Water and Land Resources Division Department of Natural Resources and Parks King Street Center 201 South Jackson Street, Suite 600 Seattle, WA 98104-3855 206-477-4800 Fax 206-296-0192 TTY Relay: 711

TECHNICAL MEMORANDUM

December 18, 2017

TO: The Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard, Water and Land Resources (WLR) Division, King County Department of Natural Resources and Parks (DNRP)

FM: Josh Kubo, Science and Technical Support Section, WLR Division, DNRP

RE: Snoqualmie River Juvenile Yearling Chinook Habitat Use and Distribution

Introduction Across the Puget Sound, Chinook salmon (Oncorhynchus tshawytscha) display a diversity of rearing strategies and migration patterns throughout juvenile and adult life‐stages. Diversity in rearing and migration help to buffer inter‐annual variability in freshwater and marine environmental conditions as well as variability in salmon population dynamics (Hilborn et al. 2003, Schindler et al. 2010). Specific patterns in rearing and migration can be broadly grouped into life‐history types including stream‐type and ocean‐type. These life‐history designations are used to characterize Chinook salmon based on the season of adult spawning migration, the age when most juveniles begin their seaward outmigration, variation in length of freshwater, estuarine, and oceanic residence, and the variation in ocean distribution (Healy 1991). Within the Puget Sound/Salish Sea region, adult ocean‐type Chinook tend to migrate upstream during fall with juveniles generally displaying seaward migration within the spring of their first year (Figure 1). Stream‐type Chinook on the other hand tend to migrate upstream during spring and summer, with juveniles generally spending around a year in freshwater habitats prior to seaward migration. Across the Puget Sound, these Chinook life‐histories have been found to be related to hydrologic regimes, with snowmelt‐dominated watersheds tending to have relatively greater proportions of stream‐type Chinook, compared to rainfall‐dominated and transitional watersheds (Beechie et al. 2006). Since rainfall‐dominated and transitional watersheds tend to have relatively greater proportions of the ocean‐type Chinook, the majority of juveniles produced in these watersheds are generally assumed to spend less than a year in freshwater habitats.

Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 2

Figure 1: Diagram of potential juvenile and adult life-stages utilized by Chinook salmon in the Puget Sound (derived from Myers et al. 1998). Red text and red arrows indicate primary rearing and migration patterns observed among ocean- and stream-type Chinook. Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 3

The Snoqualmie River supports a population of wild Chinook salmon which is one of two Chinook populations in the Snohomish River watershed. The Snoqualmie River watershed was characterized as rainfall‐dominated (Beechie et al. 2006), suggesting that Chinook likely display an ocean‐type life‐history with adult migration occurring in the fall and juvenile out‐migration generally occurring in the spring of their first year. In support of these findings, spawning ground surveys conducted by the Washington Department of Fish and Wildlife and the Tulalip Tribes indicate that adult Chinook salmon in the Snoqualmie River watershed primarily migrate and spawn from September to November in Tokul Creek, Raging River, Tolt River, and throughout the mainstem of the Snoqualmie River in reaches immediately downstream of these tributaries. Additionally, in support of an ocean‐type life‐history, juvenile salmon out‐ migration monitoring conducted in the Snoqualmie River indicate that the greatest proportion of juvenile Chinook produced tend to out‐migrate within their first year (Kubo et al. 2013). However, out‐migration monitoring efforts have also consistently observed a proportion of juveniles which remained in freshwater habitats for at least a year. While the proportion of juveniles displaying this extended freshwater residence is generally small, in some years these juveniles can contribute up to 46% of the juvenile out‐migrating cohort (Kubo et al. 2013). Furthermore, due to limitations in screw trap out‐migration monitoring (e.g., lower catch efficiency among larger fish size‐classes) the abundance of juvenile Chinook displaying extended freshwater residence is likely under‐represented. While the Snoqualmie Chinook population is generally characterized as ocean‐type, juveniles appear to display two freshwater rearing patterns including a sub‐yearling and yearling age‐class.

In the Snoqualmie River, juvenile Chinook characteristic of the sub‐yearling age‐class includes fry and parr which rear in freshwater habitats for several weeks to months and then migrate downstream from March to June (Kubo et al. 2013). These juvenile sub‐yearling patterns are similar to other ocean‐type stocks around the Puget Sound (Kinsel et al. 2008, Kiyohara and Zimmerman 2011, Topping and Zimmerman 2011). Riverine out‐migration of sub‐yearling Chinook tends to display two separate peaks with fry migrating in March and parr migrating in May and June. Following Snoqualmie River out‐migration, sub‐yearling Chinook tend to rear for extended periods in the Snohomish Estuary (Rice et al. 2013) as well as in adjacent nearshore habitats (Rice et al. 2013) and non‐natal coastal streams (Beamer et al. 2013). Juvenile Chinook characteristic of the yearling age‐class generally remain in freshwater riverine habitats for an entire year and then migrate downstream during the following late‐winter and early‐spring. Juvenile yearling Chinook tend to migrate through estuarine habitats relatively quickly, rather than rearing for an extended period of time like sub‐yearling fry and parr (Beamer et al. 2005). In general, the larger and older juvenile Chinook are at the time of out‐migration, the shorter they tend to reside in estuarine habitats (Kjelson et al. 1982, Levy and Northcote 1982, Healey 1991).

Life‐history diversity, including extended freshwater rearing observed in juvenile yearling Chinook, may be a result of both genetic variation and local adaptations to environmental conditions (Ricker 1972, Randall et al. 1987, Healy, 1991, Taylor 1990a, 1990b, Taylor 1991). Differences in gene expression may translate to differential growth rates between sub‐yearling Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 4 and yearling Chinook (Gilbert 1912, Carl and Healy 1984, Cheng et al. 1987, Taylor 1990b), which can influence the timing of volitional out‐migration, condition at out‐migration, and subsequent smoltification. Differences in environmental conditions influence Chinook life‐ history expression and the tendency of juvenile to display extended freshwater rearing. Environmental conditions that influence rearing strategies include the distance to marine environments, stream stability, stream flow, stream and air temperature regime, stream and estuary productivity, and general weather regimes (Taylor 1990a, Meyers et al. 1998). Extended freshwater residence has generally been associated with rivers or reaches with lower growth potential (as measured by lower temperatures, shorter photoperiods, and longer distances from marine areas) including latitudes north of the 55th parallel and in headwaters (Taylor 1991, Healey 1991). While the Snoqualmie River seems to provide conditions more conducive for the sub‐yearling age‐class (e.g., generally warmer temperatures and longer photoperiods), the yearling age‐class is consistently expressed. These patterns suggest that the persistence of the yearling age‐class is likely related to genetic expression and indicate that sub‐yearling and yearling Chinook may have different growth rates and survival across freshwater and marine habitat.

