Connecticut River Coal Tar Remediation

Over 100 years, intermittent releases of coal tar from a manufactured gas plant into the Connecticut River resulted in the presence of discrete tar patches in a three and a half mile stretch of the riverbed. We oversaw the placement of a large stone capping material, improving the quality of the river and the aquatic habitat for both federally and state listed species.

The river is a shortnose sturgeon habitat, but little was known about their use of the area. Our team had the unique idea to tag them with transmitters to monitor seasonal behavior and habitat use with acoustic receivers. This provided protection during construction and gathered essential information for conservation, which we presented to the scientific community and federal agencies. Mussels, another threatened species, were also protected during construction activities by using systematic transect surveys.

Our environmental scientists worked with numerous agencies to obtain the extensive permitting required for the remedial construction. We also provided daily construction compliance oversight and implemented daily surveys for adherence to the design plans, Sturgeon Protection Plans, and conditions for all project permits.