初期径流雨水是受纳水体的主要污染源，用降雨深度界定初期径流雨水量并将其截流可降低对受纳水体的污染。为便于采取工程措施有效截流初期径流雨水，以《中华人民共和国地表水环境质量标准》（GB 3838-2002）中Ⅴ类水体基本项目标准限值为依据，将污染指标值高于该标准限值的径流雨水界定为初期径流雨水，因此后期径流雨水量即为污染指标值等于或小于该标准限值时的产流量，用单位时间内的降雨体积表示。据此按钢筋混凝土圆管（满流）的水力计算图确定截流管道的管径，并采用溢流堰式截流井截流。通过实际工程验证，其截流效果显著，且工程易于实施。

The initial rainwater runoff is the main source of pollution for receiving water bodies, and using the rainwater depth to define and then intercept the initial rainwater runoff can lower the pollution of receiving water bodies. In order to facilitate the effective engineering measures in the early closure of runoff, the basic standard limit values of grade V water in "the people's Republic of China environmental quality standard for surface water" (GB 3838-2002) were used as the basis. The rainwater runoff with higher pollution index values than the standard limits were defined as the initial rainwater runoff, and therefore the late-stage rainwater runoff had the pollution index values equal to or lower than the standard limits, which were expressed by the rainfall volume in unit time. Based on this, the reinforced concrete pipe (full flow) calculation chart was used to determine the diameter of intercepting tube, and the overflow weir type was used to intercept the flow. Verified by the practical engineering, the intercepting effect was remarkable and easy for engineering implementation.

江苏建筑职业技术学院自然科学应用项目(JYA311-06)