Wind River IMW – Summary
The Wind River Intensively Monitored Watershed project is designed to measure responses of wild
summer steelhead to restoration actions in the Trout Creek sub-basin of the Wind River, WA. The Wind
River is a 582 km2 watershed which begins in Washington’s Cascade Mountains as three sub-basins;
Trout Creek, Panther Creek, and the upper mainstem Wind River, and enters the Columbia River 10 km
above Bonneville Dam (Figure 1). Shipherd Falls located at rkm 3 was historically passable only by
summer steelhead, and although a fishway was constructed, only wild steelhead and spring Chinook that
are part of an upstream hatchery program are allowed upstream. Historic habitat degradation in the Wind
watershed, which is mostly (77%) owned by the U.S. Forest Service, was primarily associated with
forestry, including logging, splash damming, and road construction, resulting in reduced abundance of
instream woody debris, sedimentation and scour, and reduced channel stability and habitat complexity,
particularly in alluvial reaches. On lower Trout Creek, the 6.7 m tall Hemlock Dam, equipped with an
antiquated fish ladder, provided poor fish passage for adult steelhead, disrupted sediment transport, and
inundated riverine habitat upstream. A collaborative monitoring and habitat restoration program
involving the Washington Department of Fish and Wildlife, USGS-WFRO, USFS, and the Underwood
Conservation District began in the 1990s. Smolt production has been monitored in the three headwater
sub-basins as well as at the mouth of the watershed since the mid-1990s, and adult total population
abundance has been estimated using a mark-resight approach since 2000. From 1992-2009 a fish trap
was operated in the Hemlock Dam fish ladder, enabling a census count of adult steelhead in the Trout
Creek sub-basin above the dam, and estimates have continued subsequently via mark-resight methods. In
2009, USFS and BPA funded the removal of Hemlock Dam, and the existence of pre-dam removal
abundance estimates and other biological data collected in the Trout Creek sub-basin and other sub-basins
provided a unique opportunity to measure the responses of steelhead populations. Other restoration
actions since dam removal have been coordinated through the interagency collaboration to ensure mutual
restoration and monitoring goals are achieved. Power analysis suggested an increase of about 50% for
adults and 24% for smolts would be necessary to have 90% chance of detecting these effects within 10
years with an alpha value of 5%.
Figure 1. Wind River subbasin with adult and juvenile trapping sites, juvenile release sites, and
snorkel and redd survey sections. Note: Hemlock Dam Fishway was removed in 2009.