1. Restoration of the Yankee Fork Salmon River
Sponsored by:
Shoshone-Bannock Tribes (Jeff Anderson)
Idaho Department of Fish and Game (Tom Curet)
USDA Forest Service (Kerry Overton; Tom Montoya)
University of Idaho (John Buffington; Peter Goodwin)

2. Statement of the problem
Snake River chinook salmon, steelhead, and bull trout have been listed under the Endangered Species Act as threatened, and westslope cutthroat trout are a Forest Service Sensitive Species.
Severe population decline of Snake River Chinook salmon has resulted from hydropower operations on the Columbia and Snake Rivers (CBFWA 1991), overharvest, introduction of exotics and hatchery fishes, and habitat degradation (Nehlsen et al. 1991).
Until passage problems are resolved, the resiliency and persistence of remaining wild salmon stocks will be largely dependent on the quality and diversity of remaining stream habitats (Lee et al. 1997).

3. Yankee Fork
Historic records indicate that the Yankee Fork of the Salmon River was a particularly productive subbasin for salmonids (Overton et al. 1999) and has been classified as critical habitat for chinook and steelhead (57 FR 14653; 62 FR 111).

4. Dredge mining
A 6 mile reach of the mainstem Yankee Fork has been severely altered by dredge mining.
The dredged reach has been straightened, simplified, and isolated from its floodplain and is no longer capable of supporting a naturally functioning riverine ecosystem, and has been identified in Section a of the Salmon Subbasin Summary as a major limiting factor.

5. Limiting factors
The dredged reach limits the productivity and biological function of the basin by reducing and degrading the available:
Rearing habitat
Spawning habitat
Spatial connectivity of quality habitat

6. 1. Rearing habitat
Wide shallow flow, lack of riparian shading, and lack of bed and bank irregularities create temperature extremes that inhibit growth and survival during rearing.

7. 1. Rearing habitat cont.
Simplified channel form in the dredged reach also creates high velocities and a lack of hiding places (undercut banks, pools, etc.) which likely decrease survival during rearing.

8. 2. Spawning Habitat

9. What limits spawning habitat?
Lack of adult holding areas due to simplified channel morphology (lack of pools) and high velocities.
Simplified morphology, high velocities, and extreme temperatures also may decrease survival to emergence and successful rearing, thereby decreasing the number of return spawners to the dredged reach.

10. Sediment supply
Lowering of the channel base-level during dredge mining has destabilized side slopes adjacent to the channel and may have initiated knick-point propagation (channel incision) along Yankee Fork tributaries.
These processes may have elevated sediment loads, possibly degrading spawning and rearing habitat.

11. 3. Spatial connectivity
The dredged reach fragments the remaining quality habitat in the basin (Overton et al. 1999).
Recent studies indicate that linkages between salmonid populations and spatial distribution of habitats may be a crucial component of ecosystem health and basin viability (Rieman and Dunham 2000).

12. The valley slope, position within the watershed, and historic records indicate that the dredged reach was probably prime rearing and spawning habitat in an otherwise steep, mountain drainage basin. Consequently, the dredge mining effectively removed a significant portion of an already limited amount of salmonid habitat within the Yankee Fork basin.

13. Restoration
A multi-year restoration plan is proposed to reclaim the historic spawning and rearing habitat within the dredged reach and to reconnect the remaining quality habitat, thereby increasing the biological integrity of the basin.
Identify physical and biological linkages to better define restoration actions and potential.
Examine the larger spatial and temporal watershed processes and conduct restoration that is likely to be successful given the imposed watershed conditions.

14. The restored channel is expected to have a pool-riffle morphology, narrower width-to-depth ratio, and a functioning floodplain and riparian zone.
These qualities should increase spawning and rearing success by reducing velocities, reducing excessive sediment transport and bed scour, reducing temperature extremes, increasing channel complexity, increasing oxygenation of buried embryos, and minimizing fine sediment deposition within the channel.

15. Restoration Approach Pre-restoration study and design
Phased restoration, allowing iterative improvement of methods
Long-term physical and biological monitoring

16. Pre-restoration Study and Design
Successful channel restoration requires a clear understanding of current watershed conditions, how they differ from those of the past, what the desired future conditions are, and how the channel is likely to respond to restoration activity.
Here, we seek to quantify past and current physical and biological conditions to provide a baseline for restoration activities and to provide data necessary to develop restoration options and designs.

17. Existing Data Habitat and spawning surveys since the 1930’s
Pilot watershed analysis related to Chinook salmon
Quantification of current and past hydrologic and geomorphic conditions

18. Data Gaps
Completion of aerial photography analysis of historic conditions
Development of spatial coverages (GIS) of existing and historic stream riparian area, channel condition, and floodplain
Geomorphic watershed analysis, including basin-wide assessment of channel morphology, physical process domains, and sediment budget (sources, magnitudes, and routing of sediment)

19. Restoration Design Design criteria:
Create a naturally-functioning channel and riparian zone
Methods:
Develop regional reference reaches, hydraulic geometry relationships, and regime diagrams (predictions of stable channel form) to provide initial guidance on channel morphology
Use hydrodynamic models to predict flow and sediment transport within the channel and across the floodplain for a range of typical discharges
Quantify hyporheic processes and the interaction of shallow groundwater with the channel and floodplain

20. Restoration Design Maximize aquatic habitat
Methods:
Use hydrodynamic models to rank potential aquatic habitat for different design options as a function of temperature, velocity, substrate size, and flow depth
Conduct laboratory studies to examine interactions between proposed channel morphology, surface and intergravel flow, and consequent aquatic habitat. Maximize intergravel oxygenation of buried salmonid embryos, and minimize sedimentation and deposition of fine particle sizes within potential spawning sites.

21. Phased Restoration
Restore natural channel characteristics and floodplain function
Grade, redistribute, and/or remove dredge spoils
Construct new channel(s) and cross-section alignment
Install restoration features (wood debris, bioengineered banks, etc.)
Restore riparian plant communities
Plant seedlings, transplant trees/shrubs
Install erosion control fabric and seed
Improve design and implementation based on results of concurrent monitoring

22. Physical and Biological Monitoring
Factors to be monitored:
Aquatic habitat, fish usage, and species abundance (Platts et al. 1983; Overton et al. 1995; 1997)
Water quality (toxins and bio-accumulation of heavy metals)
Stream temperature
Surface and subsurface sediment size (Church et al. 1987; Bunte and Abt 2001)
Channel topography and plan form
Hydraulic discharge (Nolan et al. 1998)
Sediment transport (Emmett 1980)
Riparian vegetation
Shallow groundwater and hyporheic processes

23. Restoration Performance
Conduct statistical analyses of changes in physical and biological conditions
Compare different techniques for restoration implementation in terms of their success, cost, and time involved in implementation

24. Knowledge Transfer
Involve local high schools in data collection and restoration activities
Participate in community and stakeholder meetings
Develop agency reports
Author and present study results at scientific conferences and in peer-review publications

25. Expected Outcomes A naturally-functioning riverine ecosystem
Improved spawning and rearing habitat
Reconnection of fragmented habitat and increased biological integrity of the basin

26. Questions?