Mainstem, tributary, and floodplain areas throughout the Snoqualmie provide the resources and habitat diversity needed to increase juvenile Chinook survival. The benefits of floodplain and tributary habitats for salmonid growth and survival have been well documented among other riverine systems (Sommer et al 2001, Jeffres 2008, Rice et al. 2008). Survival in both freshwater and ocean habitats is often size dependent (Hunt 1969, Holtby et al. 1990) and yearling Chinook have greater marine survival compared to sub‐yearling Chinook (Beamer et al. 2005). This may indicate why yearling Chinook are consistently expressed in the Snoqualmie watershed. While the majority of juvenile Chinook in the Snoqualmie tend to display a sub‐ yearling freshwater rearing pattern, previous scale analyses conducted on spawning adults indicate that up to 30% of returning adults display a juvenile yearling rearing pattern (SBSRTC 1999). These findings further support that juvenile yearling Chinook have relatively greater marine survival than sub‐yearling and demonstrate that yearling Chinook can significantly contribute to the abundance and life‐history diversity of the Snoqualmie River Chinook population. Additionally, the continued expression and survival of the yearling age‐class suggest that habitat diversity, availability, and connectivity associated with extended freshwater rearing are integral to Chinook salmon recovery in the Snoqualmie River watershed.

While observations indicate that yearling Chinook are an integral component of the Snoqualmie Chinook population, relatively little information is known about the freshwater distribution and habitat use specific to this freshwater rearing pattern. Additionally, aside from detailed studies conducted in the Skagit River (Beamer et al. 2010, Lowery et al. in prep), habitat use specific to juvenile Chinook with extended freshwater rearing is poorly understood among Puget Sound drainages. Thus, the goals of this technical memorandum are to organize relevant information on juvenile Chinook extended freshwater rearing and to propose a sampling plan to evaluate distribution and habitat use specific to juvenile yearling Chinook in the Snoqualmie River watershed. The main objectives discussed in this technical memorandum include: Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 5

 Regional observations specific to juvenile Chinook with extended freshwater rearing  Observations of juvenile yearling Chinook in the Snoqualmie River watershed  2017 pilot study observations of juvenile yearling Chinook in the Snoqualmie River  Development of a follow‐up study aimed at evaluating juvenile yearling Chinook habitat use and distribution throughout the Snoqualmie River watershed

Regional Observations of Habitat Use by Juvenile Chinook with Extended Freshwater Rearing As previously mentioned, Chinook salmon can broadly be grouped into stream‐type and ocean‐ type life‐histories. While juveniles of the stream‐type are more characteristic of extended freshwater residence, yearling Chinook of the ocean‐type also display extended freshwater rearing. Since information on yearling Chinook habitat use and distribution is limited, it may be beneficial to use regional observations of juvenile Chinook with extended freshwater rearing, regardless of whether a population is designated as stream‐ or ocean‐type. It should be noted that stream‐type has also been used to describe any juvenile Chinook with extended freshwater rearing lasting a year or longer (Quinn 2005). Subsequently, the following discussion will refer to stream‐type Chinook as it relates to juveniles with extended freshwater rearing rather than patterns specific to adult distribution, migration, and spawning. Regional observations of juvenile Chinook with extended freshwater rearing (i.e., stream‐type and yearling) may help to inform hypotheses specific to habitat use and distribution patterns specific to yearling Chinook in the Snoqualmie River watershed.

Within the Salish Sea region, riverine habitat use and distribution patterns specific to juvenile stream‐type Chinook have been documented across western British Columbia in the Bridge River (Bradford and Higgins 2001), Nechako River (Emmett and Convey 1990), Coldwater River (Swales et al. 1986), Nicola River (Swales et al. 1986), and Fraser River (Rosberg and Associates 1987, Leving and Lauzier 1991). Additionally, juvenile stream‐type Chinook habitat use and distribution patterns have been documented in the Skagit River in Washington State (Beamer et al. 2010, Lowery et al. in prep). Chinook with extended freshwater residence exhibit downstream dispersal and utilize a variety of habitats during freshwater residence (Myers et al. 1998). Within the Skagit River, juvenile stream‐type Chinook have been observed in relatively greater abundances during winter periods among banks, pools, and glides compared to other habitat types (e.g., riffles, bars, backwaters) (Beamer et al. 2010). Additionally, during summer periods, Beamer et al. (2010) observed the highest abundances of juvenile stream‐type Chinook in pool habitats. Juvenile stream‐type Chinook appear to be associated with mainstem edges, large log jams, secondary channels, and floodplain channels (Beamer et al. 2010, Lowery et al. in prep). Among habitat types, factors like distance upstream from major river confluences, wetted width, wood cover, and vegetation cover are associated with juvenile stream‐type Chinook presence. At a riverscape scale, habitat use for juvenile stream‐type Chinook appeared to be related to hydro‐region (i.e., areas with similar precipitation and hydrographs), channel type, and season (Lowery et al. in prep). Within and across hydro‐regions and seasons, juvenile Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 6 stream‐type Chinook appear to display distinct shifts in habitat use and distribution patterns (Table 1).

Table 1: Seasonal habitat use by juvenile stream-type Chinook across hydro-regions (precipitation and hydrograph groupings) in the Skagit River. Habitat use information from Lowery et al. in prep.

Season Snow hydro-region Mixed Hydro-region Rain Hydro-region

Floodplain channels Mainstem edges Mainstem edges Spring Secondary channels Secondary channels

Large log jams Large log jams Mainstem edges Mainstem edges Large log jams Summer Tributaries Floodplain channels

Large log jams

Winter Mainstem edges Floodplain channels Floodplain channels

Similar to observations in the Skagit River, seasonal shifts in juvenile Chinook habitat use have been documented across multiple rivers in western British Columbia. During fall and winter months, juvenile stream‐type Chinook are generally very inactive, prefer sheltered low velocity microhabitats, and are mainly nocturnal (Rosberg and Associates 1987, Emmett and Convey 1990, Bradford and Higgins 2001). Salmonid movement, activity, aggression, and feeding are relatively reduced during winter periods (Huusko et al. 2007). Juvenile Chinook tend to overwinter in off‐channel habitats (Swales and Levings 1989), mid‐channel pools containing large woody debris (Swales et al. 1986), floodplain channels (Lowery et al. in prep), tributaries and tributary confluences (Rosberg and Associates 1987, Levings and Lauzier 1990), as well as mainstem shoreline‐edges (Emmett and Convey 1990, Levings and Lauzier 1990, Lowery et al. in prep). Juvenile Chinook appear to change their behavior during the winter by switching from three‐dimensional utilization of the water column to a very inactive overwintering state in primarily benthic and substrate habitats (Rosberg and Associates 1987). During the daytime, overwintering juvenile salmonids typically use coarse substrates, aquatic vegetation, large woody debris, and/or deep‐slow flowing waters as shelter (Rosberg and Associates 1987, Muhlfeld et al. 2001, Muhlfeld et al. 2003). With overwintering juvenile salmonids generally seeking refuge and shelter during the day, foraging and feeding appears to primarily occur during dusk and evening hours (Fraser et al. 1993, 1995, Riehle & Griffith 1993, Contor & Griffith 1995, Valdimarsson et al. 1997, Metcalfe et al. 1999). In early spring, as water temperatures increase, juvenile Chinook return to a three‐dimensional utilization of the water column.

