高渗透下凹绿地对城市降雨径流的削减作用研究

针对下凹绿地的蓄水、渗水能力有限的特点,为了进一步提高其蓄水、渗水能力,对内部结构进行优化改善,开发出水平高渗透、垂直高渗透、组合高渗透3种高渗透下凹绿地。通过模拟降雨产流中试系统,分析不同降雨重现期及降雨历时条件下高渗透下凹绿地径流削减作用及洪峰削减量,并与传统上凸绿地、普通下凹绿地进行比较。结果表明,在降雨重现期1～10年、降雨历时30～120 min的芝加哥设计暴雨雨型条件下,与传统上凸绿地对比,普通下凹绿地径流总量削减率为23. 14%～67. 04%,径流峰值削减率1. 41%～100%,径流系数0. 29～0. 69;组合高渗透下凹绿地径流总量削减率为39. 93%～89. 87%,径流峰值削减率为6. 54%～100%,径流系数0. 05～0. 55。研究成果可为高水平城市绿地以及海绵城市的规划和建设提供参考。

Study on urban rainfall runoff reduction effect of high permeable concave-down green space

Aiming at the characteristics of the limited water storage and absorption capacity of the concave-down green space，theinternal structure of the green space is optimized and improved，so as to further enhance its water storage and absorption capacity，for which three types of high permeable concave-down green spaces，i. e. horizontal high permeable green space，vertical highpermeable green space and combined high permeable green space，are developed. Through simulating rainfall runoff productionpilot-scale test system，the runoff reduction effect and flood peak clipping rate of high permeable concave-down green space underdifferent rainfall recurrence periods and rainfall durations are analyzed，and then the results are compared with those of the conventional up-convex green space and the common concave-down green space. The results show that under the design rainstormpattern of Chicago hyetograph with the rainfall recurrence period of 1 ～ 10 years and the rainfall duration of 30 ～ 120 min，thetotal runoff reduction rate is 23. 14% ～ 67. 04% ，the flood peak clipping rate is 1. 41% ～ 100% and the runoff coefficient is0. 29 ～ 0. 69 for the common concave-down green space，while the total runoff reduction rate is 39. 93% ～ 89. 87% ，the floodpeak clipping rate is 6. 54% ～ 100% and the runoff coefficient is 0. 05 ～ 0. 55 for the combined high permeable concave-downgreen space，if compared with those of the conventional up-convex green space. The study results can provide references for plan-ning and construction of high level urban green space as well as sponge city.