| 不同降雨条件下植被对绿色屋顶径流调控效益影响 |
| 摘要点击 2197 全文点击 747 投稿时间：2018-01-08 修订日期：2018-04-19 |
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| 中文关键词 绿色屋顶 降雨 植被 径流/洪峰削减 产流/峰现延迟 |
| 英文关键词 green roof rainfall vegetation runoff reduction peak discharge mitigation |
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| 中文摘要 |
| 植被是绿色屋顶的重要组成部分，可通过截留雨水和蒸散耗水等过程影响绿色屋顶的径流调控效益.本文基于太阳花（Portulaca grandiflora）、佛甲草（Sedum lineare）、高羊茅（Festuca elata）和无植被等4种植被覆盖类型绿色屋顶2017年雨季26场降雨径流过程的监测数据，从径流和洪峰削减、产流和峰现时间延迟四方面定量分析植被在不同降雨条件下对绿色屋顶径流调控效益的影响.结果表明，绿色屋顶径流削减率与降雨量呈显著负相关（P<0.01），降雨量<10 mm时，绿色屋顶径流削减率等于或接近100%；降雨量超过30 mm，所有绿色屋顶的径流削减率降低到70%以下；当降雨量达到监测期内最大的81.4 mm时，各绿色屋顶径流削减率都低于55%.植被覆盖类型对绿色屋顶径流调控效益的影响随降雨条件而改变，大雨条件下不同植被覆盖类型绿色屋顶的径流削减率差异最大，中雨和暴雨条件下次之，小雨条件下因各绿色屋顶几乎都不产流而无明显差异.在中雨、大雨和暴雨条件下，有植被覆盖绿色屋顶的径流削减率、洪峰削减率、产流和峰现时间延迟等4个指标都明显优于无植被覆盖的绿色屋顶.株高和单位面积地上生物量最高的太阳花绿色屋顶的径流调控效益优于佛甲草绿色屋顶. |
| 英文摘要 |
| Vegetation is an important component of green roofs and may affect their hydrological performance through the processes of rainwater interception and evapotranspiration. Based on the rainfall-runoff observations of green roofs with four types of vegetation covers (Portulaca grandiflora, Sedum lineare, Festuca elata, and bare substrate) located in Beijing during 26 rainfall events from April to October 2017, the impacts of vegetation cover on the hydrological performance of green roofs were investigated using runoff and peak discharge reduction rates and time-delay of runoff generation and peak discharge as indices. For the 12 green roofs, there was a significantly negative correlation (P<0.01) between runoff reduction rate and rainfall event volume. For low rainfall (<10 mm), the runoff reduction rates of all the green roofs were equal or close to 100%. When the rainfall volume increased to about 30 mm, the runoff reduction rates dropped to below 70%. For the heaviest rainfall event during the observation period (81.4 mm), the runoff reduction rates of all the green roofs were less than 55%. The impacts of vegetation on the hydrological performance of green roofs changed with rainfall conditions. The differences between runoff reduction rates of green roofs with different types of vegetation cover were largest for the heavy rainfall events. For the moderate rainstorm events, the differences were slightly lower. For light rainfall events, however, no significant differences were observed among the runoff reduction rates of green roofs with different types of vegetation cover, as little runoff was generated. Vegetation cover could enhance the hydrological performance of green roofs, as the runoff and peak discharge reduction rates and time-delay of runoff generation and peak discharge of green roofs covered with vegetation were all better than those of the bare substrate for all the groups of rainfall events except the light rainfall. Vegetation-covered green roofs with P. grandiflora performed the best, as the average height and aboveground biomass per unit area of P. grandiflora were the largest. |
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