Stormwater Treatment Wetland Design and Construction
An existing borrow pond along a Bayou, and drainage ditches feeding a pond, received runoff from 21.5 acres of University property, including heavily-used parking lots, roads, and buildings. The University proposed a plan for the construction of a wetland that would reduce pollutant concentrations from stormwater runoff, provide a research area for environmental science students, enhance wildlife habitat on campus, and improve the aesthetics of the area for passive recreation. The client envisioned a design that would convert the existing swale and deep pond into a natural stream and wetland complex, with interpretive signage and infrastructure to support students’ outdoor education. The client sought a qualified firm to manage the project from the design phase to completion and through two years of maintenance.
GES designed and constructed a multiple-use stream and wetland complex on campus. As the prime contractor, GES obtained all necessary permits, and selected and managed subcontractors. Time and space were substantial constraints in completing this project. The proposed stream/wetland footprint had to occupy an existing ditch and borrow pond; maintain existing elevations within the floodplain; and minimize earthwork. A USACE Section 404 wetland permit and a water-rights permit were obtained to fulfill regulatory requirements associated with the construction of the project.
The campus amenity has been restored and greatly improved, attracting students and community members alike. Post-construction monitoring of water quality conditions has demonstrated a significant reduction in concentrations for several pollutants of concern, including E. coli, nitrogen, phosphorous, and total suspended solids. The project was completed on time, within budget, and to the client’s satisfaction.