During spring and summer months, most studies suggest that juvenile Chinook are primarily diurnal with feeding most successfully occurring at dawn and dusk (Sagar and Glova 1988, Schabetsberger et al. 2003, Huusko et al. 2007, Johnson 2008). While visual foraging conditions are most optimal during daytime hours, reduced predation risk during dusk and dawn can result Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 7

in the crepuscular and even nocturnal foraging among juvenile salmonids (Metcalfe et al. 1999, Bradford and Higgins 2001). During spring and summer, juvenile stream‐type Chinook have been observed using pool habitats (Everest and Chapman 1972, Roper et al. 1994) as well as mainstem edges, secondary channels, and floodplain channels (Beamer et al. 2010, Lowery et al. in prep). Additionally, during late‐summer and early‐fall, juvenile Chinook have been observed using mainstem edge habitats associated with sand beaches and shoreline back‐ eddies with velocity shear zones immediately offshore (Rosberg and Associates 1987).

As highlighted above, juvenile salmonids display diel variation in distribution patterns among habitats and across seasons. While juvenile salmonids can move throughout habitats and reaches, they are generally associated with mid‐channel and covered habitats during the daytime and stream edge habitats during the evening and night (Rosberg and Associates 1987, Bradford and Higgins 2001, Huusko et al. 2007). Specifically, juvenile Chinook appear to move towards the margins of the river and often rest on sand or silt substrates as light levels fall in the early evening (Bradford and Higgins 2001). Since juvenile salmon feed most successfully at dawn and dusk, these distribution patterns suggest that edge habitats are important for crepuscular foraging and feeding. Larger juvenile salmonids tend to be more crepuscular/nocturnal during summer and all sized fish are generally nocturnal in winter (Bradford and Higgins 2001). Larger fish may be more nocturnal since they can obtain adequate ration with crepuscular foraging and smaller fish may have higher metabolic rates resulting in faster digestion and more diurnal activity.

Observations of Juvenile Yearling Chinook in the Snoqualmie River Watershed Since Snoqualmie Chinook are generally characterized as ocean‐type, the following section will refer to yearling (rather than stream‐type) when discussing observations of juvenile Chinook with extended freshwater residence. Within the Snoqualmie River watershed, juvenile yearling Chinook have been observed across various mainstem, tributary, and floodplain channels. Since few studies have evaluated yearling Chinook habitat use and distribution, most information has come from monitoring observations related to agricultural ditch maintenance, restoration project effectiveness, bridge/road work, and exploratory evaluations. Observations of juvenile yearling Chinook are included in Figure 2 with details outlined in Table 2.

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Figure 2: Observations of juvenile yearling Chinook in the Snoqualmie River watershed. Included observations are prior to efforts conducted in the late-summer of 2017 (discussed below). Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 9

Table 2: Juvenile yearling Chinook observations in the Snoqualmie River watershed.

Citation or Waterbody Location Date Count Method Document Name Reference Turner_A/B April 29, 2004 1 Electrofish WSU and UW 2008 A Study of Agricultural Drainage in the Puget Sound Lowlands to Ames Determine Practices which Minimize Creek Turner_A/B October 26, 2006 1 Electrofish WSU and UW 2008 Detrimental Effects on Salmon

October 23 & 24, King Conservation Segment A 2 Electrofish Stout Farm Fish Survey Fall 2012 2012 District in prep December 2000 - Washington Trout Cherry Valley Fish and Tree Ditch Site E 3 Fyke Net May 2001 2001 Monitoring Project 2000 Annual Monitoring Report: Rasmussen Creek June 14, 2000 1 Electrofish Berge et al. 2001 King County Agricultural Drainage Assistance Program

Cherry 2001 Annual Monitoring Report: Creek Rasmussen Creek August 9, 2001 2 Electrofish Berge et al. 2002 King County Agricultural Drainage Assistance Program

Nelson-B July 12, 2004 1 Electrofish WSU and UW 2008 A Study of Agricultural Drainage in the Puget Sound Lowlands to Nelson-B April 29, 2004 23 Electrofish WSU and UW 2008 Determine Practices which Minimize Detrimental Effects on Salmonids: Nelson-B January 26, 2005 3 Electrofish WSU and UW 2008 Final Report

Olney-C October 26, 2006 1 Electrofish WSU and UW 2008

Olney-B April 29, 2004 1 Electrofish WSU and UW 2008 A Study of Agricultural Drainage in the Puget Sound Lowlands to Deer Creek Olney-B January 26, 2005 6 Electrofish WSU and UW 2008 Determine Practices which Minimize Detrimental Effects on Salmonids: Olney-B April 7, 2005 4 Electrofish WSU and UW 2008 Final Report

Pickering April 29, 2004 5 Electrofish WSU and UW 2008 Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 10

Citation or Waterbody Location Date Count Method Document Name Reference Wetland Complex Patterson Patterson Creek Basin at RM6.5 & Canyon Late Summer, 1991 9 Electrofish King County 1993 Creek Reconnaissance report Creek Underwater Videographic Washington Trout Tolt River Site 3 (~RM2.5) March-May, 2003 5 Videography Observations of Juvenile Salmonids 2003 in the Tolt and Snoqualmie Rivers

Middle Ditch August 8, 2001 4 Electrofish Berge et al. 2002 2001 Annual Monitoring Report: Tuck Creek King County Agricultural Drainage South Ditch August 9, 2001 4 Electrofish Berge et al. 2002 Assistance Program

Underwater Videographic Site 1 (Upstream of Washington Trout March-May, 2003 10 Videography Observations of Juvenile Salmonids Tolt Confluence) 2003 in the Tolt and Snoqualmie Rivers

Winkelman Levee Cataraft King County in April 26, 2016 1 (rip-rap bank) Electrofish prep Tolt Pipeline Protection Project Winkelman Levee Cataraft King County in (Winkleman) 2016 & 2017 Pre- April 3, 2017 1 (natural Bank) Electrofish prep Project Juvenile Salmonid and Low Velocity Habitat Sampling Winkelman Levee Cataraft King County in April 3, 2017 2 Mainstem (rip-rap bank) Electrofish prep Snoqualmie Tributary 1 (Tolt King County Tolt Bridge Replacement; King River May 5, 2006 2 Snorkel Macdonald Park) unpublished County

Tributary 2 King County Tolt Bridge Replacement; King (property south of May 5, 2006 8 Snorkel unpublished County NE Tolt Hill Rd)

Cataraft RM15 – RM 25 September 7, 2017 21 King County 2017b Electrofish Snoqualmie River Juvenile Yearling Chinook Habitat Use and Cataraft RM 33.5 – RM 36.3 September 11, 2017 19 King County 2017b Distribution Electrofish Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 11

