Reach Rainstorm Runoff Pollutant Control Based On The Design Philosophy Of Sponge City

The rapid urbanization has directly changed the city's bottom surface,resulting in great changes in the urban hydrological cycle conditions,which led to the fast and large flow on the surface in heavy rain.Then it also caused lots of urban water environment problems,such as water logging damage.More seriously,the non-point source pollution caused by urban rainfall runoff becomes an important source of natural water pollution.The key way to enhance urban drainage capacity,reduce rainstorm runoff pollution and repair urban water ecology is to construct a sponge city.As one of the biggest users of city water supply network,campuses consume a large quantity of water.On the other hand,universities are also an important point of drainage network control because of their large displacement and sewage.Rainstorms in the campuses often can not be discharged in time,so the campus pavement was often flooded.In addition,the campus is a functional area of the city,and the characteristics determine that it has a high degree of similarity with the city,so the sponge city research is very representative there.In order to study the characteristics of runoff and pollution at the time of heavy rain,we take the Songbei campus of Harbin Normal University as the research object.In this paper,we monitored the runoff and quality of storm water,and analyzed the characteristics of runoff and non-point pollution in different functional areas.Further more,we also used the storm runoff management model to simulate and forecast the runoff and pollution in the study area,and used the SWMM model to evaluate the low impact development measures.This study can provide the theoretical basis and reference for the campus to keep in right order when the storm struck.Also the same with the planning and construction of the sponge city.The results show that it is the worst of pavement and playground,while the roof is the best.Besides,the roof has a strong runoff erosion effect,but the road surface is relatively weak.According to the conclusion,there is a certain correlation among pollutants in rainwater runoff.We constructed the storm runoff management model in Songbei campus of Harbin Normal University,and verified the model with the measured water quantity and water quality data,which shows that the model has good applicability in this study area.After using SWMM software to generalize the drainage system,we took different rainfall recurrence periods and two hours of scenarios as the rainfall input,and simulated the rainwater drainage process.It is found that the flow of part pipes is beyond the economic flow when the recurrence period is 2 years and 5 years.We also re-simulated the rainfall drainage process at the reproduction period of 5 years by selecting some measures of low impact,and got the ideal result.The low impact development measures proposed in this paper have some reference value for more in-depth researches,planning,management of rainwater runoff and the design of sponge city.