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

May 5, 2017

TECHNICAL MEMORANDUM

TO: Beth leDoux, Snoqualmie Watershed Technical Coordinator, Water and Land Resources Division (WLRD), Department of Natural Resources and Parks (DNRP)

FM: Josh Kubo, Science and Technical Support Section, WLRD, DNRP

RE: 2016 Water Temperature Study: Results and Findings

Introduction The purpose of this technical memorandum is to summarize and discuss water temperature data collected during the summer of 2016 in a select reach of the Snoqualmie River from Fall City to Carnation. Water temperature analyses and discussion included in this technical memorandum focus on evaluating mainstem temperature trends and investigating the potential influence of hyporheic exchange and groundwater inputs, as noted in two previous studies by the Department of Ecology (Ecology 2011) and the King County Water and Land Resources Division (King County 2016).

As discussed by Ecology (2011), the Snoqualmie River appears to be a gaining reach (augmented with groundwater) between the and Carnation. These groundwater inputs can influence mainstem temperatures by cooling surface waters during the summer and warming surface waters during the winter. In addition to Ecology (2011) findings, King County (2016) highlighted that select locations in the mainstem Snoqualmie between Fall City and Carnation were potentially influenced by localized hyporheic exchange (i.e., surface water mixing with subsurface water flowing in the substrate beneath and adjacent to channel) and/or groundwater inputs. Specifically, during the summer low-flow conditions in 2015, there appeared to be localized areas of decreased mainstem daily maximum temperatures, compared to upstream and downstream reaches. King County (2016) hypothesized that observed variations in temperatures patterns may have been influenced by hyporheic exchange and/or groundwater inputs. Hyporheic exchange in a river system depends on variations in streambed topography and geomorphology, as well as the range, frequency, and spatial variation in hydraulic conductivity and hydraulic gradients (Wondzell and Swanson 1999, Dent et al. 2001, Gooseff et al. 2006, Wondzell 2006). In the Snoqualmie River, localized hyporheic exchange and groundwater inputs may be associated with areas where the valley walls narrow creating constriction points for upwelling as well as in areas such as alluvial fans and bedrock outcrops where substrate differences influence exchange rates and gradients. Beth leDoux May 5, 2017 Page 2

In an effort to further evaluate the groundwater gaining reach identified by Ecology (2011) as well as potential localized temperature variations observed by King County (2016), this follow-up study was conducted by King County, in partnership with the Snoqualmie Watershed Forum. These efforts focused on monitoring instream temperature conditions during the summer of 2016 throughout the mainstem Snoqualmie from Fall City to Carnation. This technical memorandum describes and discusses the follow-up study. Further evaluating spatial and temporal variations in water temperature trends can help in understanding summer water temperature dynamics in the Snoqualmie as well as providing information on potential cold-water refugia important for salmonid conservation and recovery.

Methods Fourteen water temperature monitoring sites were selected throughout the mainstem Snoqualmie River from Fall City (~RM 33.9) to Carnation (~RM 23.8). All the locations that were previously monitored as part of the 2015 King County study were additionally monitored in 2016 as part of this study. Nine additional locations were added throughout the mainstem Snoqualmie in 2016 to provide further insight into spatial and temporal temperature trends. Several monitoring sites were located at public access points; however, there were a few key areas in the reach from Fall City to Carnation where such locations were sparse. With the cooperation of local farmers through outreach, we were able to secure access to the mainstem through several private properties. Water temperature was subsequently monitored across a total of 14 mainstem locations (Figure 1). Between the upstream and downstream monitoring locations, there are two primary tributaries that drain into the mainstem Snoqualmie (Patterson Creek and Griffin Creek). Water temperature was also monitored at Patterson Creek by a thermistor specific to this study and at Griffin Creek by a King County flow and temperature gauge (Figure 1).

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Figure 1: Map of the Snoqualmie River 2016 study reach from Fall City to Carnation. Map includes locations of thermistors as well as the location of a King County gauging station (KC_21A). Naming convention for thermistor locations specifies sites that were monitored in 2015 and 2016 (MS_SNOQ) as well as sites monitored just in 2016 (SAFC & PATT). Site numbering was based on order of deployment resulting in non-sequential numbering from upstream to downstream.

