Coastal, River, & Wetland Restoration
- Bank Stabilization and Wetland Terrace Creation at the Charles River Park
Army Research Laboratory, Watertown, Massachusetts
the challenge The Army Research Laboratory – Watertown (ARL-WT) was used as a munitions testing, manufacturing, and storage site from 1816 until 1995. In 1994, it was placed on the EPA Superfund National Priority List, with the Record of Decision calling for the remediation of soil and groundwater including organic and radioactive contaminants. The site encompasses a popular urban park designed by Frederick Law Olmstead as part of the Boston area’s Emerald Necklace along the Charles River valued for its recreational boating and aquatic habitat.
the interdisciplinary approachThe Bioengineering Group developed designs to restore bank stability and habitat diversity as part of the remediation strategy for the site. The bank restoration designs involved the use of phytostabilization to use native wetland and riparian vegetation for containment of clean soil overlying residual contaminated soils. Bank protection measures incorporated a combination toe (coir fascines) and upper slope (brush layers and live stakes) treatment. A separate area involved the establishment of a wetland terrace and a breakwater treatment to protect the toe of the slope planted and seeded with native grasses, shrubs, and trees. The breakwater treatment needed to withstand boat wake while blending with the aesthetic character of the park. Bioengineering Group provided construction management and supervision services for both areas.
the results Our innovative approach resulted in a stabilized riverbank by the capping and immobilization of contaminated floodplain material through planting of native vegetation. This new habitat area was enhanced and protected with the creation of a littoral shelf wetland and the re-establishment of a riparian forest buffer. Agency personnel and public stakeholders were very pleased with the approach and its performance for fisheries and recreation, and this support helped reach rapid regulatory closure for the site.