East Fork Lewis River

Summary

The Lewis River is a tributary of the Columbia River, about 95 miles long, in southwestern Washington in the United States. It drains part of the Cascade Range north of the Columbia River. The drainage basin of the Lewis River covers about 1,046 square miles​​. The East Fork flows westward from headwaters on the western flanks of Lookout Mountain in Skamania County.

Native Species

  • Coastal Cutthroat Trout
  • Coho Salmon
  • Fall Chinook Salmon
  • Pacific Lamprey
  • Resident Rainbow Trout
  • summer-steelhead
  • Winter Steelhead

Location:

The Lewis River rises in the Cascades in northeastern Skamania County, high on the west flank of Mount Adams, approximately 75 miles northeast of Portland, Oregon. It flows generally southwest through Gifford Pinchot National Forest, across central Skamania County, passing south of Mount St. Helens. It forms the boundary, along the Dark Divide on its north side, between Cowlitz County, to the north, and Clark County, to the south. The East Fork Lewis enters the Columbia from the east, opposite St. Helens, Oregon, approximately 15 miles north of Vancouver, Washington. The mouth of the Lewis River is at Columbia river mile(RM) 87.

Topography & Geology :

The East Fork Lewis River has its headwaters in Skamania County and flows west, with most of the basin lying within Clark County. The EF enters the main stem of the Lewis at approximately river mile 3.5, about 4,000 ft downstream of the I-5 Bridge. The EF basin covers approximately 150,635 acres. The source of the EF resonates around the Green Lookout Mountain in the Gifford Pinchot National Forest. Elevation ranges from near sea level at the mouth to 4,442 feet. The East Fork Lewis basin has developed from volcanic, glacial and erosional process. Glaciation has shaped the valleys in the upper portions of the basin as recently as 13,000 years.

The headwaters are very steep, with narrow valleys and are dominated by bedrock and boulder substrates. The largest tributaries of the east fork are Copper Creek and upper Rock creek respectively. Lucia Falls (RM 21) blocks passage of anadromous fish except steelhead and an occasional Chinook and/or Coho. Upstream migration for steelhead was essentially blocked at Sunset Falls (RM 32) until 1982 when the falls were notched, lowering the falls from 13.5 to 8 feet; approximately 12% of the steelhead run now spawns above Sunset Falls.

Land Use/ Land Cover

The Bulk of the land is forested and is managed as a commercial forest. Agricultural and residential activies are found in the valley bottom areas. Recreation uses and residential development have increased in recent years and continues to increase. 63% of the land nearing the EF is private with about 20% of the basin area lying within the Gifford Pinchot National Forest. A number of large fires have had a lasting effect on basin hydrology, sediment transport, soil conditions and riparian function. The majority of these fires took place in the early 1900's and continue to have an effect on the land cover of EF and its riparian qualities.

Life History Diversity

Chinook -

Timing: Fall chinook enter the Lewis River from August to November, depending on early fall rain. Natural spawning in the EF Lewis River occurs in two distinct segments: the early segment in October and the late segment from November through January. Age ranges from 2-year-old jacks to 6-year-old adults, with dominant adult ages of 3, 4, and 5 (averages are 20.5%, 48.5%, and 22.7%, respectively) Fry emerge from March to August (peak usually in April), depending on time of egg deposition and water temperature; fall chinook fry spend the spring in fresh water, and emigrate in the summer as sub-yearlings.

Distribution

  • Spawning occurs primarily from Lewisville Park downstream to Daybreak Feeders (approx. 6 miles); the late spawning segment also spawns in areas upstream of Lewisville Park
  • The EF Lewis late spawning fall chinook along with North Lewis and Sandy River late spawning fall chinook comprise the lower Columbia River wild management unit

Abundance

  • Fall chinook escapement estimates by WDFW (1951) were about 4,000 into the EF Lewis River
  • EF Lewis River spawning escapement from 1986-2001 ranged from 52 to 591 (average 279)

Productivity & Persistence

  • NMFS Status Assessment for the EF Lewis River fall chinook indicated a 0.0 risk of 90% decline in 25 years, a 0.06 risk of 90% decline in 50 years, and a 0.0 risk of extinction in 50 years
  • The EF Lewis early and late components of natural produced fall chinook have been sustained at low levels with minimal influence from hatchery fish

Coho:

Distribution

• Managers refer to early coho as Type S due to their ocean distribution generally south of the Columbia River

• Managers refer to late coho as Type N due to their ocean distribution generally north of the Columbia River

• Coho historically spawned throughout the basin, including headwater tributaries now upstream of dams, such as Muddy River and Pine, Clearwater, and Clear Creeks

