Description:
Removal of two hydroelectric dams on the Elwha River is scheduled to begin in the fall of 2011 as authorized by the Elwha River Ecosystem and Fisheries Act (PL102-495). Full removal will be completed by 2014 and for the first time in over a century, anadromous fish will have access to the upper watershed. Restoration of fish populations is guided by the Elwha Fish Restoration Plan (Ward et al. 2008) which documents strategies for population rebuilding by stock, hatchery utilization, habitat restoration and monitoring. Monitoring the population response of Elwha River fish populations is fundamental to understanding the effects of the overall project. Monitoring strategies for salmon response and recovery on the Elwha rely on a suite of testable hypotheses using the concept of Viable Salmon Populations (VSP). VSP includes parameters that describe individual stock health including: Abundance, population growth rate (productivity), population spatial structure and diversity (NOAA 2000). Unfortunately there are almost no project monies available to answer these critical long term question. Project partners have secured enough internal resources to answer some of the short term (pre dam removal) questions concerning salmon abundance, productivity, and life history strategies including estimation of adult abundance and productivity for some species. However, these efforts will need to be expanded over space and time in order to be effective. This proposal would support a portion of that effort beginning in 2014-2017 to spatially expand adult salmon surveys using a combination of survey techniques (weir,foot, aerial) combined with marking strategies to assess effectiveness. Additionally we propose to add three upstream smolt trapping sites to measure production from the upper watershed and two major tributaries.
Limiting Factors Addressed:
Dam removal on the Elwha will restore access to over 30 miles of mainstem and 70 miles of tributaries. Dam removal also restores physical processes and will result in improved spawning habitat for returning adults and rearing habitat for juvenile salmonids throughout the watershed. This non-capitol project proposes to measure that response over space and time for two purposes: 1) to provide information on salmon response to project managers so that adjustments to restoration strategies can be made using real data (adaptive management), and 2) to document ecosystem response of the largest controlled dam removal conducted to date in the United States.
Benefits to Salmon:
This project will restore habitat and benefit Chinook as well as coho, steelhead, chum, pinks, bulltrout, resident rainbow trout and cutthroat trout. Improvement of upland habitat conditions will contribute to recovering health of main-stem and estuarine areas and the nearshore migration corridor. Historic aerial photographs clearly depict the loss of habitat diversity in the lower river and particularly its estuary. Over time the lower river has lost large deposits of sediment (fewer islands and bars), has much lower diversity of channels, and less diversity of vegetation (age and species). These changes are attributed to the cumulative effects of dam construction and channelization.