Contract Description:
The Wallowa River, as it flows through the Baker property, is an aggrading section of river. This, combined with habitat alteration, has resulted in a loss of riparian vegetation, poor streambank and channel stability, diminished instream habitat complexity, and a loss of available fish habitat.
This project was designed to address identified limiting factors and priority attributes and to also meet the following goal: Restore the Wallowa River to within its natural form and function, to promote natural, stable stream channels and instream habitat diversity.
The Wallowa River provides migration, spawning, and rearing habitat for federal ESA listed Snake River spring/summer Chinook salmon and Snake River summer steelhead. Summer steelhead and spring Chinook spawning, summer, and overwinter rearing have been documented in the project reach. Federal ESA listed bull trout also utilize this section of the Wallowa River at various times and life history stages for migration and rearing.
The main limiting factors for ESA listed spring/summer Chinook salmon and Snake River summer steelhead in this section of the Wallowa River are instream structural complexity, sediment quantity, bed and channel form, and riparian vegetation. The project addresses these limiting factors by improving aquatic/riparian habitat, reducing sediment delivery to the stream, improving flow and water temperatures and increasing instream habitat complexity.
Through funding secured from the GRMW and OWEB, Anderson Perry & Associates was hired to produce implementation-ready, engineer-approved, regulatory agency-reviewed plans and specifications for the Wallowa River-Baker Project. The project was designed for a 25 year event.
As designed, four side channels, with 80 foot wide floodplains, adding approximately 2,350 feet of stream length and 8.71 acres of floodplain, will be constructed on the Wallowa Baker property. Fourteen different design types of habitat structures will be installed throughout the project. Forty-seven engineered wood habitat structures will be constructed of wood material including large key members and racking and slash materials. Fourteen structures, 7 different types, will be installed on the mainstem Wallowa River. Sixteen structures, 6 different types, will be installed in Side Channel A. Two structures, 2 different types, will be installed in Side Channel B. Four structures, 2 different types, will be installed in Side Channel C. Eleven structures, 3 different types, will be installed in Side Channel D. A fish screen/diversion structure will be constructed at the head of Side Channel D to prevent fish stranding in the spring creek/irrigation return ditch.
Forty-seven engineered wood and habitat structures, fourteen different types, will be constructed for the Wallowa River-Baker Project, including: 4 Type 1, 3 Type 1A, 4 Type 2, 4 Type 3, 8 Type 3A, 2 Type 4, 2 Type 5, 9 Type 6, 1 Type 7, 1 Type 8, 2 Type 9, 2 Type 10, 3 Type 11, and 2 Type 12 (Engineered Plan Sheets 11-23). These structures will be installed at specific locations throughout the project reach to 1) increase habitat complexity; 2) promote pool development and maintenance; 3) provide cover; 4) promote sediment sorting; 5) promote gravel bar stabilization; 6) provide margin roughness; 7) break up riffles; 8) promote localized scour; 9) provide bank stabilization; 10) promote establishment of vegetation; and 11) provide mainstem and side channel maintenance and desired configuration. Habitat structures 6, 7, 8, 9, and 10 were designed specifically to provide zero to low velocity habitat with the complexity needed to support winter rearing of spring/summer Chinook salmon based on results from Favrot and Jonasson (2014) and VanDyke et al. (2008). Approved tree species include juniper, cedar, spruce, pine, white fire, or red fir. The entire tree will be imported to the extent possible, including branches and tops of trees, which will be used as racking material. Tops and limbs of some trees will be used as slash.
A riparian planting plan will be implemented to increase extent and diversity of riparian vegetation in the project area and for seeding habitat with native upland grasses. Easement fencing will be installed to prevent livestock access to the 30.2 acre easement area.
This project includes placing 30.2 acres in a 15-year conservation easement and addressing limiting factors for ESA listed Snake River spring/summer Chinook salmon and Snake River summer steelhead by improving riparian habitat and channel condition, floodplain and instream habitat creation, increasing habitat complexity, reducing sediment delivery, and contributing towards improved flow and water temperature regimes.
BPA/GRMW funding, along with McNary Fisheries Irrevocable Trust funding, will be used to construct Phase 1 and part of Phase 2 of the project. Phase 1 and the first part of Phase 2 includes constructing Side Channels A, B, C and associated habitat structures, and seven mainstem habitat structures, OWEB funding is being sought for construction of the second part of Phase 2 of the project.