US Army Corps of Engineers
Portland District

Building Strong® at the Old Mouth of the Cowlitz River

Aerial view of the Old Mouth of the Cowlitz River, courtesy of Google Earth ProThe Old Mouth of the Cowlitz River channel at Longview, Wash. is authorized to 8 feet deep and 150 feet wide, from deep water in the Columbia River through the Old Mouth of the Cowlitz River, to a point about 3,000 feet upstream from the old harbor line.

 

The navigation channel supports commercial barges shipping 288,000 tons of wood chips per year. Those chips are used to produce 144,000 tons of products worth over $84 million.

 

For more information

Contact us:

Phone: 503-808-4510

Email us about the Old Mouth of the Cowlitz River

Latest News Releases

Update on spillway gate rehabilitation work at Detroit Dam
11/21/2019
The Corps has decided to manage Detroit Dam’s reservoir levels between 1425 and 1450 ft. from now through the middle of Jan. 2020 during construction on two of the dam’s spillway gates. There are no...
Low Willamette Valley reservoir water levels pose potential dangers
11/15/2019
Due to low water levels in several Corps reservoirs in the Willamette Valley, Corps officials are warning reservoir users of potential hazards and requesting that reservoir users avoid these areas for...
Cape Disappointment State Park area closures to re-open Jan. 1, 2020
10/31/2019
The U.S. Army Corps of Engineers will extend construction on the Mouth of the Columbia River’s North Jetty to Jan. 1, 2020. ...

Operations: Old Mouth of the Cowlitz River

Collapse All Expand All

The vertical plane of reference is adopted low water. The project is subject to tidal influences and annual river freshets. A large shoal regularly forms at the Old Mouth of the Cowlitz River where it meets the Columbia River. Dredging by a contract clamshell dredge is required every 2-to-3 years to allow adequate depth for commercial barge traffic.

This shoal was last dredged by the Corps in 2002 and the material was placed at an in-water site. Limited advanced maintenance width dredging outside the authorized channel width and up to 2 feet of advanced maintenance dredging below the authorized channel depth is practiced in order to maintain adequate depth for commercial barges between dredging events.

The authorized channel is 8 feet deep and 150 feet wide, and spans from deep water in the Columbia River at Columbia River Mile 67.5 through the Old Mouth of the Cowlitz River, to a point about 3,000 feet upstream from the harbor line at the time of authorization.

The Rivers and Harbors Act of March 2, 1945, as part of the overall Columbia and Lower Willamette Rivers Project.