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200711100 - Assess impacts of flow augmentation on bull trout in the North Fork and Lower Clearwater Rivers

Sponsor: Idaho Department of Fish & Game

Budgets: FY07: $188,269 | FY08: $186,264 | FY09: $185,210

Short description: Determine the downriver effects of cold water releases from Dworshak Dam on bull trout populations inhabiting the North Fork Clearwater River tailrace and lower mainstem Clearwater River.

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Final Council recommendation (Nov 2006)

Funding category: Expense

Recommended budgets: FY07: $0 | FY08: $0 | FY09: $0


ISRP final recommendation: Not fundable


The ISRP rates this project Not Fundable. This recommendation resulted primarily, because the project objectives do not adequately address the problems identified in the technical and scientific background section of the proposal. Several aspects of this proposal raise questions: What difference does it make where the entrained bull trout originated above Dworshak Dam? The problem identified is that there is entrainment. Shouldn't the primary focus be upon reducing or eliminating entrainment, regardless of the origin of the fish? The background and rationale sections indicate that this project will address the potential problem of temperature effects (from cold water releases from Dworshak Dam) on bull trout, but the proposal does not include this as a stated objective. The use of strobe lights has not been effective in guiding fish away from turbine intakes (see Whitney et al., 1997). The proposal refers to measurements of water depth occupied by bull trout in the reservoir but makes no mention of their depth distribution at the intakes. Wouldn't the most effective use of effort in this project be to get information on their depth distribution at the intakes? The proposal suggests that the outlet structure can be set to draw water from a wide range of depths. Thus, the only piece of information missing is bull trout depth at the structure. The proposal gives the impression that Dworshak is operated primarily for the benefit of fish, which of course is not accurate. Information should be provided showing that Dworshak is primarily a hydroelectric power dam (400,000 KW). During the months of March and April, when entrainment appears to be a problem, the dam is most likely operated strictly for power production. Flow augmentation for temperature control in the Snake River occurs later in the season, when fall Chinook are emigrating out of the river. It is misleading to assign responsibility for any effects on bull trout to the flow augmentation strategy, unless more information can be provided.

State/province recommendation: Not fundable

Review group: Snake

Recommended budgets: FY07: $0 | FY08: $0 | FY09: $0

Comment: Project not prioritized