高度城市化地区屋顶绿化径流调控效益评价——以厦门岛为例

屋顶绿化的降雨径流调控效益对城市水安全与可持续发展具有重要作用，尤其是在土地资源紧缺与环境问题突出的高度城市化地区，然而目前针对城市尺度进行屋顶绿化降雨径流调控效益的研究较少。以厦门岛142 km~2的典型高度城市化地区为研究对象，采用ArcGIS与SCS-CN水文模型，研究了四种屋顶绿化实施场景在四种不同重现期(2、5、10、20年)降雨事件下各汇水区屋顶绿化的降雨径流调控效益，并依其空间分异特征制定差异化生态建设策略。结果显示，(1)平均地表径流减少率随城市屋顶绿化量的增加从0.91%增加至4.51%,随降雨强度的增加从2.86%下降到2.01%。屋顶绿化对南部城市核心区中山路商圈汇水区的地表径流削减作用最为显著，在2年重现期降雨事件和100%屋顶绿化实施场景下地表径流减少了8.84%。(2)厦门岛易积水区域主要分布在高崎机场、西北部港口、筼筜湖、五缘湾和环岛路；在四种屋顶绿化实施场景下，平均积水深度降低1.68、4.68、6.45、14.43 cm,平均积水面积减少6.11、16.89、23.29、52.06 hm~2,而随着降雨强度的增加，积水面积减少率幅度降低，屋顶绿化对中低...

Assessment of hydrological performance of green roofs in highly urbanized areas: A case study of Xiamen Island

The rapid urbanization has increased the impervious surface of cities, seriously affecting urban water security. Study of hydrological performance of green roofs is of great significance to urban water security and sustainable development, especially in areas of highly urbanization where land resources are scarce and environmental problems are prominent. However, there are still few studies on the hydrological performance of green roofs within a city range. In this study, a typical highly urbanizing area of 142 km² of Xiamen Island was chosen as a case study. Under four green roofs implementation scenarios of the return period (2, 5, 10, and 20 years), the hydrological performance of green roofs was investigated by the ArcGIS and Soil Conservation Service Curve Number (SCS-CN) model. The differentiated ecological construction strategies were formulated according to its spatial differentiation characteristics. The results show that (1) the average runoff reduction rates increase from 0.91% to 4.51% with the increasing green roofs amount, and decrease from 2.86% to 2.01% with the increasing return period of rainfall events. The catchment of the Zhongshan Road business district in the southern city core area plays a key role in reducing runoff, by 8.84% under the two-year return period of rainfall events and 100% green roofs implementation scenarios. (2) The areas prone to stagnant water on Xiamen Island are mainly distributed in Gaoqi Airport, the northwest port, Yundang Lake, Wuyuan Bay, and Huandao Road. The average ponding depth decreased by 1.68, 4.68, 6.45, 14.43 cm and the ponding area decreased by 6.11, 16.89, 23.29, 52.06 hm² under the four green roofs scenarios. The reduction rate of the ponding area decreases with the increasing rainfall return period. Green roofs have a significant effect on ponding mitigation under low to moderate intensity rainfall. The study demonstrated the positively hydrological performance contributed by green roofs in the future Xiamen Island at a city scale, and could effectively respond to the water security problems of highly urbanization. In addition, analysis of spatial heterogeneity characteristics of hydrological performance of green roofs can provide scientific guidance for urban ecological governance. Zhongshan Road should take green roofs as a key ecological strategy to mitigate pond; the northwest port should consider other broader ecological strategies; Gaoqi Airport should include roof greening as a mandatory content of the unified development plan after relocation. In addition, this study is carried out under the background of coastal cities with subtropical monsoon climate. The results may not be applicable to other climatic conditions and different types of green roofs, but it will be of reference significance for similar comparative studies.