Research On Hydrological Response Of Jinan Xinglong Area Based On Low Impact Development

With the development of urbanization brings change to underlying surface,the change makes impervious area have a huge surge.Then,it also resulted in urban rain island effect,increased urban water dissipation intensity,the distortion in hydrological process and increased the variation range of urban comprehensive runoff coefficient.Xinglong area belongs to xiaoqing river system xingji river basin xinglong river basin,it’s important part of south mountain region in Jinan.It’s located at Xinglong-Tuwu strong permeate area,it’s hydrogeological conditions are more complex and the ecological environment is very poor.In a word,it’s necessary to carry out low impact development in Xinglong area.The paper sets Xinglong area as study area,uses urban hydrological simulation software-SWMM to build stormwater module.And it sets 3 kinds of land use scenarios according to changes of underlying surface conditions,simulates hydrological response process in different return periods of 3 land use scenarios.Finally,we can get optimal development scheme of Xinglong area based on simulation result.The main conclusions are as follows:(1)According to the runoff simulation result,in the rate period,through simulating comprehensive runoff coefficient in 2-year return period,the absolute values of the coefficient of variation of comprehensive runoff coefficient are all in 5%.It shows that we get reasonable parameter settings through parameter calibration.Then we use rainfall event in 5-year return period validate calibrated module,the validation result is reasonable.So,the overall simulation effect of the model is credible.(2)The paper sets 3 kinds of land use scenarios according to the difference of underlying surface conditions,they are natural development mode,traditional urban development mode,low impact development mode.The main difference of 3 land use scenarios is pervious area,in order from big to small: natural development mode,low impact development mode,traditional urban development mode.(3)According to runoff hydrological process simulation result,we can get that: in terms of runoff volume,in order from big to small,traditional urban development mode,natural development mode,low impact development mode,their runoff curve are similar;in terms of infiltration capacity,in order from big to small,low impact development mode,naturaldevelopment mode,traditional urban development mode,their infiltration curve are similar;in terms of evaporation capacity,in order from big to small,traditional urban development mode,natural development mode,low impact development mode.(4)Water quality simulation in runoff of the paper is mainly focus on change of pollutant concentration before and after low impact development construction.According to the difference of underlying surface,we set conventional development mode and low impact development mode.The paper chooses chemical oxygen demand(COD),total nitrogen(TN)and total phosphorus(TP)as pollutant standards index to simulate water quality in runoff.Water quality simulation result shows that low impact development can improve the water quality in runoff.(5)Optimizing study low impact development technology based on SWMM,we have optimized parameter settings of module and got the optimal development scheme: the proportion of water permeable area controlled by low impact development in the whole research area,green roofs accounted for 7.93%,permeable pavement accounted for 23.78%,low elevation greenbelt accounted for 15.66%,stormwater wetlands accounted for 3.69%,bioretention ponds accounted for1.92%.In total,the scale of low-impact development facilities accounted for 52.98 percent of the research area.