Study On Key Technical Issues For “Sponge City” Construction In Chongqing

Large urban development efforts brought storm flood disaster has become a major obstacle to urban sustainable development, it is one of the current livelihood issues need to be resolved. In 2014, President Xi proposed an idea called "sponge city", which injected fresh blood to country's rainwater ecosystem, in March 2015, Chongqing was established as the first batch of "sponge city" pilot zone, opened a prelude to the construction of Mountain sponge city.Chongqing is a typical high-density urban mountain, narrow roads, big building density, great disparity of terrain, soil properties include sandy, clay, and acid. Others, because of the unique cultural characteristics and social habits of Chongqing, such sponge city building has its unique characteristics. Taking account into the natural conditions and social situation of the city, the main objective of Chongqing sponge city construction should be total runoff reduction, peak runoff reduction and runoff pollution control. Therefore, starting a technical study for the main goal naturally becomes a current major issues.This paper firstly analyzed the overview of Chongqing, on this basis, the author studied the virous sponge eco-technology measures, and proposed the technical model of sponge city construction in different urban space, put forward the soil improvement techniques and plant selection.The main achievements of this paper were as following:(1) Analyzed the hydrometeorology, precipitation and runoff characteristics, urban form and other conditions of Chongqing, put forward that Chongqing should focus on peak runoff and runoff pollution during sponge city construction,and combined with the use of rainwater na dtotal runoff. The main way to include the promotion of low-impact development techniques, strengthen the traditional drainage network system construction, strengthen reuse rainwater storage system construction, maintenance and improvement of river network in five soil.(2) Gave suitability evaluation results of different types of sponge city measures applied in Chongqing, and summarized the technical measures in the structure, materials, forms, hydraulic parameters, and scope of application, and qualitatively compared the reduction effect of total runoff, peak runoff and runoff pollutant of various technical measures, proposed the selection procedure of sponge city technical measures.(3) Put forward the technical mode of municipal roads, residential buildings and urban public areas. For municipal roads, analyzed the differences between traditional roads and sponge city roads on stormwater management model, proposed drainage way of different type of municipal roads under the concept of sponge city in Chongqing, according to the differences of land distribution, social habits, and management system between old and new areas, the author proposed appropriate construction plan and improved technical measures of sponge city in Chongqing; for residential buildings, studied the interception, collection and reuse system of rainwater in both single buildings and public areas, and put forward the suitable sponge city layout in different building types; for urban public areas, the autor proposed suitable technical scheme of ecological stormwater systems of square, large parks and waterfront. Finally, according to the meteorological and hydrological conditions of Chongqing, the autor summed up the appropriate planting plants category for actual projects selected.(4) made a case study on an eco-city called YuLai in Chongqing. The research results has a certain reference for sponge city construction in Chongqing.