American River Bull Trout Population

Overview

The American River originates in the William O. Douglas Wilderness Area and flows unimpeded for over 25 miles before converging with the Bumping River about 3.5 miles upstream of the latter’s convergence with the Little Naches River. For much of its length it is bordered by wilderness; however, SR 410 runs parallel to the river for a significant portion. The American River is fed by numerous tributary streams, three of the most significant being Union, Kettle, and Timber creeks. In addition to supporting bull trout, the American River is the most productive spring chinook spawning stream in the Naches River watershed. The American River bull trout population spawns in the mainstem, Union Creek, and Kettle Creek. The American River from RM 5.4 (just downstream of Hells Crossing Campground) to the Mesatchee Creek Trail Crossing is closed to fishing from July 16th to September 15th each year to protect bull trout during their migration and spawning season.

Population Information

Population Distribution and Life History

The American River supports what is believed to be a single local population of bull trout that displays a fluvial life history type; there may be a resident component as well but this has not been confirmed. An observation during a bull trout redd survey in Kettle Creek in 2022 noted a ~200mm bull trout upstream of multiple potential passage barriers (notably a 2m waterfall) (WDFW redd survey observation dataset). The observer noted the odd size for a fluvial adult or a juvenile and posed the question of residency. The known spawning area for the American River bull trout population includes the American River beginning just below where Kettle Creek enters the stream (~RM 9) and extending about 8.5 miles upstream (Figure 1 - Map needs to be added). It also includes 0.4 miles of Union Creek, which enters the river at RM 11.5, and 0.7 miles of Kettle Creek.

Juvenile bull trout most likely rear throughout the length of the river but presumably most remain within the spawning areas. Adult FMO habitat includes the Bumping, Little Naches, and mainstem Naches rivers. An unknown but assumed small number of adult bull trout evidently migrate up the Tieton River as well (see Population Monitoring below). Adults migrate upstream on the Naches River throughout the summer and into the American River in August.

Natural Barriers limiting distribution

There is a natural barrier (60 foot waterfall) on Union Creek at 46.935490, -121.359200 and a presumed barrier (bedrock cascades) on Kettle Creek at 46.933014, -121.3273370. There are no known natural barriers on the mainstem American River.

Population Genetics

The American River population, while genetically distinct from all other populations, clusters with the other Naches River fluvial populations, indicating some degree of gene flow. Juvenile samples for the genetics baseline were collected in spawning and rearing areas, and adults were collected in a box trap after spawning during the radio telemetry studies in Union Creek (Mizell and Anderson 2010). Samples from the American River and Union Creek were run separately to determine whether bull trout that were spawning there were genetically distinct from one another. They were found to be genetically identical (Reiss 2003; Hawkins and Von Bargen 2007). Kettle Creek was not sampled separately; it is believed to be part of the same population group because of its proximity to the other spawning locations and relatively small number of redds.

Population Monitoring

The USFWS first documented the presence of bull trout (formerly called Dolly Varden) in the American River during habitat and fish barrier surveys conducted during 1935 and 1936 (McIntosh 1990). The population was not investigated again until WDFW captured several bull trout during electroshocking surveys in 1978 and 1985 (Washington Dept of Game 1978; WDFW 1985). Returning to conduct presence/absence electroshocking surveys in 1993, they reconfirmed the presence of bull trout in the American River and also documented the species’ presence in Union, Timber, and Kettle creeks (Anderson 1993b). Also present were cutthroat trout and brook trout. In 1993 The Forest Service also caught juvenile bull trout in minnow traps in Timber, Kettle and Union creeks (USFS 1993b). As mentioned above, annual spawning surveys have been conducted since 1996.

Mizell and Anderson (2010) investigated the migratory behavior of bull trout in the Naches River and tributaries. Bull trout that spawn in the American River and tributaries overwinter in the Naches River, generally downstream from Rattlesnake Creek. Bull trout staging/holding in pools in the American River from Union Creek to the mouth in early fall has been documented on numerous occasions. The study revealed that adult bull trout leave the American River immediately after spawning, with some spending a short time in the Bumping River before moving downstream into the Naches River to overwinter.

