Based On SWMM Sponge Urban Runoff Water Quantity And Water Quality Simulation

In recent years,the global economy has developed at a high speed,and the city has become a gathering point for civilizations of all mankind.The function is no longer limited to the population,but a collection of functions such as administration,economy,culture,and transportation.In the aspect of economic development,the construction of cities must be taken as the core.In such a macroenvironment,there have been many cities with a population of 10 million in recent years.Although the rapid development of urbanization has significantly improved the people's living standards,its negative impact on the environment is also quite severe.The type of underlying surface changes,the surface infiltration capacity is weakened,the pressure on the municipal drainage network is increasing,and the Flood disasters are frequent.In order to solve such problems,China draws on foreign advanced technology cases,proposes new ideas for building sponge cities,and uses low-impact development(LID)technology to alleviate urban floods and pollution problems.This paper analyzes the research progress of stormwater management at home and abroad,and selects the experimental primary school in Qingyang City of Gansu Province as the research object,and collects the topographical,meteorological,hydrological and geological data of the study area,combined with the field measured data and professional geological survey report.Established the drainage network of the campus and the size of each sub-catchment area.The SWMM model was used to establish the field rain flood model in the study area,and the three measured rain patterns with rainfall of 17.7mm,35 mm and 77.2mm were used to evaluate the water volume and water quality simulation results.After the site design is completed according to the general plan of the building,it is calculated that the current flow reduction rate and the pollutant reduction rate index cannot be met under the current conditions.Following the regulation,the general green space and hardening pavement were reconstructed,and the sponge facility design was carried out on thecampus.The estimated design volume,runoff and pollutant reduction rate of the study area after the deployment of the LID facility were estimated.It is proved that the low-impact development of sponge city is more obvious than the traditional construction mode.The SWMM is used to analyze the campus.The results show that under the three types of rain,heavy rain and heavy rain,the peak reduction rates before and after the deployment of LID facilities are 87.0%,81.3%,and 53.1%,respectively.The runoff reduction rates are82.5.%,79.4%,58.4%;the overflow nodes were reduced by 75%,100%,and 41%,respectively;the pollutant reduction rates were 77.6%,70.4%,and 51.4%.It shows that the LID facility can not only reduce the peak of rain and flood,but also reduce runoff,relieve pipe network pressure,and purify water quality.This will provide reference for the construction of the same type of area in Qingyang City,Gansu Province.