Flow

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At each location, water temperature was monitored using HOBO Pendant Thermistors (Model# UA- 002-64) with 64KB of rewritable memory. Thermistors were launched using the Onset HOBOware software and set to record temperature in Celsius on 15 minute intervals. Thermistors were checked using a combination of a chilled (refrigerated) and room temperature bath tests. Thermistors were placed in each bath and allowed to equilibrate for at least 3 hours. The temperatures of the baths were recorded after the equilibration period and compared with the downloaded thermistor readings. None of the thermistors recorded temperatures that deviated beyond the range of variability noted by Onset (±0.10°C).

Calibrated thermistors were deployed at 14 sites in the Snoqualmie River and one site on Patterson Creek on June 29/June 30 and stayed in the water until September 30 (Table 1), with one data download event occurring during that period. The thermistors were placed in PVC housings with weighting (bolts/nuts) and secured with cable to riparian vegetation, bridges, logs, and other suitable secure points. To ensure the thermistors were retrievable at potentially higher late-summer flows, the thermistors were placed in the water no further than ~10ft from the bank, which was not the center of the channel. While typical protocols require thermistors to be placed in the thalweg of the channel, we focused on thermistor deployment that would allow for easy retrieval as well as minimize potential thermistor loss due to unexpected high flow events. It should be noted that shallower deployments in the channel may alter observed temperature patterns. Water temperature at the time of thermistor deployment was recorded with an YSI temperature probe (Model #63). Thermistors were visited on July 28 and 29 to download temperature data, verify thermistor status (e.g., recording, shut-down, or missing), and to re- deploy any necessary replacement thermistors. Stream temperature was concurrently recorded at the time of download with the YSI temperature probe to verify thermistor measurements.

Analyses and comparisons for this study were based on Washington State water temperature standards, as defined in the Washington Administrative Code (WAC 173-201a). The temperature standard in the study reach is computed as the 7-day average of the daily maximum temperatures (7-DADMAX), i.e., the arithmetic average of seven consecutive measures of daily maximum temperatures. The use of the 7-DADMAX instead of an instantaneous temperature maximum is intended to reflect that most aquatic organisms can tolerate a short period of high temperature, whereas persistent exposure to warm water is more likely to cause harm. Washington State water quality standards specify that if a water body is naturally warmer than or within 0.3°C of the criterion for that water body, human caused increases (considered cumulatively) must not increase that temperature by more than 0.3°C. Additional limits on human-caused temperature changes are described in the WAC. Across the study reach, Ecology has established 7-DADMAX thresholds of 16°C to protect core summer habitats. Ecology has also designated supplemental spawning and incubation criteria for water temperature in certain areas where salmonid spawning and egg development occurs. These criteria apply when the standard temperature criteria are insufficient. In these tributaries and mainstem reaches, the 7-DADMAX criterion is 13°C during the specified periods. In addition to evaluating 7-DADMAX temperatures, analysis for this study included discussion of maximum/minimum daily temperatures, average temperature, as well as the timing and spatial patterns of daily temperature fluctuations.

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Table 1: Snoqualmie River 2016 study reach and tributary locations. Location on bank noted in parenthases and corresponds to observer looking downstream.

Monitoring Approximate Location Details Site ID River Mile MS_SNOQ_2 33.9 Snoqualmie River downstream of confluence, Fall City, WA (left bank)

SAFC_11 32.8 Snoqualmie River near SE 28th St., Fall City, WA (left bank)

MS_SNOQ_3 32.6 Snoqualmie River near Carlson Restoration Site, Fall City, WA (right bank)

MS_SNOQ_4 31.3 Snoqualmie River near Neal Rd. Boat Launch, Fall City, WA (right bank)

SAFC_3 30.5 Snoqualmie River near Fall City Carnation Rd SE, Fall City, WA (left bank)

SAFC_4 29.5 Snoqualmie River at the end of Old Leary Rd., Fall City, WA (right bank)

PATT_5 0.3 Patterson Creek downstream of S.E. 24th St., Fall City, WA (left bank)

SAFC_5 28.6 Snoqualmie River near W. Snoqualmie River Rd. SE, Carnation, WA (right bank)

MS_SNOQ_6 28.2 Snoqualmie River downstream of Patterson Creek, Carnation, WA (left bank)

SAFC_6 27.5 Snoqualmie River near W. Snoqualmie River Rd., Carnation, WA (left bank)

SAFC_7 26.5 Snoqualmie River downstream of NE 8th St., Carnation, WA (right bank)

KC_21A 1.1 Griffin Creek near NE 11th St., Carnation, WA (right bank)

