Review of Lower Snake River Flow Augmentation Studies

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At its January 23, 2001 meeting, the Northwest Power Planning Council (Council) requested the ISAB to review a recent report by Carl Dreher of the Idaho Department of Water Resources and four co-authors on the topic of flow augmentation in the lower Snake River (Dreher et al. 2000). That report analyzed and interpreted results of studies by the National Marine Fisheries Service (NMFS) of the survival and migration timing of tagged hatchery juvenile fall chinook salmon released in test batches and detected at Lower Granite Dam (Muir et al. 1999 and subsequent unpublished data). The Council was interested in both the ISAB’s reaction to the specific report and its view of the implications of the report (and the Muir et al. studies) for the Council’s mainstem rulemaking regarding flow augmentation.In particular, the ISAB was asked to answer the following questions:Does the analysis conducted by Dreher et al. employ generally accepted scientific and statistical methods and are the conclusions consistent with the results? Does the analysis provide new insights into the biological role of water flow and augmentation in the recovery of listed anadromous fish in the Columbia and Snake rivers? What implications do the results from this analysis have on strategies, particularly the use of flow augmentation in the lower Snake River in regard to recovery of anadromous fish? Based on this analysis, research conducted by NMFS over the last several years, and other existing information, what is the ISAB’s assessment of the biological role of water velocity, temperature and other attributes of water flow in regard to the recovery of anadromous fish in the Snake and Columbia rivers? Based on this analysis, research conducted by NMFS over the last several years, and other existing information, what changes would the board recommend in regard to the experimental design of ongoing studies of the migration of anadromous fish, particularly Snake River fall chinook (to tease out the effects of flow, temperature, turbidity, and release timing)?

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