Author(s): Elizabeth A. Fassman; Minyang Liao
Linked Author(s): Elizabeth Fassman
Keywords: Grassed swale; Stormwater; Water quality; Hydrology; Low impact development
Abstract: Vegetated swales are widely used as stormwater conveyance and treatment systems along roadsides, in parking lots or in highway medians. This paper presents results of field tests conducted in Auckland, New Zealand of the performance of a series of grassed swales within a stormwater treatment train system treating parking lot runoff. Low event mean concentrations of total suspended solids, dissolved and total recoverable copper and dissolved and total recoverable zinc over eight storms show that the swale system is effective at pollutant control for these parameters, but not for total dissolved solids. Over 42 events, significant peak flow and volume reductions for storms < 25 mm is noted. Peak flow control is significantly affected by peak rainfall intensity. Hydraulic residence times for these frequently occurring events are much longer than design recommendations, likely leading to good water quality control.
Year: 2009