SAFC_8 25.5 Snoqualmie River downstream of Griffin Creek confluence, Carnation, WA (left bank)

SAFC_9 24.6 Snoqualmie River near W. Snoqualmie River Rd., Carnation, WA (right bank)

SAFC_10 24.4 Snoqualmie River near W. Snoqualmie River Rd., Carnation, WA (right bank)

MS_SNOQ_9 23.8 Snoqualmie River near N.E. Tolt Hill Rd., Carnation, WA (right bank)

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Results and Discussion The Snoqualmie River temperature time-series were summarized across the sample period (July 1 to September 30, 2016) for the 7-day average of daily maximum temperatures (7-DADMAX). Water temperature throughout the mainstem Snoqualmie River from Fall City to Carnation (hereinafter referred to as “study reach”) was consistently above the state standard for core summer habitat (16°C) from around July 17 to September 2 (Figure 2). Additionally, 7-DADMAX water temperature in the study reach was consistently above the state standard for spawning and incubation (13°C) from September 15th till end of the monitored period. Among the two primary tributaries in the study reach, Griffin Creek was consistently below the state standards (aside from July 24 to July 29) and Patterson Creek exceeded the standard from July 20 to August 2, August 11 to August 19, and September 15 to September 25. Temperatures in both tributaries were considerably lower than temperatures observed in the mainstem throughout the majority of the summer period. Peak 7-DADMAX water temperatures throughout the summer period were observed around July 28 to 29 and August 17 to 18. Peaks in water temperature tended to align with periods of relatively higher air temperatures (Figure 3). The second peak in water temperature aligned with the warmest air temperatures observed at a nearby station (Griffin Creek) during the summer of 2016.

Figure 2: Snoqualmie River 2016 temperature time-series from Fall City to Carnation. Mainstem locations are ordered from upstream (MS_SNOQ_2) to downstream (MS_SNOQ_9) with the two primary tributaries listed below.

Snoqualmie River 7DADMAX from Fall City to Carnation

22 MS_SNOQ_2

21 SAFC_11 MS_SNOQ_3 20 MS_SNOQ_4 SAFC_3

(°C) 19 SAFC_4

SAFC_5 18 MS_SNOQ_6 17 SAFC_6 SAFC_7

Temperature 16 SAFC_8

SAFC_9 15 SAFC_10 Water 14 MS_SNOQ_9 Patterson 13 Griffin State Standard 12 7/1 7/8 8/5 9/2 9/9 7/15 7/22 7/29 8/12 8/19 8/26 9/16 9/23 9/30

Date

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Figure 3: Snoqualmie River continuous temperature downstream of Patterson Creek and daily average air temperature at Griffin Creek (King County gauge KC_21A).

Snoqualmie River downstream of Patterson Creek (SAFC_5) 28 Continuous Water Temperature 26 Daily Air Temperature @ Griffin Creek KC_21A 24

22 (°C)

20

18

16 Temperature 14

12

10

8 7/1 7/8 8/5 9/2 9/9 7/15 7/22 7/29 8/12 8/19 8/26 9/16 9/23 9/30

Date

Up until around August 12, 7-DADMAX water temperatures in the Snoqualmie mainstem generally increased from upstream to downstream (Figure 4a). However, from about August 12 until August 28 and from about September 6 to September 16 there was noticeable change in upstream to downstream temperature patterns, where some downstream stations had lower 7-DADMAX temperatures than upstream stations. Specifically, during the second peak in mainstem water temperatures (August 17 to 18), there appeared to be a decrease in 7-DADMAX temperatures downstream of SAFC_6 to SAFC_9 (Figure 4b). The decrease in maximum temperatures across these sites occurred up until the middle of September. Decreases in maximum mainstem temperature throughout this subset of locations may indicate potential influences of hyporheic exchange and/or groundwater inputs. During summer months, groundwater inputs have the potential to reduce overall channel temperatures (maximums, minimums, and averages), while hyporheic exchange has the potential to reduce the diel range in channel temperatures (reduce maximum and increase minimum temperatures) as well as influence the phase of temperatures (timing of maximum and minimum temperatures) (Johnson 2004, Loheide and Gorelick 2006, Arrigoni et al. 2008). While tributaries are known to also influence mainstem temperatures, the influence of Griffin Creek and Patterson Creek is likely minimal since their combined contribution was less than 2% of the mainstem flow during the 2016 summer period. Beth leDoux May 5, 2017 Page 8

Figure 4a & 4b: Snoqualmie River 7DADMAX temperatures on 7/29/16 and 8/18/16. Labels for sample points include a site code and the 7DADMAX temperature in parentheses (°C). Temperature ranges for both 4a and 4b are binned in similar 0.2°C intervals. Segment colors align with the temperature measured at the downstream sample location for ease of interpretation and segments with missing data are colored grey.