In 2005, a hydroelectric project was constructed on Tieton Dam, at the head of the Tieton River. Thirty seven bull trout were captured in the stilling basin directly below Tieton Dam during a fish salvage effort (Ackerman 2005). Genetic samples were collected from these fish, and six were genetically assigned to the American River population (Small et al. 2009).

Redd Surveys

Figure 2. American River Redd Counts Through 2024

The American River population spawns primarily during the month of September. Complete redd surveys have been conducted for this population since 1996 in two American River index reaches and in Kettle and Union creeks. The lower mainstem index reach covers 0.4 mile below the Union Creek confluence, and the upper covers 2.8 miles at the upstream end of the known spawning area. The length of the reaches surveyed in Kettle and Union creeks are 0.7 and 0.4 miles, respectively. Both reaches begin at the mouth of the creek and end at natural fish passage barriers. Annual redd counts for the American River bull trout population has remained relatively stable over the period of record (Figure 2).

Other Distribution Data (eDNA, etc.)

As part of the Range Wide Bull Trout eDNA project, US Fish and Wildlife Service collected eDNA samples in parts of the Little Naches watershed in 2018 to determine if there was evidence of a spawning population. The results showed a few low-concentration "positive" sites. After discussion with USFWS bull trout researchers, it was determined that another round of eDNA should be collected to confirm presence or absence. WDFW conducted a demographic survey in the North fork in 2024 and re-sampled eDNA in the middle and North forks (Kline 2024). No bull trout were observed during demographic surveys and no bull trout DNA was detected. It is unlikely there is an extant spawning population (other than Crow Creek) in the Little Naches system. The South Fork Little Naches River has not been sampled for eDNA or been surveyed for bull trout.

Population Status and Trend

The USFWS (1998) did not consider the American River population singularly. The agency considered the Naches River “subpopulation” (i.e., all three Naches River fluvial populations) to be depressed with an unknown trend. WDFW similarly lumps the Naches fluvial populations and rates the status of this stock as critical (WDFW 2004).

Although there are caveats to using redd counts to determine population trends, it is currently the only long-term dataset for American River bull trout. Redd counts in American river over the last decade (2015-2024) have decreased to an average of 22 redds annually, compared to 31 redds annually for the period of record.

Habitat

Habitat Overview

The American River is a relatively high elevation watershed, from the headwaters at 5400 feet to the mouth at 2800 feet. The known spawning area for bull trout is located along the boundary of the Norse Peak Wilderness Area to the north and the William O. Douglas Wilderness Area to the south. As was noted above, this is also considered the primary juvenile rearing area. SR 410 parallels the river along this boundary, but the road’s effects on floodplain confinement are minimal as the river is naturally confined for the most part. Habitat conditions in the American River were described in detail in the Limiting Factors Analysis (Haring 2001). Good to excellent conditions were noted for channel condition, substrate condition, riparian condition, water quality, and water quantity. Concerning riparian condition, some degradation leading to bank erosion was noted in areas where Forest Service campgrounds (Pleasant Valley, Hells Crossing, Lodgepole) are located. Spawning and rearing habitat in the two important tributaries (Union and Kettle creeks) were not addressed in the analysis but were considered to be highly suitable by local bull trout experts. However, more recent data shows a substantial decline in spawning numbers in these tributaries.

The Naches River is believed to provide the primary FMO habitat for American River adult and subadult bull trout but it is probable that habitat in the Bumping and Little Naches rivers is also used to some extent. Habitat conditions in the Naches and Little Naches rivers were described previously (see Naches Fluvial Populations FMO Habitat Overview; Crow Creek Habitat Overview). Below Bumping Dam, the river flows for over 16 miles through National Forest land and is in close proximity to the William O. Douglas Wilderness Area. Like the American River, a road parallels the Bumping for much of its length. Four Forest Service campgrounds are located along its banks as well as numerous private residences, which likely impacts FMO habitat to some degree. The Bumping River is a high recreation area and channel-spanning recreational rock dams are removed each summer.

