The U.S. Army Corps of Engineers, New England District, is proposing maintenance and repair of the Nantucket Harbor east and west jetties in Nantucket, Mass.
The proposed work involves urgently needed repair and maintenance of the east and west jetties of the Nantucket Harbor Federal Navigation Project that sustained damage during Hurricane Sandy in October 2012. The east and west jetties provide protection not only for vessels entering and exiting the harbor but as a Harbor of Refuge for transiting ships looking to safely weather significant storm events throughout the year.
The existing FNP consists of an entrance channel 15 feet deep relative to Mean Lower Low Water (MLLW); a stone west jetty extending northward from west of Brant Point, 5,400 feet long; and a stone east jetty extending out from Coatue Point, 4,350 feet long. Both jetties have crown widths of 4 – 6 feet and crown heights varying from +3 to +5 feet MLLW.
“The jetties are no longer at authorized dimensions due to storm damage, especially that sustained during Hurricane Sandy,” said Project Manager Craig Martin, of the Corps’ New England District, Programs/Project Management Division in Concord, Mass. “The preliminary estimate of stone quantity to be placed is approximately 32,300 tons, with 17,800 tons required for the east jetty and 14,500 tons required for the west jetty.”
A significant portion of each jetty was built to a half-tide height to allow for sand transport around the structures to maintain the beaches and subtidal habitat adjacent to the jetties. The east and west jetties were constructed in 1886 and 1883, respectively.
Repairs to the east jetty were last completed in 1963 when 15,059 tons of stone was added to the structure. Repairs to the west jetty were last completed in 1900 when 4,750 tons of stone were added to the structure.
Construction is expected to take approximately 8–12 months and could begin in spring 2015.