Supplemental Material Journal of Hydrometeorology Linking Atmospheric Rivers to Annual and Extreme River Runoff in British Columbia and Southeastern Alaska https://doi.org/10.1175/JHM-D-19-0281.1 © Copyright 2020 American Meteorological Society Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. All AMS journals and monograph publications are registered with the Copyright Clearance Center (http://www.copyright.com). Questions about permission to use materials for which AMS holds the copyright can also be directed to [email protected]. Additional details are provided in the AMS Copyright Policy statement, available on the AMS website (http://www.ametsoc.org/CopyrightInformation). 1 Supplemental Material for 2 Linking atmospheric rivers to annual and extreme river runoff in British Columbia and 3 southeastern Alaska 4 A.R. Sharma1 and S. J. Déry2 5 1Natural Resources and Environmental Studies Program, 6 University of Northern British Columbia, Prince George, British Columbia, Canada 7 2Environmental Science and Engineering Program, 8 University of Northern British Columbia, Prince George, British Columbia, Canada 9 Contents of this file 10 Figures S1 to S9 11 Tables S1 and S2 Supplementary M a t e r i a l | i 12 13 Figure S1: Time series of annual and seasonal maximum runoff for three selected 14 watersheds representing different hydrological regimes across BCSAK (Figure 1), WYs 15 1979-2016. The black dots indicate the AR-related maximum runoff values. The scales of 16 the y-axes are different for each panel. Supplementary M a t e r i a l | ii 17 18 Figure S2: (a) Distribution of the percentage of AR contribution to annual WY runoff in the 19 pluvial San Juan River using a first order estimate based on total Water Year (WY) 20 precipitation within the watershed and a direct calculation of the percentage of AR-related 21 runoff, WYs 1979-2012. White dots show the average contribution percentage, black 22 horizontal solid lines denote medians, vertical lines show the range in the contribution Supplementary M a t e r i a l | iii 23 percentage excluding outliers, and black dots show outliers defined as values >1.5 times 24 the interquartile range of the corresponding AR contribution percentage. Of note, direct 25 calculation of the AR-related runoff is only valid for pluvial watersheds because of the lag 26 between AR-related precipitation falling as snow and runoff in the nival, glacial, and the 27 hybrid watersheds. (b) Difference between the ratio of AR-related to total WY runoff and 푅 푃 28 the ratio of AR-related to total WY precipitation i.e., 퐴푅 − 퐴푅 in the pluvial San Juan 푅푇푂푇 푃푇푂푇 29 River, WYs 1979-2012. Supplementary M a t e r i a l | iv 30 31 Figure S3: Mean annual runoff (×103 mm year-1) at 168 hydrometric stations across 32 BCSAK, WYs 1979-2016. Supplementary M a t e r i a l | v 33 34 Figure S4: Standard deviation (SD) of the contribution of ARs to total annual runoff (%) 35 across BCSAK, WYs 1979-2012. Supplementary M a t e r i a