EPA's Vessel General Permit and Small Vessel General

The smolt migration past Willamette Falls also begins in early April and proceeds into early
June, peaking in early- to mid-May (Howell et al., 1985). Smolts generally migrate through the
Columbia via Multnomah Channel rather than the mouth of the Willamette River. Most spend 2
years in the ocean before re-entering natal rivers to spawn (Busby et al. 1996). Steelhead in the
Upper Willamette River DPS generally spawn once or twice, although some may spawn three
times. Repeat spawners are predominantly female and generally account for less than 10% of the
total run size (Busby et al. 1996).
Status and Trends
NMFS originally listed Upper Willamette River steelhead as threatened in 1999 (64 FR 14517),
and reaffirmed their status as threatened on January 5, 2006 (71 FR 834). The Upper Willamette
steelhead DPS consists of four demographically independent populations, each of which remains
extant although depressed from historical levels. Available data for this DPS comes from a
combination of dam counts, redd count index surveys and hatchery trap counts. Estimates of
abundance from NMFS 1996 status review on this DPS, demonstrate a mix of trends with the
largest populations, Mollala and North Santiam Rivers, declining over the period of analysis.
The 2005 review of the status of the Upper Willamette steelhead DPS indicated that each
population showed a declining trend over the data series that extended to 2000 and 2001, while
one population, the Calapooia River, increased over the short-term (Good et al., 2005).
More recently, data reported in McElhany et al., (2007) indicate that currently the two largest
populations within the DPS are the Santiam River populations. Mean spawner abundance in
both the North Santiam River and the South Santiam River is about 2,100 native winter-run
steelhead. Long-term growth is negative for three of the populations within the DPS, with
Calapooia River demonstrating a lambda of >1 indicating long-term growth in this population
(McElhany et al., 2007). Spatial structure for the North and South Santiam populations has been
substantially reduced by the loss of access to the upper North Santiam basin and the Quartzville
Creek watershed in the South Santiam subbasin due dam construction lacking passage facilities
(McElhany et al. 2007). Additionally, habitat in the Molalla subbasin has been reduced
significantly by habitat degradation and in the Calapooia by habitat degradation as well as
passage barriers. Finally, the diversity of some populations has been eroded by small population
size, the loss of access to historical habitat, legacy effects of past winter-run hatchery releases,
and the ongoing release of summer steelhead (McElhany et al. 2007).
Critical Habitat
NMFS designated critical habitat for Upper Willamette River steelhead on September 2, 2005
(70 FR 52488). Designated critical habitat includes the following subbasins: Upper Willamette,
North Santiam, South Santiam, Middle Willamette, Molalla/Pudding, Yamhill, Tualatin, and the
Lower Willamette subbasins, and the lower Willamette/Columbia River corridor. These areas
are important for the species’ overall conservation by protecting quality growth, reproduction,
and feeding. The critical habitat designation for this DPS identifies primary constituent elements
that include sites necessary to support one or more steelhead life stages. Specific sites include
freshwater spawning sites, freshwater rearing sites, freshwater migration corridors, nearshore
marine habitat and estuarine areas. The physical or biological features that characterize these
sites include water quality and quantity, natural cover, forage, adequate passage conditions, and
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