Willamette Confluence Project
The Willamette River Floodplain Conservation Opportunity Area (COA) spans almost the entire
length of the Willamette Ecoregion encompassing the floodplain of the Willamette River from
south of Springfield to the confluence with the Columbia River. Over the past two centuries,
the Willamette River system has been transformed from a complex and dynamic river system to
a simplified and largely channelized river. Throughout the Willamette Basin, there has been
widespread loss of floodplain and off-channel habitat due to a combination of human
encroachment onto the floodplain, physical barriers (such as rip-rap and revetments), loss of
side channels, and changes in flow regimes that eliminate floodplain-inundating flows. These
changes have significantly harmed native species, resulting in state and federal listings of
several plant and wildlife species associated with the river and its floodplain. Protection and
restoration of channel complexity, riparian habitat and floodplain forest have been identified as
critical conservation needs in the Willamette Ecoregion by multiple plans and programs,
including Upper Willamette River Conservation and Recovery Plan for Chinook Salmon and
Steelhead, Oregon Conservation Strategy, Willamette Subbasin Plan, and Willamette River
Floodplain Restoration Study Draft Integrated Feasibility Report/Environmental Assessment.
Working in concert, several entities have been instrumental in addressing the complex issues
facing the Willamette River floodplain. A partnership of three grant-making organizations
(Meyer Memorial Trust -MMT, Oregon Watershed Enhancement Board-OWEB, and Bonneville
Power Administration-BPA) developed an integrated strategy to help narrow the gap between
need and capacity. These funders work together to support one another’s objectives, while
simultaneously pursuing their own mainstem agendas. Significant support from the funders has
enabled non-profits, watershed councils, and soil and water conservation districts to increase
the extent and pace of protection and restoration efforts along the Willamette River. Other
significant partners working in this area include local private landowners, Oregon Departments
of Fish and Wildlife and State Parks, and Army Corps of Engineers.
Benefiting from the collective strength of a number of these entities, significant protection and
restoration efforts are occurring in a section of the Willamette River floodplain south of
Springfield in the vicinity of the confluence of the Coast Fork and Middle Fork Willamette rivers.
The Oregon Conservation Strategy identifies the confluence area as the Mt. Pisgah COA, a
subdivision of the Willamette River Floodplain COA. Featuring extensive habitats that are
increasingly endangered in the Willamette Valley, the Mt Pisgah COA includes river corridor,
floodplain forest, wetlands, upland oak woodlands and native prairie. The confluence area is
designated as critical habitat for Chinook salmon in the Upper Willamette River Conservation
and Recovery Plan for Chinook Salmon and Steelhead and provides habitat for resident
threatened bull trout and Oregon chub, as well as western pond turtle and red-legged frogs.
The floodplain in the confluence area contains some of the largest northwestern pond turtle
populations in the Willamette Valley Ecoregion.
In 2010, The Nature Conservancy (TNC) with significant help from the Bonneville Power
Administration and OWEB acquired the 1271-acre Willamette Confluence Preserve. Historically,
the property was used for a floodplain gravel mining operation, with extraction actively
occurring from the 1950s through the 1980s. As a result, the floodplain became disconnected
from the river by levees designed to protect the gravel pits. Although portions of the property
were significantly altered, an intact floodplain forest remained, which is a limiting feature
throughout most of the low-gradient portions of the Willamette Basin.
In 2014, TNC, with funding from the NOAA Restoration Center, OWEB, Meyer Memorial Trust,
Bonneville Environmental Foundation, and others completed an extensive restoration project
to increase the amount and quality of floodplain and off-channel habitat and improve water
quality. The project reconnects the Willamette River to its floodplain, creates new river
channels and increases and improves shoreline habitats. A major goal of this work is to restore
natural floodplain and inchannel habitat forming processes to provide critical juvenile rearing
and adult holding habitat for native fish, including Chinook salmon.
Spring 2014, Before construction. Three deep, steep-sided, warm water former gravel extraction pits
(ponds) disconnected from the Middle Fork Willamette River. (Photo Source, © RaptorViews Philip
Bayles)
September 2014, after grading, contouring and sloping banks, connection to the Midd le Fork
Willamette River and installation of habitat structures (Photo Source: © RaptorViews Philip Bayles.