城市屋面雨水利用潜力分析——以南京市河西地区某小区为例

ANALYSIS OF POTENTIAL OF URBAN ROOF RAINWATER UTILIZATION ——A CASE STUDY ON A COMMUNITY OF HEXI IN NANJING

城市雨水利用是解决城市水资源短缺和减轻内涝灾害的手段之一。以南京市某小区为例,在分析南京市降雨特征的基础上,利用1∶500地形图资料计算了不同降雨保证率条件下该小区屋面雨水可收集量,分析了雨水收集利用在减轻城市内涝方面的作用,并提出了设置地面蓄水池的4条原则,在此基础上调查分析了该小区设置地面蓄水池的可行性。结果表明:在降雨保证率为50%时,通过屋面年可收集利用的雨量为114 272.1m3;在日降雨量为50.0和95.5mm(南京市多年平均年最大日降雨量)时,屋面雨水利用可减少21.4%和11.2%的地表径流;小区内可设置蓄水池的建筑屋面面积占总屋面面积的55%,其中住宅和其他类建筑中可设置蓄水池的建筑屋面面积比例占77%。

Rainwater utilization is a means used to lessen urban water shortage and reduce waterlogging dis- asters. Based on a large scale of topographic map data （1：500） and the rainfall data of Nanjing,the volume of available harvesting rainwater in a year with different guaranteed ratio of rainfall and the potential for surface runoff volume reduction are calculated in a community in Nanjing. Then,an analysis of cistern set- ting feasibility is performed under four principles. The results show that the annual collectable rainwater is approximate 114 272.1 m3 with the guaranteed ratio of rainfall at 50%. And urban waterlogging disasters could be effectively reduced by rainwater harvesting. 21.4% and 11.2% of runoff volume could be reduced by roof rainwater utilization in two cases of 50 mm and 95.5 mm respectively （the average annual maxi- mum daily rainfall）. The roof area which is suitable to set cisterns is 55% of the total roof area,while the a- vailability rate reached about 77% for residential and the other types of buildings＇ roof areas.