Study On Methodology And Its Application For The LID Green Space System Planning

With the fast development of urbanization, urban waterlogging were moreserious in most parts of China. One important issue in China’s urban construction ishow to reduce the storm water runoff and utilize rainwater and develop the new waterresources.Creating a methodology of green space planning system based on Low ImpactDevelopment (LID), this study aims to provide a new idea for China urbanconstruction by integrating drainage network, surface water body and green space.Through the reasonable green space planning, the negative influence of naturalecosystem would be reduced in the urban construction.The methodology of green space system planning was proposed according to theresult from combing available LID techniques, and summarizing the advantages,disadvantages and applicable conditions of them which were used more frequently atthe present stage, such as Rain Garden, Green Roof, Grassed Swales and so on.The LID green space system planning was such a method that combines the citygreen space and municipal drainage network at the beginning and makes cutting downthe runoff coefficient, reducing stormwater runoff, and purifying water quality itspurposes. Compared to the traditional green ones, the LID green space systemplanning increased indexes of controlling were a runoff coefficient and storm waterquality in the index system. The planning includes the following steps: analysis ofcurrent situation, division of ecological unit, adjustment of runoff coefficient,implement of LID technology and so on. The green space base on LID technologypossesses more functions, looks more natural, and has a lower cost.Taking the green space planning of Tianfu District in Chengdu as a case, it was astudy by putting LID green space system planning into practices. According to theactual situation of the Planning Area, the study builds a "one pair of finger-palms "ecological pattern and calculated that the reasonable area of water is22.57km2, andthe area of green space is453km2, whose layout plans were confirmed at the sametime. At last the LID technique was displayed in Xinglong Lake eco-demonstrationregion, and cut50%stream flow of5year frequencies in24hours. The implementation of this case indicated that the LID green space system planningmethod was feasible, and also has a referential significance for later researches.