The Independent Scientific Advisory Board (ISAB) is responding to a request from the Northwest Power Planning Council for assistance with a congressional query. The direction from Congress identified a concern about a lack of agreed upon priorities and a set of principles and criteria for setting those priorities in the Corps Capital Construction Program. We believe the perception of a lack of prioritization stems from two sources, 1) the lack of agreement on the technical bases for action (due to uncertainties in available information), and 2) the fact that it may be necessary to provide more than one technological approach to achieve the passage goals set by the National Marine Fisheries Service (NMFS) and the Northwest Power Planning Council (Council). The U.S. Army Corps of Engineers’ (Corps’) capital construction program for fish passage at hydroelectric projects in the mainstem Columbia and Snake rivers (the Corps of Engineers' Columbia River Fisheries Mitigation Program or CRFMP) is to an extent a reflection of the region’s plans and assumptions for salmon restoration. Even so, we believe the CRFMP is insufficient for restoration efforts partly because of its lack of balance in application of measures across species and life history types. Evidence of insufficiency comes from the continuing low adult returns in most runs. We recognize that the hydroelectric system is one of many natural and anthropogenic factors that could be impacting salmon abundance; however, the steady downward trend is symptomatic of a chronic problem. Unfortunately the possible role of hydroelectric passage in causing mortalities after passage, delayed mortality, is one of the major missing pieces in the Columbia Basin research program. We advise caution in making inferences about future salmon abundance based on estimates of survivals measured within the hydroelectric system until the effects of delayed mortality can be ruled out.
