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Grays Harbor Navigation Improvement

The U.S. Army Corps of Engineers is deepening the federal navigation deep-draft channel in Grays Harbor from the currently maintained depth of -36 feet MLLW to the fully authorized depth of -38 feet MLLW. The deepening will occur from the South Reach upstream to Cow Point Reach where the Port of Grays Harbor Terminal 4 is located. The Grays Harbor Navigation Improvement Project will deepen approximately 14.5 miles of the 27.5-mile channel.

Previously, the Corps removed an average of 1.2 million cubic yards of sediment annually from the channel. The dredged material is disposed of at various approved disposal sites, including open-water disposal at the Point Chehalis, South Beach, South Jetty, and Southwest disposal sites, as well as beneficial use for beach nourishment at Half Moon Bay.


The Corps 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.

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 - December 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.

The Grays Harbor Navigation Improvement Project is located 50 miles west of Olympia on the central coast of Washington. The cities of Aberdeen, Hoquiam, Ocean Shores, and Westport surround Grays Harbor. Based on a General Design Memorandum dated February 1989, the deep draft channel was deepened to -36 feet mean lower low water (MLLW), two feet less than the fully-authorized depth of -38 feet MLLW. The Port of Grays Harbor requested deepening the channel the additional two feet to better accommodate current vessel traffic for existing Port tenants and commodities.

The purpose of the Project is to improve the efficiency of deep-draft vessel navigation in Grays Harbor. The Project is needed to alleviate large vessel restrictions imposed by the insufficient channel depths. Ship transportation in the existing upstream channel is limited by depth. Current depths are inadequate to accommodate vessels with drafts exceeding -36 feet MLLW.