4a: 7/29/16 4b: 8/18/16

Flow Flow

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Localized variation in upstream to downstream temperature patterns appeared to align with periods of low flow and high air temperature. For example, during the first peak in summer water temperatures (July 28 to 29), when water temperatures generally increased from upstream to downstream, average flows were around 1030-1070 cfs. However, during the second peak in summer water temperatures (August 17 to 18), when there was a localized decrease in mainstem temperatures from SAFC_6 to SAFC_9, average flows were around 635-646 cfs. This may indicate that hyporheic exchange and/or groundwater inputs are more likely to shift mainstem temperatures during periods of lower flows. Additionally, the percent contribution of hyporheic exchange and/or groundwater inputs may only be significant enough to influence mainstem temperatures at lower flows. Our observations indicate that areas with lower 7-DADMAX temperatures (compared to adjacent upstream and downstream locations) were detectable from August 12 until August 28 and from about September 6 to September 16, which appeared to align with the lowest summer flows in the Snoqualmie during 2016 (Figure 5). King County (2016) observed areas of lower 7-DADMAX temperatures throughout the majority of the 2015 monitored summer period (up to late August), which may have been attributed to the early onset and duration of extreme low flows observed throughout that unusually hot and dry summer (Figure 5).

As previously mentioned, the second peak in summer water temperatures (August 17 to 18) aligned with the warmest summer air temperatures. The Snoqualmie River is likely sensitive to summer air temperatures and solar radiation during periods of low flow as well as periods of lower precipitation and less cloud cover. However, while the Snoqualmie is likely sensitive to air temperature during low flow conditions, hyporheic exchange and/or groundwater inputs may mitigate temperature increases in certain locations due to a relatively greater percent contribution during the summer. Primary drivers of water temperature in the Snoqualmie include stream depth, discharge, air temperature, solar radiation, tributaries, and groundwater (Adams and Sullivan 1989). Spatial and temporal variation among these drivers subsequently influences the thermal regimes and site-specific patterns observed throughout the Snoqualmie River.

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Figure 5: Daily mean flow in the mainstem Snoqualmie River at USGS 12149000 near Carnation, WA in 2016, 2015, and across 1929–2014.

Snoqualmie River near Chinook Bend 5500 1929‐2014 Discharge @ USGS 12149000 5000 2015 Discharge @ USGS 12149000 4500 2016 Discharge @ USGS 12149000

4000

3500 (cfs)

3000

2500

Discharge 2000

1500

1000

500

0 7/1 7/8 8/5 9/2 9/9 6/10 6/17 6/24 7/15 7/22 7/29 8/12 8/19 8/26 9/16 9/23 9/30 Date

As noted by Ecology (2011), at a broad scale there appears to be a gaining reach (augmented with groundwater) between Snoqualmie Falls and Carnation in the Snoqualmie River. This study, as well as King County (2016) suggests that at a finer scale, there appears to be spatial and temporal variation in the potential influence of hyporheic exchange and/or groundwater inputs. The localized decreases in 7- DADMAX temperatures observed in this study suggest that hyporheic exchange and/or groundwater inputs potentially influence mainstem temperatures.

Groundwater mapping efforts from USGS (1995) and King County (2005) indicate that groundwater inputs likely occur throughout the study reach (Figure 6). While groundwater inputs can influence mainstem Snoqualmie temperatures, observations from this study support that localized variations in upstream to downstream temperature patterns along this reach are likely influenced primarily by hyporheic exchange. For example, evaluation of a longitudinal temperature profile during the second peak in summer temperatures show that downstream of SAFC_6 to SAFC_9 the range in maximum/minimum temperatures was significantly reduced while average temperatures showed minimal change (Figure 7). As previously mentioned, hyporheic exchange has the potential to reduce the diel range in channel temperatures (reduce maximum and increase minimum temperatures), but generally has minimal influence on average temperatures (Arrigoni et al. 2008). As surface waters interact with the hyporheic zone, these waters are less influenced by atmospheric heat flux processes (i.e., warming by the sun during the day and cooling during the night). Waters traveling through the hyporheic zone are cooling/heating towards temperatures of the substrate, which are more constant Beth leDoux April 2017 Page 11 compared to stream channel temperatures. While our observations support that hyporheic exchange may influence mainstem summer temperatures at select locations, further field investigation, flow modelling, and analyses will help to fully understand the relative contributions of hyporheic and/or groundwater inputs.

