Upstream Migration and Spawning Success of Chinook Salmon in a Highly Developed, Seasonally Warm River System

Figures & data

Figure 1. The river system including the lower, middle, and upper stretches where the studies reviewed were conducted and the new data analyzed were collected. The spawning areas located within the Lower Snake and Clearwater sub-water sheds covered in Table 2 are also shown.

Table 1. Tailrace, ladder, and reservoir distances (km) calculated from the tailrace of Bonneville Dam to the upper end of the south arm of Lower Granite Reservoir.

	Distances
Dam or Reservoir	Tailrace^a	Ladder^b1	Reservoir	Total
Bonneville^2	3.5	0.3	71.7	75.6
The Dalles	1.8	0.4	36.0	38.1
John Day	2.3	0.3	120.9	123.5
McNary	2.3	0.5	66.8	69.6
Ice Harbor	0.8	0.4	49.3	50.5
Lower Monumental	2.1	0.3	44.5	47.0
Little Goose	1.6	0.3	57.4	59.2
Lower Granite	2.2	0.3	61.0	63.5
Total	16.6	2.8	507.6	527.0

^a Rakowski et al. (2010), ^bMeasured from aerial plots.

¹ When there were two ladders distances of unequal length at a dam, the mean distance was used.

² Information on the ladders at Bonneville Dam was not found, thus the mean ladder length at The Dalles Dam was used after adjusting for differences in dam height.

Figure 2. Net distances fall Chinook salmon adults must travel to complete tailrace-to-dam and reservoir passage events in the lower and middle stretches of the river system, and to the most consistently and heavily used spawning sites within the spawning areas located within the upper stretch.

Figure 3. Inter-annual daily mean temperature (°C) measured in the lower stretch of the river system in the tailrace of McNary Dam, the middle stretch in the tailrace of Ice Harbor Dam, and the upper stretch within the spawning areas within the Lower Snake River sub-watershed, and within the Clearwater River lower and upper reaches within the Clearwater River sub-watershed, 2010–2015. Data for the dams are from CBR (2017). Data for the Lower Snake River watershed, S.F. Clearwater lower reach, M.F. Clearwater, and Selway River lower reach were collected by the authors of this review and their staff. Data for the remaining spawning areas within the Clearwater River watershed were collected by the U.S. Geological Survey at Spalding (Station 13342500) and Orofino (Station 13340000), Idaho.

Figure 4. Inter-annual daily mean flow (KCFS) measured in the lower and middle stretches of the river system in the tailraces of McNary and Ice Harbor dams, respectively, 2010–2015 (CBR, 2017).

Figure 5. Inter-annual daily mean simulated velocities (cm/s) for the dam tailraces and reservoirs in the lower stretch of the river system (see Eqs. 3 and 4 in Table A1), for the dam tailraces and reservoirs in the middle stretch of the river system (see Eqs. 9 and 10A–10O in Table A1), and for the Upper and Lower Hells Canyon spawning areas (distance weighted 1-D modeling; Borden and Manning, 2011).

Table 2. Snake River basin fall Chinook salmon spawning areas located upstream of Lower Granite Dam. Accessible channel length is given in kms. Channel length (kms) was determined from river charts or redd locations documented by the authors except for the Lower Snake upper and lower reaches that are from Dauble et al. (2003). Abbreviations: rkm, river km (river mouth = rkm 0); D., Dam; Res., Reservoir; S. F., South Fork; M.F., Middle Fork.

				Accessible	Production
Spawning area	Reach	Upper end^1	Lower end^1	length	ranking
Upper Hells Canyon	Contiguous	Hells Canyon Dam rkm 398.7	Salmon River rkm 302.9	95.8	Primary
Lower Hells Canyon^1	Contiguous	Salmon River rkm 302.9	Lower Granite Reservoir rkm 234.0	68.9	Primary
Grande Ronde	Lower	rkm 116.0	rkm 0.0	116.0	Secondary
Imnaha	Lower	rkm 33.0	rkm 0.0	33.0	Tertiary
Salmon	Lower	rkm 176.9	rkm 0.0	176.9	Tertiary
Clearwater	Lower	rkm 65.0	Lower Granite Reservoir rkm 6.0	59.0	Primary
	Upper	rkm 120.0	rkm 65.0	55.0	Tertiary
S. F. Clearwater	Lower	rkm 30.9	rkm 0.0	30.9	Tertiary
M. F. Clearwater	Contiguous	Selway River. rkm 157.0	S. F. Clearwater River rkm 120.0	37.0	Tertiary
Selway	Lower	rkm 31.0	rkm 0.0	31.0	Tertiary

¹ Presented as one reach for simplicity, but can also be divided into two reaches using the Grande Ronde River as the dividing point.

Figure 6. Inter-annual mean total redd counts estimated on the end dates of six spawning intervals (21-Sep‒04-Oct, 05-Oct‒18-Oct, 19-Oct‒01-Nov, 02-Nov‒15-Nov, 16-Nov‒29-Nov, 30-Nov‒13-Dec) from data collected during aerial surveys conducted by the authors and their staff during 1991‒2015 (methods, Groves and Chandler, 1999; Groves et al., 2013, 2016) within the primary, secondary, and tertiary spawning areas used by Snake River basin fall Chinook salmon upstream of Lower Granite Reservoir (Figure 1; Table 2).

Figure 7. Standardized passage date distributions (2010‒2015) at Bonneville (panel A), McNary (panel B), Ice Harbor (panel C), and Lower Granite (panel D) dams for PIT-tagged, hatchery-origin fall Chinook salmon adults compared to the run schedules at those dams (CBR, 2017).

Table 3. Information on fallback of presumed, upriver bright fall Chinook salmon adults at the lower dams within the lower and middle stretches of the river system. The data are from Boggs et al. (2004; years 1998, 2000, and 2001) and was pooled across years for this table. The denominator for gross and net fallback percentages was the number of unique fish that passed. The numerator for net fallback was the number of unique fish that re-ascended the ladder (n under Reascension). The denominator for all other percentages was the number of unique fallbacks.

				Reascension		Overshoot fallback		Unknown fate
Number of unique fish that passed	Number of unique fallbacks	Gross fallback percentage	Net fallback percentage	n	%	n	%	n	%
Bonneville Dam^a
2,093	83	4.0	2.1	40	48.2	10	12.0	33	39.8
The Dalles Dam
2,080	176	8.5	6.0	51	29.0	73	41.5	52	29.5
John Day Dam
1,633	48	2.9	2.7	4	8.3	23	47.9	21	43.8
McNary Dam
1,366	35	2.6	1.8	10	28.6	16	45.7	9	25.7
Ice Harbor Dam
155	14	9.0	7.7	2	14.3	12	85.7	0	0.0
Lower Monumental Dam
146	9	6.2	4.8	2	22.2	5	55.6	2	22.2
Little Goose Dam
125	23	18.4	13.6	6	26.1	13	56.5	4	17.4
Lower Granite Dam
95	15	15.8	8.4	7	46.7	4	26.7	4	26.7

^a Data were not collected downstream of Bonneville Dam in 2000 and 2001.

