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，增加径流集中时间并从而提高排水系统容量来帮助进行雨水管理。这项研究调查了SuDS在减少联合下水道溢流（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，可渗透路面，雨桶和绿色屋顶）在一个小型城市集水区和下水道组合系统的空间覆盖增量水平下的性能。我们还使用了分析层次结构过程（AHP），其中考虑了端点CSO，土地使用，防渗性，坡度和海拔标准，以确定SuDS部署的优先领域。结果表明，集水区的CSO体积衰减最大为50–99％，取决于每种技术的部署策略和底层机制。我们还发现，在AHP选择的子集水区中部署SuDS只能减少雨桶和绿色屋顶的CSO降低，而不能改善生物保留单元和可渗透的人行道的CSO降低。SuDS也是一种经济高效的改装方案：要减少40％的体积，SuDS的成本最多仅为大型CSO储罐所需等效成本的25％。这项研究的结果证明了SuDS在控制CSO方面的功效，为它们日益被认可的多功能性又增加了另一个明显的好处。如果要减少40％的体积，SuDS成本最多仅为大型CSO储罐所需等效成本的25％。这项研究的结果证明了SuDS在控制CSO方面的功效，为它们日益被认可的多功能性又增加了另一个明显的好处。如果要减少40％的体积，SuDS成本最多仅为大型CSO储罐所需等效成本的25％。这项研究的结果证明了SuDS在控制CSO方面的功效，为它们日益被认可的多功能性又增加了另一个明显的好处。