Upper Colorado River Basin WY 2011 Water Supply

Upper Colorado River Basin WY 2011 Water Supply Forecast Verification CBRFC 2011 Stakeholder Forum November 3, 2011

Green River Basin Upper Green Duchesne Yampa • Slightly above normal seasonal precipitation through March 2011 • Sustained cool and wet period April-June • Runoff delayed (especially to the north and west) • Many record or near records for precipitation, runoff volumes, etc

Upper Green Basin Conditions 160 % 120 % 115 % • Two new records for April-July volume at points coming off the north slope of the Uintas.

1926 162%

Duchesne Basin Conditions 145 % 215 % • 10/16 forecast points set records for April-July volume.

158 268%

Yampa Basin Conditions • Record Snowpack • All forecast points set records for April. July volume.

1988 201%

881 241%

Elk River nr Milner……. the Record Breaker!! Record Snow Record (42 yr) Volume: 742 KAF Old Record : 552 KAF Record (42 yr) Peak: 7110 cfs

Green River Basin Records LOCATION East Fork of Smiths Fork Blacks Fork nr Robertson Yampa abv Stagecoach Yampa at Steamboat Springs Elk nr Milner Elk Head nr Hayden Yampa at Maybell Little Snake nr Slater Little Snake at Dixon Little Snake at Lily White River nr Meeker West Fork Duchesne nr Tabiona Upper Stillwater-Rock Creek Strawberry nr Solider Springs Lake Fork- Moon Lake Yellowstone nr Altonah Duchesne-Myton Duchesne-Randlett Green River-Green River, UT NEW RECORD OLD RECORD % DIFF OLD RECORD YEAR 64 202 69 507 742 171 1988 353 775 881 521 44 217 153 186 158 127 125 824 1011 6490 RED=Single Month Volume > April-July Average *POR after regulation 57 125 56 506 552 119 1921 281 754 790 519 38 189 136 158 137 112 114 766 942 5856* 12% 62% 23% 0% 34% 44% 3% 26% 3% 12% 0% 16% 15% 13% 18% 15% 13% 10% 8% 7% 11% 1983 1975 1997 1984 1917 1997 1984 1984 1986 1952 1986 2005 1952 1983 White/Yampa=10 /10 Duchesne=10/16

Upper Colorado Basin Mainstem Gunnison Dolores • Slightly above normal seasonal precipitation through March 2011 • Sustained cool and wet period April-June • Many record or near records for precipitation, runoff volumes, etc • Precipitation and runoff volumes greater to the north (e. g. Granby, Dillon, etc) and less to the south (e. g. Gunnison) and still less in the Dolores

Upper Colorado Mainstem Basin Conditions As of July 1, 2011 As of August 1, 2011

Record Runoff 428 190% 343 (1984) 225

276 (1984) 268 161% 167

577 172% 4489 (1984) 4200 174% 2420 1026 145%

Upper Colorado Mainstem 2011 Volumes Lake Granby Willow Creek Res Fraser - Winter Park Williams Fork Res Dillon Res Green Mountain Res Wolford Mountain Res Colorado - Kremmling Eagle - Gypsum Colorado - Dotsero Ruedi Res Roaring Fork - Glenwood Colorado - Cameo Plateau Ck - Cameo Colorado - Cisco Lake Powell April - July 2011 Volume (kaf) % avg 428 190% 125 245% 32 159% 155 163% 268 161% 468 167% 114 190% 1, 767 203% 577 172% 2, 720 189% 218 154% 1, 026 145% 3, 730 173% 4, 200 174% 164 142% 6, 894 148% 12, 920 163% Ranking 1 / 84 1 / 92 2 / 41 2 / 52 3 / 74 1 / 30 1 / 41 2 / 65 1 / 71 2 / 42 3 / 42 1 / 55 2 / 78 13 / 76 5 / 42 3 / 48 Historical Max (kaf) 343 85 34 162 276 490 112 1, 562 608 2, 496 255 1, 244 3, 716 4, 489 318 8, 988 15, 406 Year 1984 1986 1984 1984 1984 1983 1984

Gunnison Basin Conditions

893 124%

Dolores Basin Conditions

275 86%

San Juan Basin • Near to Below normal year • Evidence of La Nina

San Juan Basin Conditions

579 75%

431 98%

Lake Powell 2011 – 12, 920 (la nina) 3 rd highest April. July volume since the closure of the dam Historical Observed Apr-Jul Volumes (kaf) 1970 -2010 (winter ENSO status) ( 1) - 1984 ( 2) - 1983 ( 3) - 1986 ( 4) - 1995 ( 5) - 1985 ( 6) - 1997 ( 7) - 1973 ( 8) - 1979 ( 9) - 1980 ( 10) - 1993 ( 11) - 1975 ( 12) - 2008 ( 13) - 2005 ( 14) - 1978 ( 15) - 1998 ( 16) - 1982 ( 17) - 1971 ( 18) - 1970 ( 19) - 2009 ( 20) - 1999 ( 21) - 1987 ( 22) - 1996 ( 23) - 1974 ( 24) - 2010 ( 25) - 1972 ( 26) - 2006 ( 27) - 1976 ( 28) - 1991 ( 29) - 1988 ( 30) - 2000 ( 31) - 2001 ( 32) - 1992 ( 33) - 2007 ( 34) - 2003 ( 35) - 1994 ( 36) - 2004 ( 37) - 1989 ( 38) - 1990 ( 39) - 1981 ( 40) - 1977 ( 41) - 2002 - 15406. 41 14838. 93 12601. 21 11833. 18 11701. 11 11320. 89 11262. 74 11104. 25 10606. 60 9984. 42 9953. 16 8908. 50 8844. 02 8678. 09 8510. 14 8210. 63 8180. 35 8037. 76 7806. 72 7788. 09 7758. 54 7233. 47 6915. 13 5795. 43 5494. 26 5319. 56 5297. 75 5159. 33 4567. 47 4367. 05 4320. 62 4124. 42 4053. 47 3910. 17 3766. 48 3542. 00 3524. 63 3228. 85 3058. 61 1277. 39 1126. 76 (neutral) (el nino) (la nina) (neutral) (el nino) (neutral) (la nina 2) (la nina) (el nino 2) (el nino) (neutral) (la nina) (el nino) (la nina) (el nino) (neutral) (la nina 3) (el nino 2) (la nina 3) (neutral) (el nino) (neutral) (la nina) (neutral) (el nino) (neutral)

Lake Powell Basin Conditions Percent of 1971 -2000 Average. As of Jan 1, 2011 300 As of Feb 1, 2011 As of Mar 1, 2011 250 As of Apr 1, 2011 200 As of May 1, 2011 As of Jun 1, 2011 150 As of Jul 1, 2011 As of Aug 1, 2011 100 50 0 Monthly Precipitation Water Year Precipitation Snow Water Equivalent Monthly Inflow

15. 7 (1917) 12. 9 maf 163% 7. 9

6490 205% 6894 148% 888 72% 12. 9 163%

Lower Colorado Basin • • Much below average except in northwest (e. g. Virgin, Muddy, etc) Virgin: – December 2010 storm track was important, but also wet April-May. – Snowpack persisted due to cool temperatures; melt delayed. Virgin Phoenix dust storm

Precipitation for December 2010

Virgin Basin Conditions

149 217%

2011 Summary Extremely wet in the north and dry in the south – dryness in the south was consistent with La Nina. Volume forecasts generally started too low in the north and too high in the south. Extremes are difficult to predict but many forecasts this year were for extremes. 34