Decompose The Control Target Of Urban Total Runoff Of Sponge City And Validate It By SWMM Model

The paradox that urban rains to floods, after to drought has brought great losses to people’s lives and property. Today how to coordinate the relationship between the city and the water in the rapid development of urbanization has become the mainstream of urban stormwater management. In this context the nation put forward a sponge city.Sponge city is a new urban development model, however most of city faced the fist problem is which kind of the indicators does the sponge city can achieved and how to achieve it. The goal of the total runoff volume control of this paper based on the advanced stormwater management concept and implementation experience of developed countries, and combined with the progress of urban stormwater management of our country and the current conditions of E Jing watershed. The paper decomposed the total runoff volume control by planning point of view, and then used the SWMM model to validated it though differents rainfall events. This can provided a method for study the total runoff volume control of sponge city.The paper first put forward the total runoff volume control according to the progress of the control of hydrological indicators about the stormwater management,and the current conditions of study area. Then introduced the domestic and foreign common stormwater management model and highlighted the SWMM model used in this paper, the model of the LID module can be simulated the effects of sponge facilities,this can provided a method to assessment sponge urban runoff control targets.Secondly, integrated the region, vertical elevation, rain water pipe network and other data of the study area, to build the status of SWMM model. The improved Morris screening method was used to analyze the local sensitivity of water quantity and quality parameters of the SWMM, and calibrated parameters by three differents rainfall events.Calibration coefficients ENS was in the range of 0.634~0.861, R2 was in the range of0.698~0.96, calibration result was better, and we got a set of local applicable model parameters.Again, decomposed the volume of the sponge urban planning on study area form the planning perspective, and developed a general idea of the total runoff control indicators of decomposition, that: Determine the total indexâ†'Determine the land layoutâ†'Preliminary the sponge facilities layoutâ†'Volum of each sponge facilitiesâ†'Total volum of area sponge facilitiesâ†'Repeated testing until to the total indexâ†'Finalize sponge facility types and sizes.Finally, according to the regional planning and construction, used the local parameters to built planning SWMM model, and simulated the result of the decomposition by three different rainfall events, the results show that the the average annual runoff control rate could reach the proposed index value which indicates that at this stage the volumetric method of runoff control indicators decomposition can achieve the desired effect.