In 2017, the Norse Peak and American Fires burned 55,920 acres within the lower American River, lower Bumping River, Crow Creek, and the upper Little Naches River watersheds (USFS 2017). Observations during redd surveys the following year noted increased levels of silt in the mainstem American, and silty substate with burned forest and riparian areas throughout the Kettle Creek survey reach (WDFW redd survey observations). Surveyors have also observed a reduction in spawning gravels in Union Creek over the past several years

Habitat Monitoring

Field Habitat Surveys

The Forest Service completed habitat surveys on the American River in 1992 (22.4 miles) and again in 2001 (9.8 miles) using the Forest Service Region Six Stream Survey Protocol (Moore et al. 2002). The 2001 data were used in a thesis project evaluating long term effectiveness of in-stream, road, and riparian restoration actions in the Little Naches River (Muir 2003). Muir used the American River as a reference stream with "natural conditions and processes." Muir stated "the American River exhibited a more complex and diverse array of habitat for both juvenile and adult salmonids.  Pool habitat, side channel habitat and LWD were all more abundant in the American River.  Pools also had more total cover and deeper residual depths.  The more dynamic and unconfined nature of the American river was illustrated by a high percentage of pool habitat associated with meander bends, floodplain connectivity and gravel bar dynamics." Kettle Creek (1.5 miles) was surveyed in 1993. In all of these surveys, data were collected on pool/riffle frequency, riparian and channel condition, substrate, LWD, and temperature.

In addition, the Forest Service completed a watershed analysis of the American River system in 1998. Banish (2003) measured bull trout microhabitat and mesohabitat in 10 Eastern Washington and Oregon streams. Banish conducted day and night snorkeling in Kettle Creek; however, he pooled his data and did not report results for individual steams.

Stream Temperature Data

In 2001, the Forest Service contracted aerial thermal infrared remote sensing surveys on the American River from the mouth to the confluence with Rainier Fork (Watershed Sciences 2002). Accuracy of temperatures was confirmed with instream sensors. The flights were completed in early September and stream temperatures ranged from 8.8-12.8 °C. Kettle Creek and Union Creek were measured at their confluences with the American River, and the temperatures were 10.1 °C and 9.7 °C respectively.

Temperature monitoring in the American River system is primarily from Forest Service thermographs deployed during the summer low flow period. One thermograph on the American River at the USGS gauge was deployed in most years from 1991-2007. Other thermographs were deployed in five other locations on the American River and on associated tributaries, including Union and Kettle creeks, during the years from 1995-2007, although not consistently (USFS 2011a). Temperature data from 2007 - 2024 is a monitoring gap.

In 2024, MCF's Bull Trout Task Force deployed temperature loggers in the American River near the Mesatchee Creek Trail, just upstream of the Union Creek confluence, just upstream of the Bumping River confluence, and in Kettle and Union creeks. The logger deployed in Kettle Creek was later found to have swung into the mainstem American River so data for 2024 is inconsistent there. The BTTF plans to re-install temperature loggers in the same locations in 2025.

Restoration Actions

There have been no restoration activities on the American River in recent years. See completed actions below for more details.

Threats

Connectivity

Fish Passage Barriers

Threat Severity: unknown

Tieton and Bumping dams have eliminated fish passage upstream, leaving the American River population constrained to parts of the Naches River system downstream of the dams.

Entrainment

Threat Severity: insignificant

There are no major dams or diversions known to entrain American River bull trout.

Dewatering due to flow management

Threat Severity: insignificant

There is no known dewatering due to flow management that impacts American River bull trout.

Land-use Issues

Forestry

Threat Severity: Unknown, but likely insignificant

Although there is no accessible documentation of commercial timber harvest in the American River valley upstream of the bumping river confluence, there is field evidence of some legacy logging in the valley bottom. Some of the current low standard roads that lead to recreation access were likely old logging roads. Some of these primitive roads are visible in 1949 aerial photos (CITATION). There have been commercial harvests in the Naches river watershed, downstream of the Bumping River confluence between the 1990s and 2020. The impact of commercial harvest on Naches FMO habitat is unknown.