Figure 8. Relation between the percent of presumed upriver bright fall Chinook salmon adults that used cool water tributaries for more than 12 h along the lower stretch of the river system and mean weekly water temperatures at Bonneville Dam. Circles represent 52 weekly bins (mean 41 fish/bin; range 4‒122 fish/bin). The curve is the exponential regression line that best fits the data (r² = 0.80; P ≤ 0.0001; percent = 6.558^‒7e^{0.802xtemperature}). The figure originally published in Goniea et al. (2006) was provided for use by the editorial staff of Transactions of American Fisheries Society. The font was modified and color added.

Figure 9. Travel time distributions (2010‒2015) for PIT-tagged, hatchery-origin fall Chinook salmon adults that swam from Bonneville Dam to Lower Granite Dam. The lower whisker is the 2.5th percentile, the bottom of the box is the 25th percentile, the horizontal line in the box is the median, the circle in the box is the mean, the upper end of the box is the 75th percentile and the top whisker is the 97.5th percentile. The numbers above the 97th percentile are the sample sizes.

Figure 10. Upstream movement rate (km/d) distributions (2010‒2015) calculated for PIT-tagged, hatchery-origin fall Chinook salmon adults that swam from Bonneville Dam to McNary Dam (BONMCN), McNary Dam to Ice Harbor Dam (MCNICH), and Ice Harbor Dam to Lower Granite Dam (ICHLGR). The lower whisker is the 2.5th percentile, the bottom of the box is the 25th percentile, the horizontal line in the box is the median, the circle in the box is the mean, the upper end of the box is the 75th percentile and the top whisker is the 97.5th percentile. The numbers above the 97th percentile are the sample sizes.

Figure 11. Upstream movement rates (km/d) of PIT-tagged, hatchery-origin fall Chinook salmon adults that swam from Bonneville Dam to McNary Dam plotted against the mean temperature measured in the tailrace of McNary Dam for each fish between detection at the two dams during 2010‒2015. Annual sample sizes are given in Figure 10.

Figure 12. The relation between the annual mean upstream movement rate (km/d) and annual mean temperature calculated from the data in Figure 11.

Table 4. Mean travel times of PIT-tagged, hatchery-origin fall Chinook salmon adults from Bonneville Dam to McNary Dam for fish that were and were not detected at Lower Granite Dam (i.e., successful [S] and unsuccessful [U] migrants). Fisher's test for honestly significant differences showed that every annual mean travel time (log_e transformed) of successful migrants was significantly (P < 0.05) shorter than the corresponding annual mean travel time of unsuccessful migrants. Results of logistic regression models fitted separately by year and jointly across years (All) to predict g(x) and calculate the probability of success P_i (set at 0.5; P_i = e^g(x) / 1 + e^g(x)) of individual fish from their travel times are given. The percentage of the known unsuccessful and successful migrants that were predicted to be successful by those models is also given.

		S		U		Mean travel time (±SD)			Models for predicting g(x)				Predicted S (%)
Year	N	n	%	n	%	S	U	P	βo ± SE	P	β1 ± SE	P	S	U
2010	2,398	2,299	95.9%	99	4.1%	6.3 ± 2.9	12.0 ± 14.3	< 0.0001	4.01 ± 0.16	< 0.0001	-0.11 ± 0.02	< 0.0001	99.9	91.9
2011	1,308	1,227	93.8%	81	6.2%	6.5 ± 2.6	10.9 ± 11.9	< 0.0001	3.79 ± 0.25	< 0.0001	-0.14 ± 0.03	< 0.0001	99.9	93.8
2012	2,316	2,164	93.4%	152	6.6%	6.1 ± 2.9	12.5 ± 14.2	< 0.0001	3.58 ± 0.14	< 0.0001	-0.12 ± 0.01	< 0.0001	99.5	90.1
2013	3,183	2,852	89.6%	331	10.4%	8.2 ± 5.1	10.5 ± 9.1	< 0.0001	2.62 ± 0.10	< 0.0001	-0.05 ± 0.01	< 0.0001	100.0	98.5
2014	2,642	2,494	94.4%	148	5.6%	6.1 ± 2.7	9.8 ± 10.8	< 0.0001	3.63 ± 0.15	< 0.0001	-0.11 ± 0.02	< 0.0001	100.0	93.9
2015	1,377	1,311	95.2%	66	4.8%	6.7 ± 3.2	11.3 ± 11.4	< 0.0001	3.88 ± 0.21	< 0.0001	-0.11 ± 0.02	< 0.0001	100.0	92.4
All	13,224	12,347	93.4%	877	6.6%	6.7 ± 0.9	11.2 ± 2.0

Figure 13. The relation between the annual percentages of the PIT-tagged, hatchery-origin fall Chinook salmon adults that migrated successfully between McNary and Lower Granite dams, and the annual mean temperature measured in the tailrace of Ice Harbor Dam from 12-Aug to 14-Sep, 2010‒2015.

Figure 14. Travel time distributions (across 2010‒2015) calculated for PIT-tagged, hatchery-origin fall Chinook salmon adults that swam upstream from Bonneville Dam to McNary Dam, and were subsequently detected or not detected at Lower Granite Dam (i.e., successful panel A and unsuccessful migrants panel B).

Figure 15. Pie charts showing the annual percentages (2010‒2015; charts A‒F, respectively) of the PIT-tagged, hatchery-origin fall Chinook salmon adults that did not migrate successfully from McNary to Lower Granite Dam (N = 877), but were last detected as permanent fallbacks downstream of McNary Dam, as mid-Columbia strays between McNary and Priest Rapids dams, as undershoots between Ice Harbor and Little Goose dams, or as upper Columbia strays at dams, within tributaries, or at hatcheries upstream of the Lower Snake River mouth.

Figure 16. The relation between the annual (2010‒2015) percentages of the PIT-tagged, hatchery-origin fall Chinook salmon adults that were identified as upper Columbia strays (Figure 15) and annual mean temperature measured in the tailrace of Ice Harbor Dam from 12-Aug to 14-Sep, 2010‒2015.

Figure 17. Examples of detection plots for natural-origin male (panel A), natural-origin female (panel B), and hatchery-origin female (panel C) fall Chinook salmon adults including the migratory phase, transition date and location, search phase, spawning site selection, and detections made after spawning site selection. The arrows next to y axis show the river km where the adults were released as Age-0 juveniles. The figure originally published in Connor and Garcia (2006) was provided for use by the editorial staff of Transactions of American Fisheries Society. The font was modified and color added.

