Study On The Regulation Of Stormwater Runoff In Sponge Reconstructed Community Based On SWMM

Rapid urbanization is accompanied by a series of water and environmental issues.At present,the construction of sponge cities is being accelerated in various cities.New residential quarters must be constructed according to the sponge city concept,and old communities must also be reconstructed in strict accordance with the sponge body.It is often difficult to reconstruct old communities that have already been built,and scientific and effective guidance methods are lacking.In this dissertation,a sponge reconstruction demonstration project located in a building district in Tongzhou,Beijing was selected as the research object.The SWMM rainwater management model was used to calibrate and verify model parameters based on the measured data of rainfall runoff.Through outdoor rainwater quality monitoring experiments and indoor model simulation methods,making full use of the full path before rainwater flows out of the community,a multi-level regulation system for rainwater runoff in a sponge reconstruction community is constructed.The governing equations of LID facilities based on the water balance equation and the continuity equation were explored;the problems existing in the sponge reconstruction district and the regulation effect of the sponge transformation scheme were analyzed;the simulation effect of the storm water runoff regulation before and after sponge transformation was analyzed based on the model;The effects of LID facility parameters and pipeline parameters on rainwater regulation capacity under different rainfall scenarios are explored.The effects of multi-level regulation on conserving groundwater,restoring the hydrological cycle before urban development,urban waterlogging,and achieving the goal of rainwater utilization are explored with a view to transforming sponges in building communities,we will choose scientific and effective control measures to provide technical solution support and theoretical basis.a)Based on the water balance equation and the continuity equation,the relationship between the changes in the amount of rainwater in the LID facility is analyzed.The LID type can be simulated by adjusting the parameters of the relevant layers,and the control capability can also be adjusted through the relevant parameters.This provides the possibility of adjusting relevant LID facility parameters for rainwater regulation in engineering practice.b)Using outdoor indoor synchronous monitoring experiment and model simulation method,calibrate the model according to the monitoring data.The hydraulic parameter rate determined the Nash efficiency coefficient to be 0.89,and the simulated values of the water quality parameters and the monitored values fit well,indicating that the simulation results of the model are objective and credible.c)Analyze and simulate the hydraulic and water quality effects of rainwater before and after the sponge reconstruction of the plot under different reproduction periods.The sponge LID facility has a good control effect,which significantly increased the overall rainfall infiltration in the residential area by 6.96-12.66 mm,the runoff decreased by 7.43-13.15 mm,and the total annual runoff control rate can reach 41.51% ~ 57.40%.The reduction rates of pollutants are all above 25%,indicating that the research area has a significant effect on sponge reconstruction and has a good effect of peak reduction and flow reduction,which can effectively purify rainwater and restore the hydrological cycle before urban development.d)The simulation results of the rainwater runoff multi-level regulation system in the sponge reconstruction area show that the improvement of the surface roughness of the LID facility by the regulation of the first-level LID measures can increase its interception and purification of rainwater,and increasing the thickness of the soil layer can play a role in retaining and purifying rainwater in the soil layer.The capacity and thickness of the aquifer have no significant effect on the overall system;the secondary regulation of the size of the rainwater pipeline is most effective.When the width or maximum depth of the drainage ditch is increased by 60%,it can ensure that the plot has no accumulation under the rainfall recurrence period of 10 years.Water phenomenon occurs;the regulation of the third-stage end cistern is only related to the storage volume of the cistern,and has little effect on the number and location of the cistern.At the same time,the regulation of the cistern volume can achieve heavy rainfall every three years There is no standing water in the current period,and the utilization rate of rainwater resources has reached 3.93%.