Simulation On The Effect Of Runoff Reduction In Typical Sponge Campus

Under the intensification of global climate change and the rapid development of urbanization in China,the condition of natural underlying surface has changed drastically.And the standard of urban rainwater discharge system is low.So the urban flood disasters has frequently appeared.And a series of water problems are caused,such as water environmental pollution and water ecological degradation.In that situation,the“Sponge City”was put forward in China,which implemented in many places.A series of“Gray+Green”basic measures were advocated by the“Sponge City”to restore the original natural ecosystem,and allow rainwater to be stored in situ to alleviate frequent urban waterlogging disasters.After the occurrence of the sponge city,its construction effect has gradually become the focus of today's society.The evaluation of sponge measures on campus,community,town and other units has become the research focus and hotspot in the field of urban hydrology.This paper takes the new campus of Foshan University as the research region.On the basis of summarizing the domestic and international urban Stormwater Management Model,stormwater control on the urban and campus,the theoretical connotation of sponge campus and its role in the construction of sponge city were analyzed.Combined with tools such as AutoCAD and ArcGIS,the SWMM?Storm Water Management Model?of the study region in the construction period,traditional campus and sponge campus were generalized.Then the rainfall runoff datas were monitored and collected by WatchDog 2900ET small weather station and related methods to verify the uncertainty parameters in SWMM.The rainfall with different return periods-durations-rain peak coefficients in the region were designed to simulate the rainwater runoff response processes under the traditional campus and the sponge campus.The total volume,outflow peak,peak time of the typical outlet and the total discharge of the whole study region were selected as the evaluation factors.The effect of rainfall-flood-runoff reduction and control in the whole region and typical outlet O₆ were compared and analyzed.The main results are as follows.?1?Under different design rainfall boundaries,the total volume of discharge,total outflow and peak output of the sponge campus are significantly smaller than the response of traditional campus scenarios,and the effect of reduction is obvious.The sensitivity of the peak of the outflow to the rainfall event is higher than the total amount of the outflow and the total discharge.?2?Under the same duration and rain peak coefficient,with the increase of design rainfall return periods,the ability of sponge measures to reduce total runoff,total flow and peak output is gradually weakened.The ability of sponge measures to reduce and control runoff is more significant for medium-scale and small-scale rainfall events,and the stagnation effect of medium-sized rainfall events is more significant;?3?Under the same return period and rain peak coefficient,with the extension of design rainfall durations,the ability of sponge measures to reduce total runoff,total outflow and peak outflow is gradually weakened,and its ability to reduce runoff is shorter for short-duration rainfall events.Significantly,the lag peak effect of the mid-day rainfall event is more significant;?4?Under the same return period and duration,with the increase of rain peak coefficient of design rain,the ability of sponge measures to reduce the peak of outflow is weakened,but the ability to reduce the total amount of water and total runoff is basically unchanged.The ability to control runoff is more significant for the rain events in front of the rain peak,and the peak effect of the rain events centered at the peak time is more significant.Based on the above content,this paper is difficult to verify the stormwater runoff model in the study region without the measured pipe flow datas.Combined with the hydraulics and hydrological monitoring methods,the regional model is calibrated and verified,which has certain characteristics.For other cities without measured runoff data,it provides references for the construction of stormwater runoff model.On the basis of fully considering the different characteristics of rainfall in the study area,rainfall events with different scenarios and different factors were designed.The runoff response process at different scales on campus scale was compared and analyzed.The effect of the sponge campus was evaluated.The sponge transformation work provides the basis for decision-making and provides reference for the construction of a sponge-like campus.The decision-making basis for the next sponge renovation work in the study region and references for the construction of similar sponge campus were provide.