Duxbury Harbor Maintenance Dredging

The Town of Duxbury is located 25 miles south of the City of Boston. Duxbury Harbor is located at the northwestern end of Cape Cod Bay in Duxbury, about 20 miles northwest of the Cape Cod Canal. It is an active recreational boating center. The Duxbury Harbor Federal Navigation Channel Project consisted of an 8-foot-deep, 100-foot-wide, 1-mile-long Entrance Channel, and an 8-foot-deep, 21-acre Anchorage in the inner harbor. The Harbor had not been dredged since 1997, and the accumulated sediment made parts of the harbor very shallow and caused boats to hit ground.


PROJECT HIGHLIGHTS

• Both the anchorage and entrance channel portions of the project had a one-foot overdraft to 9 feet.
• Work consisted of maintenance dredging of ~200,000 yd³ of predominantly silt-clay by mechanical dredge; ~180,000 yd³ from the Anchorage, and ~45,000 yd³ from the Entrance Channel.
• A closed bucket was used while dredging in silty material to minimize turbidity adjacent to the dredge.
• Dredged sediment was transported and placed at the Cape Cod Bay Disposal Site located ~20 nautical miles from Duxbury Harbor.
• Some dredging was limited to an environmental window between September 1 and December 31, 2015; the project was completed by March 2016.