Figure 18. The relation between travel time (d) from Lower Granite Dam to spawning site selection and day of the initiation of redd construction along the Upper and Lower Hells Canyon spawning areas combined and passage day of year (01/01 = 1) at the dam for radio-tagged fall Chinook salmon adults, 1998, 2000, and 2001. The data for the regression were collected by Connor and Garcia (2006).

Figure 19. An overhead example of a spawning site located along the Upper Hells Canyon spawning area including spawning substrate distribution (e.g., Figure 20), channel bathymetry, redd locations, and a sampling transect where depth, velocity, and substrate were measured to quantify spawning habitat. The figure originally published in Connor et al. (2001) was provided for use by the editorial staff of Northwest Science. The font was modified and color added.

Figure 20. Frequency distribution of combined dominant (left) and subdominant (right) substrate types observed at fall Chinook salmon redds in the Upper and Lower Hells Canyon spawning areas, 1993‒1995. The figure originally published in Groves and Chandler (1999) was provided for use by the editorial staff of Transactions of the American Fisheries Society. The font was modified and color added.

Figure 21. Frequency distribution of water depths measured at fall Chinook salmon redds in the Upper and Lower Hells Canyon spawning areas, 1993‒1995. Reproduced from Groves and Chandler (1999) with permission from the American Fisheries Society. The font was changed and color added.

Figure 22. Frequency distribution of mean water column (panel A) and substrate-level (panel B) velocities measured at fall Chinook salmon redds in the Upper and Lower Hells Canyon spawning areas, 1993‒1995. Reproduced from Groves and Chandler (1999) with permission from the American Fisheries Society. The font was changed and color added.

Figure 23. The post-spawn incubation environment according to the conceptual model of Geist and Dauble (1998) including downwelling (A) and upwelling (B) of surface water (i.e., river water), and ground water inflow (C). Not drawn to scale. The figure of the fish digging the redd was adapted from Burner (1951) with permission of the National Oceanic and Atmospheric Administration. The font was changed and color added.

Table 5. Embryo loss (%) from fertilization to button up (equivalent to fry emergence in the wild) and degree days above 20°C (DD>20) measured on female fall Chinook salmon fitted with temperature loggers at Ice Harbor Dam, trapped at Lower Granite Dam, and spawned at either Lyons Ferry or Nez Perce Tribal hatcheries during 2004 (from Mann, 2007). To calculate DD>20 in the middle stretch of the river system (i.e., observed), the daily mean temperature each fish was exposed to between Ice Harbor and Lower Granite dams was determined. If a daily mean temperature was greater than 20°C, 20 was subtracted from that mean to obtain a daily difference. The daily differences were summed to calculate DD>20 in the middle stretch. Bonneville Dam passage dates and DD>20 in the lower stretch of the river system were simulated (Eq. 14; Table A1) to provide data for fitting Eq. 15 (Table A1) that predicted embryo mortality from a spatially-extended value of DD>20.

	Passage date		DD>20
Tag code	Egg batch	Bonneville (simulated)	Ice Harbor (observed)	Lower stretch (simulated)	Middle stretch (observed)	Total	Embryo loss
2465	3051	18-Sep	28-Sep	0.00	0.00	0.00	2.5
25180	4245	20-Sep	30-Sep	0.00	0.00	0.00	2.2
25144	4378	12-Sep	21-Sep	0.00	0.00	0.00	2.7
25155	5087	12-Sep	21-Sep	0.00	0.00	0.00	2.8
25133	4095	01-Sep	09-Sep	2.52	0.04	2.56	1.4
25176	3028	25-Aug	02-Sep	5.08	0.71	5.79	1.4
25106	2095	24-Aug	01-Sep	5.77	0.94	6.71	1.7
25127	3129	24-Aug	01-Sep	5.77	1.04	6.81	1.9
25206	2013	24-Aug	01-Sep	5.77	1.42	7.19	3.4
2086	3002	23-Aug	31-Aug	6.51	1.54	8.05	1.5
25150	2137	22-Aug	30-Aug	7.68	2.40	10.08	9.0
25105	5031	19-Aug	26-Aug	12.80	3.91	16.71	8.3
2060	2145	18-Aug	25-Aug	14.30	4.15	18.45	3.8
2055	4036	19-Aug	26-Aug	12.80	6.94	19.74	5.9
25162^a	3007	07-Sep	16-Sep	0.00	0.00	0.00	19.8

^a Outlier removed from regression analysis.

Figure 24. The relation between degree days above 20°C (DD>20) calculated for the female parent and embryo loss measured from spawning to the button-up stage (equivalent to fry emergence in the wild). The equation was fitted by Mann (2007). The untransformed data are given in Table 5 (x = DD>20 in the middle stretch of the river system; y = observed embryo loss).

Figure 25. Embryo loss (%) predicted (± 95% CI) for the primary, secondary, and tertiary fall Chinook salmon spawning areas in the sub-watersheds that make up the upper stretch of the river system. The equation was: embryo loss (%) = -52.689 – 0.160*S_0.85 + 0.186*S_0.85S_0.85 (N = 8; r² = 0.89; P = 0.004); S0.85 was the mean percentage of fines less than 0.85 mm in diameter in each of the substrate samples collected by either Arnsberg et al. (1992) or Bennett et al. (2003). The prediction marked by an asterisk in panel was 105.1 ± 27.8%.

Figure 26. Stages of the model developed to simulate somatic energy use, migration success, and spawning success of PIT-tagged, hatchery-origin fall Chinook salmon adults during 2010‒2015.

Figure 27. The percentage of the apparent ocean age II, III, IV, and V PIT-tagged, hatchery-origin fall Chinook salmon adults that migrated successfully during Stage II modeling (i.e., McNary Dam forebay to Lower Granite Dam forebay) that were classified as successful spawners, 2010–2015. The numbers above the bars are the sample sizes of fish classified as successful spawners.

Figure 28. Pre-spawning mortality (%) distributions (5th, 25th, 50th, 75th, and 95th percentiles) for basin-level groupings of fall Chinook salmon calculated with empirical data from Bowerman et al. (2016) compared to the distributions calculated from simulations made with the somatic energy use model for the PIT-tagged, hatchery-origin fall Chinook salmon adults in the Upper Hells Canyon spawning area (UHC). The numbers above the 95th percentile are the sample sizes. Other abbreviations: CLR, Clearwater River lower reach, ID; KAL, Klamath Falls, OR; MCOL, Mid-Columbia, OR; PUG, Puget Sound, WA; SAC, Sacramento, CA; SJO, San Joaquin, CA. The data were provided by the corresponding author of Bowerman et al. (2016), except for the Clearwater River lower reach that were taken from Arnsberg et al. (2007, 2010) and Arnsberg and Kellar (2007a, 2007b, 2007c).

