Portland Project Wins Engineering Excellence Award

MACTEC's Portland, Maine office has received an Engineering Excellence Award by the American Council of Engineering Companies (ACEC)-Maine for its work on the Eastland Woolen Mill Site project for the U.S. Army Corps of Engineers. Our project team provided SI/RI/FS and design services that fast-tracked this Superfund Site cleanup and literally paved the way for Corinna's downtown redevelopment.

Soils and sediments underlying the Main Street road and bridge (State Highway Rte. 7/11), downtown buildings, and the Sebasticook River had been contaminated by the Eastland Woolen Mill's discharge of chlorobenzene compounds in its process wastewater. Working closely USACE, USEPA and many other stakeholders resulted in the cleanup, site restoration, and improvement of the downtown hub of Corinna being completed in four years (a year ahead of schedule) and $1 million below budget.

The project required relocation of nearly all of the downtown hub - roadway, bridge, river, and a historic building - so that underlying contamination could be excavated and treated. Abandoned mill buildings contaminated with asbestos were demolished and removed. An indirect-fired, low-temperature thermal treatment (LTTT) batch system was selected to treat 100,000 tons of chlorinated, benzene-contaminated soil and sediment. This system was more cost-effective than other treatment options and well-suited to the phased approach that was required to allow for relocation of the road and bridge infrastructure.

To access contaminated soil and sediment, it was necessary to remove a dam and divert the river. To meet State of Maine fishery management objectives for the river, the dam was permanently removed and the Mill Pond was converted back to a free-flowing river. The design of the river diversion called for temporary bypass using pumping and piping and box culverts in the existing stream channel to handle river flows during contaminated sediment excavation and the subsequent construction of the new roadway and river channel. The river restoration design included the creation of a new free-running river with low-flow channel for fish passage, channel blocks, and riffels, runs and pools. Riverbank wetlands were allowed to naturally re-vegetate, avoiding costly planting and seeding.

MACTEC also designed a new highway alignment for the project. Through coordination with the Maine Department of Transportation and the Town, which had been planning highway and bridge improvements on Route 7/11 prior to this project, duplication of effort and cost was avoided in improving this important highway/bridge gateway to the Moosehead Lake Region and the Town of Corinna was provided with a completed road, bridge, infrastructure, and restored site for its planned revitalization. Severe site constraints that complicated the design included: 1) Proximity of road/bridge/river to contaminated area requiring road detours/relocation and river diversion; 2) Location in downtown area requiring relocation of water and sewer lines and a historic building and removal of businesses and homes; and 3) Access issue with Railroad Property, requiring design to avoid impact to old railroad line running through the site.