Research On The Evaluation Of Sponge Program Of Changsha High-speed Railway District Based On SWMM

Sponge city construction can effectively reduce the runoff pollution,avoid water shortages,renovate urban water ecological environment,reduce the Urban Heat-island Effect,improve the living environment and so on.It makes it become today’s hot spot.In this thesis,the conventional construction program and sponge construction program were developed in the high-speed railway city of Changsha,and the effects of the programs were simulated and evaluated by SWMM.In the process of establishing urban rainwater model,the hydrological data,pipe network data and underlying surface data of high-speed railway city were collected,and rainfall data in2013,2014,and 2015 obtaining by the short-duration rainstorm system of Hunan Province provided support for the real reliability of the model.Using the ARCGIS software to divide sub-catchment area,to extract the average gradient of sub-catchment area improved the accuracy of model.And then generalize the pipe network,including 1988 pipes,8 pumps.2013 nodes,1929 inspection wells,30 discharge ports,28 Distributary well and 26 impounding reservoirs.After the model was established,the annual runoff control rate in the conventional development program was 37.57% in 2013,39.78% in 2014 and 39.69%in 2015.The comprehensive runoff control rate was 39.09% in three years.Through the analysis of the underlying surface of the first sponge development program(ie,permeable pavement + green roof).The annual runoff control rate was 70.25% in2013,73.3% in 2014 and 73.59% in 2015,and the comprehensive runoff control rate was 72.45% in three years.The results showed that the sponge construction program was better than the conventional construction program,but both of them did’t meet the requirement of 75%.It is necessary to optimize the sponge program.On the basis of program 1,we proposed sponge program 2(permeable pavement+ green roof + biological delay facility),sponge program 3(permeable pavement +green roof + sunken green land),and sponge program 4(permeable pavement + green roof + biological delay facility + sunken green land).And then we calculated annual runoff control rate,By comparing the four sponge development programs,we found out that program four(Water pavement + green roof + biological delay facility +sunken green land)was the best development program with an annual runoff control rate of 80.68% in 2013,81.61% in 2014,82.80% in 2015,and the comprehensiverunoff control rate was 81.79% in three years.It meets the annual runoff control requirement.The optimization of the program can provide some reference for the future research.Finally,three kinds of rainstorms were designed,and the sponge program was studied by sponge program 4(water pavement + green roof + biological detention facility + sunken green space).The results showed that the sponge program was suitable for coping with the former peak,the middle peak and the rear peak,and the effect coping with the former peak type rainfall was the best.The sponge construction program is suitable for the rainfall type in Changsha area.