The U.S. Army Corps of Engineers, New England District, is proposing maintenance dredging of the Block Island Harbor of Refuge Federal Navigation Project (FNP) on Block Island, Rhode Island.
The Town of New Shoreham is the sponsor and requested that this project be maintained, said USACE.
The proposed work involves maintenance dredging of portions of the 15-foot-deep Mean Lower Low Water (MLLW) inner harbor which is made up of an anchorage area, inner channel, and inner basin, plus 2 feet authorized overdepth, in the Harbor of Refuge FNP.
No maintenance dredging of the FNP entrance channel will occur as a part of the proposed work. Sediment in the western portion of the 15-foot inner basin has been determined to be unsuitable for open water placement and will not be dredged.
Natural shoaling processes have reduced available depths to as little as 1.0 foot in the 15-foot MLLW anchorage making navigation hazardous at lower stages of the tide. Maintenance dredging of approximately 50,000 cubic yards of silt and fine-grained sand from approximately 6 acres of the authorized project area will restore the inner harbor portion of the FNP to authorized dimensions.
Approximately 32,000 cubic yards of sand material is proposed for placement at the previously-used, nearshore placement site off of Crescent Beach. The remaining silty material (approximately 18,000 cubic yards) will be placed at the Rhode Island Sound Disposal Site (RISDS).
A private contractor, under contract to the government, will use a mechanical dredge and scows to remove the material and then transport it for placement at the disposal sites.
Construction is expected to take between 3-4 months between Oct. 1 and Jan. 31 of the year(s) in which funds become available.