北京市雨水收集利用蓄水池容积计算与分析

Volume calculation and analysis of rainwater collection and utilization reservoir in Beijing

基于北京市1984—2013年的日降雨资料,以北京林业大学林业楼及其周边绿地为研究区,设置3种用水情景(冲厕、绿地灌溉及冲厕+绿地灌溉),采用连续模拟法,分别绘制3种用水情景下雨水收集利用工程的雨水截留率、自来水替代率、供水保证率以及效益费用比变化曲线,并通过综合分析这些曲线的变化特征确定雨水蓄水池最佳设计容积(60~82 m3)。同时采用设计暴雨法计算1~5年不同重现期的蓄水池设计容积(77~248 m3)。结果表明,连续模拟法计算过程相对复杂,但可用于综合衡量雨水收集利用工程的雨洪管理效益,以及缓解水资源短缺效益、供水可靠性及经济可行性分析。

In this study, based on the daily rainfall data of Beijing from 1984 to 2013, the Forestry Building and the surrounding lawns in the main campus of Beijing Forestry University are choosen as the study area, three types of rainwater usage scenarios （i. e. , flushing toilets inside the building, irrigating lawns around the building and combination of flushing the toilets and irrigating the lawns） are set, the continuous simulation approach is appliedto draw the variation curves of rainfall interception rate, tap water replacement rate, probability of water supply and cost-benefit rate for these rainwater collection and utilization projects under the said three kinds of rainwater usage scenarios. Then the optimal design capacity （60 ~ 82 m3 ） of the rainwater storage reservoir is determined by comprehensively analyzing the change features of these curves. Meanwhile, the design storm approach is also applied to calculate the design storage capacities of the reservoir for 1 ~ 5 years of different recurrence interval. Comparison of the two design approaches shows that the continuous simulation approach can be used to comprehensively measure stormwater management effects, effects of relieving water resources shortage, water supply reliability as well as economic feasibility analysis of these rainwater collection and utilization projects, though its computation process is relatively more complex.