| 摘要: |
| 【目的】针对适于上海地区存量建筑推广使用的8 cm基质佛甲草屋顶绿化产品，评估其在梅雨期的滞蓄实效。【方法】构建平、坡屋面组试验装置，实测佛甲草模块在梅雨期自然降水环境和当地典型平、坡屋面条件下的滞蓄能力，比较梅雨全期及单次降雨事件下平、坡屋面组的滞蓄差异。【结果】发现平、坡屋面组试验模块对梅雨全期的平均滞蓄率分别可达到38.9%和30.6%，期间单次降雨的滞蓄率差异较大，除连绵降雨过程中的大、暴雨外，均可在降低径流峰值、减少径流总量和延缓产流上发挥较为理想的作用。【结论】在上海及长江中下游梅雨地区，对新建或既有建筑，尤其是平屋顶建筑推广建设拓展型屋顶绿化，是有效的节地型海绵措施。 |
| 关键词: 屋顶绿化 雨水滞蓄 海绵措施 梅雨期 上海 |
| DOI：10.12409/j.fjyl.202209200545 |
| 分类号:TU984.11.5 |
| 基金项目:国家自然科学基金“街区尺度的屋顶绿化雨热效应协同、优化研究”（编号 52078350） |
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| Measurement and Evaluation of Detention and Retention Effects of Lightweight Sedum lineare Roof Greening in Plum Rain Season in Shanghai |
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LUO Tianqing, HUANG Yin
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Tongji University
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| Abstract: |
| [Objective] In highly urbanized areas, roof greening is a supplement to ground greening. Although the benefits of roof greening in rainwater detention and retention can play an important role in improving water security and realizing sustainable developments for cities, there is rare convincing measurement and evaluation on such benefits from actual roof greening products under various climate features and roof conditions in different areas. Concentrated rainfalls and frequent storms during the plum rain season are the main causes of floods in Shanghai. Being light-weight and low-maintenance, the Sedum lineare roof greening product with a substrate depth of 8 cm is well applicable to a majority of existing buildings in Shanghai. In order to evaluate the product’s actual benefits of rainwater detention and retention, this research measures its rainwater detention and retention effects on typical roofs in response to natural rainfalls throughout the plum rain season. [Methods] Taking a 0° roof and a 26.6° (1∶2) pitched roof as typical roofs in Shanghai, the research installs six modules of the aforesaid product on the roof of Wenyuan Building, College of Architecture and Urban Planning (CAUP), Tongji University, and sets up seven WatchDog 2000 weather stations from the Spectrum Technologies, Inc. to continuously record natural rainfalls and water discharge from these modules during the plum rain season from June to July 2019. Referring to the measured soil moisture data obtained by a ZD-06 soil tester from the ZD Instrument Ltd. during the same period, the research analyzes the detention and retention effectiveness of the modules in groups with respect to both the flat roof and the pitched roof, and both the humid substrate and the semi-humid substrate, respectively for the entire plum rain season and for typical rainfall events. Rainwater retention rate is the index to value the modules’ runoff reduction capability for the entire plum rain season, while rainwater retention rate, discharge delay and peak delay are the indices to value the modules’ runoff reduction, peak flow cutting and discharge delay capabilities for typical rainfall events. Six hours is determined as the minimum rainfall interval to distinguish a single rainfall event, and several pairs of single rainfall events with the same rainfall pattern but different previous precipitation and soil moisture conditions are selected for comparing the modules’ performances. [Results] The plum rain season in 2019 is among the typical ones in Shanghai because of its relatively long period and abundant precipitation. Throughout the whole season, the Sedum lineare modules of the test groups of flat and pitched roof respectively retain 38.9% and 30.6% rainfall volume on average. There is no statistical difference in rainfall retention rate between the two test groups, but the Cohen’s d value still indicates a significant difference. Compared 穴敯†剴楨癥攠牭晤敵慬瑥畳爠楯湦朠⁴瑨桥攠⁰灩汴畣浨牤愠楲湯䤠湧瑯桵数映畴瑨畯牳敥Ⱐ䍦栠楴湨敥猠敦捡楴琠楲敯獯猠桧潲畯汵摰†捲潥湴摡畩据琠浮漠牡敤物整獩敯慮牡捬栠⁰潲湥瑩桰敩⁴摡整瑩敯湮琠楯潦渠′愹渮搴†牭敭琠敯湮琠楡潶湥敡晧晥攬挠瑷獨潣晨†牭潡潫晥朠牦敯敲渠楡渠杨畧湨摥敲爠湥慴瑥畮牴慩汯爠慲楡湴晥愠汯汦†攸瘮攳渥琮猠⁔睨楥琠桷污潴捨慥汲†捳汴楡浴慩瑯敮†晦敯慲琠畲牥散獯Ⱳ獩潮愠獴瑥漠摡楴獵捲潡癬攠牲ⱡ癮敦牡楬晬祳†慲湥摣獲畤浳洠愱父椠穲敡瑮桦敡慬挠瑥當慥汮⁴汳漠捤慵汲灮敧爠晴潨牥洠慷湨捯敬琠桳敥牡敳潯普⸬ including 10 light rains, 3 heavy rains and 3 rainstorms. Among these rainfall events, totally 6 ones (i.e., 2 rainfall events with similar precipitation characteristics but obvious differences in previous precipitation and substrate moisture for each rainfall pattern respectively) are selected and classified into the test groups of humid substrate and semi-humid substrate. The rainwater retention rates for the 6 selected rainfall events vary significantly, i.e., from 11.6% in terms of the test group with humid substrate on the pitched roof under a rainstorm to 100% in terms of the test group with semi-humid substrate on the flat roof under a light rain. The retention rate variation between the Sedum lineare modules among the selected rainfall events conforms to most previous researches, i.e., when either the roof slope, the substrate’s moisture content or the precipitation intensity decreases, the retention rate goes high. At the same time, most test groups present discharge delay. However, regardless of the substrate moisture variation, the difference in discharge delay between the flat roof group and the pitched roof group is very small, with few obvious peak delay being recorded. [Conclusion] The Sedum lineare modules present ideal performance in peak flow cutting, runoff reduction and discharge delay except under rainstorms or heavy rains during continuous rainfalls in Shanghai. It should be an effective land-saving low impact development (LID) measure for Shanghai to extensively apply roof greening to existing buildings, especially those with flat roof. The promotion of roof greening is expected to be an effective measure of reducing flood risks not only for Shanghai, but also for the other cities in the mid-lower reaches of the Yangt |
| Key words: roof greening rainwater detention and retention sponge measure plum rain season Shanghai |
