Study On Planning And Design Method Of Sponge City In Sea Reclamation Areas

With the rapid development of national economy,urbanization process accelerates constantly,leading to the city scale expansion and growing population.These has also brought about a series of water-related problems,such as water resources shortage,water environment pollution,increased rain and flood disasters,etc.How to coordinate the relationship between urban development and water has become an urgent problem needs to be solved.The Sponge City is a comprehensive urban construction model aiming at the specific conditions of our country.In 2016,the Ministry of Housing and Construction issued “the Sponge City Special Planning interim regulations”,requiring all cities to speed up the process of formulating special plans for sponge cities.In the same year,Shenzhen became one of the second batch of national “sponge city”construction of the pilot.How to formulate the construction goal of sponge city and put forward the corresponding planning methods according to local conditions has become the key.Firstly,this research takes Dakonggang district in Shenzhen as the research subject,analyzing the basic conditions of the present situation of the research area to find out the problems of urban water system and the demands of sponge city construction.Then using the Arc GIS and SWMM to build digital models according to the related hydrological data.Furthermore,identifying the target of the annual runoff control rate at Dakonggang district and decomposing the low impact development control indexes to the plots.Finally,formulating the layout of the construction ofsponge city in order to achieve the targets of the annual runoff control rate.Results show that:(1)The annual runoff control rate at Dakonggang district is 70%,the corresponding design rainfall 31.3mm;(2)Results after SWMM modeling show: before the city exploitation,assuming the ratio of impervious area at Dakonggang district is 8% and taking typical annual rainfall as the rainfall data,the total rainfall is 1723.20 mm.The surface runoff of Dakonggang district is 471.9mm in the model simulation results.And the annual runoff control rate of Dakonggang districtbefore the city exploitation is 72.6%;(3)According to the distribution of the river system,the Dakonggang district is divided into eight units,and the annual runoff control rates are 82.4%?64.5%?78.0%?67.6%?68.9%?68.6%?63.6%?69.3% respectively;(4)The eight units were further divided into 331 plots.Based on the area of each plot and theannual runoff control rate,the calculation results show that the water storage capacity of the research area is 164000 cubic metres,and the total annual runoff control rate is 70.1mm,corresponding to the design rainfall of 31.3mm,which meets the target of 70% of the total runoff control rate.