l | vi 36 37 Figure S5: Percentage of AR-related annual maximum runoff due to direct contribution of 38 extreme precipitation within the extreme runoff day or previous six days across BCSAK, 39 WYs 1979-2012. Supplementary M a t e r i a l | vii 40 41 Figure S6: AR linkages to seasonal daily maximum runoff across BCSAK, WYs 1979-2016. Supplementary M a t e r i a l | viii 42 43 Figure S7: Temporal change in AR-related AM runoff percentage across BCSAK, WYs 44 1979-2016 as given by the Mann-Kendall trend test. The change over time is decreasing or 45 increasing if the p <0.05 otherwise there is no change. Supplementary M a t e r i a l | ix 46 47 Figure S8: Temporal change in AR-related seasonal daily maximum runoff across BCSAK, 48 WYs 1979-2016 as given by the Mann-Kendall trend test. The change over time is 49 increasing or decreasing if the p <0.05 otherwise there is no change. Supplementary M a t e r i a l | x 50 51 Figure S9: Mean daily air temperatures at different elevation grid cells during AR and 52 non-AR spring maximum runoff days for three selected watersheds representing the 53 pluvial, nival, and glacial hydrological regimes. Vertical solid lines show 0°C. Supplementary M a t e r i a l | xi 54 Table S1: Hydrometric stations identification number (Figure 1), coordinates, gauged area, daily mean and maximum runoff 55 and coefficient of variation (CV) for WYs 1979-2016 in BCSAK. STATION DAILY DAILY DAILY MEAN MEAN GAUGED GLACIER DAILY Nested STATION NUMBER LAT. LON. SLOPE MEAN MEAN MAXIMUM ANNUAL RIVER ELEVATION AREA COVERAGE MAXIMUM (Y=Yes, ID REFERENCED (°N) (°W) (°) RUNOFF RUNOFF RUNOFF RUNOFF (m) (km2) (%) RUNOFF CV N=No) TO FIGURE 1 (mm day-1) CV (mm day-1) (mm year-1) COASTAL BC AND SOUTHEASTERN ALASKA SALMON R NR A008000 146 56.0 130.1 1228 277 37.00 23.1 9.39 0.16 170.80 0.91 3397 N HYDER LEMON C NR A052000 159 58.4 134.4 1009 32 48.00 23.3 12.82 0.04 123.92 0.30 4815 N JUNEAU MENDENHALL R A052500 160 58.4 134.6 1009 220 56.00 23.3 13.31 0.02 110.53 0.21 4936 N NR AUKE BAY TAIYA R NR A056210 166 59.5 135.3 1069 461 29.00 23.5 6.42 0.03 37.53 0.14 2340 N SKAGWAY FISH C NR A072000 134 55.4 131.2 389 90 NA 23.7 11.58 0.03 91.38 0.16 4269 N KETCHIKAN OLD TOM C NR A085100 135 55.4 132.4 331 16 NA 23.8 6.49 0.04 84.88 0.23 2546 N KASAAN STIKINE RIVER 08CE001 AT TELEGRAPH 157 57.9 131.2 1368 29300 1.66 2.5 1.21 0.03 8.72 0.15 451 Y CREEK STIKINE RIVER 08CF003 NEAR 153 56.7 132.1 1286 51600 NA 2.8 2.65 0.02 11.90 0.13 971 N WRANGELL ISKUT RIVER 08CG001 BELOW 155 56.7 131.7 1227 9350 NA 2.9 4.26 0.02 32.23 0.34 1583 Y JOHNSON RIVER SURPRISE 08DA005 CREEK NEAR 147 56.1 129.5 1276 221 35.73 2.9 6.11 0.03 42.89 0.30 2290 Y THE MOUTH NASS RIVER 08DB001 ABOVE SHUMAL 133 55.3 129.1 1091 18500 11.79 3.4 3.65 0.02 23.86 0.28 1328 N CREEK NANIKA RIVER 08ED001 AT OUTLET OF 108 53.9 127.5 1306 741 10.10 3.9 3.39 0.02 20.75 0.16 1238 Y KIDPRICE LAKE MORICE RIVER 08ED002 117 54.1 127.4 1254 1910 10.76 4.3 3.41 0.02 16.38 0.06 1230 Y NEAR HOUSTON BUCK