Agriculture and Grazing

Threat Severity: Unknown, but likely insignificant

National Forest grazing allotments occur in the American River watershed. The lower three miles of the American River has been classified as a sheep grazing allotment but has been vacant for at least 25 years (Gary Torretta, personal communication). The current Bighorn Sheep Grazing EIS is analyzing the feasibility of stocking this allotment with cattle. There is no agriculture in the American River valley. The mainstem Naches river downstream of the Bumping River confluence is flanked by the Naches cattle allotment on the North side and the Nile sheep allotment on the South side. Impacts of grazing on Naches FMO habitat are unknown.

Recreation

Threat Severity: Unknown, but likely significant

Recreation is probably one of the more significant threats for this population. The American River has several developed and dispersed campgrounds along its length, including in FMO habitat (Bumping and Naches rivers). American River campgrounds including Pleasant Valley, Hells Crossing and Lodgepole camps were noted as having degraded riparian condition during a habitat survey (Haring 2001). This habitat degradation is probably occurring at a site-scale as data from the 2001 stream survey showed that outside recreational sites, LWM counts were high (330 pcs/mile). Mid-Columbia Fisheries' Bull Trout Task Force visits these camp areas in the summer season and removes recreational rock dams regularly, although not many are found to be channel spanning. The team has also noted downed wood being taken from riparian areas near campgrounds (likely for campfires). Trash has been a problem in dispersed camping locations, especially along the Bumping River in FMO habitat (Aimee Taylor, personal comm.)

Roads and Development

Threat Rating: Unknown, likely insignificant

There is minimal development in the upper American River area, except developed campgrounds and summer home group sites. Highway 410 borders the river for much of its length. For approximately five miles upstream of the Bumping river confluence the river is naturally confined in a canyon with the road up above. Upstream of there, the river meanders and has access to its floodplain. Overall road density in the American River watershed is low. Past timber harvest appears to have been minimal and over 80% of the watershed is within designated wilderness.

The American River population of bull trout uses the Naches and Bumping rivers as FMO habitat where there is more development (See more on the Naches FMO page).

Mining

Threat Severity: Unknown, likely insignificant

Mineral resources were one of the major draws for white settlement in the American River area in the late 1800s. Gold, copper, and iron ore were all mined in the headwaters of the American River, especially near "Gold Hill" the ridgeline that sits between the headwaters of the American River (Morse Creek) and Union Creek. Tom Fife was the "superintendent" of mining during this time, whom "Fife Peak" is named after. In the vicinity of Goose Prairie and Cliffdell there were over 2000 mining claims. According to The Diggings (accessed in 2024) there are currently around 35 active mining claims in the area, which are on average 20 acres in size. None of these mining claims are commercial operations. The current impact of mining on bull trout is unknown, but likely insignificant as dredge mining has been outlawed.

Ecological Interactions

Brook Trout

Threat Severity: Unknown, likely significant

Brook trout were not listed in the 2012 Action Plan as a threat, nor addressed in the 2017 update. Fishing reports for the American River are few and far between, but many reports dating back to the early 2000s note fishing wasn't very fruitful, and that only small brook trout were encountered (Washington Fly Fishing Forum). An early electrofishing survey noted the presence of brook trout in Timber Creek, a tributary to the American River (Anderson 1993b).

Brook Trout have been observed spawning in the American River in the same reach that bull trout spawn (WDFW redd survey observational data). The impact of brook trout on the bull trout population is unknown. There have been no documented cases of hybridization but there is no active monitoring or genetic analysis.

Other Invasive Species

Threat Severity: Insignificant

Other invasive species have not been documented.

Diminished Prey Base

Threat Severity: Unknown, likely significant

The American River is an area where Spring Chinook and steelhead spawn, potentially supplementing prey for American River bull trout. However, spawning populations of these anadromous species are not very abundant. Nutrient enhancement was suggested as a new recovery action in the 2016 update for the American River population of bull trout. Fishing reports describe the American River as "sterile" with anglers not encountering many fish or bugs (Washington Fly Fishing Forum).

