Assessing ability of a wet swale to manage road runoff: A case study in Hefei, China

Abstract

The ability of a wet swale, constructed in an area of poor soil permeability, to manage runoff from a roadway was monitored through 27 storm events over a period of 8 months. During the monitoring period, the wet swale reduced the total runoff volume by 50.4% through exfiltration and evapotranspiration. The wet swale significantly decreased the influent pollutant concentrations, and the effluent mean concentrations of total suspended solids, total phosphorus, chemical oxygen demand, ammonium, oxidized nitrogen, and total nitrogen in the effluent were 31 mg/L, 0.10 mg/L, 29 mg/L, 0.52 mg/L, 0.35 mg/L and 1.28 mg/L, respectively. Pollutant loads were also substantially reduced from 70% to 85%. Plant uptake played an important role in nutrient removal in the wet swale. Approximately half of the nitrogen (53.8%) and phosphorus (51.5%) that entered the wet swale was incorporated in above-ground plants. It is shown that wet swales are useful for managing runoff from roads in areas of poor soil permeability.

Keywords

wet swale / stormwater runoff / water quality improvement / water quantity reduction / removal mechanism / vegetation

References

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