Study On The Effect Of Rainfall Runoff Pollution Reduction And Storage Of Kunming Urban Green Space

In recent years, the level of urbanization in China continues improving. In the process of urbanization, the urban surface structure and function have been changed, so impervious surface area is increasing, the probability of occurrence of urban rainwater disaster increasing, the city natural hydrological cycle is destructed. At the same time, the urbanization makes the rainfall-runoff pollution become more and more serious. If the rainfall-runoff directly is discharged into the sewage treatment plant, it increases the burden on the municipal sewage treatment plant. Green space own well permeability and play an important role in rainwater infiltration recharge groundwater. If the rainfall-runoff is infiltrated by green space, it can realize the goal that the water resource is protected, water conservation, controlling the city soil erosion and preventing water logging. At the same time, it will achieve the source interception in place and reduce water pollution load, reduce the load of the drainage system to reduce floods. It will play an important role in the governance and protection of Dianchi Lake and improve the urban ecological environment.If Kunming Green Space System can remove the pollutants in rainwater runoff well, as well as storing function in rainwater runoff is obviously not clear, therefore. The paper relies on the Kunming Department of Water Resources Project rainwater resources utilization projects sub-topics-"Study on the Effect of Rainfall Runoff Storage and Pollution Reduction of Kunming Urban Green Space ".on the basis of the data collection, test analysis, data statistical analysis, Researching the effect of Kunming urban green space system for rainwater runoff pollution reduction and purification law and exploring the green space system for each pollutant removal mechanism. To demonstrate the storing effect of the Kunming urban green space system to rainwater runoff. The main results are as follows:(1) The typical soil is paddy soil in Kunming, It’s stable penetration rate is 0.322mm/min, that is 5.4 × 10-6m/s, Kunming soil stable infiltration rate of green is between 8.25 × 10-6m/s and 5.76 × 10-5m/s, The soil stable infiltration rate of green space is higher than bare land soil about 5%-25%.(2) After the rainwater run-off is purified by the green surface soil penetration, the effect of removing the pollutants in rainwater runoff is very good. It will reduce the burden of green space system urban sewage treatment plants and reduce the pollutants in rainwater runoff to groundwater greatly.(3) According to estimating sunken green space, the results show that the sunken green space can store and infiltrate runoff rainwater well and reduce the city’s water logging disasters substantially. The infiltration rate of the soil, green area ratio, depth of concave and other parameters affect the critical parameters of the sunken green infiltration storage capacity. To provide a basis for future practical application of information and technical support, future research can improve its shortcomings and realize more effective rainwater utilization.(4) Based on the concept of low-impact development, designing a district of Kunming in accordance with the Kunming 5-year return storm intensity standard. Controlling the controllable rainfall forecast, the design enables Kunming 5-year design efflux flow than ordinary facilities a one-year case design efflux flow. It can reduce the rainwater efflux flow, reduce the amount of drainage system transformation and the investment of municipal pipe network construction efficiently and effectively. To achieve unified the benefits of environmental, economic and ecological.