• Natural spawning is thought to occur in most areas accessible to coho; coho currently spawn in the North Lewis tributaries below Merwin Dam including Ross, Cedar, North and South Fork Chelatchie, Johnson, and Colvin Creeks; Cedar Creek is the most utilized stream on the mainstem

• On the East Fork, spawning occurs primarily below Lucia Falls (RM 21); Lockwood, Mason, and Rock Creeks are extensively used

• Construction of Merwin Dam was completed in 1932; coho adults were trapped and passed above Merwin Dam from 1932-1957; the transportation of coho ended after the completion of Yale Dam (1953) and just prior to completion of Swift Dam (1959)

• As part of the current hydro re-licensing process, reintroduction of coho into habitat upstream of the three dams (Merwin, Yale, and Swift) is being evaluated.

Life History

• Adults enter the Columbia River from August through January (early stock primarily from mid-August through September and late stock primarily from late September through

November)

• Peak spawning occurs in late October for early stock and December to early January for late stock

• Adults return as 2-year-old jacks (age 1.1) or 3-year-old adults (age 1.2)

• Fry emerge in the spring, spend one year in fresh water, and emigrate as age-1 smolts the following spring

Diversity

• Late stock coho (or Type N) were historically present in the Lewis basin with spawning occurring from late November into March

• Early stock coho (or Type S) were historically present in the Lewis basin with spawning occurring from late October to November

• Columbia River early and late stock coho produced at Washington hatcheries are genetically similar

Abundance

• Lewis River wild coho run is a fraction of its historical size

• An escapement survey in the late 1930s observed 7,919 coho in the North Fork and 1,166 coho in the East Fork

• In 1951, WDF estimated coho escapement to the basin was 15,000 fish; 10,000 in the North Fork (primarily early run) and 5,000 in the East Fork (primarily late run)

• Escapement surveys from 1944-1999 on the North and South Fork Chelatchie, Johnson, and Cedar Creeks documented a range of 1-584 fish/mile

• Hatchery production accounts for most coho returning to the Lewis River

Productivity & Persistence

• Natural coho production is presumed to be generally low in most tributaries

• Juvenile sampling in Lockwood Creek in 1994-95 found a low level of coho

• A smolt trap at lower Cedar Creek has shown recent year coho production to be fair to good in North and South forks of Chelatchie Creek (tributary of Cedar Creek) and in main-stem Cedar Creek

Chum

Distribution

• Spawning occurs in the lower reaches of the mainstem NF and EF Lewis River.

• Historically, chum salmon were common in the lower Lewis and were reported to ascent to the mainstem above the Merwin Dam site and spawn in the reservoir area

• Chum were also abundant in Cedar Creek, with at least 1,000 annual spawners (Smoker et al 1951)

Life History

• Lower Columbia River chum salmon run from mid-October through November; peak spawner abundance occurs in late November

• Dominant age classes of adults are age 3 and 4

• Fry emerge in early spring; chum emigrate as age-0 smolts, generally from March to mid-May

• 1951 report estimated escapement of approximately 3,000 chum annually in the mainstem Lewis and East Fork and 1,000 in Cedar Creek

• 96 chum observed spawning downstream of Merwin Dam in 1955

• In 1973, spawning population of both the Lewis and Kalama subbasins estimated at only a few hundred fish

• Annually, 3-4 adult chum are captured at the Merwin Dam fish trap

Productivity & Persistence

Harvest, habitat degradation, and construction of Merwin, Yale, and Swift Dams contributed to decreased productivity

• WDFW consistently observed chum production in the North Lewis in March-May, 1977-1979 during wild chinook seining operations

Summer Steelhead

Distribution

• Spawning occurs in the EF Lewis River as well as Rock Creek and other tributaries; rearing habitat is available throughout most of the basin

• Upstream migration was essentially blocked at Sunset Falls until 1982 when the falls were “notched”, lowering the falls from 13.5 to 8 feet; approximately 12% of the run now spawns above Sunset Falls

Life History

• Adult migration timing for EF Lewis River summer steelhead is from May through November

• Spawning timing on the EF Lewis River is generally from early March through early June

• Age composition data are not available for EF Lewis River summer steelhead

• Wild steelhead fry emerge from late April through July; juveniles generally rear in fresh water for two years; juvenile emigration occurs from March to May, with peak migration in

early May

Diversity

• Stock designated based on distinct spawning distribution and early run timing

• Progeny from Elochoman, Chambers Creek, Cowlitz, and Skamania Hatcheries have been planted in the Lewis basin; interbreeding among wild and hatchery stocks has not been

measured

• After Mt. St. Helens 1980 eruption, straying Cowlitz River steelhead may have spawned with native Lewis stocks