Figure 29. The percentages of the PIT-tagged, hatchery-origin fall Chinook salmon adults that were classified as unsuccessful spawners and fell into the pre-spawning or premature spawning mortality categories, 2010–2015. The numbers above the bar are the sample sizes of fish classified as unsuccessful spawners.

Figure 30. Simulated daily pre-spawning mortality rates (%) of PIT-tagged, hatchery-origin fall Chinook salmon adults along the Upper Hells Canyon spawning area, 2010–2015.

Figure 31. Standardized, simulated spawning initiation date distributions for PIT-tagged, hatchery-origin fall Chinook salmon adults classified as premature spawning mortalities and successful spawners (combined) compared to the actual distributions observed during the four annual redd survey intervals along the Upper Hells Canyon spawning area, 2010–2015 (data collected by the authors and their staff; e.g., Groves et al., 2013).

Figure 32. Standardized, simulated spawning initiation date distributions for PIT-tagged, hatchery-origin fall Chinook salmon adults that fell into the pre-spawning mortality category (had they survived to initiate spawning), into the category of premature spawning mortalities, or were classified as successful spawners, 2010–2015.

Figure 33. Annual mean (95% C.I.) cumulative temperature exposures (panel A) and expended useable energy (cumulative %; panel B) simulated during Stage I modeling (i.e., Bonneville Dam tailrace to McNary Dam forebay) for PIT-tagged, hatchery-origin fall Chinook salmon adults that were either successful or unsuccessful migrants from McNary Dam forebay to Lower Granite Dam forebay, 2010–2015. Sample sizes are given in Table 4.

Figure 34. Annual mean (95% C.I) day of passage at Lower Granite Dam (panel a; numbers in bars = n), simulated cumulative temperature exposures between Bonneville and Lower Granite dams (panel b), and simulated expended useable energy (cumulative %; panel c) during Stages I and II for PIT-tagged, hatchery-origin fall Chinook salmon adults that were classified as either successful or unsuccessful spawners, 2010–2015.

Figure 35. Annual cumulative temperature exposure indices for the PIT-tagged, hatchery-origin fall Chinook salmon adults that successfully migrated to Lower Granite Dam forebay, and were subsequently classified as either successful (S) or unsuccessful (U) spawners during 2010–2015. Sample sizes are given in Table 4.

Table 6. Logistic regression diagnostics for models fitted to predict the probability of a PIT-tagged, hatchery-origin fall Chinook salmon adult being a successful spawner based on fish weight at Bonneville Dam, and cumulative temperature exposure during Stages I, II, and II. Abbreviations: CUMDEGR, cumulative temperature exposure; S, successful spawner; U, unsuccessful spawner.

	AIC by model					N		Accuracy (%)
					Odds
Year	Null	Full	Parameter	β (SE)	ratio	S	U	S	U
2010	1,725.124	15.255	Intercept	1,149.500 (522.200)		2,014	285	100.0	99.7
			Weight at Bonneville	42.146 (35.823	> 999.999
			Stage I CUMDEGR	-0.638 (0.270)	0.529
			Stage II CUMDEGR	-0.541 (0.244)	0.582
			Stage III CUMDEGR	-1.218 (0.525)	0.296
2011	1,393.387	30.909	Intercept	74.987 (13.975)		915	312	100.0	100.0
			Weight at Bonneville	17.209 (3.166)	> 999.999
			Stage I CUMDEGR	-0.110 (0.024)	0.896
			Stage II CUMDEGR	-0.077 (0.015)	0.926
			Stage III CUMDEGR	-0.168 (0.031)	0.845
2012	2,495.398	330.403	Intercept	67.187 (6.270)		1,595	569	98.7	98.8
			Weight at Bonneville	8.142 (0.788)	> 999.999
			Stage I CUMDEGR	-0.057 (0.007)	0.945
			Stage II CUMDEGR	-0.058 (0.006)	0.944
			Stage III CUMDEGR	-0.102 (0.009)	0.903
2013	3,637.280	210.888	Intercept	84.508 (8.615)		1,898	954	99.4	98.7
			Weight at Bonneville	19.876 (1.924)	> 999.999
			Stage I CUMDEGR	-0.104 (0.010)	0.901
			Stage II CUMDEGR	-0.088 (0.009)	0.916
			Stage III CUMDEGR	-0.178 (0.017)	0.837
2014	1,874.508	235.664	Intercept	33.414 (3.544)		2,184	310	99.7	93.9
			Weight at Bonneville	9.706 (0.989)	> 999.999
			Stage I CUMDEGR	-0.045 (0.005)	0.956
			Stage II CUMDEGR	-0.041 (0.005)	0.960
			Stage III CUMDEGR	-0.074 (0.007)	0.929
2015	845.102	257.054	Intercept	16.483 (1.804)		1,182	129	98.7	73.6
			Weight at Bonneville	2.059 (0.223)	7.837
			Stage I CUMDEGR	-0.017 (0.003)	0.983
			Stage II CUMDEGR	-0.012 (0.002)	0.988
			Stage III CUMDEGR	-0.023 (0.002)	0.978

Figure 36. The mean (95% C.I.) total amount of simulated somatic energy used for swimming during tailrace-to-dam passage, reservoir passage, and pre-spawning movement events by PIT-tagged, hatchery-origin fall Chinook salmon adults classified as successful spawners expressed in kcal (panel A) and kcal/km/d (panel B), 2010–2015. Sample sizes are given in Table 4.

Figure 37. Median tailrace-to-dam passage time (d) of presumed upriver bright fall Chinook salmon adults at dams in the lower and middle stretches of the river system during 1998, 2000, and 2001. The inter-annual mean (±95%CI) are given above the bars. The data are from Keefer et al. (2004). Abbreviations: Bonneville, BON; The Dalles, DAL; John Day, JD; McNary, MCN; Ice Harbor, ICH;, Lower Monumental, LMN; Little Goose, LGS; and Lower Granite, LGR.

Figure 38. System-wide values of degree days above 20°C (DD>20) for PIT-tagged, hatchery-origin fall Chinook salmon adults that were classified as successful spawners by the somatic energy use model plotted against the observed dates of passage at Bonneville Dam of those adults, 2010‒2015.

Figure 39. The annual mean (±95% C.L.) number of degree day units above 20°C (DD>20) accumulated by PIT-tagged, hatchery-origin fall Chinook salmon adults that were classified as successful spawners by the somatic energy use model as they swam through the lower, middle, and upper stretches of the river system, 2010‒2015. The upper stretch was divided into Lower Granite Reservoir, Lower Hells Canyon, and Upper Hells Canyon.

