ABSTRACT Stormwater control measures (SCMs) are effective measures to reduce the risks of urban flooding and pollutants being transferred to receiving water bodies. However, the selection of appropriate SCMs and maintenance is essential to ensure reliable performance in both the short and long term. To improve insights into these factors, a residential catchment was modelled using the EPA Storm Water Management Model (SWMM) with various SCM alternatives covering different spatial distributions and degrees of naturalness. Changes over time were also considered to assess performance decline after clogging due to insufficient maintenance. The results confirmed the effectiveness of SCM alternatives for flood mitigation by demonstrating reduced runoff, peak flows and flood volumes compared with a baseline model with a conventional drainage system. Stormwater quality modelling showed decreased pollutant concentrations and loads for the SCM alternatives. Clogging of the media was found to have a substantial impact on efficiency. For complex constructed SCMs, the proportion of overflow increased greatly, resulting in higher pollutant loads and concentrations and a greater risk of flooding. Conversely, simpler constructed SCMs showed substantially decreased runoff and peak flows due to decreased infiltration of stormwater. The results highlight the importance of careful planning, design and maintenance of SCMs.
Otte et al. (Mon,) studied this question.