Evaluate the Restoration Potential of Snake River Fall Chinook Salmon Spawning Habitat
Statement of Work and Budget FY2006


The goal of this study is to identify hydrosystem operational conditions that could expand and restore spawning populations the Snake River stock of fall Chinook salmon.  This project addresses NOAA's 2000 FCRPS BiOp RPA 155, and contributes to the ESA commitments made by BPA and the FCRPS Action Agencies under NOAA's revised 2004 BiOp.  This project is identified in the Crosswalk of Draft UPA (August 2004, page 30) as the project that is implementing RPA 155.  The objectives of this project are consistent with and are integral components for implementing the 2005-2007 Final Implementation Plan for the FCRPS Updated Proposed Action (May 2005).  This project is specifically identified in the Implementation Plan (page 41, Table 22) as one of the hydrosystem RM&E projects that the Action Agencies will implement in the 2005-2007 timeframe to address their UPA commitments.  Continuation of this project helps reduce critical hydrosystem uncertainties and provides status monitoring for restoring Snake River fall Chinook salmon spawning habitat.

This project was recently started in FY04 and continues in FY05.  The research to be conducted under this proposal will evaluate the restoration potential of mainstem habitats for fall Chinook salmon.  The studies will address two research questions: "Are there sections not currently used by spawning fall Chinook salmon within the impounded lower Snake River that possess the physical characteristics for potentially suitable fall Chinook spawning habitat?" and "Can hydrosystem operations affecting these sections be adjusted such that the sections closely resemble the physical characteristics of current fall Chinook salmon spawning areas in similar physical settings?"  We propose to focus our efforts at two study sites: 1) the Ice Harbor Dam tailrace downstream to the confluence with the Columbia River, and 2) the Lower Granite Dam tailrace.  Our previous studies indicated that these two areas have the highest potential for restoring Snake River fall Chinook salmon spawning habitat.

The study sites will be evaluated under existing structural configurations at the dams (i.e., without partial removal of a dam structure), and alternative operational scenarios (e.g., varying forebay/tailwater elevations).  The areas to be studied represent tailwater habitat (i.e., riverine segments extending from a dam downstream to the backwater influence from the next dam downstream).  We will use a reference site, indicative of current fall Chinook salmon spawning areas in tailwater habitat, against which to compare the physical characteristics of each study site.  The reference site for tailwater habitats will be the section extending downstream from the Wanapum Dam tailrace on the Columbia River.  Escapement estimates for fall of 2000 indicate more than 9000 adult fall Chinook salmon returned to this area, accounting for more than 2100 redds within a 5 km section of river (Grant Co. PUD, personal communications).  Using the National Marine Fisheries Service Reasonable and Prudent Action (RPA) 155 (NMFS 2000) as a guide, we will collect baseline data on physical habitat conditions, identify opportunities for mimicking the range and diversity of historic habitat conditions, and monitor and evaluate the results of any operational changes (actual or modeled).

The results to be reported during FY2006 will be used as a guideline to develop additional hypotheses regarding potential Snake River fall Chinook salmon spawning habitat.  We expect that these hypotheses will include hydrosystem operational scenarios not considered in the initial analyses (FY04-06), as well as alternative reaches of the Snake River not initially considered.  It is also expected that future fall Chinook salmon spawning periods (fall of 2006 and 2007) will provide ideal opportunities for monitoring spawning habitat use and conditions, as well as calibrating and verifying our model results.  We will be seeking continued funding in FY2007 to address all of these efforts.