基于SWMM的杭州小和山区域LID措施

On LID measures in Xiaoheshan area of Hangzhou based on SWMM

【目的】缓解杭州城西小和山区域涝水问题。【方法】基于海绵城市理念,利用层次分析法(analytic hierarchy process, AHP)针对研究区域设置的5种低影响开发(low impact development, LID)改造设施的效益指标权重进行判别,实现不同LID设施下的综合效益优选,并利用暴雨管理模型(storm water management model, SWMM)构建研究区域雨洪模型,比较LID设施布设前后的汇水情况。【结果】对研究区域中12%的学校和住宅区域用地增添雨水花园,25%的广场铺装改造为透水铺装,65%的道路设置渗渠,可使洪峰出现时刻延迟45 min,洪峰流量削减率达61.5%,径流系数削减率为19.2%。可见,改造措施对洪峰流量、地表径流系数和洪峰时间等均起到显著的削弱作用。【结论】本研究结果对缓解同类区域涝水问题及提升防涝治理技术具有参考意义。

[Objective]It is imperative to alleviate the problem of waterlogging in the Xiaoheshan area in the west of Hangzhou city.[Method]Based on the concept of sponge city,the benefit index weights of five kinds of low impact development(LID)renovation facilities set up in the study area were discriminated by using the analytic hierarchy process(AHP)to realize the comprehensive benefit preference under different LID facilities,and the storm water management model(SWMM)was used to construct the rainwater model of the study area to compare the catchment situation before and after the deployment of LID facilities.The storm water management model(SWMM)was used to construct a rainfall model for the study area to compare the catchment conditions before and after the deployment of LID facilities.[Result]By adding rain gardens to 12%of the residential school sites in the study area,converting 25%of the plaza paving to permeable paving,and installing infiltration drains on 65%of the roads,the timing of the flood peak is delayed by 45 min,with a reduction in the peak flow rate of 61.5%and a reduction in the runoff coefficient of 19.2%,which shows that the retrofitting measures play a significant role in weakening the peak flow rate,the surface runoff coefficient,and the timing of the flood peak.[Conclusion]The results of this study are informative for mitigating flooding problems in similar areas and upgrading flood control and management techniques.