Objective: Improve habitat conditions for ESA-listed fish species and other focal species of concern. The Project goal can be accomplished by restoring hydraulic and geomorphic processes, while enhancing instream, side channel and wetland habitat.

Overview: Project Area is located on private property within the active river channel and floodplain of the Wallowa River, downstream of its confluence with the Wallowa River. The project area is identified as a high priority for restoration actions in the Wallowa River [Grande Ronde Subbasin Plan and Supplement (NPCC 2004)], ranked as: a) the number-one priority for protection benefit, and number-two ranked priority for restoration benefit from among the 12 Wallowa-Lostine spring Chinook population areas; and b) the number-5 and number-3 ranked priorities for protection and restoration benefit, respectively, from among the 24 Wallowa steelhead population areas.  Based on impact to steelhead and Chinook salmon populations throughout the Grande Ronde subbasin, the Wallowa-Lostine area was ranked number one among the eight watersheds listed for having the greatest projected population response (i.e., increased productivity and abundance) to restoration actions.

Background: The project reach is located in the middle Wallowa River which supports three salmonid species listed under the Endangered Species Act: spring Chinook salmon, summer steelhead, and bull trout; the project area is within designated critical habitat for all three species. Juvenile spring Chinook and summer steelhead inhabit the project reach year-round.  The channel lacks habitat complexity and, as a result, contains limited spawning and rearing habitat for steelhead and Chinook salmon. Both species utilize the area for juvenile rearing; however, limited suitable spawning habitat exists due to the riffle-dominated, high gradient nature of the channelized river. There are few pools, and therefore, very limited quantities of slow-water holding habitat where migrating salmonids can rest. The sinuosity is low, and the river is entrenched, significantly limiting connectivity to the historic floodplain.

Project Summary: Enhancing and restoring instream habitat in this project area will be accomplished through a variety of treatment actions in the main channel, along the banks, and within the floodplain. These treatments include side-channel excavation, construction of instream habitat features such as engineered log jams (ELJs), removal of infrastructure such as spoils material and artificial embankment, and the installation of riparian and floodplain roughness plantings. The principal benefits of project implementation will be restoration of historic spring Chinook spawning, rearing, resting and migration corridor habitats. The associated treatment of riparian areas is expected to induce naturally occurring repair, restoration, and recovery of both floodplain and riparian zone function and processes.

Purpose:  Promote and maintain the habitat objectives in this project area: force pools and hydraulic variability in the plane-bed channel sections, decrease instream velocities, and provide additional hydraulic complexity in the deep, incised sections, providing year-round juvenile rearing and potential spawning habitat for ESA-listed fish species. Improved floodplain connection and roughness intended to enhance and promote natural stream conditions and function, provide spawning and rearing habitat for ESA-listed Chinook salmon and steelhead, reintroduced lamprey, coho, and other native fish species, and improve water quality at the reach scale.

Expected Implementation Actions (from the Project Proposal): Creation of side channel and wetland habitat incorporating backwater pools and alcoves; addition of large wood structures (LWD) within the side-channel network; additional wood placements throughout the stream channel-segment; constructed riffle substrate; interception of groundwater seeps/springs/runoff/irrigation returns; development of one acre of roughened floodplain including the installation of eight ditch plugs; bankline treatments and floodplain roughness plantings.  

Biological Benefits: Immediate biological benefits of the project include: increased channel complexity and diverse habitat elements (large wood, pools); and better connectivity between existing functioning habitats. Interception of local springs, hill slope runoff, and irrigation return water throughout the project site is expected to contribute cold water in the new side channel. The inclusion of these water sources along with alcove and pool creation will enable and enhance both overwinter and summer refuge for juvenile salmon.

Geomorphic Implications:  The addition of more structure in the initial LWD placement areas, will support retention of additional LWD and bed-loading that will promote build-up of the bed elevation over-time, increasing floodplain connectivity to ease channel confinement and allow for better floodplain connectivity and function during high flows.