SEATTLE – Dredging is scheduled to begin October 3 to bring the federal Grays Harbor navigation channel to a deeper depth of -38 feet Mean Lower Low Water and remove accumulated sediments since the last maintenance dredging.
The purpose of the dredging is to improve deep-draft vessel navigation in the Grays Harbor channel by reducing tidal delays and tidally-related draft restrictions experienced by current Port tenants’ vessel traffic. Deepening the navigation channel is intended to reduce navigation transportation costs for the existing and projected future traffic of deep-draft vessels, and improve efficiency and reliability of navigation to and from Grays Harbor.
The Seattle District, U.S. Army Corps of Engineers, awarded a $27.1 million dredging contract to American Construction Company for combined deepening and maintenance dredging of the Grays Harbor Inner Harbor federal navigation channel.
The Grays Harbor project is an existing 24-mile deep-draft navigation channel located on Washington's southwest coast. A 38-foot channel was authorized by Congress in November 1986. However, a 1989 post-authorization analysis determined that only dredging to -36 feet MLLW was economically justified at that time, and beginning in 1990 the channel was deepened to -36 feet.
Faced with increasing costly shipping inefficiencies experienced by the current deep-draft traffic, the Port of Grays Harbor, requested deepening the channel to the fully-authorized depth of -38 feet MLLW in order to accommodate current shipping requirements. The Seattle District determined in 2014 that there is a federal Interest in deepening the channel to the authorized -38 feet MLLW, and the project was approved for construction in 2015.
"This deepening project is critical to our ability to serve our customers, our community and our country today and well into the future as the Port of Grays Harbor continues to provide a crucial link between U.S. growers and producers and international markets," explained Port of Grays Harbor Executive Director Gary Nelson. “We value our partnerships with the Corps and our federal elected officials and thank them for all of their hard work on the project and their continued recognition and support of Grays Harbor as a port of national significance."
Maintenance and deepening will include dredging approximately 3.5 million cubic yards of material. The contract contains three distinct work windows: October 1, 2016 - February 14, 2017; July 16, 2017 - February 14, 2018; and July 16 - September 30, 2018.
Mechanical dredging under this contract will occur from the beginning of Crossover Reach (middle of the harbor) through Cow Point (eastern end of Terminal 4). Suitable dredged material will be placed in either the South Jetty or shifted Point Chehalis disposal sites. Approximately 22,000 cubic yards of material was determined to be unsuitable for open water disposal. This material will be placed in an upland placement site near Terminal 3. Special loading, transport, and placement requirements will be conducted for this material.