Institute of Ecosystem Studies

2007 BES Annual Meeting Presentation and Poster Abstracts

Efficiency of a constructed wetland in improving water quality in an urban stream
Stanko, Gwendolyn
Co-Authors: Gwendolyn M. Stanko, Kenneth T. Belt, Erle C. Ellis, Richard V. Pouyat, Peter M. Groffman
Abstract: Water quality is of utmost concern in todayís ever growing urban areas. The Gwynns Run Pollution Control Facility in Carroll Park, Baltimore, Maryland, was designed to improve water quality in Gwynns Run, a highly impacted urban stream, by the partial diversion of its flow through a constructed treatment wetland. This projectís goal was to assess the efficiency of this treatment wetland in improving the water quality. Water samples were collected six different times during summer 2006 from stream locations above and below the treatment wetland, and at the intake and outlet of the wetland. Samples were then analyzed for water quality parameters including nitrogen (NO2-, NO3-, NH4+), phosphate (PO43-), and total and volatile suspended solids (TSS, VSS). Flow measurements were made on four of the six dates and used to estimate pollutant removal efficiencies in terms of load. The average concentration removal efficiency of NO2-, NO3-, total inorganic N, Cl-, and SO42- was 4%, 68%, 59%, 56%, and 50%, respectively. For total NH4+, PO43-, o-phosphate, TSS, and VSS the average concentration removal efficiencies were negative. Loads of pollutants and other materials were not significantly lowered by passage through the treatment wetland, and the only material with a positive load removal efficiency was NO3-, but these results may be explained by an observed imbalance between inflow and outflow. Prior to this study, no monitoring had been performed at the Gwynns Run Facility to assess its impact on water quality. This study demonstrates the importance of establishing monitoring programs to track the progress of remediation efforts and to make necessary repairs and alterations to the remediation system.