US Coast Guard
South Weymouth Buoy Depot
South Weymouth, MA

The United States Coast Guard (USCG) has contracted Nobis Engineering, Inc. to provide engineering services for the removal action at the South Weymouth Buoy Depot.

The Buoy Depot is a 5.5-acre lot, located on the former Naval Air Station (NAS) in South Weymouth, Massachusetts. A two-story, steel and concrete block building, approximately 20,000 square feet in area occupies the northwestern portion of the property. The building houses the primary equipment used to sandblast, repair, and paint buoys. Asphalt driveways surround the building, and paved parking areas are located adjacent to the northern and western sides of the building. Unpaved buoy storage areas are located south and east of the building. Operated as a principle east coast facility for storing, cleaning, repairing and painting navigational buoys. The activities involved in processing the buoys have contaminated the soil in the outside buoy storage areas with paint chips containing lead. Lead was used to increase paint durability up to the early 1980s. As a result of stormwater run-off from the USCG property, the soil in the adjacent swale and wetland, owned by the Navy, has also become contaminated with lead from the paint chips.

Phase I – Remedial Action
Nobis was responsible for the remedial action that included preconstruction activities such as preparing a Work Plan, Health and Safety Plan, and Sampling and Analysis Plan. Construction activities included investigating floor drain construction, removing the floor drains and drywells inside and outside the existing building, confirmation soil sampling and testing for volatile organic compounds (VOCs), metals, pesticides, and polynuclear aromatic hydrocarbons (PAHs), characterization soil testing, disposal of 40 tons of contaminated soil, and restoring the site to its original condition. Post construction activities included preparing a Final Closure Report documenting the field activities.

Phase II – The Stormwater Management Plan and The Removal Action Plan
Nobis will be responsible for the remedial action and storm water management design and construction for the swale and wetlands at the USCG Buoy Depot.

Nobis was contracted by the USCG to perform the installation and oversight of the Stormwater Management Plan. The Stormwater Management Plan specifies the installation of earthen and bituminous concrete berms to prevent off-site stormwater run-off, installation of catch basins to collect the stormwater on-site, the creation of an infiltration trench to allow stormwater to leach into the soil, installation of underground detention galleries to hold stormwater. Construction activities will include the excavation of over 150 cubic yards of contaminated hydric soil, confirmation soil sampling and testing for metals and polychlorinated biphenyls (PCBs), characterization soil testing, disposal of contaminated soil, and restoring the wetlands and swale to there original condition. Nobis has designed the Stormwater runoff control system to mitigate the transport of lead contaminated sediment from the facility’s storage areas to the swale and wetlands. The storm water design considered an area of influence of approximately 5.5 acres.

Nobis developed the Removal Action Work Plan for the USCG to satisfy the regulatory requirements of the MADEP and the USEPA. The plan details the operations and safety hazards involved in excavating, sampling, and disposing of the lead contaminated soil from the swale and wetland. The plan also includes he backfill and restoration operations associated with the excavation of the contaminated soil. Nobis has been contracted to perform the removal and restoration work detailed in the work plan.