ISAB consultation recommendations on Council Staff's Draft Issue Paper: "Analysis of 2001 Federal Columbia River Power System Operations on Fish Survival"

April 19, 2001  |  document ISAB 2001-4

Memorandum

To: Mr. Frank L. Cassidy Jr., Chair
Northwest Power Planning Council

From: ISAB Subcommittee - Chuck Coutant, Lyman McDonald, Dan Goodman, Dennis Lettenmaier, and Dick Whitney (ISRP)

Re: ISAB consultation recommendations on Council Staff's Draft Issue Paper: "Analysis of 2001 Federal Columbia River Power System Operations on Fish Survival."

At its April 4^th meeting, the Council requested an ISAB review of the Council Staff's Draft Issue Paper regarding the effects on ESA-listed fish stocks of an emergency spill elimination in this low-flow year. The ISAB was requested to have its review completed for the Council's April 24 and 25 meeting. This memorandum summarizes the ISAB's response to that request.

The ISAB conducted an expedited review process in the form of a "consultation." A subcommittee of ISAB was established to conduct this review and participate in discussions with the Council staff. In a "consultation" we do not attempt to obtain consensus of the full ISAB, principally because of timing. The subcommittee consisted of Lyman McDonald, Dan Goodman, and Chuck Coutant, with ad hoc assistance from Dick Whitney. Dennis Lettenmaier also joined phone discussions. Lyman and Chuck reviewed two drafts of Bruce Suzumoto's issue paper (March 28 and 30), and prepared comments for Bruce and e-mailed them to him, followed by a conference call with Bruce on Thursday, April 12. Dick Whitney was asked to comment on the SIMPAS model (he was also examining it for ISRP). Subcommittee comments were consolidated after the phone call with Bruce (who planned to accommodate our thoughts in a revision or whatever follow-up paper comes from staff) and we drafted bottom lines. Dan Goodman reviewed our efforts and assisted in preparation of the bottom lines. The consolidated comments and bottom lines were e-mailed to Council staff on April 17 in preparation for a conference call on April 18. The full ISAB was sent the same material and was invited to participate in the conference call (Dennis Lettenmaier did so). The main product is to be the outcome of discussions, not a formal report, although we have provided the bottom lines in this letter.

BOTTOM LINES

1. The SIMPASS model is a spreadsheet with a logical set of calculations using assumed intermediate survival values, FGEs, etc., for calculating total juvenile survival of ESA-listed species during downstream migration through different passage routes and hydropower projects. As used by both NMFS for the BiOp and by Council staff for these analyses, it provided a common approach that illustrates the numerical consequences of particular sets of assumptions.
2. Council staff appear to have used the model in a way that was mathematically correct, but the reasonableness and applicability of the results depends on more than this. We recommended sample hand calculations, which matched the model's calculations reasonably well. We have no reason to doubt the calculation procedure, but need to stress that the applicability of the results to a given set of circumstances depends entirely on the applicability of the assumed input values for those circumstances. We were not able to confirm the reasonableness of all input values, however. Most values are extrapolated from a relatively few scientific studies or are based totally on professional judgment.
3. The focus on ESA-listed stocks leaves questions of non-listed stocks and biodiversity unanswered, contrary to the thrust of the Council's program. The SIMPAS model and the readily available input values do not consider other species (e.g., sockeye, lamprey) or the potential effects of either spill reduction or increased transportation on selection for particular fish stocks that could have long-term effects on species diversity and diversity of life-history types. Additional analyses may not be timely, but this drawback of the current results should be acknowledged.
4. Several aspects of the analysis could be explained better in the issue paper (or added to the list of caveats) in order to avoid misunderstandings. These include (1) that the analysis compared a "no spill/maximum transportation" option with the BiOp recommendations for spill and transportation in an extreme low water year (not the normal-year BiOp recommendation), (2) methods for translation of juvenile survival to adult survival through SARs, (3) the sources of D values that were used and where the "below Bonneville" point is, (4) sources of in-river survival rates, and (5) a more thorough description of SIMPAS model that does not require the reader to search out the BiOp appendix. These are mostly matters of communication rather than problems with the analyses, as far as we can tell.
5. Juvenile survival often seems to be the most practical basis for decision-making for spill and transportation at individual projects, because SARs are so heavily influenced by large year to year variation in ocean/estuary survival, and because the sample size of returning adults often is too small for statistically stable estimation of the SAR. On the other hand, focus on juvenile survival at the individual project ignores the possible differences in delayed mortality, and neglects the reality that we cannot declare a management strategy successful until we have assurance that the entire resulting life cycle is successful. For this reason, assessment procedures based on SARs (as the staff analysis attempted) are preferable whenever a feasible design is available.
6. A clearer basis for prioritizing available water for spill among the projects would be helpful. Criteria should include biological information as well as configurations of the projects. Explicit consideration should be given in this prioritization to the unlisted upriver stocks and those stocks originating in the lower Columbia tributaries downstream of collector dams for transportation. We recommend consideration be given in the prioritization to surface spill opportunities, as discussed in the ISAB's recent letter.
7. It would have been useful to have included the Mid-Columbia dams in the calculations.
8. There is great need to monitor the hydrosystem this year to see if these estimated survival rates and D values are anywhere near reality. For example, the scientific studies to compare survival of transported juveniles to survival of juveniles migrating inriver should be continued. Monitoring the effects of this low-flow year are so important that we suggest the Council staff seriously consider requesting additional BPA funds or selective reprogramming to ensure that this monitoring takes place. The especially low-flow year offers unique opportunities for studying fish behavior, survival, and guidance systems when normal flow-related (often spill-related) migration cues are missing or at low levels.
9. While the assumptions behind the input values used in the modeling are consistent with the available data, and are also consistent with professional judgment of many scientists (they represent committee consensus), these are only "point estimates" and are subject to a considerable degree of uncertainty. For this reason, it is not appropriate to develop a long-range management plan just on the basis of results from assuming that these uncertain estimates are true. "Best science" under these circumstances would explore the results from a range of assumptions corresponding to the range of the uncertainty. "Best professional judgment" under these circumstances would recommend a course of action that was predicted to perform acceptably throughout the range of predicted possible outcomes. "Precautionary" best professional judgment would be sensitive to plausible worst cases within the range of predicted possible outcomes. Although not possible before decisions must be made this year, the importance of uncertainty in assessments of this type needs to be evaluated carefully.

We hope that the ISAB subcommittee's rapid review of the staff's drafts and subsequent discussions with the staff have been helpful to them and that this summary of impressions is useful to the Council.

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