The Model Design Of The Low Impact Development Of The Residential District Under The Target Of Sponge City

With the rapid of China’s reform and opening-up over the past 30 years, urban development is facing a huge transformation, economic and social development has entered a new normal. People’s demand is also changing with the improvement of the quality of life and spiritual culture, so that more attention to the ecological environment and the pursuit of high quality of life.18th National Congress of the CPC put forward the " Four Comprehensives" to achieve, including ecological civilization, "five in one" requirements, The fifth Plenary Session of the 18th CPC Central Committee through the Firmly establish the concept of innovation, coordination, green, open, shared development" macroe conomic policy, ecological security, ecological civilization, Happiness and living has become a national level of the new strategy, the new requirements. Under this macro background, to actively promote the construction of the sponge City is not only a response to the country to strengthen the development of ecological civilization is the inevitable choice, but also to adapt to the new normal urban transformation and development requirements of the practical measures.Firstly summarizes the research progress of foreign urban stormwater management and practice, the foreign advanced stormwater management concept, technical measures, technical specifications analysis, step by step to obtain foreign based on low impact development of stormwater management philosophy and our current sponge city construction concept has a high degree of fit, and further to the case of low impact development abroad are analyzed. Then in accordance with the development of the concept of the concept of sponge in China to sort out the sponge city system, and Shenzhen Guangming New District low impact development as an example of China’s low impact on the development of practical cases. Analysis should be combined with the characteristics of China’s urban and residential area drainage requirements, local conditions to low impact development technology and urban residential area combination, carry out for Chinese residential characteristics of low impact development mode research.Secondly, from the policy, management and technology in the three layers in the face of urban residential district rainwater system planning status and problems were summarized and the applicability of our urban residential area of low impact development analysis, and summarize the current low impact development in different spatial scales of practical cases. Then from the residential land use, residential area structure planning, residential area drainage system design three aspects of the development of China’s urban residential area low impact analysis. Further in the comparative analysis of different low impact development of individual facilities on the basis of suitable for China’s residential areas of low impact development facilities for the combination of system optimization.Again, the selection of the Island Home in Nanjing Jiangxinzhou as the study area, according to the standards of the construction of the sponge city of national level control objectives and local level rain pipes, design the island home residential area of low impact development of rainwater system model, using a basic scenario, economic and applicable scenario and effectiveness maximization scenario three scenarios analysis, come to the conclusion that the technology of low impact development of surface runoff and the pipeline flow has obvious effect of reducing. To evaluate the effect of low impact development, it can be concluded that the economic and applicable scenario and the effectiveness maximization scenario to meet the requirements of the sponge City, but when the rainfall return period of 3 years (design rainfall 71.71mm) and the effectiveness maximization scenario in capture ratio of total annual runoff volume can also be maintained at more than 65%, highlighting the advantage of controlling the total amount of runoff, reached a preliminary Nanjing new area 3 years once the total annual runoff volume control standards. Recommended to the effectiveness maximization scenario on the Island Home residential area layout of low impact development facilities, including permeable pavement, green roofs, subsided green space, bio retention facilities, grassed swales.Finally, combined with the sponge city goal, for residential low impact development planning needs to solve problems as the starting point, the covering residential area of rainwater planning principles, controls the target and rainwater utilization system planning and design strategies. Residential area of low impact development should be in before the development of the natural conditions as the basis to develop intensive and highly efficient rainwater utilization principles and patterns, the rational allocation of point, line and plane digestion unit. Then a hierarchical determine residential area in total annual runoff control objectives, and further in the planning at all levels gradually decompose residential annual total amount of runoff control indicators, construction of residential district of the elements (buildings, roads, green spaces, public place) coordination of rain utilization system.