Citation or Waterbody Location Date Count Method Document Name Reference Chinook Bend Vanderhoof and (below water November, 2011 1 Electrofish Higgins 2013 control structure) Snoqualmie Chinook Bend Natural Area Wetland River Chinook Bend Monitoring Year 5 Fish Surveys March and June, Vanderhoof and Floodplain- (above water 4 Electrofish 2012 Higgins 2013 Wetland control structure) Channels Hook and Higgins personal Camp Gilead July 6, 2006 1 Line communication Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 12

Observations related to agricultural waterway maintenance, as part of King County’s Agricultural and Drainage Assistance Program (ADAP), have documented juvenile yearling Chinook in ditches and channels of Cherry Creek, Tuck Creek, Deer Creek, and Ames Creek (Berge et al. 2001, 2002, WSU and UW 2008, King County Conservation District in prep). Efforts from WSU and UW (2008) focused on juvenile Chinook observations across seasons and used fork‐length frequencies to differentiate sub‐yearling and yearling age classes. Most of the other agricultural waterway observations occurred during construction activities in late‐summer when juvenile Chinook were assumed to be of a yearling rearing pattern since the outmigration of sub‐yearling Chinook generally tails‐off by July (Kubo et al. 2013).

All of these efforts were focused on evaluating the impacts of agricultural waterway maintenance on salmonids as well as documenting salmonid presence before and after waterway maintenance. These observations provide useful habitat use and distribution information specific to juvenile yearling Chinook. Across all of these ADAP evaluations and monitoring efforts, observations of juvenile yearling Chinook suggest that floodplain channels and agricultural ditches provide rearing habitats during spring, summer, fall, and winter. These observations indicate that juvenile Chinook occupy agricultural ditches throughout the year with highest abundances observed during winter and spring. Observations specific to floodplain channels of Cherry Creek suggest that yearling Chinook are associated with sites having relatively cooler summer temperatures and higher summer water velocities (compared to other floodplain ditches) (Washington Trout 2001). Additionally, WSU and UW (2008) noted that juvenile Chinook were far more likely to be observed in close proximity to the mouth of drainage, among waterways with natural flow regime, and within natural or mixed vegetative habitats. Agricultural ditches which maintain natural flow regimes and support vegetated buffers are likely to support juvenile yearling Chinook abundance and survival.

Juvenile yearling Chinook have been observed during project effectiveness monitoring throughout the lower Snoqualmie River on several occasions. At the Chinook Bend Natural Area, floodplain and wetland channels were utilized by juvenile Chinook in both fall and spring (King County 2013). Since the outlets to these channels are generally not fish passable, it was suggested that salmon using these channels entered during flood conditions and potentially left when higher flows returned. However, it is not known whether these fish were overwintering volitionally or if they had become trapped. Observations during pre‐project baseline monitoring, related to the Tolt Pipeline Protection Project, have documented juvenile yearling Chinook during late‐winter and spring along natural and rip‐rapped banks (King County in prep). These pre‐project monitoring efforts noted that juvenile Chinook were observed in relatively greater abundances on sand bars, compared to all other edge habitat types. These findings support that edge habitats, specifically sand bars, are potentially important for foraging and crepuscular feeding. The potential preference of sand bar habitats by juvenile yearling Chinook in the Snoqualmie were additionally highlighted during exploratory observations conducted in late‐summer of 2017 (discussed below in 2017 Exploratory Pilot Study of Juvenile Chinook Late‐ Summer Presence in the Snoqualmie River Watershed).

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When the Tolt Bridge over the Snoqualmie River was replaced in 2006, juvenile yearling Chinook were observed in two floodplain‐wetland channels just north and south of the Tolt River confluence (King County unpublished). While these efforts were focused on species documentation for construction project mitigation, these observations further support the use of floodplain‐wetland channels by juvenile yearling Chinook.

Several exploratory evaluations and observations in the Snoqualmie River watershed have documented juvenile yearling Chinook. During the Patterson Creek Basin reconnaissance report, juvenile yearling Chinook were observed in late‐summer across wetland reaches around RM 6.5 down to lower reaches in mainstem Patterson Creek (King County 1993). Additionally, juvenile Chinook were observed within select reaches of Canyon Creek, a tributary to Patterson Creek. During underwater videographic observations conducted in the lower Tolt and adjacent mainstem Snoqualmie locations, juvenile yearling Chinook were documented at multiple sites across the study area (Washington Trout 2003). With efforts focused on evaluating juvenile salmonid habitat preference, videographic observations documented yearling Chinook habitat use around RM 2.5 in the Tolt and along the mainstem Snoqualmie just upstream of the Tolt‐ Snoqualmie confluence. These observations highlighted juvenile Chinook preference in low‐ velocity edge habitats, side‐channel habitats, and among areas of predominantly silt/sand substrates. These finding further corroborate the use of edge habitats and low‐velocity habitats by juvenile yearling Chinook. Finally, prior to backwater connection through a levee removal, juvenile yearling Chinook were observed in a tributary floodplain‐wetland channel near RM 23.7 of the mainstem Snoqualmie. Similar to other floodplain‐wetland channels, juvenile Chinook likely entered these channels during flood conditions. Yearling Chinook have occasionally been observed in Snoqualmie floodplain oxbows; however, extensive sampling conducted by King County’s Water and Land Resources Division in 2008 and 2009 were not able to document any yearling Chinook in oxbow habitats (King County unpublished).

2017 Exploratory Pilot Study of Juvenile Chinook Late‐Summer Presence in the Snoqualmie River Watershed In an effort to provide further observational presence and distribution information specific to juvenile Chinook with extended freshwater residence (i.e., yearling rearing pattern), an exploratory pilot study was conducted in the Snoqualmie River by King County’s Science Technical Support Section during the late‐summer of 2017. Prior to this investigation, minimal efforts had focused on surveying mainstem Snoqualmie habitats during summer periods (aside from snorkel surveys related to select project effectiveness monitoring). Positive identification of juvenile Chinook may be difficult through solely snorkel surveys since turbidity in the Snoqualmie make it difficult to identify juvenile salmonids to species level (Martin Environmental and Shreffler Environmental 2002, Washington Trout 2003). Additionally, the use of an electrofishing cataraft provided a sampling method that was not previously available for mainstem surveys. The electrofishing cataraft had shown great utility for winter‐spring project effectiveness monitoring in the Snoqualmie River but had not been used during late‐ summer periods. The goal of the pilot study surveys were to better understand the presence of Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 14

juvenile Chinook with extended freshwater rearing in the Snoqualmie River as well as provide supportive information for future follow‐up studies.

