PORTLAND, Ore. -- A giant vibratory hammer pounds away at a 65-foot-long steel rod to help warn boaters that pile dikes are in the vicinity, Oct. 26, 2020.
This $2.1 million U.S. Army Corps of Engineers project to replace missing king piles, some of which have been in place since 1885, is part of a greater effort to repair pile dikes. In total, boaters and barge operators will see 68 new king pile markers sporadically from Puget Island (river mile 41) to Multnomah Falls (river mile 136).
King piles mark the end and location of pile dikes to increase visibility for boaters. The tops of the Corps’ pile dikes in the Columbia River are frequently just below the river surface during high water events and can seriously damage vessels trying to transit over them. Repairing missing safety markers is the priority for pile dike maintenance.
“This job is all about marking them for safety,” said Portland District project engineer Matt Joerin.
The Corps partnered with U.S. Coast Guard and boating safety groups to improve safe navigation around pile dikes and increase public awareness. Pile dike locations are shown on publicly available NOAA navigation charts and Corps hydro survey charts. (https://charts.noaa.gov/OnLineViewer/18524.shtml)
“The fact that the pile dikes themselves could be a potential danger if you are not aware of them, and the water is often high enough that you cannot see them makes the project a priority,” said Portland District spokesperson Tom Conning.
Also known as wing dams, the century-old sentries are made of alternating vertical timber piles running perpendicularly to the river. The underwater dam structure slows the water’s flow near the shore and pushes faster flowing water toward the center of the channel. Their design reduces dredging requirements, increases channel stabilization and bank protection to keep the river channel in shape and prevent navigation-blocking sand bars from forming.
“By affecting the velocity of the river flow, you are helping keep sand on the shoreline and you are helping to prevent sand from depositing in the channel at the same time,” said Jessica Stokke, Portland District project manager.
Pile dikes play an important role in the Corps’ equation to keep the Columbia River navigation channel in shape and free of sand bars by reducing the amount of dredging necessary to keep the river usable by large ships.
“(Pile dikes) are like unsung heroes out there working every single day to help us maintain the navigation channel,” Stokke said.
View the work, here: and stay current with the Portland District by visiting our website at: www.nwp.usace.army.mil or follow us on Facebook, Twitter and Instagram, @PortlandCorps.