Assessing the effectiveness of a residential-scale detention tank operated in a multi-objective approach using SWMM

The volume capture ratio of annual rainfall (VCRAR) of low-impact development measures is significantly influenced by its operating characteristics, particularly for residential stormwater detention tanks (SWDTs). The multi-objective operation strategy of SWDTs, encompassing toilet flushing (TF), green space irrigation (GSI), combined TF and GSI (TF-GSI), and peak flow reduction (PFR) rate, were compared using a case study in Beijing based on the stormwater management model. The findings indicate that the VCRAR for TF, GSI, and TF-GSI rainwater harvesting targets was 89.05, 77.16, and 91.21%, respectively. The operating scheme and return periods have a significant impact on the PFR rate's effectiveness. When the return period was lower than 10 years, the SWDT does not reach its maximum storage capacity, and the PFR rate was increased with increasing the return period: the PFR rate was 71.47% when the design return period was 10 years. It will also produce the phenomena of water inrush, and the overflow volume will grow rapidly when the SWDT reaches its maximum storage capacity. Hence, the operation of SWDTs may be integrated with real-time control to optimize the VCRAR for rainwater reuse and flood migration, thereby enhancing the volume utilization efficiency of SWDTs.