Study On Storm Water Planning And Design System Of Sponge City-Oriented Site

Ecological stormwater management has been widely studied and applied in the world.With the development of urbanization,there are many problems in the cities,such as high pressure of flood discharge and loss of rainwater resources.In order to meet the needs of ecological protection and social development,sponge cities were proposed in 2013.Stormwater planning at site level is directly managed from the source of rainwater runoff,and undertakes the important task of sponge city construction.However,there are still many confusions and challenges in the planning of site rainwater and flood,such as different site problems,scattered demands,controversial planning and lack of system,which lags behind the mature management of rainwater and flood in foreign countries.This paper uses case study method to analyze the objectives,standards,strategies,measures and technical models of projects at home and abroad.It points out that the puzzles and challenges lie in the lack of awareness of problems and objectives,the lack of cost-benefit analysis and technical support,the isolation from the economic and social background of the site,the limitation of the application scope of sponge facilities,and the construction of Shenzhen International Low Carbon City.In the framework,we can see that China’s spatial planning and municipal system are separated.To play a leading role in sponge city planning,we must achieve disciplinary coordination and technical cooperation.The task of this paper is to put forward the rainwater planning system of the site under the sponge city system,including construction ideas,problem identification and target selection,index system and model technology support,focusing on the planning and design content.The planning should be based on the construction ideas of problem-oriented,goal-oriented,technical feasibility and grey-green combination,and identify the problems of water resources,water environment,water ecology,water safety and other water systems and key site management and control issues.Establish the target system,realize the function of rainwater and flood through the primary goal,integrate the spatial elements through the secondary goal,and meet the development requirements of landscape shaping,environment comfort,style protection,education demonstration and so on.Rainfall planning can be divided into three levels: macro-model design,meso-factor control and micro-sponge facility application.Rainfall models can be divided into three categories: infiltration + fusion,group +highlight,and center + aggregation,which are coupled with secondary targets respectively.Vertical elements are combined with meridian path,water body elements combined with rain-flood cycle,green space elements combined with source reduction,Street elements combined with drainage facilities.Taking the site of Dalian University of Technology as an example.The current situation of the campus is mainly water ecological problems,defining the relevant objectives and indicators;adopting the mixed rain-flood pattern of infiltration + fusion and center +aggregation in the core control area;and carrying out storm street planning,detention zone planning,continuous layout of green space,vertical transformation and drainage network facilities assistance according to the distribution of spillover points.SWMM participates in the three aspects of pre-analysis,planning and design,and scheme evaluation.The simulation results show that it meets the requirement of 70% annual runoff control rate,improves the unhealthy rainwater drainage system,and improves the benefits of site environment.