Impact Assessment of Socio-Economic Scenarios on a Water Quality Swale: An Exploratory Analysis with WinSLAMM

Sustainable long-term performance of water quality swales, a common stormwater control measure (SCM), requires a futuristic view that considers the impact of socio-economic conditions. The impact of five socio-economic scenarios on a water quality swale in Knightdale, North Carolina, USA, was assessed using WinSLAMM, a stormwater quality model. Scenarios included changing annual average daily traffic (AADT) and maintenance regimes mimicking environmental protection and degradation. Statistical performance evaluation criteria (e.g., RMSE, R2) were used to assess model suitability and calibration for runoff volume and sediment. Results indicated that sediment delivery to the swale increased with AADT, and reduced maintenance negatively impacted swale performance. While the reduced AADT during the COVID-19 pandemic provided short-term water quality benefits, a lack of maintenance impacted treatment through the swale. SCM inspection and maintenance is critical for accommodating increased AADT and enhancing swale life-cycle. This exploratory impact assessment focused on the socio-economic axis of climate change scenario framework and underscored the importance of sound environmental policies for sustainable swale performance. Future studies are needed in other areas to influence local environmental policies.