Revitalizing River Ecology with Dam Removal
The purpose of the Tel-Electric Dam Removal Project was to improve ecological conditions of the West Branch of the Housatonic River by eliminating public safety hazards and help lead the revitalization of adjacent urban neighborhood areas. The project required the off-site disposal of approximately 5,400 cubic yards of sediment-containing polychlorinated biphenyls (PCBs) and other contaminants associated with urban runoff and historic discharges. During the pre-construction planning and permitting process, Tighe & Bond completed a sediment characterization study to evaluate contaminant distribution throughout the project area.
Due to the presence of PCBs, sediment generated during the dam removal project met the definition of a PCB Remediation Waste regulated under the Toxic Substance Control Act (TSCA) 40 CFR 761. The Project Team implemented an EPA-approved Risk-Based Disposal plan for the river restoration and urban revitalization effort. The area of sediment removal extended from the dam structure approximately 400 LF upstream.
Sediment in floodplain areas was stabilized through the construction of revetments along the riverbank. Placement of six inches of topsoil, plantings, and vegetative cover seeding was completed in disturbed portions of the floodplain. Undisturbed areas of the floodplain, primarily on the western riverbank and in the upper portions of the project area, quickly transitioned into floodplain wetlands following the removal of the dam and lowering of the impoundment. Further stabilization of sediment in these areas occurs with each successive growing season.
The overall project construction costs for the dam removal project were estimated at $3.1M, of which, approximately $1.1M were associated with the handling and off-site disposal of sediment-containing PCBs at Casella’s Clinton County Landfill in Clinton, New York. After construction was completed and sediment was removed, the Housatonic River and floodplains in the vicinity of the dam were notably improved and ready for additional greenway construction.
Services Snapshot
Tighe and Bond assisted the Massachusetts Department of Fish & Game Division of Ecological Restoration (DER) with design, bidding, permitting, and construction phase services for the Tel-Electric Dam Removal Project.