Figure 40. Simulated embryo loss (%) due to exposure to degree days above 20°C for PIT-tagged, hatchery-origin fall Chinook salmon adults that were classified as successful spawners by the somatic energy use model plotted against the simulated spawning initiation dates of those adults along the Upper Hells Canyon spawning area, 2010‒2015.

Figure 41. Baseline (1991‒2006 average) and adjusted 2080 flows for Upper Hells Canyon from Hells Canyon Dam to the Imnaha River mouth. Refer to the Appendix to see how flows were simulated starting with information provided by Hamlet et al. (2010). The figure style is also attributed to Hamlet et al. (2010).

Figure 42. The baseline scenarios (1991‒2006 average), and 2080 average flow scenarios adjusted to match the pattern in the hydrograph in the baseline scenario, for Upper Hells Canyon from Hells Canyon Dam to the Imnaha River mouth (panel A), Upper Hells Canyon from the Imnaha River mouth to the Salmon River mouth (panel B), Lower Hells Canyon from the Salmon River mouth to Grande Ronde River mouth (panel C), Lower Hells Canyon from the Grande Ronde River mouth to the Clearwater River mouth (panel D), Lower Granite Dam (panel E), Ice Harbor Dam (panel F), and McNary Dam (panel G). Refer to the Appendix to see how flows were simulated starting with information provided by Hamlet et al. (2010).

Figure 43. Baseline (1991‒2006 average) and adjusted 2080 daily mean temperatures for Upper Hells Canyon (panel A), Lower Hells Canyon (panel B), Lower Granite Dam (panel C), Ice Harbor Dam (panel D), and McNary Dam (panel E). Refer to the Appendix to see how temperatures were simulated starting with information provided by Hamlet et al. (2010).

Figure 44. Simulated success rates (%) migration from Bonneville Dam to the Upper Hells Canyon spawning area, from Bonneville Dam to spawning completion, and from Bonneville Dam to fry emergence simulated for natural-origin fall Chinook salmon females under the baseline and 2080 scenarios, where N is the starting number of adults that arrived at Bonneville Dam and n is the number of adults that successfully completed each event given above the bars (except in the case of emergence; see text for description).

Table A1. The regression equations used in the somatic energy model and other models developed in this review. Abbreviation: LGR, Lower Granite.

Equation	Response variable	N	Study years	Intercepts and predictor variables	β (SE)	P (β = 0)	Model P	R^2/r^2
1^a	O2 consumption (mg/kg/h)^1,2	51		Intercept	-81.619(73.492)	0.272	< 0.0001	0.67
				Weight (kg)	-7.137(2.796)	0.014
				Temperature (°C)	11.591(3.663)	0.003
				Swimming speed (cm/s)	2.022(0.233)	< 0.0001
2^b	loge Weight (kg)	1,094	2004-2005	Intercept	0.794 (0.009)	< 0.0001	< 0.0001	0.94
				Predicted ocean age (years)	0.376(0.003)	< 0.0001
3^c	Mean velocity of the tailrace area (cm/s)	3^3		Intercept	33.933(2.885)	0.054	0.019	0.99
				Flow (KCFS)	0.362(0.011)	0.019
4^d	Mean cross- sectional reservoir velocity (cm/s)	2^4		Intercept	0.975
				Flow (KCFS)	0.119
5^e	Fork length (cm)	18		Intercept	52.633(2.352)	< 0.0001	< 0.0001	0.90
				Ocean age (years)	9.100(0.756)	< 0.0001
6^f	Energy content at	33	2002	Intercept	-131668.000		< 0.0001	0.86
	Bonneville Dam (kJ)			Fork length (cm)^5	2425.200
7^f	Energy threshold for death (kJ)	19	2002	Intercept	-1784.170		0.15	0.12
				Fork length (cm)^5	124.580
8^g	Elapsed days between LGR passage and spawning initiation	36	1998,	Intercept	197.792(10.468)	< 0.0001	0.005	0.31
			1999,	Passage date at	-0.568(0.147)	0.005
			2001	LGR Dam (day of year)
9^c	Mean velocity of the tailrace area (cm/s)	3^6		Intercept	12.825(0.041)	0.002	0.0003	1.0
				Flow (KCFS)	1.732(0.001)	0.0003
10A^i	Mean cross-sectional reservoir velocity (cm/s)	5^7		Intercept	2.379(1.404)	0.189	< 0.0001	0.99
				Flow (KCFS)	0.559(0.016)	< 0.0001
10B		5		Intercept	4.107(1.687)	0.093	< 0.0001	0.99
				Flow (KCFS)	0.577(0.019)	< 0.0001
10C		5		Intercept	5.145(2.289)	0.110	0.001	0.99
				Flow (KCFS)	0.568(0.026)	0.001
10D		5		Intercept	3.401(1.555)	0.117	0.001	0.99
				Flow (KCFS)	0.485(0.017)	0.001
				Intercept	1.092(0.912)	0.317	< 0.0001	0.99
				Flow (KCFS)	0.365(0.010)	< 0.0001
10E		5		Intercept	3.462(1.411)	0.091	0.001	0.99
				Flow (KCFS)	0.349(0.016)	0.001
10F		5		Intercept	2.818(1.665)	0.189	0.001	0.99
				Flow (KCFS)	0.313(0.019)	0.001
10G		5		Intercept	2.274(1.416)	0.207	0.001	0.99
				Flow (KCFS)	0.360(0.016)	0.001
10H		5		Intercept	3.761(2.380)	0.212	0.003	0.97
				Flow (KCFS)	0.248(0.027)	0.003
10I		5		Intercept	2.935(1.900)	0.220	0.003	0.96
				Flow (KCFS)	0.184(0.021)	0.003
10J		5		Intercept	3.037(2.159)	0.254	0.003	0.96
				Flow (KCFS)	0.212(0.024)	0.003
10K		5		Intercept	2.030(1.694)	0.317	0.002	0.98
				Flow (KCFS)	0.215(0.019)	0.002
10L		5		Intercept	3.377(1.067)	0.051	0.001	0.99
				Flow (KCFS)	0.247(0.012)	0.001
10M		5		Intercept	3.413(0.600)	0.011	0.001	0.99
				Flow (KCFS)	0.142(0.007)	0.001
10N		5		Intercept	2.710(0.349)	0.005	< 0.0001	0.99
				Flow (KCFS)	0.176(0.004)	< 0.0001
10O		5		Intercept	1.459(0.570)	0.083	0.001	0.99
				Flow (KCFS)	0.108(0.006)	0.001
11A^i	Mean cross-sectional transition zone velocity (cm/s)	5^8		Intercept	43.686(10.062)	0.023	0.001	0.98
				Flow	2.088(0.179)	0.001
11B		5		Intercept	11.819(4.929)	0.096	0.001	0.99
				Flow	1.850(0.088)	0.001
11C		5		Intercept	4.469(2.042)	0.116	< 0.0001	0.99
				Flow	1.145(0.036)	< 0.0001
11D		5		Intercept	-0.670(4.165)	0.882	0.001	0.99
				Flow	1.388(0.074)	0.001
11E		5		Intercept	0.235(4.151)	0.958	0.001	0.98
				Flow	1.001(0.074)	0.001
11F		5		Intercept	-2.383(5.949)	0.716	0.001	0.98
				Flow	1.279(0.106)	0.001
12A^g	Cumulative pre-spawning energy use	36	2010	Intercept	27826.000(4653.763)	< 0.0001	< 0.0001	0.78
				Passage date at LGR	-98.013(16.851)	< 0.0001
				Dam (day of year)
				Weight at LGR (kg)	601.212(85.206)	< 0.0001
12B		36	2011	Intercept	30940.000(5503.062)	< 0.0001	< 0.0001	0.77
				Passage date at LGR	-109.571(19.927)	< 0.0001
				Dam (day of year)
				Weight at LGR (kg)	698.572 (85.206)	< 0.0001
12C		36	2012	Intercept	27740.000(4783.819)	< 0.0001	< 0.0001	0.77
				Passage date at LGR	-97.797(17.322)	< 0.0001
				Dam (day of year)
				Weight at LGR (kg)	587.338(87.587)	< 0.0001
12D		36	2013	Intercept	28308.000(4947.572)	< 0.0001	< 0.0001	0.75
				Passage date at LGR	-100.249(17.322)	< 0.0001
				Dam (day of year)
				Weight at LGR (kg)	579.898(90.585)	< 0.0001
12E		36	2014	Intercept	27359.000(4700.228)	< 0.0001	< 0.0001	0.77
				Passage date at LGR	-96.220(17.020)	< 0.0001
				Dam (day of year)
				Weight at LGR (kg)	594.765(86.057)	< 0.0001
12F		36	2015	Intercept	27701.000(4691.733)	< 0.0001	< 0.0001	0.78
				Passage date at LGR	-97.363(16.989)	< 0.0001
				Dam (day of year)
				Weight at LGR (kg)	611.973(85.901)	< 0.0001
13A ^g	Cumulative °C between LGR passage and spawning initiation or pre-spawning mortality	36	2010^9	Intercept	5076.371(519.805)	< 0.0001	< 0.0001	0.67
				Passage date at	-16.227(1.940)	< 0.0001
				LGR Dam (day of year)
13B		36	2011^9	Intercept	5081.570(520.497)	< 0.0001	< 0.0001	0.67
				Passage date at	-16.247(1.943)	< 0.0001
				LGR Dam (day of year)
13C		36	2012^9	Intercept	5156.337(524.105)	< 0.0001	< 0.0001	0.68
				Passage date at	-16.550(1.956)	< 0.0001
				LGR Dam (day of year)
13D		36	2013^9	Intercept	5257.318(508.689)	< 0.0001	< 0.0001	0.70
				Passage date at	-17.043(1.899)	< 0.0001
				LGR Dam (day of year)
13E		36	2014^9	Intercept	5304.329(531.548)	< 0.0001	< 0.0001	0.68
				Passage date at	-16.989(1.984)	< 0.0001
				LGR Dam (day of year)
13F		36	2015^9	Intercept	5253.356(553.124)	< 0.0001	< 0.0001	0.66
				Passage date at	-16.713(2.064)	< 0.0001
				LGR Dam (day of year)
14	Passage date at Bonneville dam (day of year)	12,299^10	2010‒2015	Intercept	9.024(0.808)	< 0.0001	< 0.0001	0.88
				Passage date at	0.931(0.003)	< 0.0001	< 0.0001	0.99
				Ice Harbor Dam (day of year)
15	Embryo loss (%)^k	14	2004	Intercept	1.864(0.823)	0.044	0.023	0.36
				Degree days > 20^l	0.220(0.084)	0.023
16	Fecundity^m	10		Intercept	-7419.581(3294.576)	0.050	0.006	0.64
				FL (mm)	16.288(4.322)	0.006

