CONCORD, Mass. – The U.S. Army Corps of Engineers, New England District is proposing to perform removal of hazardous rock outcrops in Boston Harbor in Boston and the Weymouth Fore River Federal navigation channel in Weymouth, Hull and Hingham, Mass.
“Recent maintenance dredging of the Federal navigation channels in Boston Harbor and the Weymouth Fore River revealed rock outcrops that are above the authorized depth,” said Project Manager Mike Keegan, of the Corps’ New England District, Programs/Project Management Division. “Exposed rock poses a safety hazard to ships transiting the navigation channels.”
Corps policy requires that rock be removed to at least two feet below the authorized depth in a navigation channel. A total of approximately 3,140 cubic yards of rock would be removed from both Federal navigation projects. The rock and incidental dredged material is expected to be disposed of at the Massachusetts Bay Rock Reef Site located about 20 miles offshore.
The Boston Harbor Main Ship Channel is composed of two navigation lanes that are 35 feet and 40 feet deep at mean lower low water (MLLW). Potentially hazardous rock outcrops have been identified at two areas within the Main Ship Channel. Of these outcrops, approximately 40 percent may need to be blasted prior to removal with a dredge. The remaining 60 percent of the rock may be removed using mechanical means such as through grinding, a hydraulic impact hammer or an excavator. A total of approximately 140 cubic yards of rock and about one month of construction time will be needed to remove these hazards. Previous dredging of this portion of the Main Ship Channel in Boston Harbor was done in 2008.
The authorized Federal project for the Weymouth Fore River includes a navigation channel 35 feet below MLLW. The channel is 500 feet wide from deep water in Nantasket Roads through the Nantasket (Hull) gut, and then is reduced to 400 feet wide through Hingham Bay to the mouth of the Weymouth Fore River where the channel is further reduced in width to 300 feet up to the Fore River Bridge (also known as the Washington Street Bridge). The channel widens to 400 feet above the bridge.
Approximately 3,000 cubic yards of rock would need to be removed from two areas located in the outer channel leading to Weymouth Fore River. This rock will need to be blasted prior to removal with a mechanical dredge and is expected to take approximately two to three months to remove this material. Previous dredging of the Weymouth Fore River was done in 2007.
An Environmental Assessment for this work is being prepared and will be made available for review upon request.
The proposed work is being coordinated with the following Federal and state agencies: U.S. Environmental Protection Agency; U.S. Fish and Wildlife Service; the National Marine Fisheries Service; the Massachusetts Department of Environmental Protection; the Massachusetts Executive Office of Energy and Environmental Affairs; the Massachusetts Department of Marine Fisheries; the Massachusetts Division of Fisheries and Wildlife; and the Massachusetts State Historic Preservation Office.
The public notice for this proposed work, with more detailed information, is available for review on the Corps of Engineers, New England District website at http://www.nae.usace.army.mil. Select “navigation” and then “public notices.” To go directly to the weblink for the public notice go to:
http://www.nae.usace.army.mil/navigation/publicnotices/BostonWeymouthRockRemovalPN_10032011.pdf.
Public comments on this proposed work should be forwarded no later than Nov. 1, 2011 to the U.S. Army Corps of Engineers, New England District, Programs/Project Management Division (ATTN: Mr. Mike Keegan), 696 Virginia Road, Concord, MA 01742-2751 or by email to nae-pn-nav@usace.army.mil.