US Army Corps of Engineers
Walla Walla District

Lower Snake River Fish Passage Improvement Plan - 2010 AMIP

In the Adaptive Management Implementation Plan (AMIP), the Corps completed a Plan of Study laying out the scope, schedule, and budget to complete technical studies and a decision-making process concerning breaching the four lower Snake River dams. This Plan of Study was coordinated with NOAA Fisheries and the other Action Agencies. The Lower Snake River Fish Passage Improvement Study: Dam Breaching Update Plan of Study (Plan of Study) has been completed in accordance with the AMIP provisions. 

In addition to coordination with NOAA Fisheries, the Bureau of Reclamation and the Bonneville Power Administration, the Corps requested review and comment of the draft Plan of Study from the other regional sovereigns including the Federal Caucus agencies and the Regional Implementation Oversight Group (RIOG). A number of sovereign parties provided comments on the draft Plan of Study. The Corps considered the comments pertaining to the Plan of Study and modified the plan accordingly.

Now that the Plan of Study has been completed, it is available if a Snake River spring/summer Chinook, steelhead, or fall Chinook Significant Decline Trigger is tripped. In this event, an All-H analysis including life-cycling modeling will be conducted in coordination with NOAA Fisheries, the RIOG, and other regional parties to determine if Rapid Response Actions are likely to be sufficient or if Long Term Contingency Actions are needed. This assessment will include determining if dam breaching is necessary to address and alleviate the biological trigger conditions for the applicable Snake River species. The goal is to have this analysis completed within 4 – 6 months of tripping a Significant Decline Trigger. 

We anticipate that updated and new information may be available if and when a Significant Decline Trigger is tripped. At such time, the Corps will review the Plan of Study to verify that the scope of studies and other assumptions and costs outlined in the plan are still applicable. The Plan of Study may require updating to incorporate new information, methodologies, scientific data, and if necessary, cost estimates will be revised. At that time, if it is determined that the Corps will proceed with technical studies, additional coordination with regional parties will be considered.