;the average annual river base flow is 82.83 million m~3,and the average annual surface water resources is 518.82 million m~3,The total amount of surface water resources in the flood year,normal flow year,drought year and special drought year is 694.78 million m~3,524.74 million m~3,411.31 million m~3,and 282.22million m~3,respectively.2)The average annual available water resources of the basin is 328.68 million m~3,and the annual surface water availability of the flood year,normal flow year,drought year and special drought year is 450.9 million m~3,334.01million m3,231.92 million m~3,and 115.74 million m~3,respectively;the groundwater resources can be extracted 147.97 million m~3;3)At present,the potential for development and utilization of groundwater in Shu River Basin at Rizhao City is63.70 million m~3;the potential for development and utilization of surface water resources is 231.93 million m~3,and the potential for development and utilization of surface water resources in the flood year,normal flow year,drought year and special drought year are respectively 354.24 million m~3,237.26 million m~3,135.17 million m3,and 18.99 million m~3.(3)Based on the calculation of the river base flow in the control section of the Jixian station based on the SWAT model,the applicability and filter coefficient of the Hyne-Hollick filter method in Shu River Basin is verified,and its daily,weekly and monthly runoff sequences are determined.The results show that the Lyne-Hollick digital filtering method can be applied to the baseflow separation of the daily runoff series,weekly runoff series and monthly runoff seriesin in Shu River basin,and when the method is applied in daily runoff series,the filtering times is 3,and filtering parameter is 0.925,when the method is applied in weekly runoff series,the filtering times is 3,and filtering parameter is 0.76;when the method is applied in monthly runoff series,the filtering times is 2,and filtering parameter is 0.71.And when the Lyne-Hollick digital filtering method is uesd in baseflow separation,the separation result is more approximate with daily baseflow separation result in normal flow year and drought year than it in flood year.(4)This paper uses the SCS-CN model combined with ArcGIS to analyze the runoff potential of the study area,and lists the constraint set according to the requirements of each rain collection measure,including water storage pits,residential rainwater collection areas,large wells,and dams.The spatial layout of the five measures of the reservoir is determined and the increased rainfall can be calculated at different rainfall frequencies.It is calculated that the rainfall can be increased at 25%,50%,75%,95%rainfall frequency,they are 40.36 million m~3,33.23 million m~3,27.31million m~3,and 21.00 million m~3 respectively.