Study On Runoff Regulation Effect And Application Of A Measure Composed Of Seepage Well And Permeable Grid

Under the background of the continuous advancement of the sponge city concept,the construction of low impact development(LID)measures has increasingly become an inevitable choice for many cities to sponge.The permeable grid is considered to be a LID measure with good rainwater control effect,which is widely used in the ground treatment of residential areas,squares and parking lots.However,in general,in order to ensure the overall bearing capacity of permeable grid measures,the structural layer is mostly the soil with poor permeability or the lower part of the brick body is hardened with cement,which makes it difficult to effectively exert the benefits of runoff regulation and seepage.Therefore,it is necessary to design a new type of LID measure on the structure of the original permeable grid measure,which has extremely important value for improving the ability of regional rainwater retention,reducing surface runoff,and promoting the perfect development of the low impact development system in sponge cities.Based on the above situation,this paper designs a measure composed of seepage well and permeable grid.Through the combination of laboratory experiments and model simulations,the superiority of this measure at the unit scale compared with the permeable grid at the unit scale in the effect of runoff regulation was verified.At the same time,the effect of rainwater control on campus areas after large-scale planning of this measure was studied.The main research process of this paper is as follows:(1)This paper constructs the measure composed of seepage well and permeable grid on the unit scale,carries out the rainfall-runoff-infiltration experiments for the two measures under two rainfall conditions,and preliminarily determines the quantitative improvement effect of the new type of LID measure compared with permeable grid measure in terms of runoff regulation index,providing reliable data support for model prediction.(2)The SWMM model of two kinds of unit scale measures was constructed,and the parameter calibration and accuracy were verified by referring to the experimental data.At the same time,the sensitivity of model parameters was analyzed,and 72 rainfall conditions were designed under different combinations of reappearing period,duration and rainfall peak coefficient in Shijiazhuang area.The effects of the two measures on runoff regulation under different rainfall conditions were analyzed.(3)Combined with the information of campus geography,hydrology and drainage network,the SWMM model of campus area before and after the construction of the measure composed of seepage well and permeable grid is constructed.The surface hydrology,inflow of outlet and drainage network hydrological conditions in different rainfall conditions are compared and analyzed,and the construction effect of LID measures in campus area is evaluated.