Methods The pilot study focused primarily on mainstem Snoqualmie River habitats; however, various locations among select tributaries were also sampled (including the Raging River, Tolt River, Griffin Creek, and Cherry Creek). Across these waterbodies, sampling efforts focused on juvenile yearling Chinook presence/absence during late‐summer (August 30 – September 12, 2017). As previously mentioned, juvenile Chinook observed in late‐summer were assumed to be of the yearling rearing pattern since the outmigration of juvenile sub‐yearling Chinook generally tails‐off by July (Kubo et al. 2013).Two primary reaches were surveyed across the mainstem Snoqualmie River, including a reach from the Raging River confluence (~RM36.3) downstream to the boat launch at Neal Road (~RM 33.5), and a reach from the Chinook Bend Natural Area (~RM 23) downstream to the NE 124th Street bridge crossing (~RM 15). Across these mainstem reaches, various instream edge habitats were sampled for juvenile Chinook presence including rip‐rap edges, sand/gravel‐bar edges, large woody debris edges, and glides. Large pools occur throughout the lower Snoqualmie; however, limitations in the effective depth of the electrofishing cataraft precluded this habitat type. Among the sampled tributaries, pool habitats were primarily targeted for juvenile Chinook presence.

Habitat edges across the mainstem Snoqualmie River were surveyed during the crepuscular (i.e, dusk) and night periods with an electrofishing cataraft. These periods were selected under the assumptions that juvenile Chinook display crepuscular foraging and utilize edge habitats during these periods (as previously discussed in the supporting literature). Additionally, mainstem edge habitats were targeted since the electrofishing cataraft has the greatest efficiency in capturing juvenile salmon along shallower water depths (as compared to deeper mid‐channel areas).

Across locations in the selected tributaries, habitats were sampled using a Smith‐Root LR‐20B® backpack electrofisher system using established protocols (Reynolds and Kolz 2012). Habitat sampling procedures consisted of single‐pass electrofishing conducted in an upstream direction during the day. Day periods were chosen for tributaries under the assumption that entire habitat units could be sampled and therefore account for juvenile salmonid presence regardless of diel movement patterns.

Observations During the late‐summer of 2017, juvenile Chinook were observed across several locations in the mainstem Snoqualmie River (Figure 3). Among 18 sampled locations in the mainstem, juvenile yearling Chinook were observed at 10 sites. Across these 10 sites, 40 juvenile Chinook were observed and measured (refer to Appendix A for example images and Appendix B for sample site observations). The pilot study did not observe any juvenile Chinook among the select tributaries; however, as previously discussed, several observations have documented yearling Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 15

Chinook across tributaries of the Snoqualmie River (Table 2). Since pilot study efforts were focused on the mainstem and only sampled few locations among select tributaries during day‐ time periods (unbalanced sample design), it is likely that sampling efforts underrepresented juvenile Chinook presence and distribution across tributaries.

Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 16

Figure 3: 2017 exploratory pilot study sample sites and juvenile Chinook observations during late- summer in the Snoqualmie River watershed. Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 17

Among the mainstem Snoqualmie River sample sites, juvenile Chinook were consistently observed in sand/gravel‐bar edge habitats (Table 3). Juvenile Coho of similar size classes were consistently captured across waterbodies and habitat types, which suggest that observed juvenile Chinook presence/absence patterns were not solely due to sampling/observation bias (e.g., size selectivity from electrofishing methods). While Coho were consistently observed across waterbodies and habitat types, juvenile Chinook were only captured in sand/gravel‐bar edge habitats. These observations highlight that juvenile Chinook with extended freshwater rearing can be documented in the mainstem Snoqualmie and that habitat‐specific use may be detectable.

Table 3: Juvenile salmon observed across waterbodies and habitat types in the Snoqualmie River watershed during late-summer, 2017. Observed Chinook presence is highlighted in red.

Habitat Replicates Juvenile Juvenile Waterbody Habitat Type in Each Waterbody Chinook Count Coho Count

Cherry Creek Pool 2 0 36

Griffin Creek Pool 3 0 59

Riffle 4 0 4 Raging River Pool 8 0 40

Rip-Rap Edge 4 0 21

Mainstem Sand/Gravel Bar Edge 10 40 24 Snoqualmie River Large Woody Debris Edge 2 0 57

Glide 2 0 0

Tolt River Pool 10 0 217

Fork‐lengths for the juvenile Chinook and coho captured across mainstem Snoqualmie habitats ranged from 54mm to 108mm (Figure 2). Juvenile Chinook appeared to be on the higher end of the observed fork‐length frequency distribution, which likely highlights species‐specific differences in the timing of fry emergence, but may also represent differential growth rates. Juvenile coho appeared to be relatively smaller among tributaries compared to the mainstem Snoqualmie River (Figure 3), which may suggest potential differential growth rates across the watershed due to temperature regimes and resource availability. Assuming food availability is not limiting, mainstem fish may be larger due to higher growth rates associated with warmer mainstem water temperatures (compared to cooler tributaries). However, if food resource availability is not uniform across mainstem and tributary habitats, then differences in growth rates may also be due to greater resource availability in the mainstem. Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 18

30 Chinook coho 25

20

15

Frequency 10

5

0

Forklength (mm)

Figure 4: Fork-length frequency distribution of juvenile Chinook and coho salmon observed in the mainstem of the Snoqualmie River.

30 Tributaries Mainstem 25

20

15

Frequency 10

5

0

Forklength (mm)

Figure 5: Fork-length frequency distribution of juvenile coho salmon observed across select tributaries (Cherry Creek, Griffin Creek, Tolt River, and Raging River) and within the mainstem of the Snoqualmie River. Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 19

Observations from this pilot study suggest that mainstem edge habitats in the Snoqualmie are utilized by juvenile Chinook during summer periods, which further support observations from the Skagit River (Beamer et al. 2010, Lower et al. in prep) as well as in western British Columbia (Rosberg and Associates 1987, Bradford and Higgins 2001). Additionally, similar to other rivers in the region, juvenile Chinook in the Snoqualmie appear to display crepuscular activity (potentially foraging) with evening distributions seemingly associated with edge habitats. Observations from the 2017 Snoqualmie pilot study as well as previously documented findings indicate that a detailed follow‐up study could provide new and statistically sound information on the relative abundance, distribution, and habitat‐specific use of juvenile yearling Chinook in the Snoqualmie River watershed.

Implications for Salmon Recovery Since the listing of Puget Sound Chinook salmon as threatened in 1999 under the Endangered Species Act, salmon habitat restoration and protection strategies in the Snoqualmie River have primarily focused on the sub‐yearling age‐class. Specifically, restoration projects and related project effectiveness monitoring has been structured around the rearing habitat requirements and out‐migration periods of sub‐yearling Chinook. As highlighted in previous sections, various mainstem, tributary, and floodplain habitats can also support extended freshwater rearing for yearling Chinook. Since yearling Chinook contribute to the abundance and diversity of the Snoqualmie River Chinook population, habitat strategies which support extended freshwater rearing are integral to Chinook salmon recovery in the Snoqualmie River watershed. In order for protection and restoration strategies to support juvenile Chinook freshwater life‐stages, conservation efforts will need to consider habitat requirements and rearing periods specific to both sub‐yearling and yearling Chinook.

