The U.S. Army Corps of Engineers, New England District, in partnership with the New Hampshire Pease Development Authority, Division of Ports and Harbors (New Hampshire Port Authority), has prepared a Draft Feasibility Report and Draft Environmental Assessment (FR/EA) to examine improvements to the turning basin located at the head of the Federal navigation channel in Portsmouth Harbor in Newington, New Hampshire, and Eliot, Maine.
The purpose of the proposed project is to reduce transportation costs from navigation inefficiencies, and to address navigation safety concerns for commercial navigation in the upper reaches of the deep draft channel. The Piscataqua River is known for its strong tidal currents and tight turns that make navigation through this area difficult.
“Vessels use the upper turning basin to access the commercial terminals on the New Hampshire side of the river above the I-95 Bridge,” said Study Manager Mark Habel, of the Corps’ New England District, Engineering and Planning Division, in Concord, Mass. “The existing width of the upper turning basin is too narrow for efficient and safe turning and maneuvering of these large vessels.”
As a result of the narrow turning basin, ships have been damaged from grounding and incur delays in channel transit. To compensate for the narrow turning basin, the harbor pilots will only turn ships when currents are slower during the high or low slack tidal periods and during daylight hours.
These conditions put a severe constraint on the available time to transit the river and to unload goods. Additional costs associated with these delays include the cost to remain at the berth until the tide is right, and the cost of additional tugs to turn and maneuver the ships up and down the river. Cargo vessel sizes are limited by these conditions requiring extra ships to transport the same amount of goods.
The Recommended Plan would widen the existing 35-foot deep MLLW 800-foot wide turning basin located at the upstream end of the Federal navigation channel to 1,200 feet. The existing project depth of 35 feet MLLW plus two feet of allowable overdepth will be retained.
Approximately 728,100 cubic yards of coarse grained sandy and gravelly material, and approximately 25,300 cubic yards of rock will be removed.
Press Release, April 2, 2014