Corps to Dredge Post Office Bar on Summer of 2011 (USA)

The U.S. Army Corps of Engineers is postponing plans to dredge Post Office Bar in the Willamette River in Portland, Ore.

Corps officials said ensuring the appropriate environmental protections were in place pushed the project late into the current in-water work window making it impossible to complete the work now. The next seasonal work window is in summer 2011.

“We’ve been working with the sponsor and other state and federal agencies for more than two years,” said Sheryl Carrubba, Portland District operations manager for Channels and Harbors. “We described the work, analyzed sediment and the potential impacts. Our science is good, our proposed plan is environmentally protective and we received all the required concurrences from the other agencies.”

Carrubba said it is more cost effective to reschedule the project rather than to split the work into two seasons, or award a contract so time-limited that it doesn’t really address the restrictive shoaling in the channel.

The Corps has not ruled out the possibility of dredging as an emergency action. The Columbia River Pilots have expressed concerns about the increasingly hazardous area and have specifically requested that the Corps dredge as soon as possible. Survey data from June 2010 shows severe shoaling reaches across two-thirds of the outbound channel, increasing the chances of vessels running aground or collisions between passing vessels. Hydrographic surveys will be done in the area more frequently to monitor the situation. More than 1,100 vessels transited Post Office Bar in 2008. The area was last dredged in 1989.

The final Environmental Assessment by the Corps can be found at

Post Office Bar lies within an area of Portland Harbor listed by the U.S. Environmental Protection Agency on the National Priority List of Superfund sites, and maintenance dredging of the Lower Willamette River was suspended in 2000.


Source: usace, October 8, 2010