Sponge Perspective Planning And Application Of Infrastructures On Storm Water Management In Hilly Regions

Rapid urbanization in recent years has led to dramatically land-use and land-cover(LCCC)change.The extremely fragile and sensitive ecosystem in hilly regions further increased the frequency and intensity of flood risk in this region.However,depending on the traditional storm-water management concept of ’rapid drainage oriented’ and aging gray infrastructure is hardly solving the pluvial flooding issues.Therefor,the concept of ’Sponge city’ planning has developed allover China among experts and scholars,which carrying out large amount of positive exploration,technologies and methods in pluvial flooding management.Regarding the particularity of the hilly area in Hunan Province,this study takes the microscopic site scale as the starting point,through the comparison and layout planning of Green Stormwater Infrastructure,built the way controls the rainfall runoff from the capillary end of the sponge construction to solve the waterlogging in Hunan hilly regions.Taking Meixihu Middle School in Changsha as a case study,makes the practical research through the planning way of "target setting-revision model-original program simulation evaluation-facility comparison-determining preliminary plan-feedback adjustment-final plan",The research process is as follow:For the Green Stormwater Infrastructure storm-water management selection system:firstly,through the sorted out and summarized about Green Stormwater Infrastructure used in Hunan hilly regions in the view of site scale.while also considering the suitability of land use,hydrology and terrain in Hunan hilly regions context;secondly,focus on the functional and cost-effective aspects of Green Stormwater Infrastructure.The study analyzes and compares the functional aspect of Green Stormwater Infrastructure from the vertical and horizontal dimensions,and the cost-effective aspect from the construction and maintenance cost.Then the study uses normalized approach to comprehensive evaluate all the selected Green Stormwater Infrastructure practices.And provide reference for the selection of facilities in planning and construction.For the spatial planning of Green Stormwater Infrastructure:firstly,the study builds the drainage model in the urban context of hilly towns and then simulates the precipitation scenario to identify the potential waterlogging areas in the site;secondly,places the Green Stormwater Infrastructure in the potential waterlogging areas,which also considering the land use,green space rate,water area conditions.This study also focuses on the multi-functional dynamics of public spaces,efficient uses of facilities,and combination of storm-water management and landscape.Accurately planning of Green Stormwater Infrastructure can not only effectively control flood risk but also avoid inefficiency investment of Green Stormwater Infrastructure.The research takes Meixihu Middle School as a case study.Firstly,this study analyzes the current site context and simulates the scenario of 3year,50 year rainstorm frequency and the whole year precipitation from 2015.03.01 to 2016.03.01 in order to identify the potential waterlogging area.Secondly,according to the characteristics of the site conditions,the study selects the subsided green space,the green roof,the rain garden and the porous pavement from the Green Stormwater Infrastructure selection system.The goal of the planning is to reduce 80%of annual runoff,Then in order to the annual runoff control rate of 80%as the core control objective,layout infrastructures and adjust the scale by DS.And finally to determine the green rainwater infrastructure benefits and economic optimal spatial layout.