Historic river and floodplain alterations, including channelization, levees and revetments, road fill, and wood removal has reduced habitat area, diversity, and connectivity (Mount 1995, Collins and Sheikh 2002, Tockner and Stanford 2002, Beamer et al. 2005, Jeffres et al. 2008). These hydro‐modifications isolate floodplain and off‐channel areas, which can change the distribution and availability of habitat types for juvenile Chinook at different times of the year (Beamer et al. 2005). The continued expression and survival of yearling Chinook is inherently tied to habitat conditions across mainstem, tributary, and floodplain channels. Increasing habitat area and connectivity across these channels and throughout the year may support yearling Chinook by providing flood refuge, spring and summer rearing habitats, as well overwintering habitats. Habitat restoration strategies aimed at restoring floodplain habitat access (e.g., levee removal and set‐backs), reconnecting side‐ and off‐channel areas, increasing tributary connectivity (e.g., flap gate and culvert improvements), and supporting natural channel migration and processes would benefit yearling Chinook (Beamer et al. 2005). Current Snoqualmie River salmon recovery efforts are structured on these strategies; however, consideration of yearling Chinook may further inform the location of restoration projects and help to emphasize the need for habitat connectivity across channel types and seasons. For example, focusing on yearling Chinook may require additional emphasis on channels and Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 20

reaches lower in the Snoqualmie River, which would support juveniles volitionally dispersing throughout the watershed. Additionally, consideration of yearling Chinook may require a focus on channel and habitat connectivity across seasons to support habitat access during flood conditions, when flood waters subside, during summer low‐flow conditions, and throughout the winter.

Studies conducted in the Skagit River indicate that natural banks and complex wood cover supports up to 5 times the density of sub‐yearling juvenile Chinook, compared to rip‐rap banks (Beamer and Henderson 1998). While these findings are not specific to yearling Chinook, they further support observations from Lowery et al (in prep) and the 2017 Snoqualmie pilot study, which indicate that mainstem edge habitats and log jams are utilized by both sub‐yearling and yearling Chinook. Combined, these collective studies suggest that levee/revetment removal, restoration of a natural channel migration processes, and restoration of complex edge habitats are needed to support both sub‐yearling and yearling Chinook. Current salmon restoration strategies primarily focus on flood refuge and spring rearing specific to sub‐yearling Chinook. Consideration of yearling Chinook may require additional emphasis on edge habitat conditions during summer low‐flow and overwintering periods. For example, installation of wood complexes throughout reaches which interact with high‐ and low‐flows conditions would increase edge complexity and support the temperature and instream cover requirements needed by juvenile yearling Chinook during summer and winter periods.

Summer habitat conditions in the Snoqualmie River have primarily been discussed in regard to adult Chinook life‐stages, since adults enter the Snoqualmie River in late summer. However, juvenile Chinook with extended freshwater rearing are also likely to be impacted by summer water temperatures and low‐flow conditions. With summer water temperatures known to reach detrimental levels throughout the Snoqualmie River watershed (Ecology 2011, King County 2016, 2017a), it will be important to moderate and protect headwaters, cooler tributaries, and mainstem areas of hyporheic and groundwater exchange. These various channels and mainstem areas may provide thermal refugia by supporting thermal heterogeneity at a local scale (Arscott et al. 2001, Fernald et al. 2006, Arrigoni et al. 2008) as well as thermal complexity across the watershed (Steel et al. 2016). Across the lower Snoqualmie River watershed, restoration and protection specific to headwater, tributary, and floodplain channels has received less attention since current efforts are focused on mainstem restoration. However, since juvenile yearling Chinook utilize headwater, tributary, and floodplain channels throughout the year, it may be necessary to elevate the priority of these waterbodies. Additionally, prioritization of mainstem areas influenced by hyporheic and groundwater exchange is likely required to provide thermal refugia for juvenile yearling Chinook. Restoration strategies specific to summer low‐flow conditions may include remove of channel constraints such as levees and revetments (which inhibit hyporheic and groundwater exchange), instream flow augmentation through reduced withdrawals or improved recharge (e.g., wetland complex restoration), installation of instream structures such as log jams (which stimulates vertical hyporheic and groundwater exchange), and extensive riparian plantings (which maintain and buffer cooler water temperatures). As highlighted by agricultural Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 21 waterway maintenance observations, juvenile Chinook with extended freshwater rearing in floodplain channels appear to prefer natural flow regimes and areas of cooler summer temperatures. It may be appropriate to reconsider existing best management practices for drainage maintenance of floodplain channels (e.g. dredging) to more directly account for flow and riparian buffer conditions. Furthermore, restoration of riparian buffers along mainstem, tributary, and floodplain channels throughout the lower Snoqualmie may help to maintain cooler water temperatures important for juvenile Chinook with extended freshwater rearing.

The aforementioned habitat restoration and protection strategies are likely integral to the continued expression and survival of juvenile yearling Chinook in the Snoqualmie River. However, further investigation of habitat use and distribution patterns specific to juvenile yearling Chinook would assist in effectively evaluating and refining Snoqualmie‐specific conservation strategies. Factors like temperature, flow, riparian cover, wood cover, wetted width, channel type (e.g., mainstem, tributary, and floodplain), and habitat condition (e.g., complexity, connectivity, and availability) are hypothesized to influence yearling Chinook habitat use and distribution. A detailed study investigating and verifying these relationships will be important for conservation and restoration strategies aimed at supporting extended freshwater rearing in the Snoqualmie River watershed.

Recommendations for a Detailed/Comprehensive Study Plan for Juvenile Chinook Distribution and Habitat use in the Snoqualmie River watershed

Potential Guiding Hypotheses  The spatial distribution of juvenile Chinook across the Snoqualmie River watershed is not uniform across spring, summer, fall, and winter.  The relative abundance and/or density of juvenile yearling Chinook are different among mainstem, tributary, and floodplain‐wetland channels.  The distribution of juvenile yearling Chinook is dependent on channel and habitat connectivity and availability.  The distribution of juvenile yearling Chinook will differ among habitat types (e.g., pool, riffle, glides) and within habitat types (e.g., pool sand bar edges vs. pool rip‐rap bank edge).  Juvenile yearling Chinook habitat use and distribution among and within channel types differs based on diel strata.  The condition and growth of juvenile yearling Chinook varies across channel and habitat types.  Environmental variables associated with juvenile yearling Chinook habitat use include, flow, temperature, substrate, riparian cover, wood/vegetation cover, wetted width, and habitat depth. Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 22

Site Selection, Habitat Measurements, and Periodicity While a randomly selected and spatially balanced sample design may facilitate the strongest statistical inference, known limitations in the lower Snoqualmie River warrant an alternate approach. Specifically, habitats are likely unevenly distributed across the lower Snoqualmie River since hydro‐modifications have significantly altered riverine processes and the related formation of instream habitats. Additionally, using randomly selected sites would likely be limited by site access availability since much of the lower Snoqualmie River floodplain is in private ownership. Subsequently, rather than using randomly selected points, we suggest focusing on multiple channel and habitat unit replicates throughout documented areas of Chinook spawning and juvenile distribution. A power analysis using previous Snoqualmie River observation as well as the 2017 pilot study results can help to determine the approximate number of channel and habitat unit replicates needed to detect differences in habitat use and distribution. Suitable sample sites can be verified based on access availability as well as safety.

