北京市房地产项目雨水径流的研究

Research on Rainwater Runoff from Real Estate Project in Beijing

房地产项目建设会形成4种不同类型的下垫面:不透水建筑物屋顶、硬化地面、透水型地面和绿地。国家相关标准与规范确定,4种下垫面面积占总面积的比重分别为24%、22.8%、28.2%、25%,据此对各自径流系数加权平均得出北京市房地产项目建设形成的下垫面的总的径流系数为0.60。同时对2006年-2011年6年间北京市的房地产项目的雨水径流量进行计算分析,结果表明,北京市房地产项目7月、8月份产流量最大;4种下垫面形成的雨水径流量顺序为:不透水建筑物屋顶>硬化地面>透水型地面>绿地。基于对房地产项目特点及其雨水径流特征考虑,房地产项目建设过程中,应注重透水铺装、集雨池、屋顶绿化和下凹式绿地等雨水收集与利用措施建设,加大雨水入渗与利用,缓解城市雨水管道排水压力。

Accelerated urbanization causes rainwater loss and decline of groundwater level, which further exacerbates the urban water resources exhaustion. The underlying surface, which is formed by the real estate construction, is divided into four types： waterproof building roof, indurative ground, pervious ground, and greenbelt. On the basis of the national standards and regula- tions, the proportion of each of the four underlying surface area is 24 %, 22. 8%, 28. 2%, and 25% of the total area, respectively. Using the weighted average value of these proportion values with individual runoff coefficient, the total runoff coefficient of the underlying surface formed by the real estate project construction in Beijing is calculated as 0. 60. The rain runoff from the real estate project in Beijing is calculated from 2006 to 2011, which shows that the rain runoff reaches its maximum in July and Au- gust. The waterproof building roof has the highest rain runoff, followed by indurative ground and pervious ground, whereas greenbelt has the lowest rain runoff. Based on the analysis of the characteristics of real estate project and rainwater runoff, we should pay attention to the construction measures of rainwater collection and utilization, such as permeable pavement, catchment basin, roof greening, and undercut type green space, to increase rain infiltration and utilization and to alleviate the pressure of ur- ban rainwater pipe drainage during the real estate construction.