Disease

Threat Severity: Unknown

Instances of disease have not been reported in the American River.

Water Quantity and Quality

Flow issues/dewatering

Threat severity: insignificant

Dewatering has not been reported in the American River. Low summer flows may impact FMO habitat in the Naches River.

Current and modeled future temperature conditions

Threat Severity: Likely significant

Figure 3. Daily maximum water temperature in the American River at three sites. Add union and kettle??

The NorWest stream temperature model predicts mean August temperatures in the mainstem American River to rise to 12-14°C by 2080, with FMO habitat in the upper Naches and Bumping rivers reaching 18-20°C. In the vicinity of the Naches River and Yakima River confluence the mainstem Naches is predicted to reach 20-30°C. One season of temperature monitoring in 2024, upstream of the Bumping River Confluence, showed maximum daily temperatures consistently above 12°C from July through early September (Figure 3). It is important to note that 2024 was a drought year.

Other changes in hydrology

Threat Severity: unknown, likely significant

The flow regime for the American River is changing to have an earlier peak runoff and longer duration of base flows.

Additionally, recent wildfires have increased sediment deposition (tributaries and mainstem) and degraded riparian condition (Kettle Creek).

Fisheries Impacts

Angling Regulations/Fisheries Use/Poaching (Recreational)

Threat Severity: Unknown, likely significant

The impact of illegal angling and harvest of bull trout in the American River is unknown, but the Bull Trout Task Force encounters anglers that are fishing in closed areas each year. The regulations for the American River are unique in that there isn't a season-long opening or closure, which might be confusing to anglers. The river is closed to fishing from RM 5.4 upstream to the Mesatchee Creek Trailhead from July 16th through September 15th in an attempt to protect bull trout and Chinook spawning habitat. There is no "closed fishing" signage because the closure is only for a short time. Permanent signage with the closure dates should be installed at popular river access sites.

FMO habitat in the Bumping and Naches rivers is open to fishing from the end of May through the end of October. Data on poaching instances is very difficult to query due to their records management system, but WDFW law enforcement reported that one person was cited for a retained bull trout on the Naches river in October 2024 (WDFW Capt. Weaver, personal comm).

One member of the public disclosed that they caught numerous bull trout below Bumping Dam during the winter time, when fishing was closed. It was unclear if they were referring to the spillway pool or the outlet channel pool (BTTF, personal comm).

Fisheries Management/Monitoring (Research)

Threat Severity: Insignificant

Aside from annual redd surveys in the American River, there is no ongoing or special research that may impact bull trout. The WDFW Ecological Interactions Team visits a large number of sites in the Naches watershed each year. Their goal is to understand anadromous productivity throughout the Yakima River Basin. Their target species is O. Mykiss but they do encounter around 10 juvenile - subadult bull trout per year in their sampling efforts, primarily in the Naches headwaters (American River, Crow and Rattlesnake creeks) (Gabe Temple, personal comm.). Non-O.Mykiss species are usually not netted and the crew will move to a different part of the stream as to not disturb them. They do not collect biodata on bull trout, aside from a few years around 2015 where USFWS was directing the team to PIT tag any bull trout.

Other Threats

Low Population Resiliency

Threat Severity: Unknown, likely significant

Low abundance has been cited as a primary threat to this population. Although American River bull trout may occasionally spawn with bull trout that were entrained through Tieton or Bumping dam, the extent of geneflow is unknown.

Climate Change

Threat Severity: Unknown, likely significant

Reduced snowpack and warming temperatures will likely impact this population.

Summary of Primary Limiting Factors

With a geometric mean of <50 redds annually (and <30 in recent years) low abundance is identified as a threat but this population is not considered a candidate for supplementation due to a stable population trend and lack of understanding about which limiting factors have the highest priority to correct. Threats that are likely significant are angling, prey base, recreation, and brook trout. The American River, Union Creek, and Kettle Creek spawning reaches are closed to fishing but rearing and FMO areas downstream are currently open. Illegal and/or incidental catch of bull trout can cause direct mortality of adults and reduce overall population productivity. There are dispersed and developed campsites as well as trails and trailheads along the spawning and rearing reaches on the American River and Union Creek. These may affect the bull trout population via habitat degradation and direct harassment. Introduced brook trout are present within the spawning area, but no hybrids have been documented.

