The Grays Harbor federal navigation deep draft channel is 250 feet wide at Cosmopolis, increasing to 1,000 feet over the Bar at the mouth of Grays Harbor. The currently maintained channel depth is -36 feet Mean Lower Low Water (MLLW) from the South Reach to the Cow Point Reach, where Port of Grays Harbor Terminal 4 is located. The channel then decreases to -32 feet MLLW through Cosmopolis.
The Corps is investigating the feasibility of dredging the channel from the South Reach upstream to Cow Point to its fully authorized depth of -38 feet MLLW. This project covers approximately 14.5 miles of the 27.5 mile channel. Deepening of the relevant portion of the Grays Harbor navigation channel to -38 feet MLLW was authorized by Congress in 1986, but a 1989 economic evaluation found that dredging only to -36 feet MLLW was economically justified at that time. The study will evaluate implementing the previously authorized -38-foot depth through a Limited Reevaluation Report and a Supplemental Environmental Impact Statement (EIS), building on the original 1982 EIS and its 1989 Supplement.
The Corps dredges the deep draft channel annually at an average cost of $9 million. The annual volume removed averages 1.7 million cubic yards. Westport Marina and the entrance channel require infrequent maintenance dredging. However, periodic maintenance of the groin, revetment and breakwater structures is currently required.
Although there are overlapping resource considerations, such as disposition of material dredged from a deepened channel, this Navigation Improvement Project is distinct from and independent of the Long Term Management Strategy addressing operation and maintenance of the present channel.
For additional information about Grays Harbor Navigation visit our website at: http://www.nws.usace.army.mil
and click on “Grays Harbor Navigation” under “Most Requested.”
Questions relating to the meeting prior to the actual event should be directed to Josh Jackson, Grays Harbor General Investigation project manager, at (206) 764- 6583.