A long-awaited dredging project in the iconic Portland Harbor is now complete.

The effort to clear more than 40 marine sites along Portland’s waterfront began in December, with many of them untouched for 70 years.

The city says Portland’s harbor has been dramatically improved for vessel activity after many slips were lost due to rising sediment in the harbor.

More than 10,000 linear feet of berthing have been deepened and restored.

(Portland Harbor dredging project – City of Portland)

The contaminated sediment that was dredged has been dropped into a specially engineered underwater containment area near the Casco Bay Bridge.

The containment area is known as a Confined Aquatic Disposal (CAD) cell. The city says this step alone took years to design and complete, and was crucial for dredging harbor material that could not be deposited on land. The CAD cell is the first of its kind in Maine.

More than 45,000 cubic yards (equivalent to 4,500 dump trucks) of material were relocated to the CAD cell.

The city says the second half of the project will take place next winter, where the work will concentrate on South Portland marinas, the East End Beach recreational boat ramp, and Maine Yacht Center.

The project is estimated to cost $26 million.