Supporting the working waterfront with the first contained aquatic disposal (CAD) cell in the State of Maine

Portland Harbor CAD Cell

For years, the economic growth of Portland Harbor’s historic working waterfront was increasingly threatened by the lack of adequate berthing room due to shallow depth between piers, caused by decades of sediment accumulation. Something needed to change—that’s where we came in.

Wharf owners identified sediment buildup as a key barrier to economic growth and reinvestment—to help remedy this, we set out to create the first contained aquatic disposal (CAD) cell in the State of Maine. This solution would stimulate waterfront economic development by dredging and disposing sediments from berthing areas, some of which have not been dredged in over 70 years. 

Finding a CAD cell location in Portland Harbor required meeting sophisticated geotechnical, environmental, and engineering criteria. We completed bathymetric surveys, sub-bottom profiling, geotechnical borings, vibracore sampling, underwater video, and SCUBA surveys as part of the characterization of the proposed CAD cell site for both engineering feasibility and permitting. Working with the US Army Corps of Engineers, we developed a sampling strategy to test the CAD cell sediments for suitability for offshore disposal. 

Once the removed materials are cleaned for offshore disposal, Portland Harbor will have cleared berthing areas and a more secure economic future.