Institute of Environmental Engineering (IfU), Swiss Federal Institute of Technology (ETH) Zürich, 8093 Zurich, Switzerland.
Department of Urban Water Management, Swiss Federal Institute of Aquatic Science and Technology (Eawag), 8600 Dübendorf, Switzerland.
Water Res. 2021 Mar 1;191:116780. doi: 10.1016/j.watres.2020.116780. Epub 2020 Dec 23.
Sustainable urban drainage systems (SuDS) help in stormwater management by reducing runoff volume, increasing runoff concentration time and thereby improving the drainage system capacity. This study investigated the potential and cost-effectiveness of SuDS in reducing combined sewer overflows (CSOs). We simulated the performance of four SuDS techniques (bioretention cell, permeable pavement, rain barrel and green roof) at incremental levels of spatial coverage for a small urban catchment with a combined sewer system. We also used an Analytic Hierarchy Process (AHP) considering end-point CSO, land use, imperviousness, slope and elevation criteria to identify priority areas for SuDS deployment. Results showed that CSO volume attenuation ranged a maximum of 50-99% for the catchment, depending on the deployment strategy and underlying mechanisms of each technology. We also found that deployment of SuDS in AHP-selected sub-catchments improved CSO reduction only for rain barrels and green roofs, but not for bioretention cells and permeable pavements. SuDS were also a cost-effective retrofit option: for a 40% volume reduction, the SuDS cost, at most, 25% of the equivalent cost required for a large CSO tank. Outcomes of this study demonstrate the efficacy of SuDS in controlling CSOs, adding yet another tangible benefit to their increasingly recognised multi-functionality.
可持续城市排水系统 (SuDS) 通过减少径流量、增加径流水位峰值时间，从而提高排水系统能力，有助于进行雨水管理。本研究探讨了 SuDS 在减少合流制污水溢流 (CSO) 方面的潜力和成本效益。我们模拟了四种 SuDS 技术（生物滞留池、透水铺装、雨水桶和绿色屋顶）在具有合流制污水系统的小城区中不同空间覆盖度水平下的性能。我们还使用了层次分析法 (AHP)，考虑端点 CSO、土地利用、不透水率、坡度和海拔标准，确定了 SuDS 部署的优先区域。结果表明，取决于部署策略和每种技术的基本机制，CSO 体积衰减的最大范围为流域的 50-99%。我们还发现，在 AHP 选定的子流域中部署 SuDS 仅能提高雨水桶和绿色屋顶的 CSO 减排效果，而对生物滞留池和透水铺装则没有效果。SuDS 也是一种具有成本效益的改造选择：对于 40%的体积减少，SuDS 的成本最高仅占大型 CSO 罐所需成本的 25%。本研究的结果表明，SuDS 在控制 CSO 方面的效果显著，这进一步证明了其日益被认可的多功能性的另一个切实好处。
