Willamette River Historic Channel Reconnection at Snag Boat Bend

The project is located at Willamette River mile 144 south of Peoria at Snag Boat Bend, a unit of William L. Finley National Wildlife Refuge managed by the U.S. Fish and Wildlife Service (USFWS). The installation of the Porter Spoil Embankment and Porter Right Bank revetment on the property in 1964 as part of the Willamette Valley flood control project disconnected the river from off-channel habitat and disrupted fluvial processes by completely cutting off the upstream end of a segment of historic mainstem Willamette River channel. This has increased fine sediment deposition, degraded water quality, and created ideal conditions for non-native aquatic weeds in 16 acres of perennial open water habitat. The proposed restoration project will implement a design developed by a previous OWEB-funded technical assistance project. The project will install a 44 wide conveyance structure in the Porter Embankment to reconnect the historic channel segment and restore fluvial processes. To connect the river to the conveyance structure and its historic channel, the project will excavate an inlet channel to connect the upstream perennially-inundated alcove to the conveyance structure. A number of log/boulder structures will be installed in the historic channel to improve habitat complexity for aquatic species. Project partners include USFWS and the U.S. Army Corps of Engineers.

The project will increase the quality of one mile of side channel rearing habitat for UWR Chinook salmon by restoring inflow, and thereby the fluvial processes that create and maintain habitat complexity. Where water depths are currently very uniform there will be deeper pools and gravel bars. Increasing bed erosion and decreasing emergent plant growth will result in decreased water temperatures and increased levels of dissolved oxygen.