Jetties Reconstruction

Through a generous grant from the United States Army Corps of Engineers, the reconstruction of the East and West Jetties is scheduled to start in the fall of 2016 and be completed in 2017. The main channel will be maintenance dredged in conjunction with the jetty reconstruction. Work is scheduled to begin on the west jetty during the fall months of 2016 and then transition to the east jetty afterwards.  35,000 tons of rock will be used for this project with 75% of individual rocks weighing 3 tons. Updated 11/1/16
History of the Jetties

Considered both a Harbor of Refuge and a Subsistence Harbor, Nantucket Harbor, plays a critical role to the economy of Nantucket Island and the safety of island residents/visitors. In 1829, a channel was dredged through an existing sandbar to allow deep draft vessels passage into the harbor. After a period of 1 year the channel had completely shoaled in and no further maintenance was considered until the development of a sediment management system could be constructed

The project for improvement of Nantucket Harbor was authorized by the River and Harbor Act (RHA) of 1880, and further supplemented by RHAs of 1886, 1945, and 1963.  It has been noted that without the construction of the East and West Jetty dredging would have been required on an annual basis at a cost many times the original cost of jetty construction maintenance schedule. The last maintenance on any part of the Jetty system was completed in 1963, some 50 years ago.

Estimated Cost
$400k Development of Environmental Permits, Plans & Specifications, and Supervisoin & Administration
$7.6 M Repair of East Jetty – 16,100 CY of 2 to 2.5 ton stone size
$2.2 M Repair of West Jetty – 4,600 CY of 2 to 2.5 ton stone size
Mohawk Northeast Graphic Schedule
Historic Timeline

• 1880 – West Jetty constructed (3,955 ft in length) with the purpose of concentrating the ebb tide to encourage natural scouring of channel. Jetty Crown above Mean High Water (MHW) through all phases of tide—considered “Full Cross Section”.
• 1900 – West Jetty extended an additional 600 ft Full Cross Section and 400 ft “Half Tide Section” for a total of 1,000 ft.
• 1907 – East Jetty constructed completed after study determines West Jetty alone does not maintain the navigational channel. First 834 feet constructed to Full Cross Section and 6.153 ft of Half-Tide Section for a total of 6,987ft.
• 1917 – Stone mound added to head of East Jetty for the addition of navigation light.
• 1926 – Repairs made to all but the last 300 ft of the East Jetty.
• 1937 – Repairs made to various spots on the East Jetty.
• 1962 – Major rehabilitation increasing the size of armor stones and height of structure above tide level (+3.0 MLW vs past +1.5 MLW); Increasing the Interval between maintenance periods and reduce the tidal flow over the Jetty during periods of high tide (navigational safety).
• 1962-Today - No additional maintenance has been performed to the East or West Jetty.

Helpful Links

"Nantucket Jetties" by Matt Byrne