^a Raw data were a provided by the corresponding author of Geist et al. (2000a).

^b FL and weight data collected on upriver brights at Bonneville Dam were provided by the corresponding author of Keefer et al. (2004) and ocean age of each of the fish was predicted with the supplemental regression equation: ocean age = -4.909 + 0.099*FL (r² = 0.90; N = 18; P < 0.0001) fitted with unpublished data collected at Lyons Ferry Hatchery during 2010–2015.

^c Mean velocities of the tailrace area were visually approximated from 2-D tailrace velocity versus discharge figures in Rakowski et al. (2010) for Bonneville, The Dalles, John Day, and McNary dams and then used in regression as described in footnote 3 below.

^d Raw data were provided by the corresponding author of Tiffan et al. (2006) and used in regression as described in footnote 4 below.

^e Unpublished data collected at Lyons Ferry Hatchery.

^f Mann et al. (2009).

^g Raw data from Connor and Garcia (2006).

^h Mean velocities in the tailrace area were visually approximated from the 2-D tailrace velocity versus discharge figures in Rakowski et al. (2010) for Ice Harbor, Lower Monumental, Little Goose, and Lower Granite dams and then used in regression as described in footnote 6 below.

ⁱ Equation from Tiffan et al. (2009) used as described in footnote 7 below.

^j Equation set was obtained from the corresponding author of Tiffan et al. (2009), and used as described in footnote 8 below.

^k From Mann (2007) reported in main body Table 5.

^l DD>20 was the sum of the simulated and observed levels of DD>20 (i.e., total) reported in main body Table 5.

^m From Quinn and Bloomberg (1992).

¹ Energy use (kcal/kg/d) = (O₂ consumption [mg/kg/h] * weight [kg] * (travel time [d] * 24[h]) * 3.25)/ weight [kg] / travel time [d] / 1000 where 3.25 is the an oxygen to caloric conversion factor (after Geist et al. 2000a from Brafield and Solomon 1972).

² Energy use (kcal) = energy use (kcal/kg/d) * weight (kg) * travel time (d).

³ Rakowski et al. (2010) modeled velocity in the tailraces of the four Columbia River dams at flows of 150, 250, and 300 KCFS, and the modeled velocities at each flow were averaged across dams to provide three mean velocities to regress against those three flows measured in the tailrace of McNary Dam for Stage II modeling.

⁴ Tiffan et al. (2006) measured mean cross-sectional velocity within 21 longitudinal sections of John Day Reservoir at flows of 156 and 300 KCFS, and a mean cross-sectional velocity weighted based on the length of the reservoir represented by each section was calculated to provide two weighted mean velocities to interpolate against the two flows measured in McNary Dam tailrace for Stage II modeling.