• Genetic analysis in 1996 provided little information in determining stock distinctiveness

Abundance

• From 1925-1933, run size was estimated at 4,000 summer steelhead

• In 1936, steelhead were reported in the Lewis River during escapement surveys

• From 1963-1967, run size estimates averaged 6,500 summer steelhead

• Wild summer steelhead escapement to the EF Lewis River was estimated at 600 fish in 1984

• Average wild summer steelhead escapement to the EF Lewis River from 1991-1996 was 851

• Snorkel index escapement surveys have been conducted since 1996

• The escapement goal for the EF Lewis River is 814 wild adults

Productivity & Persistence

• Wild fish production is believed to be moderate

Hatchery

• The Lewis River Hatchery (about 4 miles downstream of Merwin Dam) and Speelyai Hatchery (Speelyai Creek in Merwin Reservoir) do not produce summer steelhead

• A net pen system has been in operation on Merwin Reservoir since 1979; annual average smolt production has been 60,000 summer steelhead; release data are available from 1982- 2002; current annual stocking levels in the East Fork are around 40,000 smolts

• The portion of wild summer steelhead in the run at Lucia Falls averaged 27% from 1974-1983

• Recent snorkel surveys indicate hatchery summer steelhead comprise about 70% of the spawning escapement on the EF Lewis River

Winter Steelhead

Distribution

• Spawning occurs in the EF Lewis River as well as Rock Creek and other tributaries; rearing habitat is available throughout most of the basin

• Upstream migration was essentially blocked at Sunset Falls until 1982 when the falls were “notched”, lowering the falls from 13.5 to 8 feet; approximately 12% of the run now spawns above Sunset Falls

Life History

• Adult migration timing for EF Lewis winter steelhead is from December through April

• Spawning timing on the EF Lewis is generally from early March to early June

• Limited age composition data for Lewis River winter steelhead suggest that most steelhead are two-ocean fish

• Wild steelhead fry emerge from March through May; juveniles generally rear in fresh water for two years; juvenile emigration occurs from April to May, with peak migration in early

May

Abundance

• In 1936, steelhead were reported in the Lewis River during escapement surveys

• Historical winter steelhead annual escapement in the Lewis River ranged from 1,000 to 11,000 fish

• Redd index escapement counts from 1986-2001 ranged from 53 to 282 (average 157); a new escapement index was instituted in 1997 and the relationship to the previous index is

unknown

• Escapement goal for the EF Lewis River is 875 wild adult steelhead

• The portion of wild winter steelhead at Lucia Falls found in the creel ranged from 35% to 74% from 1974-1983

• Recent data suggests that 51% of spawning steelhead in the East Fork are of hatchery origin

Productivity & Persistence

• NMFS Status Assessment for the EF Lewis River winter steelhead predicted a risk of 1.0 for the risk of 90% decline in both 25 and 50 years; the risk of extinction in 50 years was not applicable

• Winter steelhead natural production is unknown

Threats:

  • Loss of habitat quantity and quality has the highest relative impact on populations in the EF Lewis
  • Loss of estuary habitat quantity and quality has high relative impacts on chum and moderate impacts on fall Chinook and winter steelhead. Impacts to summer steelhead are minor
  • Harvest has relatively high impacts on fall Chinook, but impacts to chum, steelhead, and Coho are relatively minor
  • Hatchery impacts are high to moderate for summer steelhead and Coho, but are low for chum, fall Chinook, and winter steelhead
  • Impacts of predation are moderately important to winter and summer steelhead, Coho and chum, but are relatively minor for fall Chinook
  • Pool abundance and quality
  • High Water Temperature
  • Low Flows

Wild, Native Fish:

As of 2014, the East Fork Lewis has been designated as a wild Steelhead gene bank thanks to the hard work of wild Steelhead advocacy groups, local participants, and with the help and cooperation of Washington State Fish and Wildlife. This wild gene bank designation will allow the native Steelhead population to sustain its genetic diversity and conservation under natural habitat conditions.

  • The East Fork Lewis was designated as one of Native Fish Society's Most improved wild fish rivers of 2014. "The recent, hard-won selection of the East Fork of the Lewis River as both a winter-run and summer-run Gene Bank river eliminates all hatchery plants, protects fish with new angling regulations and provides an all-wild salmonid future for this majestic river."

News Articles:

Sources:

Northwest Power and Conservation Council. “Lewis River Subbasin - East Fork.” In Columbia River Basin Fish and Wildlife Program.Portland, Oregon, 2004.

http://www.nwcouncil.org/media/21078/Vol._II_Ch._1...

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