Isles of Shoals Harbor of Refuge, NH & ME

The proposed work consists of repairing each of the three stone breakwaters connecting Star, Cedar, Smuttynose, and Malaga Islands, which were damaged during recent storms. The Isles of Shoals are located about 7 miles off the coast of Rye, New Hampshire in the Gulf of Maine, about 20 miles north of Cape Ann, MA and 45 miles south of Cape Elizabeth, ME. The work includes dismantling, removing, stockpiling, reworking and reinstalling existing armor stone as well as acquiring and installing new armor in the jetty repair areas. The repaired areas must be properly interlocked and be within specified design tolerances. The three breakwaters total about 1900 feet in length. The repairs will restore the three structures to a design top elevation of +15.5 feet at mean lower low water, with a crest width of 20 feet, with slopes of 1:1 leeward and 1:1.5 seaward. The breakwaters and the islands they connect form a refuge for vessels seeking shelter during storms that are unable to make a mainland port. The islands are all privately owned, though Star Island hosts a hotel and conference center and the village of Gosport, NH which attract day visitors to that island in the summer months. The New Hampshire-Maine state border bisects the harbor. The breakwater between Malaga and Smuttynose Islands was about 220 feet long at the crest, was constructed in 1821, and has been reduced to a low mound of rubblestone. About 1,500 tons of new 10 to 18-ton armor stone will be needed to restore this breakwater along with partial removal, stockpiling and reuse of the existing stone berm as bedding and core stone. The breakwater between Smuttynose and Cedar Islands is about 900 feet long at its crest. It was originally built in 1822 and last repaired in 1904 using 5 to 10-ton armor stone. It is in fair condition and about 2,500 tons of new 10 to 18-ton armor stone will be needed to restore this breakwater. The breakwater between Cedar and Star Islands is about 800 feet long at its crest, was initially constructed in 1913, and was last repaired in 1974 using 7 to 10 ton stone. About 1,500 tons of new 5 to 15-ton armor stone will be needed to restore this breakwater. Specific work tasks are intended to reconstruct severely deteriorated areas of the three breakwaters to their authorized dimensions. These tasks include the recovery and resetting of displaced armor stone, and delivery and installation of approximately 6,000 to 10,000 tons of new 10 to 18 ton armor stone. Existing gaps in the structures will be filled, and the structures brought up to their design elevations, crest widths and slopes. Repairs will require substantial moving and rehandling of existing stones to obtain the required interlocking placement and construction tolerances. The completed repairs will provide a crest width of 20 feet, crest elevation of 15.5 feet at mllw, and slopes of 1:1 leeward and 1:1.5 seaward for each structure. Given the nature and characteristics of this structure, it is anticipated that all repair and improvement construction activities will have to be performed from marine based plant. Environmental coordination and permitting is being completed by the U.S. Army of Engineers, New England District. The tide range between Mean High Water (MHHW) and mean low water (MLW) is about 8.7 feet. Due to the shallow conditions adjacent to the jetty structures it is expected that the contractor will have to ground work barges or find another means for a stable work platform to complete repairs during times of low tide. To prevent damage to environmental resources in the area work will be completed from a single side of each jetty for significant lengths of the work area.

Division 31 -	Earthwork, Erosion and Sedimentation Controls.
Division 33 -	Utilities, Storm Drainage Utilities, Ponds and Reservoirs.
Division 35 -	Waterway and Marine Construction, Common Work Results for Waterway and Marine Construction, Waterway and Marine Construction and Equipment, Shoreline Protection, Waterway Construction and Equipment, Marine Construction and Equipment.