Donjon Marine Makes Good Progress in Old Saybrook

The state of Connecticut together with the contractor, Donjon Marine of Hillside (NJ), is continuing maintenance dredging of the North Cove Federal Navigation Project in Old Saybrook.

The project has been maintained a number of times since it was authorized, with the most recent past dredging event in 2008.

At that time, 175,000 cubic yards of sediment were removed, but due to funding constraints the authorized dimensions of the project were not obtained.

The current cycle of maintenance was initiated by the town of Old Saybrook when availability of the project began to be impacted during times of low tide.

Dredging areas include the 11-foot deep entrance channel, 11-foot deep anchorage and 6-foot deep anchorage. Donjon Marine is performing the work under a $4.3 million contract awarded Sept. 20, 2017.

The contractor started dredging on Nov. 14, 2017, and has removed about 230,000 cubic yards of material from the project so far. Approximately 286,000 cubic yards of predominantly silty sediment will be removed by mechanical dredge.

Around 56,000 cubic yards of material still needs to be dredged from the 6-foot anchorage area by the coordinated dredging window ending on March 31.

This project is unique for the District employing a second trans-loading dredge to transfer shoal material from small hopper scows used to access shallow portions of the project to large capacity dump scows. After the trans-loading process is complete the large dump scows are hauled to the Central Long Island Sound Disposal Site, about 35 miles away from the project, and placed at predesignated coordinates.

Additionally, the project will deploy a turbidity curtain during the latter stages of the project to allow dredging to continue into time of year restrictions to protect sensitive species. Despite equipment breakdowns and cold weather resulting in several inches of ice within the project, the contractor expects to complete the project this dredging season.

 

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