Fisheries Enhancement in the Fish Creek Basin; Evaluation of In-Channel and Off-Channel Projects, 1984 Annual Report.
- Oregon State University, Pacific Northwest Forest and Range Experiment Station, Corvallis, OR
- Mount Hood National Forest, Clackamas River Ranger District, Estacada, OR
This S-year project which began in 1983 is designed to construct and evaluate habitat improvements in the Fish Creek basin by personnel of the Estacada Ranger District, Ht. Hood National Forest, and the Pacific Northwest Forest and Range Experiment Station. The work is jointly funded by BPA and USDA-Forest Service. The evaluation has focused on activities designed to improve spawning and rearing habitat for chinook and coho salmon and steelhead trout. Specific habitat improvements being evaluated include: boulder berms, an off-channel pond, a side-channel, addition of large woody debris to stream edge habitats, and hardwood plantings to improve riparian vegetation. The initial phases of habitat work have proceeded cautiously in concert with the evaluation so that knowledge gained could be immediately applied to future proposed habitat work. The evaluation has been conducted at the basin level, rather than reach or site level, and has focused intensely on identification of factors limiting production of salmonids in Fish Creek, as well as physical and biological changes resulting from habitat improvement. Identification of limiting factors has proven to be difficult and requires several years of all-season investigation. Results of this work to date indicate that spawning habitat is not limiting production of steelhead or coho in the basin. Coho habitat is presently underseeded because of inadequate escapement. Key summer habitats for coho, age 0 and age 1+ steelhead are beaver ponds, side channels, and pools, respectively. Key winter habitats appear to be groundwater-fed side channels and boulder-rubble stream margins with 30+ cm depth and low velocity water. Additional work is needed to determine whether summer habitat or winter habitat is limiting steelhead and coho production. Chinook use of the basin appears to be related to the timing of fall freshets that control migratory access into the system. Instream habitat improvements show varying degrees of promise for meeting their Intended objectives, but all will require some modification to the original design for future use. Boulder berms designed to increase spawning habitat have already Impounded small amounts of gravel and are providing spawning areas for steelhead. Some winter habitat was lost, however, due to construction at each berm site. An off-channel coho rearing pond produced a few exceptionally large coho smolts the first year after construction. A side channel development was used by spawning coho and chinook soon after construction in 1984, but few juvenile salmonids were found there in the winter of 1984-85. It is too soon to evaluate riparian plantings or addition of woody debris to stream edges. Comprehensive benefits or losses are difficult to determine for projects only one or two years old since fish response to improvements often takes several years. The success of each improvement must be measured in terms of increased smolt outputs. Our work indicates that the risk of failure associated with habitat improvement projects is very high without: (1) a detailed analysis of limiting factors in a basin, and (2) an evaluation of physical and biological changes in a basin, including smolts produced, resulting from improvements.
- Research Organization:
- Oregon State University, Pacific Northwest Forest and Range Experiment Station; Mount Hood National Forest, Clackamas River Ranger District
- Sponsoring Organization:
- United States. Bonneville Power Administration.
- DOE Contract Number:
- 1984BP16726
- OSTI ID:
- 901439
- Report Number(s):
- DOE/BP-16726-1; R&D Project: 198401100; TRN: US200714%%219
- Country of Publication:
- United States
- Language:
- English
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