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Yakima Dams Fish Passage Study

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The Bureau of Reclamation is leading a cooperative investigation with the Yakama Nation, state and Federal agencies, and others, to study the feasibility of providing fish passage at the five large storage dams of the Yakima Project. These dams—Bumping Lake, Kachess, Keechelus, Cle Elum, and Tieton—were never equipped with fish passage facilities. Four of the five reservoirs were originally natural lakes and historically supported Native American fisheries for sockeye salmon and other anadromous and resident fish. Implementation of passage features at the dams has the potential to reintroduce sockeye salmon to the watershed; to increase populations of upper basin steelhead, coho salmon, and Chinook salmon; restore life history and genetic diversity of salmon; and reconnect isolated populations of bull trout.

 
Preliminary Assessment Studies

Reclamation began the preliminary assessment of fish passage potential at the Yakima Project storage dams in April 2002. Funding in FY 2002 and FY 2003 came primarily from transfers from other programs. FY 2004 was the first year of feasibility study funding. Reclamation proceeded with the preliminary assessment in phases. An informal core team of biologists and engineers from Reclamation, NOAA Fisheries, Fish and Wildlife Service, U.S. Forest Service, Washington Department of Fish and Wildlife, irrigation interests, local governments, and others was organized in April 2002.

The core team and sub-groups met (and continue to meet) on a regular basis to work through biological, engineering, and operational issues associated with fish passage at the storage dams.

 
Phase 1 Assessment

The Phase 1 assessment process determined that there are a range of options and opportunities for providing fish passage and potentially reestablishing populations of anadromous salmonids in some tributaries of the five Yakima Project storage reservoirs. Some combinations of passage options and associated biological benefits are more feasible than others. All five reservoirs have some tributary habitat that would be available if passage were provided at the dams. However, the amount and quality of the habitat varies considerably from reservoir to reservoir. The effective passage window also varies considerably from one option to another and would significantly affect the feasibility of a given proposal.

From this initial assessment, it appears that some form of upstream and downstream passage for anadromous salmonids and bull trout connectivity is technically possible at all of the storage projects. Passage at some would be much more expensive in relation to available habitat than at other locations.

Optimizing fish passage at one storage project might require changing operations at another in order to ensure continuity of water delivery obligations and other Yakima Project purposes. For purposes of the Phase I Assessment, each project was considered separately, based on existing operational considerations and constraints.

 
Major Study Activities

Feasibility Study
In fiscal year 2004, following completion of the Phase I Assessment Report in 2003, Reclamation began detailed studies to evaluate the feasibility of providing passage at the dams. Current feasibility-grade investigations are focused on the engineering, operational, and biological parameters needed to provide fish passage at Cle Elum and Bumping Lake dams. Evaluation of passage opportunities at the other three dams will follow later. The feasibility report on Cle Elum and Bumping Lake dams is scheduled for completion in 2008.

 
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Cle Elum Dam Interim Downstream Fish Passage
An interesting component of current investigations will be to provide interim (temporary, experimental) passage features at Cle Elum Dam to test the ability of juvenile salmon to find and move out of the reservoir under their own volition. Uniquely marked fish will be monitored as they exit the reservoir, migrate downstream, and return as adults. Results of these interim passage experiments over a period of 5 to 8 years will be used as one indicator of the feasibility of reintroducing anadromous fish species above the dam and reservoir.
 
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Cle Elum Juvenile Pit Tag Fish Bypass System
The Cle Elum Dam downstream interim passage features were completed in the spring of 2005. However, low reservoir levels caused by drought conditions in 2005, precluded the planned release of 10,000 PIT-tagged coho salmon smolts into the reservoir. Instead, the fish were released at several points downstream of Cle Elum Dam. In addition, 2,500 PIT-tagged coho salmon parr were released into the Cle Elum River above Cle Elum Reservoir in August 2005, to test rearing, overwintering survival, and outmigration in the spring of 2006. Current plans are to also release 10,000 PIT-tagged coho salmon smolts into the reservoir in the spring of 2006.
 
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Bumping Lake Interim Downstream and Upstream Fish Passage
Proposed interim fish passage features at Bumping Lake Dam (an overflow gate installed in a notch to be cut into the spillway) would serve a dual purpose of fish passage and also provide operational flexibility needed for maintenance of the outlet works gates. However, plans for interim fish passage at Bumping Lake Dam have been postponed indefinitely because of funding uncertainties and authority concerns. The characteristics of the proposed interim fish passage facilities at Bumping Lake are such that they would, in fact, be permanent facilities. Reclamation currently has no authority to build permanent fish passage facilities at Bumping Lake Dam (or any of the dams, except for downstream passage at Cle Elum). In addition, there currently is inadequate funding in the feasibility study budget to build the interim facilities.
 
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Limnology and Macroinvertebrate Studies
Field sampling in Cle Elum and Bumping Lake reservoirs and tributaries was completed in FY 2004. Additional limnology sampling was done in FY 2005 at Cle Elum Reservoir. Laboratory analysis of collected samples and preparation of reports is nearly complete. The results of these studies inidicate that the reservoirs have very low nutrient levels and mostly poor to fair macroinvertebrate populations. This would affect their ability to support anadromous fish populations.
 
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Habitat Surveys
The U. S. Forest Service conducted habitat surveys in the Cle Elum and Bumping Lake tributaries in FY 2004 (and in earlier years). They updated and expanded these surveys in FY 2005. This habitat information is a key input in the modeling of production capability above the reservoirs.
 
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Modeling of Production Potential
Reclamation has developed a preliminary estimate of the capability to generate self-sustaining populations of coho salmon and sockeye salmon above Cle Elum Dam. Similar modeling of production potential for Bumping Lake and tributaries was started in FY 2005 and will be completed in FY 2006. These estimates will help to determine passage feasibility and to refine reintroduction plans.
 
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Fisheries Reintroduction Plans
The fisheries co-managers (Yakama Nation and Washington Department of Fish and Wildlife) are developing plans for reintroduction of anadromous fish upstream of the dams. They are developing goals and objectives, evaluating disease issues, preparing plans for monitoring and evaluation, and making arrangements to supply and handle fish.
 

Last Update: April 11, 2011 9:47 AM