Constructed Wetlands for Stormwater Management

About the report:

This report presents the results of research to evaluate the potential of utilizing mitigated wetlands as stormwater Best Management Practices (BMPs). Results of wetland monitoring, wetland modeling, and geographic information system (GIS) development are presented. Average removal rates as high as 90% for total suspended solids (TSS), 65% for chemical oxygen demand (COD), 70% for total phosphorus (TP) and orthophosphate (OP), and 50% for zinc (Zn) were observed at study sites. Despite having stormwater runoff as a primary water source, the monitored sites supported apparently healthy and diverse vegetation, and a variety of wildlife. A mathematical model of transport of a pollutant in dissolved and particulate forms in a two segment, two-state system was developed. The model includes settling, diffusion, adsorption to plant and substrate, and vegetative uptake mechanisms. A GIS was developed to improve management of existing mitigated wetlands and to aid in siting of future mitigation sites. A link between a watershed model and this GIS is also described. The report concludes that mitigated wetlands may be as effective as conventional BMPs at improving the quality and at controlling the quantity of highway storm runoff.

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