A hierarchical structure can be applied to areas of available access and known juvenile and/or adult Chinook distribution to determine sample site designations, survey lengths, and habitat measurement specifics (Table 4) (adapted from Beamer et al. 2010 and Lowery et al. in prep). Across the mainstem Snoqualmie, sampled habitat units will include rip‐rap bank edges, natural‐bank edges, sand‐bar edges, gravel‐bar edges, backwaters, and pools. Rip‐rap bank edges include areas of placed bare rock which are part of a revetment or levee. Natural‐bank edges no artificial hardening with vegetation, are depositional areas on the river‐side of a levee/revetment, or are areas where a levee/revetment is buried back in the floodplain. Sand‐ bar edges are gently sloping depositional areas characteristic of sand substrates and gravel bar edges are gently sloping depositional areas characteristic of gravel substrates. Backwaters are slow water alcoves and areas where water has backed up due to an obstruction. Sampled pools will include areas of scour which do not exceed depths of 1.5m (extent of the cataraft electrical field). Tributaries with known juvenile and/or adult Chinook distribution will be grouped based on the relative drainage areas of respective tributaries (e.g., small or large). Across tributaries, primary sampled habitat units include pools, riffles, glides, backwaters, side‐channels, and ponds. Many smaller tributaries channels located within the broader Snoqualmie River floodplain have been heavily modified to improve agricultural drainage (e.g. dredged, straightened, lacking in riparian vegetation). Floodplain channels are any low flow channel in the floodplain of the mainstem or tributaries. Floodplain channels are either dominated by river flows, dominated by ground water, or can originate as a wall base channel. Similar to tributaries, many floodplain channels have also been modified for agricultural drainage.

Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 23

Table 4: Channel and habitat unit descriptions (adapted from Lowery et al. in prep).

Sample Reach Data Collected From Each Channel Type Habitat Unit Length (m) Channel and Habitat Unit

– % Vegetation cover – % Wood cover – Rip-rap bank edge – Large wood frequency – Natural bank edge – Visibility – Sand bar edge Mainstem 400 – Width – Gravel bar edge – Depth – Backwater – Unit length – Pool – Velocity – Temperature

Tributary – Large* 300 – Bank-full width – Riffle – % Riparian cover – Glide – % Vegetation cover – Pool – % Wood cover Tributary - Small* 200 – Backwater – Large wood frequency – Side-channel – Velocity – Pond – Temperature – Dominant substrate Floodplain Channel* 75 – Sub-dominant substrate

*Can include agricultural ditches

Among habitat units, wetted widths, bank‐full widths, and unit lengths can be measured with a handheld laser range finder. Depth and flow velocities can be measured using a Swoffer flow meter. Water temperatures can be measured with an YSI temperature probe at the time of sampling, and when possible, a HOBO temperature logger can be deployed to capture variation in temperature regimes. Percent cover of wood and riparian vegetation, large woody debris counts, and dominant and subdominant substrates within each unit can be visually estimated. Dominant and subdominant substrate designations can be categorized following Kaufmann et al. (1999), including: 1) fines <0.06mm, 2) sand 0.06‐2mm, 3) gravel (fine) 2‐16mm, 4) gravel (course) 16‐64mm, 5) cobbles 64‐250mm, and 6) boulders 250‐4000mm.

Since differences in salmonid distribution and habitat use across seasons have been well documented, multiple temporal strata should be considered when evaluation juvenile Chinook freshwater rearing patterns. Sample events among channel types and habitat units should occur across winter, spring, summer, and fall periods. Sampling across seasons will help in determining temporal patterns in juvenile Chinook rearing and help to target the yearling age‐ class. Additionally, since juvenile Chinook are known to display diel movement and migration patterns among habitat types and throughout a watershed, sample events should cover both diel strata. Day and evening/night periods should be sampled across mainstem, tributary, and floodplain channels. Sampling across diel strata will help to capture movement and migration Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 24 patterns, which may inform how difference habitat units or channel types support freshwater rearing for juvenile Chinook (e.g, predator refuge vs. foraging).

Salmonid Collection/Sampling Electrofishing, as compared to snorkel surveys, is suggested for Snoqualmie River due to relatively turbid conditions. The turbid conditions can make it difficult to identify juvenile salmonids to species level through solely visual methods (Martin Environmental and Shreffler Environmental 2002, Washington Trout 2003). Additionally, capture of juveniles is needed to accurately assess length and weight information.

Across mainstem sample reaches, juvenile salmonids should be collected along edge habitat areas using an electrofishing cataraft. As previously discussed, since juvenile Chinook tend to utilize mainstem edges and since the electrofishing cataraft is most efficient along edge habitats, sampling along edges is likely to increase the probability of salmon observation and capture. Electrofishing settings should align with site‐specific conductivity measurements to ensure relatively similar capture efficiencies across reaches and seasons. Seconds of electrofishing should be recorded for each sample site to allow for estimation of relative abundance.

Across tributaries and floodplain channels, juvenile salmonids should be collected using a Smith‐Root LR‐20B® backpack electrofisher system using established protocols (Reynolds and Kolz 2012). Entire habitat units should be sampled across these channel types (as compared to just mainstem edge habitats). Seconds of electrofishing should be recorded for each sample site to allow for estimation of relative abundance.

Salmonids immobilized by the electrical current should be netted and placed in recovery buckets. All captured salmonids should be placed in an anesthetizing water bath of MS‐222, identified, measured for length (nearest millimeter), and weighed (nearest gram). After a recovery period, captured fish should be released back into the sampled channel/habitat. During summer periods, in order to minimize stress from warmer summer water temperatures, holding buckets should be continually oxygenated as well as shaded from direct sunlight.

Analyses Pattern of channel‐ and habitat‐specific use can be evaluated through differences in the relative abundances of juvenile Chinook. Relative abundance can be represented as catch per unit effort (CPUE), which can be quantified as the number of juvenile Chinook captured in a channel or habitat type and standardized by the number of seconds that area was electrofished.

