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200733600 - Effects of short-term flow fluctuations on salmon migration

Sponsor: Oak Ridge National Laboratory

Budgets: FY07: $129,646 | FY08: $164,968 | FY09: $188,194

Short description: Research will determine if short-term flow fluctuations affect juvenile salmonid migration through the Snake River.

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Final Council recommendation (Nov 2006)

Funding category: Expense

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


ISRP final recommendation: Fundable


This is a well-prepared proposal that addresses a major uncertainty in smolt passage -- the effects of short-term flow fluctuations from mainstem dams on smolt movements in mainstem reservoirs that may affect survival, particularly in the Snake River. Despite control of reservoir elevations to within one foot during outmigrations, large flow fluctuations occur on hourly time frames, based on available flow records, especially during late spring-summer outmigration of fall Chinook juveniles. These flow fluctuations propagate through the reservoirs. Technical and Scientific Background: The proposal describes a problem, which is the lack of a good computational hydraulic model to provide instantaneous values of hydraulic variables (volumetric flux, cross-sectional average velocity, cross-sectional flow area, water surface elevation, and cross-sectional average temperature) in Columbia and Snake river reservoirs. Such a model would help the region design studies to determine the potential effects of short-term flow fluctuations on fish migration behavior. The ISAB (2003-1) identified the problem, documented a suggestive relationship between the flow fluctuations and smolt survival, and later recommended an experiment to measure the effects of load following on survival of juvenile salmonids (ISAB 2005-3). These are referenced in the proposal. Further documentation of actual Snake River flow fluctuations during late spring and summer migrations of ESA-listed fall Chinook would have been helpful for making the case for the study. Rationale and significance to subbasin plans and regional programs: There is no relevant subbasin plan for the mainstem Snake River. For significance to the Council's Fish and Wildlife Program the proposal refers to the ISAB review of Council's Proposed 2003 Mainstem Amendments. Relationships to other projects: The proposed work is linked to several other projects with respect to sharing data and analysis. There is an appearance of a possible minor duplication with part of Proposal 200736400, but there is really no overlap because this is a modeling project and that one is an empirical one. This proposal mentions that it will obtain data on fish behavior from ongoing projects in the Snake River. However, the proponents were apparently unaware of one another's decision to present a proposal on this subject. Our summary and recommendations consider what might be done to take this into account as BPA funds them both. At a broad scale, this project makes use of similar modeling conducted by the Tennessee Valley Authority for operating its chain of reservoirs. Objectives: There are clear biological objectives to analyze the impact of load-following or other short-term flow fluctuations on patterns of flow downstream to assess possible effects on migrations of juvenile salmon. Tasks (work elements) and methods: Further thought should be given to description of the parameters to be used in the analysis, particularly the practical boundaries to be set in describing the load following episodes. The proposal discusses "indexes." These indexes should in some way incorporate measures of magnitude of flow fluctuation relative to base flow, as well as duration and frequency of the episodes. It would have been helpful to describe what the indexes would include. Monitoring and evaluation: This is a project in which there is no experimental manipulation, so M&E is inherent in the study design. Facilities, Equipment, and Personnel: The personnel and facilities are exceptional. Information Transfer: An interim report is specified. There is no mention of data storage. Plans for long-term storage of data and meta-data should be specified. Benefit to focal and non-focal species: It is very likely that this project will provide important information for the management of the hydrosystem related to juvenile salmon migration with benefits to focal species. Summary: This project deserves support because this information is of vital importance in isolating causes of low survival of Snake River juvenile salmonids and such a study is long overdue. The two proposals to study this issue are both worthy of support. Where 200733600 proposes work only in Little Goose Reservoir and puts primary emphasis upon radio tracking of juvenile fish to record their behavior in response to load following episodes, with secondary emphasis upon monitoring of hydraulic conditions associated with those episodes, the present proposal, 200733600, encompasses the reservoirs of all four lower Snake River projects and puts primary emphasis upon measurement of hydraulic conditions as affected by load following, and would depend upon information on fish behavior that would be available from ongoing projects. It is apparent that neither group was aware of the proposal being developed by the other, but they complement each other very well. Both proposals are well prepared and submitted by well-qualified groups. Funding of both would have merit because information on hydraulic conditions in all four reservoirs is certain to be useful in extrapolating the implications for fish behavior observations beyond Little Goose Dam. We recommend that the BPA contracting officer arrange for the two proponents to agree among themselves as to whether there is any duplication of effort that could or should be avoided. Both groups would benefit from further thought given to the designation of the parameters that would serve as the basis for analysis. Proposal 200733600 is probably overly concerned about refining time intervals of turbine adjustment beyond hourly to include what are likely minor, short-term, fine-tuning adjustments by the hydrosystem operators that are not likely to have measurable effects on fish behavior. It is our feeling, that since there are hourly coordination agreements in place among the hydropower operators, the hourly changes are likely to be those of most significance. Otherwise, particularly in the lower Snake River, due to lack of storage capacity, operations of powerhouses in either upstream or downstream directions could lead to violation of reservoir levels established in the BiOp and elsewhere. Similarly the proponents of proposal 200736400, need to give further thought to the boundaries to be set in the analysis of load following episodes. Some sort of grouping would seem to be necessary in order to conduct a meaningful analysis of effects of magnitude, duration, and/or frequency of episodes on fish behavior, which in turn will probably differ according to those features of load following. Similar groupings should be used in both proposals.

State/province recommendation: MS: Recommended Action

Review group: MSRT

Recommended budgets: FY07: (n/a) | FY08: (n/a) | FY09: (n/a)

Comment: This is a load following study at mainstem Snake River dams where load following is not currently allowed because these projects are held within one foot of minimum operating pool (MOP) during fish migration season. A significant policy shift would have to occur to implement results from this study due to current MOP operations.