Willamette River Dredged Material Management Plan
The U.S. Army Corps of Engineers is charged with maintaining the navigation channels of the Willamette and Columbia rivers. As part of that responsibility, in 2007 and 2008, the Corps worked on a Dredged Material Management Plan (DMMP) for the existing 40-foot deep Lower Willamette River Navigation Channel (WRNC). The Port of Portland, as non-federal sponsor of the WRNC, was an active participant in that process. The WRNC stretches from the Broadway Bridge in downtown Portland downstream to the Columbia River. A completed DMMP would outline a 20-year plan for managing all material dredged from this channel to maintain its authorized depth and provide for 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. A draft Feasibility Study of various cleanup options is expected to be approved in 2015 and will be followed by an EPA-developed proposed cleanup plan and record of decision. Once those milestones are more certain, it is anticipated that the Army Corps will restart its work on the Willamette River DMMP.
Historically, the Corps dredged between 500,000 to 750,000 cubic yards of sediment from the Willamette River navigation channel every three to five years. Significant maintenance dredging has not occurred on the Willamette’s navigation channel since 1997. Lack of maintenance dredging presents a continuing impediment to safe navigation. It hinders access to Willamette River terminals and berths, and impacts regional commerce.
The Willamette's navigation channel was last maintained by the Corps in the summer of 2011 when a small shoal was removed from the channel at Post Office Bar, just south of its confluence with the Columbia River. This shoal had created a risk to safe navigation of vessels on the river. The project removed about 50,000 cubic yards of material, which was placed at the approved dredge material placement site on West Hayden Island. Aside from this one project, no other maintenance dredging has taken place in the Willamette River navigation channel since 1997.
The permitting process required for each individual Willamette River dredging action ultimately determines the appropriate disposition of dredged material, including its potential beneficial use as upland fill. As the non-federal sponsor of the Lower Willamette River navigation channel, the Port is obligated to provide the lands, easements, and rights-of-way for upland placement of dredged material by the Corps.
Acting in its role as non-federal sponsor, the Port assists 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 to this site when renewed work on the DMMP for the WRNC is planned.