CREEK AT 08EE013 122 54.4 126.7 1120 580 NA 4.9 0.65 0.05 10.77 0.17 237 Y THE MOUTH SKEENA RIVER 08EF001 129 54.6 128.4 1121 42200 1.47 5.2 1.85 0.02 14.54 0.13 681 N AT USK ZYMOETZ 08EF005 RIVER ABOVE 124 54.5 128.3 1179 2980 4.69 5.2 3.07 0.03 25.24 0.41 1117 N O.K. CREEK EXCHAMSIKS 08EG012 RIVER NEAR 121 54.4 129.3 878 370 14.07 5.2 10.18 0.03 98.08 0.22 3732 N TERRACE Supplementary M a t e r i a l | xii WANNOCK RIVER AT 08FA002 84 51.7 127.2 1209 3940 23.22 5.8 7.12 0.02 36.13 0.20 2518 N OUTLET OF OWIKENO LAKE SALLOOMT 08FB004 RIVER NEAR 91 52.4 126.5 1123 161 5.89 6.3 4.74 0.03 43.57 0.35 1686 N HAGENSBORG ATNARKO 08FB006 RIVER NEAR 89 52.4 126.0 1436 2430 0.70 6.3 1.02 0.01 8.06 0.11 351 Y THE MOUTH BELLA COOLA RIVER ABOVE 08FB007 90 52.4 126.2 1491 3730 10.55 7.2 2.16 0.02 11.61 0.17 763 N BURNT BRIDGE CREEK KEMANO RIVER ABOVE 08FE003 105 53.6 127.9 1169 583 13.19 7.6 6.87 0.03 63.45 0.37 2500 N POWERHOUSE TAILRACE KITIMAT RIVER 08FF001 BELOW HIRSCH 112 54.0 128.7 830 1990 4.48 7.7 5.74 0.03 56.86 0.38 2083 N CREEK HIRSCH CREEK 08FF002 NEAR THE 113 54.1 128.6 940 347 1.45 8.4 5.42 0.03 67.97 0.43 1997 Y MOUTH LITTLE WEDEENE 08FF003 RIVER BELOW 118 54.1 128.7 762 182 0.97 9.2 7.95 0.04 81.57 0.39 3059 Y BOWBYES CREEK HOMATHKO 08GD004 RIVER AT THE 62 51.0 124.9 1645 5720 22.35 9.2 4.10 0.02 24.13 0.26 1489 N MOUTH HOMATHKO RIVER AT INLET 08GD008 81 51.7 124.4 1453 500 0.47 9.4 0.31 0.02 2.40 0.23 113 Y TO TATLAYOKO LAKE KLINAKLINI RIVER EAST 08GE002 CHANNEL 66 51.1 125.6 1511 5780 19.81 9.5 4.51 0.03 22.04 0.31 1637 N (MAIN) NEAR THE MOUTH CHEMAINUS 08HA001 RIVER NEAR 3 48.9 123.7 642 355 NA 9.9 4.60 0.06 81.34 0.27 1661 N WESTHOLME KOKSILAH RIVER AT 08HA003 2 48.7 123.7 458 209 NA 10.5 4.00 0.08 71.45 0.19 1451 N COWICHAN STATION SAN JUAN 08HA010 RIVER NEAR 1 48.6 124.3 547 580 NA 10.6 7.21 0.06 104.85 0.19 2587 N PORT RENFREW ENGLISHMAN 08HB002 RIVER NEAR 27 49.3 124.3 576 324 NA 10.8 3.59 0.08 66.01 0.28 1316 N PARKSVILLE Supplementary M a t e r i a l | xiii SARITA RIVER 08HB014 NEAR 4 48.9 125.0 414 162 NA 10.8 10.52 0.04 198.59 0.31 3798 N BAMFIELD OYSTER RIVER BELOW 08HD011 47 49.9 125.2 914 298 0.51 10.9 4.02 0.05 53.19 0.26 1473 N WOODHUS CREEK ZEBALLOS 08HE006 RIVER NEAR 51 50.0 126.8 728 181 0.15 10.9 12.23 0.05 215.01 0.32 4285 N ZEBALLOS TSITIKA RIVER BELOW 08HF004 57 50.4 126.6 779 360 NA 10.9 5.44 0.05 76.54 0.36 1999 N CATHERINE CREEK LAVENTIE 08JA015 CREEK NEAR 106 53.6 127.5 1432 87 19.47 11.1 5.41 0.05 64.99 0.45 1939 N THE MOUTH NAHATLATCH RIVER BELOW 08MF065 49 50.0 121.9 1487 715 2.54 14.5 4.34 0.02 28.98 0.14 1583 N TACHEWANA CREEK COQUIHALLA RIVER ABOVE 08MF068 28 49.4 121.4 1205 720 NA 14.8 3.83 0.02 35.76 0.40 1380 N ALEXANDER CREEK CHEHALIS RIVER NEAR 08MG001 26 49.3 121.9 839 383 0.20 14.8 8.69 0.05 93.33 0.23 3139 N HARRISON MILLS LILLOOET 08MG005 RIVER NEAR 55 50.3 122.8 1551 2160 19.22 15.0 5.03 0.02 29.38 0.28 1786 Y PEMBERTON HARRISON RIVER NEAR 08MG013 25 49.3 121.8 1289 7870 8.25 15.0 4.87 0.01 18.62