⁵ Fork length for the PIT-tagged fish was estimated with Eq 5.

⁶ Rakowski et al. (2010) modeled velocity in the tailraces of the four Snake River dams at flows of 19, 30, and 85 KCFS, and the velocities at each flow were averaged across dams to provide three mean velocities to regress against those three flows measured at Ice Harbor Dam for Stage II modeling.

⁷ Tiffan et al. (2009) measured mean cross-sectional velocities at 16 transects spaced at 3 km intervals from Lower Granite Dam forebay to the upper end of Lower Granite Reservoir at flows of 14.3, 32.1, 48.9, 82.4, and 172.3 KCFS, and the average of the 16 mean cross-sectional velocities predicted using the regression equations for each of the 16 transects was taken to represent velocities in the Ice Harbor, Lower Monumental, and Little Goose Reservoirs in the Stage II modeling. When a radio-tagged fish used to create the pre-spawning movement templates passed the location of the transect, the predicted velocity for that transect was included in the calculation of the distance-weighted velocity for the fish for Stage III modeling.

⁸ Tiffan et al. (2009) measured mean cross-sectional velocities at 5 transects spaced at 3 km intervals from the upper end of Lower Granite Reservoir to the upper end of the transition zone at flows of 12.4, 16.3, 37.4, 57.7, and 103 KCFS. When a radio-tagged fish used to create the pre-spawning movement templates passed the location of the transect the estimated velocity for that transect was included in the calculation of the distance and time weighted velocity for the fish for Stage III modeling.

⁹ Cumulative temperature exposure was calculated for each of the 36 fish used to form the movement templates by multiplying the mean temperature measured between tracking events, by the number of days represented by the tracking event, and summing the resulting products across tracking events.

¹⁰ The sample size of PIT-tagged adults that successfully migrated from Bonneville Dam to Lower Granite Dam and were also detected passing Ice Harbor Dam.

Figure 45. Effective spawn timing distributions simulated for natural-origin fall Chinook salmon females along the Upper Hells Canyon spawning area under the baseline and 2080 scenarios, where N is the total number of fish classified as successful spawners expressed in adult equivalents (see text), and n is the total number of adult equivalents in each spawning interval given above the bars.

Table A2. A movement template for a hatchery-origin female adult that had been PIT-tagged and released upstream of Lower Granite Dam as a subyearling in 1999, radio tagged at Lower Granite Dam (rkm 173) as a 68-cm FL (measured), 3.3 kg (predicted¹) adult female in 2001, tracked to the lower end of the spawning grounds 0.4 d after being released at the dam, and then tracked to a spawning site (rkm 379.2) along the Upper Hells Canyon spawning area where it was assumed to have initiated redd construction. Distance and time weighted velocities and temperatures for 2010 were entered into the template. Abbreviation: DOY.h/24, day of year.hour divided by 24.

Tracking			Speed (cm/s)				O2 consumption	Energy use
Date	DOY.h/24	rkm	Fish	Water	Swimming	Temperature (°C)	(mg/kg/h)	kcal/kg/d	kcal	Cumulative
30-Sep	273.38	173.0
01-Oct	274.21	240.7	94	31	125	18.3	361	28	101
01-Oct	274.78	270.5	61	131	166	19.1	451	35	86	187
03-Oct	276.53	316.3	30	127	132	19.2	385	30	227	414
04-Oct	277.62	342.7	28	133	134	19.4	391	30	143	557
05-Oct	278.3	345.8	5	219	180	19.2	482	38	110	667
09-Oct	282.38	345.8	0	80	80	18.9	276	22	378	1045
11-Oct	284.49	316.3	16	135	16	18.6	143	11	102	1147
13-Oct	286.65	316.3	0	80	80	18.1	267	21	194	1341
15-Oct	288.44	345.8	19	116	112	17.7	327	25	197	1537
23-Oct	296.73	345.8	0	80	80	16.9	253	20	704	2241
24-Oct	297.65	316.3	37	116	37	16.5	161	13	50	2291
27-Oct	300.64	316.3	0	80	80	16.0	242	19	243	2535
29-Oct	302.43	345.8	19	116	112	15.7	304	24	183	2717
01-Nov	305.28	379.2	14	108	100	15.2	272	21	261	2979

¹ Weight at Bonneville Dam was estimated using the equation log_e(WT) = -11.04346 * 2.96350*log_e(FL) fitted from unpublished data collected on presumed upriver bright fall Chinook salmon at Bonneville Dam and provided by the corresponding author of Keefer et al. (2004; N = 1,117, r² = 0.94, P < 0.001), and then the weight at Lower Granite Dam was calculated by subtracting ≈ 1.0 kg (0.002279 kg/km traveled from Bonneville Dam to Lower Granite Dam; Mann et al., 2009) from the estimated weight at Bonneville Dam.

Table A3. The historical combined monthly average total runoff and base flows for the Snake River basin upstream of Hells Canyon Dam expressed as an average depth (inches); the average, minimum, maximum value of that combined monthly average from the GCM for the B1 greenhouse gas scenario; and the adjustment statistics (historical divided by the average, minimum, or maximum values) for each month used to adjust the 2080 daily simulation flows for expected hydropower operations for Upper Hells Canyon from Hells Canyon Dam to the Imnaha River mouth. Details are given in Hamlet et al. (2010). The data were downloaded from http://warm.atmos.washington.edu/2860/products/sites/?site = 4010 (Available May 2017).

		From the GCM models			Adjustment statistics
Month	Historical	Average	Minimum	Maximum	Average	Minimum	Maximum
October	0.116	0.115	0.098	0.140	1.009	1.184	0.829
November	0.138	0.165	0.125	0.190	0.836	1.104	0.726
December	0.163	0.238	0.179	0.337	0.685	0.911	0.484
January	0.170	0.279	0.199	0.388	0.609	0.854	0.438
February	0.185	0.323	0.220	0.475	0.573	0.841	0.389
March	0.310	0.428	0.361	0.489	0.724	0.859	0.634
April	0.478	0.552	0.484	0.699	0.866	0.988	0.684
May	0.554	0.484	0.416	0.563	1.145	1.332	0.984
June	0.387	0.274	0.227	0.325	1.412	1.705	1.191
July	0.198	0.154	0.133	0.175	1.286	1.489	1.131
August	0.122	0.111	0.098	0.125	1.099	1.245	0.976
September	0.104	0.099	0.084	0.113	1.051	1.238	0.920

Table A4. The series of equations that were used to calculate simulation flows under the 2080 climate change scenario. Abbrevations: Q^, location-specific equation; 2080 Qsimadj, daily flow data adjusted for 2080 conditions assuming the dam could be operated to match the baseline hydrograph pattern; 2080 Qsim, daily flow data adjusted for 2080 conditions in an unregulated tributary. The locations are shown in Figure 1.

