城市汇水区流量径流系数确定法研究

Research on the method of determining discharge runoff coefficient in urban catchment area

技术标准和管控措施是全面推进海绵城市建设的重要手段。北京市在地方标准中用流量径流系数Ψm对建设区域的雨水控制与利用工程进行规范,在水影响评价中用Ψm对建设项目的排水影响进行分析和管控,但目前缺乏由实测或模拟排水过程计算Ψm的具体方法。基于对雨水管渠设计公式的原理和Ψm内涵的分析,提出了汇流时间和Ψm的计算方法,采用水科学院绿化屋顶和双紫小区降雨径流过程的实测数据,求得绿化屋顶和双紫小区的Ψm,并分析了其受降雨强度的影响规律。结果表明,这种方法可应用于城市汇水区的Ψm计算,为水影响评价工作和海绵城市建设提供支撑。

Technical standards and control measures are important means to comprehensively promotethe construction of sponge city.The discharge runoff coefficient have been used to regulate rainwatermanagement and utilization projects of construction areas in local standards in Beijing.In the waterimpact assessments,discharge runoff coefficient was used to analyze and control the drainage impacts ofconstruction projects.But currently,there is no specific method to calculate the discharge runoffcoefficient from the measured or simulated drainage process.In this paper,a method for calculating therunoff concentration time and the discharge runoff coefficient was put forward based on the analysis of theprinciple of the rational formula and the connotation of the discharge runoff coefficient.Through themeasured data of the rainfall runoff process of the green roof in Beijing Water Science and TechnologyInstitute(BWSTI)and the Shuangzi community,the discharge runoff coefficients were obtained and theinfluence law of the rainfall intensity was analyzed.The results showed that this method could be appliedto the calculation of runoff coefficient in urban catchment area,providing support for water impactassessment and sponge city construction.