To evaluate explanatory variables potentially driving observed juvenile Chinook distribution and channel/habitat use across sample periods, analyses can utilize multivariate ordination methods, recursive partitioning, and/or graphical assessments. Multivariate ordination such as non‐metric multidimensional scaling or principal component analyses can help in determining Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 25 differences in salmonid assemblages across sites, potential environmental factors influencing differences in assemblages, as well as dominant gradients across environmental variables. Recursive partitioning such as classification and regression tree analyses can help determine the environmental factors associated with observed salmonid presence/ absence as well as partition observed relative abundances based on explanatory variables. Graphical assessments such as length frequency histograms and relative abundances can help in understanding the size structure and relative abundance across channels and habitat units.

As previously mentioned, in addition to environmental factors, habitat conditions (i.e., complexity, availability, and connectivity) are likely associated with juvenile Chinook habitat use and distribution. The availability, complexity, and connectivity of channel and habitat types can be evaluated using landscape and spatial analysis methods (e.g., FRAGSTATS and ArcGIS Network Analyst). Additionally, complexity and availability can be evaluated through specific habitat metrics (e.g., wood frequency, % vegetation cover, habitat frequency).

Potential Applications of Information  Habitat use and distribution information to support Snoqualmie River restoration strategies  Support for summer–fall project effectiveness monitoring  Support for temperature and habitat considerations during summer periods  Support for a follow‐up adult scale/otolith analysis to understand inter‐annual variation in the relative contribution of juvenile yearling Chinook in returning adults  Support for coordination throughout WRIA 7 to better understand habitat use and distribution of yearling Chinook across waterbodies and throughout seasons  Improved understanding of Endangered Species Act risks created by farm activities (i.e. drainage maintenance) Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 26

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Appendix A

Juvenile Chinook captured on September 7th, 2017 at 22:15 on a sand/gravel‐bar edge habitat. Located at 47.6909, ‐121.964.

Juvenile Chinook captured on September 7th, 2017 at 22:15 on a sand/gravel‐bar edge habitat. Located at 47.6909, ‐121.964.

Juvenile Chinook (left) and juvenile coho (right) captured on September 7th, 2017 at 21:30 on a sand/gravel‐bar edge habitat. Located at 47.6878, ‐121.947. Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 34

Juvenile Chinook captured on September 11th, 2017 at 20:15 on a sand/gravel‐bar edge habitat. Located at 47.568, ‐121.889.

Juvenile Chinook captured on September 11th, 2017 at 22:15 on a sand/gravel‐bar edge habitat. Located at 47.5893, ‐121.920. Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 35

Appendix B

Waterbody Date Latitude Longitude Habitat Type Chinook Count coho Count

Snoqualmie River (RM15 – RM23) 9/7/2017 47.6732 -121.919 Rip-Rap Edge 0 5

Snoqualmie River (RM15 – RM23) 9/7/2017 47.6737 -121.923 Rip-Rap Edge 0 0

Snoqualmie River (RM15 – RM23) 9/7/2017 47.672 -121.929 Glide 0 0

Snoqualmie River (RM15 – RM23) 9/7/2017 47.6878 -121.947 Sand Bar Edge 7 4

Snoqualmie River (RM15 – RM23) 9/7/2017 47.6878 -121.954 Sand Bar Edge 1 1

Snoqualmie River (RM15 – RM23) 9/7/2017 47.6909 -121.964 Sand Bar Edge 5 4

Snoqualmie River (RM15 – RM23) 9/7/2017 47.692 -121.964 Large Woody Debris Edge 0 29

Snoqualmie River (RM15 – RM23) 9/7/2017 47.7058 -121.999 Sand Bar Edge 8 0

Snoqualmie River (RM33.5 – RM36.3) 9/11/2017 47.5686 -121.886 Glide 0 0

Snoqualmie River (RM33.5 – RM36.3) 9/11/2017 47.568 -121.889 Sand/Gravel Bar Edge 2 0

Snoqualmie River (RM33.5 – RM36.3) 9/11/2017 47.5701 -121.893 Rip-Rap Edge 0 10

Snoqualmie River (RM33.5 – RM36.3) 9/11/2017 47.5753 -121.896 Sand/Gravel Bar Edge 2 0

Snoqualmie River (RM33.5 – RM36.3) 9/11/2017 47.5796 -121.905 Rip-Rap Edge 0 6

Snoqualmie River (RM33.5 – RM36.3) 9/11/2017 47.5822 -121.907 Sand/Gravel Bar Edge 1 9

Snoqualmie River (RM33.5 – RM36.3) 9/11/2017 47.5829 -121.907 Large Woody Debris Edge 0 28 Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 36

Snoqualmie River (RM33.5 – RM36.3) 9/11/2017 47.5829 -121.908 Sand/Gravel Bar Edge 1 6

Snoqualmie River (RM33.5 – RM36.3) 9/11/2017 47.5893 -121.920 Sand/Gravel Bar Edge 3 0

Snoqualmie River (RM33.5 – RM36.3) 9/11/2017 47.5915 -121.923 Sand/Gravel Bar Edge 10 0

Cherry Creek 9/12/2017 47.7669 -121.958 Pool 0 25

Cherry Creek 9/12/2017 47.7663 -121.957 Pool 0 11

Griffin Creek 9/12/2017 47.617 -121.914 Pool 0 19

Griffin Creek 9/12/2017 47.617 -121.913 Pool 0 22

Griffin Creek 9/12/2017 47.6158 -121.904 Pool 0 18

Raging River 9/6/2017 47.5129 -121.920 Pool 0 5

Raging River 9/6/2017 47.5548 -121.900 Riffle 0 0

Raging River 9/6/2017 47.566 -121.883 Riffle 0 2

Raging River 9/6/2017 47.5668 -121.883 Pool 0 0

Raging River 9/6/2017 47.5131 -121.921 Riffle 0 1

Raging River 9/6/2017 47.5133 -121.922 Pool 0 7

Raging River 9/6/2017 47.5181 -121.925 Pool 0 16

Raging River 9/6/2017 47.5181 -121.925 Pool 0 3

Raging River 9/6/2017 47.5399 -121.909 Pool 0 2 Snoqualmie Watershed Forum, Beth leDoux, and Elissa Ostergaard December 18, 2017 Page 37

Raging River 9/6/2017 47.5403 -121.908 Pool 0 0

Raging River 9/6/2017 47.5542 -121.901 Pool 0 7

Raging River 9/6/2017 47.5543 -121.901 Riffle 0 1

Tolt River 9/14/2017 47.6495 -121.879 Pool 0 50

Tolt River 9/14/2017 47.6424 -121.895 Pool 0 7

Tolt River 9/14/2017 47.6483 -121.879 Pool 0 36

Tolt River 9/14/2017 47.6478 -121.879 Pool 0 31

Tolt River 9/14/2017 47.6471 -121.880 Pool 0 41

Tolt River 9/14/2017 47.640 -121.927 Pool 0 2

Tolt River 9/14/2017 47.6398 -121.926 Pool 0 20

Tolt River 9/14/2017 47.6397 -121.926 Pool 0 28

Tolt River 9/14/2017 47.6401 -121.925 Pool 0 0

Tolt River 9/14/2017 47.6398 -121.924 Pool 0 2