长三角地区典型海绵设施水文效益试验研究

Field experiment-based investigation on hydrological benefits of typical sponge facilities in the Yangtze Delta region

  • 摘要: 开展不同海绵设施在中国长三角气候模式下的水文效益研究, 对增强城市应对内涝能力从而提高城市对变化环境的适应性具有重要科学意义。选择国家首批海绵试点城市镇江海绵基地4种典型海绵设施作为研究案例, 采用径流系数、削减率、削峰率及洪峰流量等指标, 评估场次降雨与海绵设施出流相关性, 分析海绵设施在不同降水量级和降雨雨型下的水文性能, 以及运行时间对海绵设施水文效益的影响。结果表明: ①透水铺装类海绵设施的降雨—径流关系呈单一式; 而绿植类则表现为分段式, 即在场次降水量超过一定临界暴雨量之后关系线发生转折, 其中平均径流系数增加了8.4~38.5倍, 平均削峰率和削减率分别减少了50.4%和44.6%。②暴雨条件下不同海绵设施的产流能力和洪峰流量最大, 对径流总量消减能力及洪峰流量削减能力最弱, 且从暴雨到大雨变化规律比大雨到中雨变化规律更显著。③海绵设施的水文性能受到降雨雨型、平均降雨强度和最大单位降雨强度等因子多重复合影响。除雨水花园外, 其他海绵设施的径流系数对上述影响因子变化最为敏感, 洪峰流量次之, 削减率第3, 削峰率的敏感性显著低于前面三者。④车行透水砖运行1 a后, 其产流能力与洪峰流量分别显著增加1.7~2.1倍和1.9~2.5倍; 径流控制能力显著减弱, 其中消减能力降低了16%。

     

    Abstract: In order to enhance the ability of urban waterlogging prevention and improve urban adaptability of urban areas to changing environments, it is significantly important to investigate the hydrological benefits of different sponge facilities under the climate pattern of the Yangtze Delta region. Four typical sponge facilities in the Zhenjiang Sponge Base, the first national sponge pilot city, were selected as the study cases. Several indicators, such as runoff coefficient, runoff reduction rate, peak-cutting rate, and flood peak, were selected to evaluate the rainfall-runoff relationship, analyze the hydrological performance under different rainfall intensities and patterns, and explore the impact of operation time on the hydrological benefits of the sponge facilities. The results showed that the permeable pavement sponge facilities demonstrated a single rainfall-runoff relationship, and in contrast the green plant facilities showed a segmented rainfall—runoff relationship. For the green plant, the rainfall—runoff curve underwent a transition when the event rainfall amount exceeded a critical storm rainfall amount. As a result, the mean rainfall coefficient increased by 8.4 to 38.5 times, and the average peak-cutting rate and runoff reduction rate decreased by 50.4% and 44.6%, respectively. Under storm conditions, all sponge facilities exhibited the highest runoff generation capability and flood peak but displayed the lowest total runoff reduction and peak-cutting abilities. This effect was more remarkable in the conditions of storm to heavy rain than in the conditions of heavy rain to moderate rain. The hydrological performance of the sponge facilities was jointly affected by the rainfall pattern, the average rainfall intensity, and the maximum unit rainfall intensity. Except for the rain garden, the runoff coefficient of all sponge facilities was most sensitive to the changes of the aforementioned factors, followed by the flood peak, and the runoff reduction rate was the lowest. The permeable pavement showed a significantly weakened runoff control ability after 1-year operation, and its runoff generation capability and flood peak were significantly augmented by 1.7 to 2.1 times and 1.9 to 2.5 times, respectively.

     

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