Figure 6 (adapted from King County 2005): Map of Snoqualmie River groundwater elevations and approximate flow directions from Fall City to Carnation.

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Figure 7: Longitudinal temperature time-series for the mainstem Snoqualmie River on August 18, 2016. One day maximum (1DMAX), one day minimum (1DMIN), and average temperatures are reported with relative locations of primary tributaries noted.

Mainstem Snoqualmie Temperatures on 8/18/16 22

21 (°C) 20

19 Temperature 18

Water Tributaries 17 1DMAX Creek 1DMIN Average

16 Patterson Creek Griffin

Upstream Downstream

In addition to spatial variation in hyporheic exchange, this study observed temporal variation in the influence of hyporheic inputs. For example, observed decreases in the range of temperatures from SAFC_6 to SAFC_9 appeared to primarily align with the second peak in summer temperatures. During the first peak in summer water temperatures (July 28 to 29), the daily temperature range from SAFC_6 to SAFC_9 was only slightly different among locations (Figure 8). However, during the second peak in summer water temperatures (August 17 to 18), temperature ranges were significantly buffered downstream of SAFC_6 to SAFC_9 (Figure 9). Specifically, at SAFC_6 the daily water temperature range fluctuated around 2.8°C in a 24-hr period. In comparison, downstream from SAFC_7 to SAFC_9, the daily water temperature range was muted and only fluctuated between 0.7 – 1.0°C in a 24-hr period.

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Figure 8: Snoqualmie River continuous temperature at four select locations from 7/27/16–7/30/16. SAFC_6 is furthest upstream and SAFC_9 is furthest downstream.

Snoqualmie River Temperature 7/27 ‐7/30 24

22 (°C)

20

18 Temperature

SAFC_6

Water 16 SAFC_7 SAFC_8 SAFC_9 14

Date ‐ Time

Figure 9: Snoqualmie River continuous temperature at four select locations from 8/16/16–8/19/16. SAFC_6 is furthest upstream and SAFC_9 is furthest downstream.

Snoqualmie River Temperature 8/16 ‐ 8/19 24

22 (°C)

20

18 Temperature

SAFC_6 16 Water SAFC_7 SAFC_8 SAFC_9 14

Date ‐ Time Beth leDoux April 2017 Page 14

Observations from this study also indicated that the timing of daily maximum and minimum temperatures (temperature phase) was quite variable across the study reach. Comparing select locations from the upstream extent of the reach (MS_SNOQ_2), within the middle of the reach (SAFC_6 & SAFC_7), and at the lower extent of the reach (MS_SNOQ_9) indicate that the timing of maximum/minimum temperatures was quite variable across a 24h and 48-hr period (Figure 10). For example, maximum temperature on August 16 occurred around 17:00 at the most upstream location (MS_SNOQ_2), 14:30 on the most downstream location and between 21:00–23:00 in the middle sites (SAFC_6 & SAFC_7). These results may further support the spatial and temporal influence of hyporheic exchange, since hyporheic inputs can influence the phase of instream temperatures (Johnson 2004, Loheide and Gorelick 2006, Arrigoni et al. 2008). Surface waters that enter the hyporheic zone are essentially delayed as they move through substrates and subsequently re-enter the river channel out-of- phase with upstream or downstream surface water temperature signals. Variability in the timing of maximum/minimum temperatures was observed throughout the monitored summer period (July 1 to September 30); however, the degree of asynchrony and specific timing of peak temperatures varied throughout the summer period.

Figure 10: Snoqualmie River continuous temperature at four select locationsfrom 8/16/16–8/19/16. MS_SNOQ_2 is furthest upstream and MS_SNOQ_9 is furthest downstream.

