Through 2007 and half of 2008, The U.S. Army Corps of Engineers worked on a dredged material management plan for the existing 40-foot deep Lower Willamette River navigation channel. The federal navigation channel in the Willamette stretches from the Broadway Bridge in Portland downstream to the Columbia River. A completed DMMP would lay out a 20-year plan for managing material dredged from this channel to maintain its authorized depth and provide safe navigation.
In September 2008, the Corps suspended work on the DMMP pending the outcome of the Portland Harbor Superfund investigation and cleanup. The Environmental Protection Agency has overseen studies of the Portland Harbor since it was listed as a Superfund site in 2000. EPA is expected to select the final cleanup remedy in 2012.
The Willamette’s navigation channel was last maintained by the Corps in 1997. Historically, the Corps dredged between 500,000 to 750,000 cubic yards of sediment from the channel every three to five years. With the lack of maintenance dredging since 1997 presenting an impairment to navigation and access to Willamette River terminals and berths, the Corps is planning an interim dredging action that will address one significantly shoaled site at Post Office Bar, located approximately two miles upstream from the confluence of the Willamette and Columbia rivers. This project is currently anticipated for the summer of 2010, pending the outcome of an Environmental Assessment and associated permitting.
The permitting process required for this action will ultimately determine the appropriate disposition of dredged material, including potential beneficial use as upland fill. As the non-federal sponsor of the Lower Willamette River navigation channel, the Port of Portland is obligated to provide the lands, easements, and rights-of-way identified in the DMMP for upland disposal of dredged material by the Corps.
Also acting in its role as non-federal sponsor, the Port has agreed to assist the Corps in disseminating information about the navigational dredging and the handling and management of dredged materials by hosting this Web site. Information will be added as the Environmental Assessment progresses and when the DMMP project continues.