Ahtna Engineering Services. LLC (Ahtna) performed the removal and disposal of a utiliduct system, sewer outflow piping, a lift station, a cistern, and other foundations and associated infrastructure at the McGrath, Alaska, airport. Prior to fieldwork, we performed a site walk with the Federal Aviation Administration (FAA), held a safety meeting with the project team, and completed an equipment inspection.
We began work on the north utiliduct, followed by the east utiliduct, the south utiliduct, and finally the west utiliduct. Ahtna’s field crew relocated various structures and equipment including a small shelter, a lift station, sidewalks, concrete pads, as well as communication poles, antennae, and wiring. A fuel line was found in the north utiliduct and contaminated water and fuel were removed. Wastes and sorbents were placed in a U.S. Environmental Protection Agency and U.S. Department of Transportation approved container for disposal. Wells also required decommissioning.
Ahtna investigated and identified various asbestos-containing materials within the former living quarters Building 106 foundation and located a 6-inch asbestos cement sewer pipe from the former WB-6 located to the east of former lift station, in Building 602.
Ahtna removed and relocated local maintenance equipment from the former 400 building pad. We removed, disposed, and backfilled a 24-inch-thick by 13’-foot by 9-foot concrete slab that was formally used to support a fuel tank, a 16-foot by 12-foot patio slab, and a swing set. In addition, we encountered two formerly closed wells that were not properly decommissioned that we dug out, bent back to 5 feet below the surface, and backfilled.
Throughout project execution, Ahtna actively coordinated with onsite FAA personnel who identified and located existing utility and communications lines including low and high voltage power lines. In addition to these tasks, Ahtna performed some work around existing operations.
Challenges during project execution ranged from high voltage power supply lines crossing the utiliduct to contaminated soil adjacent to the utiliduct. In all cases Ahtna worked closely with FAA personnel for advisement and direction.