Snoqualmie River Temperature 8/16 ‐ 8/19 24

22 (°C)

20

18 Temperature

MS_SNOQ_2 16 Water SAFC_6 SAFC_7 MS_SNOQ_9 14

Date ‐ Time

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Conclusions Results from this study indicate that during the summer of 2016, 7-DADMAX water temperature throughout the mainstem Snoqualmie River from Fall City to Carnation were consistently above state standards for designated uses. However, while temperatures were consistently warm, during the latter part of the summer there appeared to be areas of localized decreases in 7-DADMAX temperatures. Locations across the study reach displayed two peaks in maximum summer water temperatures; however, upstream-downstream temperature patterns were quite different between peak events. During the second peak in maximum summer water temperatures several sites displayed a decrease in 7- DADMAX temperatures, relative to upstream and downstream locations. These patterns were observed during periods of low flow and may have been attributed to the relative contributions of hyporheic exchange and/or groundwater inputs. In addition to decreases in observed maximum temperatures, the daily range in temperature fluctuations as well as the timing of maximum/minimum events appeared to display upstream-downstream variation across the study reach. This study suggests that spatial and temporal variation in hyporheic exchange influences mainstem water temperatures in the Snoqualmie River from Fall City to Carnation. Study results also support findings from King County (2016) suggesting that hyporheic and/or groundwater expression influences thermal heterogeneity throughout reaches of the Snoqualmie River during summer low-flow conditions.

At a watershed-scale, the Snoqualmie River appears to follow a linear temperature profile indicating that water temperatures generally increase from upstream to downstream (Fullerton 2015). However, as highlighted by this study and King County (2016), at a reach-scale, there appears to be variation in upstream-downstream temperature patterns with localized areas of temperature moderation. Hyporheic exchange and groundwater inputs can create thermal heterogeneity across channel units (Arscott et al. 2001, Fernald et al. 2006, Arrigoni et al. 2008), and these spatial and temporal variations in temperature patterns can subsequently influence the complexity of thermal regimes across the Snoqualmie River (Steel et al. 2016). Areas where colder water enters the system can have physiological and ecological significance for fishes as well as provide thermal refugia (Torgersen et al. 2012). Since salmonids require cooler waters for various freshwater life stages, areas of hyporheic exchange and groundwater inputs have the potential to provide important thermal refugia necessary for salmonid survival. Since salmonids are known to detect and preferentially utilize even small differences in temperature, differences in the spatial and temporal variations in temperature regimes may provide opportunities to utilize refuge areas to avoid the most harmful temperature conditions (Torgersen et al. 2012). For example, the asynchrony in daily maximum temperatures and reduction in diel temperature ranges observed in this study may provide the opportunity for salmonids to reduce thermal stress through daily movements across relatively short distances.

Since salmonid behavior, ecology, and biology are closely related to thermal regimes and temperature conditions, variations across the Snoqualmie may provide a thermally diverse landscape influencing salmonid growth, reproduction, and survival. Conservation and restoration efforts focused on supporting thermal diversity may help to provide the habitat and temperature conditions needed to help salmonids adapt and moderate changing watershed conditions. Information from this study as well as efforts from Ecology (2011) and King County (2016) can help in developing conservation and restoration strategies aimed at supporting such thermal diversity. Discussion of strategies specific to the Snoqualmie River watershed is included in King County (2016).

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There are several follow-up studies suggested to better understand temperature dynamics in the Snoqualmie River as well as their potential impacts on salmonid populations. While this study does not provide a detailed evaluation of primary drivers of Snoqualmie water temperatures, the patterns observed during the summers of 2015 and 2016 may provide a useful framework to prioritize further evaluations. Some supplemental studies may include:

 Spatial and temporal analysis of relative contributions from smaller tributaries, spring, and modified floodplain features (e.g., pipes and modified outlets) on mainstem temperatures  Evaluation of hyporheic and groundwater relative contribution based on longitudinal profiles of temperature and conductivity and instream wells/piezometers  Spatial analysis of relict channels and alluvial floodplain features and how they relate to hyporheic exchange zones and groundwater flow paths  Evaluation of levee/revetment influence on hyporheic flow and connectivity  Spatial and temporal analysis of mainstem thermal regimes and salmonid habitat use to understand dynamics between the riverine thermal landscape and salmonid distributions

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Steel, E.A., S. Colin, and E.E. Peterson. 2016. Spatial and Temporal Variation of Water Temperature Regimes on the Snoqualmie River Network. Journal of the American Water Resources Association 1-19. DOI: 10.1111/1752-1688.12423

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Wondzell, S.M. 2006. Effect of morphology and discharge on hyporheic exchange flows in two small streams in the Cascade Mountains of Oregon, USA, Hydrol. Process., 20(2), 267– 287, doi:10.1002/hyp.5902