Effect of climate change on stormwater runoff characteristics and treatment efficiencies of stormwater retention ponds: a case study from Denmark using TSS and Cu as indicator pollutants

Abstract

This study investigated the potential effect of climate changes on stormwater pollution runoff characteristics and the treatment efficiency of a stormwater retention pond in a 95 ha catchment in Denmark. An integrated dynamic stormwater runoff quality and treatment model was used to simulate two scenarios: one representing the current climate and another representing a future climate scenario with increased intensity of extreme rainfall events and longer dry weather periods. 100-year long high-resolution rainfall time series downscaled from regional climate model projections were used as input. The collected data showed that total suspended solids (TSS) and total copper (Cu) concentrations in stormwater runoff were related to flow, rainfall intensity and antecedent dry period. Extreme peak intensities resulted in high particulate concentrations and high loads but did not affect dissolved Cu concentrations. The future climate simulations showed an increased frequency of higher flows and increased total concentrations discharged from the catchment. The effect on the outlet from the pond was an increase in the total concentrations (TSS and Cu), whereas no major effect was observed on dissolved Cu concentrations. Similar results are expected for other particle bound pollutants including metals and slowly biodegradable organic substances such as PAH. Acute toxicity impacts to downstream surface waters seem to be only slightly affected. A minor increase in yearly loads of sediments and particle-bound pollutants is expected, mainly caused by large events disrupting the settling process. This may be important to consider for the many stormwater retention ponds existing in Denmark and across the world.

Improved reliability of stormwater detention basin performance through water quality data-informed real-time control

“…Across the generated rainfall scenarios, the TSS control resulted in zero h,g and the lowest and least variable system failure. Due to climate change, increased TSS load is expected (He et al, 2010;Wilson and Weng, 2011;Sharma et al, 2016 performance for the whole range of particle size distribution of TSS thus different settling velocities. Therefore, the overall TSS removal was also dependent on the settling velocities of different particle sizes.…”

Revised design criteria for stormwater facilities to meet pollution reduction and flow control requirements, also considering predicted climate effects

“…With the expected climate change, the total precipitation will increase (in Sweden), maximum flows will increase and the period without precipitation will be longer. This is expected to result in higher peak concentrations and event mean concentrations, and an increased total load (Sharma et al, 2011) which may lead to that existing treatment facilities are undersized. "Storm water treatment"…”

Modeling of <i>E. coli</i> distribution for hazard assessment of bathing waters affected by combined sewer overflows

“…Liu and Huang (2012) developed a 2D model of an estuary exposed to tides. Sokolova et al (2013) and Thupaki et al (2010) presented hydrodynamic 3D models of lakes to simulate E. coli based on pollutant discharges estimated from observations at affluent rivers and/or sewers. Also, coupled urban drainage and water quality models of receiving water bodies were developed to simulate spatial and temporal variations of bacterial concentrations for bathing water quality affected by CSOs (Andersen et al, 2013;De Marchis et al, 2013).…”