Analysis Of Runoff Water Volume Regulation Of Rainwater Retention Facilities And Research On Its Implementation And Application

As one of the classic rainwater management measures under low-impact development(LID)measures,rainwater retention facilities are favored because of their better runoff regulation and pollutant removal effects.As the key structural layer of rainwater retention facilities,the filling layer plays an important role in the operation effect of the facility,and its different types of filling methods will directly affect the facility’s control ability.Through experiments and SWMM models,this thesis studies the regulation effect of bio-retention facilities on rainwater runoff,and conducts a preliminary feasibility study after the engineering of bio-retention facilities,hoping to provide a reference for the optimization of bio-retention technology and provide a reference for bio-retention facilities.Provide basis for application in actual engineering.The results of the study show that:(1)A material with a larger particle size and a single material has a higher penetration rate and better penetration performance.(2)Vermiculite has better performance than medium sand,zeolite and other fillers.When we set up the matrix layer packing of the rainwater retention facility,there should be no more packing types,and the selected packing size should be larger.It is recommended to choose vermiculite as the matrix layer packing.(3)When the other three fillers are added to the loam,the infiltration rate decreases with the increase of the loam content.The field water holding rate first increases with the increase of the loam content.When the maximum field water holding rate is reached,continue to increase the loam,and the field water holding rate will increase.The increase in loam content decreases.(4)The return period and rainfall are important rainfall characteristic factors that affect the runoff regulation effect of rainwater retention facilities.(5)Experimental No.6 rainwater retention pond {loam: vermiculite: zeolite(volume ratio)= 50%: 25%: 25%} has a better runoff control effect.(6)After adding vermiculite,medium sand,zeolite and other fillers to the loam,the runoff delay increased by 74.08% ～ 188.94%,the delay time increased to18.96min～31.47min;the peak delay increased by 71.70%～125.87%,and the delay time increased to 34.68min～45.62min;peak reduction rate increased by 170.96%～287.35%,reduction rate increased to 40.11%～57.34%;runoff reduction rate increased by 210.80%～375.73%%,reduction rate increased to 34.71%～53.13%.(7)The results of SWMM model calibration and verification have a certain degree of reliability.The model simulates the hydrological effects of three scenarios in the study area under different recurrence periods,namely,site simulation before development,site simulation of no rainwater retention facilities after development,and site simulation of rainwater retention facilities after development.The establishment of rainwater retention facilities in the research area after development has a good hydrological control effect.(8)The preliminary feasibility study and analysis of the combined rainwater reuse system after the rainwater retention facility project is scaled up shows that the project construction is very necessary and feasible.However,for a separately constructed rainwater retention facility project,the financial evaluation of the project cannot meet the requirements of the investment payback period and financial internal rate of return,but its indirect economic and social benefits are significant.