Equation	Location	2080 simulation flow calculations
Eq. 1Q^	Hells Canyon Dam to the Imnaha	Hells Canyon Dam2080 Qsimadj
Eq. 2Q^	Imnaha to Salmon	Eq. 1Q^ + Imnaha2080Qsim
Eq. 3Q^	Salmon to Grande Ronde	Eq. 2Q^ + Salmon2080Qsim
Eq. 4Q^	Grande Ronde to Clearwater	Eq. 3Q^ + Grande Ronde 2080Qsim
Eq. 5Q^	Clearwater lower reach	Clearwater upper2080Qsim + Dworshak Dam2080 Qsimadj
Eq. 6Q^	Lower Granite Reservoir	Eq.4Q^ + Eq. 5Q^
Eq. 7Q^	Palouse	Palouse2080Qsim
Eq. 8Q^	Tucannon	Tucannon2080Qsim
Eq. 9Q^	Ice Harbor Dam	Eq.6Q^ + Eq. 7Q^ + Eq. 8Q^
Eq. 10Q^	Hanford Reach to Yakima	Priest Rapids Dam2080 Qsimadj
Eq. 11Q^	Yakima at Kiona	Eq. 10Q^ + Yakima2080 Qsimadj
Eq. 12Q^	McNary Dam	Eq. 9Q^ + Eq. 10Q^ + Eq. 11Q^

Table A5. Information on regression equations fitted to predict baseline monthly average water temperatures at the locations required for simulating migration and spawning success of Snake River fall Chinook salmon within the Upper Hells Canyon spawning area from historical monthly average air temperatures predicted from meteorological data and the GCM models by Hamlet et al. (2010). The historical air temperatures were downloaded from http://warm.atmos.washington.edu/2860/products/sites/?site = 4010 (Available May 2017).

	January‒July models						August‒December models
Location	N	Parameter	β	SE	r^2	P	N	Parameter	β	SE	r^2	P
Upper Hells Canyon	7	Intercept	6.234	0.390	0.986	<0.0001	5	Intercept	10.214	0.792	0.968	0.0024
		Air temperature	0.704	0.037				Air temperature	0.697	0.073
Imnaha River	7	Intercept	6.362	0.601	0.962	< 0.0001	5	Intercept	5.382	0.121	0.999	< 0.0001
		Air temperature	0.778	0.069				Air temperature	0.987	0.013
Salmon River	7	Intercept	7.902	0.490	0.974	< 0.0001	5	Intercept	7.929	0.050	0.999	< 0.0001
		Air temperature	0.794	0.059				Air temperature	0.971	0.006
Grande Ronde River	7	Intercept	5.326	0.566	0.978	< 0.0001	5	Intercept	4.007	0.363	0.997	< 0.0001
		Air temperature	0.935	0.063				Air temperature	1.112	0.037
Lower Hells Canyon	7	Intercept	6.289	0.360	0.987	< 0.0001	5	Intercept	8.819	0.470	0.990	0.0004
		Air temperature	0.706	0.036				Air temperature	0.788	0.045
Clearwater River	7	Intercept	5.688	0.244	0.988	< 0.0001	5	Intercept	6.262	0.734	0.945	0.0056
		Air temperature	0.544	0.027				Air temperature	0.550	0.077
Lower Granite Dam	7	Intercept	5.880	0.297	0.990	< 0.0001	5	Intercept	7.906	0.729	0.974	0.0018
		Air temperature	0.669	0.030				Air temperature	0.742	0.071
Ice Harbor Dam	7	Intercept	6.129	0.339	0.988	< 0.0001	5	Intercept	10.195	0.901	0.953	0.9533
		Air temperature	0.678	0.034				Air temperature	0.677	0.087
McNary Dam	7	Intercept	6.733	0.478	0.973	< 0.0001	5	Intercept	11.028	0.627	0.973	0.0019
		Air temperature	0.682	0.051				Air temperature	0.676	0.065

Table A6. The historical monthly average air temperatures (°C) predicted from meteorological data and the GCM models by Hamlet et al. (2010) for the Snake River basin upstream of Hells Canyon Dam, baseline monthly average water temperatures (°C) measured in Upper Hells Canyon during 1991‒2006, and the baseline monthly average water temperatures in Upper Hells Canyon predicted with the January‒July and August‒December regression equations in Table A5. The average, minimum, maximum values of the 2080 monthly average air temperatures were taken from the GCMs using the B1 greenhouse gas scenario and used to predict 2080 monthly average water temperatures with those regression equations. Adjustment statistics (predicted baseline monthly average water temperatures divided by the predicted 2080 monthly average water temperatures) are also given. Details are reported in Hamlet et al. (2010). The data were downloaded from http://warm.atmos.washington.edu/2860/products/sites/?site = 4010 (Available May 2017).

	From the GCM models
			Predicted	2080 air °C			Predicted 2080 water °C			Adjustment statistics
	Historical	Baseline	baseline
Month	air °C	water °C	water °C	Average	Minimum	Maximum	Average	Minimum	Maximum	Average	Minimum	Maximum
January	-4.9	4.2	2.8	-2.2	-3.8	-0.4	4.7	3.6	6.0	0.593	0.783	0.468
February	-2.5	3.6	4.5	0.5	-2.0	2.1	6.6	4.8	7.7	0.681	0.927	0.580
March	0.6	5.9	6.7	3.3	1.9	4.7	8.6	7.6	9.5	0.778	0.879	0.698
April	5.4	9.9	10.0	8.1	6.9	12.0	12.0	11.1	14.7	0.839	0.905	0.684
May	10.3	13.4	13.5	12.9	11.7	14.6	15.3	14.5	16.5	0.880	0.932	0.817
June	14.4	16.7	16.4	17.6	15.8	18.4	18.6	17.4	19.2	0.880	0.943	0.853
July	19.7	20.2	20.1	23.0	21.0	24.3	22.4	21.0	23.3	0.897	0.956	0.861
August	18.5	21.8	23.1	22.2	20.1	23.6	25.7	24.2	26.7	0.900	0.954	0.867
September	13.4	20.5	19.6	16.8	15.0	18.2	22.0	20.7	22.9	0.891	0.946	0.854
October	7.5	16.5	15.4	10.1	8.8	10.8	17.2	16.4	17.7	0.895	0.945	0.870
November	0.7	11.1	10.7	3.1	1.8	4.2	12.3	11.5	13.1	0.867	0.933	0.814
December	-3.2	6.9	8.0	-0.8	-2.2	0.5	9.7	8.7	10.6	0.825	0.920	0.756

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