Altered flows, development, transportation, and forest management issues are present within the population area (spawning and rearing or FMO) but are not considered significant threats. The following threats are absent: agriculture, dewatering, entrainment, grazing, limited extent of habitat, mining, and passage barriers.

Recovery Strategy

Population-level Recovery Strategy

(High-level discussion of priority needs)

This population has been identified as a “Protection” population with a priority for continuation of population monitoring but with limited restoration actions recommended. Although spawning and rearing occurs outside of the wilderness, the American River and associated spawning tributaries (Union and Kettle creeks) were previously thought to have generally excellent habitat. However, with climate change impacts, including drought and wildfire, these habitats have diminished in quality and should be assessed for restoration potential. Outreach is a top priority in order to document angling pressures and to educate anglers and recreationists throughout the watershed. Low productivity in general likely has a major influence on this population of bull trout. Stronger anadromous fish runs would increase nutrients, but increased salmon abundance would need to be substantial to start seeing a measurable effect on the ecosystem. The Broad Scale Actions that apply to the American River population include: Restore Healthy Salmon Populations and Passage at Major Storage Dams (Bumping and Rimrock). Revitalizing salmon and steelhead runs across the Yakima Basin would significantly improve the prey base for all bull trout life stages. Providing passage at the two storage dams in the Naches subbasin would benefit all of the Naches River fluvial bull trout populations. Recreation sites along the river are the source of some habitat degradation but actions to minimize and prevent riparian damage in developed camping areas are a low priority.

Monitoring Needs/Key Questions

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• Assess habitat to identify high priority areas for restoration actions.
• Investigate the extent of nutrient enhancement or influx of marine derived nutrients that would be needed for population growth.
• Gain a better understanding of poaching and bull trout harassment.

Actions

Completed Bull Trout Recovery Actions

• Approximately 2.8 miles of dispersed camp roads were closed between 2003 and 2006.
• Between Pinus Creek and Timber Creek over 27 acres of riparian/valley floor acres habitat have been protected with 6.5 acres replanted with native grass and shrubs between 2003 and 2006.
• Fishing regulations have been implemented to protect American River bull trout.

Recommended Actions

Implementation Monitoring of Completed and Recommended Actions

• Forest Service to continue monitoring of restored riparian areas to ensure compliance with camping exclusions.

Relevant Multiple Population Actions

• Multiple Populations #1: Outreach on bull trout conservation issues (landowners, recreationists, anglers, school groups, and others)
• Multiple Populations #6: Floodplain acquisition/easements along the mainstem Naches River to benefit FMO habitat quality.
• Multiple Populations #5: Carcass analog placement if pilot studies demonstrate success.
• Multiple Populations #2: Continue redd surveys within the established index areas to monitor long-term abundance trends.
• Multiple Populations #3: Continue temperature monitoring.

American River Actions

• American River #1: Protect and restore stream banks by relocating and restoring campsites.
• American River #2: Increase outreach and enforcement
• American River #3: Expanded redd surveys
• American River #4: Nutrient enhancement

Actions in the Yakima Steelhead Recovery Plan that benefit this population

Naches River Action #5: Restore lower Naches River floodplain

Naches River Action #7: Protect habitats in Naches River mainstem above Tieton River confluence

Naches River Action #9: Provide passage at Bumping Lake Dam

Naches River Action #13: Reduce dispersed recreation impacts in key tributaries

Update Notes

2012 BTAP text copied into Yakipedia and edited to match new format in December 2024 by Aimee Taylor. ADD LINK TO 2012 BTAP pdf placemark

Additional edits proposed by Alex Conley, Aimee Taylor and XXXX populations small group. Reviewed, and updated and approved by BTWG in XXXXX

Use this space for specific detail on out of cycle updates