Assessing the Influence of Operational Controls on Flow Behavior in a Constructed Stormwater Wetland through Residence Time Analysis

Constructed wetlands are designed to slow and treat stormwater runoff in developed watersheds, but static operation can limit efficiency across a broad range of hydrologic conditions.  This study utilized dye tracer testing to assess existing and proposed control devices’ influence on a stormwater wetland’s performance under varying weather conditions.  At Villanova’s Constructed Stormwater Wetland, dynamic operation of an adjustable sluice gate increased upstream retention time from 2.4 hr to 4.1 hr during stormflow conditions, though flow behavior remained responsive to storm characteristics.  Under baseflow, a mean residence time of 7.0 hr within a selected analysis segment (M3) constrains water quality reaction times in this zone.