Water Year 2012:Review of Water Supply Forecasts

in the Colorado River Basin

CRFS November 14, 2012

Green River BasinUpper Green

Duchesne Yampa

• Dry everywhere• Extreme dry conditions in

Yampa, Duchesne

Upper Green: Basin Conditions

Precipitation % of Average

October 120

November 115

December 48

January 130

February 112

March 48

April 64

May 43

June 5

July 104

Water Year 71

103%

98%83%

508 KAF 70%

ESP SWS NRCS COOR %

Jan 545 553 540 550 76

Feb 665 707 685 685 94

Mar 725 750 730 730 101

April 670 665 660 665 92

May 590 528 538 538 74

Jun 497 488 478 488 67

FONTENELLE RESERVOIR

2012 MAEJan : 42 KAFFeb: 177 KAFMar: 222 KAFApr: 157 KAFMay: 30 KAFJune: 20 KAF

570 KAF 58%

ESP SWS NRCS COOR %

Jan 650 753 760 760 78

Feb 860 932 880 880 90

Mar 940 1000 945 945 96

April 800870

898 795 810 83

May 698 719 620 630 64

Jun 574 616 550 560 57

FLAMING GORGE

2012 MAEJan : 190 KAFFeb: 310 KAFMar: 375 KAFApr: 240 KAFMay: 64 KAFJune: 11 KAF

FLAMING GORGE LOCAL: (Flaming Gorge Inflow-Fontenelle Inflow)

Observed Local 62 KAF/24% 4th Lowest

Obs Average %April 38.3 48 80%May 23.1 79 29%June -0.7 92 0%July 1.2 34 3%

ESP local too high….

Yampa: Basin Conditions

Precipitation 2012% of Average

2002% of Average

October 96 110

November 94 87

December 28 65

January 62 56

February 126 51

March 31 84

April 55 57

May 24 19

June 3 18

July 111 68

Water Year 60 67

66%

80%

52%

337 KAF 36%

Yampa nr MaybellESP SWS NRCS COOR %

Jan 700 693 700 700 75

Feb 660 636 635 635 68

Mar 730 713 715 715 76

April 540 520 485 500 53

May 410 418 398 398 43

Jun 365 395 368 368 39

#1 1977: 261 KAF#2 2002: 269 KAF#3 1934: 278 KAF#4 2012: 337 KAF

2012 MAEJan : 363 KAFFeb: 298 KAFMar: 378 KAFApr: 163 KAFMay: 61 KAFJune: 31 KAF

April-July Volume (KAF) Historical

Volume (KAF) % Average 2012 L-H Min (KAF) Min Year

Yampa abv Stagecoach 3.52 15% 2/23 1.46 2002

Yampa at Steamboat Springs 105 40% 4/105 82 2002

Elk near Milner 173 54% 3/43 135 2002

Elkhead Creek abv Long Gulch 20.3 28% 2/17 14.8 2002

Yampa at Maybell 337 36% 4/96 261 1977

Little Snake nr Slater 73 47% 4/65 51 1977

Little Snake nr Savery 90 26% 1/23 90 2012

Little Snake nr Lily 111 32% 4/90 59 1934

White near Meeker 111 39% 4/108 81 1977

White near Watson 98 35% 4/84 72 1977

All April-July Volumes are in bottom five of historical records!

Duchesne: Basin Conditions

67 % 53%

72%Precipitation % of Average

October 146

November 84

December 39

January 72

February 92

March 62

April 60

May 16

June 2

July 174

Water Year 76

31 KAF 42%

31KAF 47%

Neola and Lake Fork

-Over forecast issues (~20-30% over forecast in May)-Same pattern at all points on the south slope of the Uintas

2012 MAEJan : 25 KAFFeb: 21 KAFMar: 21 KAFApr: 19 KAFMay: 13 KAFJune: 5 KAF

Upper Colorado Basin

Mainstem

GunnisonDolores

• Extreme dry

Upper Colorado Mainstem Basin Conditions

April Forecast

900 KAF38%

Colorado - CameoESP SWS

rawpref rtd

NRCS rawpref rtd

COOR %

Jan 1910 17551800p

16701700p

1750 74%

Feb 1950 18101830p

17301730p

1750 74%

Mar 1930 17251790p

17601760p

1760 75%

April 1435 6701300p

10301280p

1280 54%

May 1070 6001030p

9901030p

1030 44%

Jun 935 895930p

885930p

930 39%

Upper Colorado 2012 VolumesApril - July 2012 Historical

2011 H-L RankingVolume (kaf) % avg

2012 L-H Ranking Min (kaf) Year

Lake Granby 116 52% 3 / 85 88 2002 1Willow Creek Res 20 43% 6 / 93 9.5 2002 1Fraser - Winter Park 8.24 42% 2 / 76 8.21 2002 2Williams Fork Res 39 41% 2 / 53 30 2002 2Dillon Res 60 37% 2 / 53 54 2002 2Green Mountain Res 112 41% 2 / 75 93 2002 2Wolford Mountain Res 21 39% 3 / 31 10.1 2002 1Colorado - Kremmling 351 41% 2 / 50 246 2002 1Eagle - Gypsum 133 40% 3 / 66 119 2002 2Colorado - Dotsero 550 39% 2 / 72 416 2002 1Ruedi Res 56 41% 3 / 43 50 2002 2Roaring Fork - Glenwood 262 38% 3 / 43 203 1977 3Colorado -Glenwood 851 40% 3 / 46 664 2002 2Colorado - Cameo 900 38% 3 / 79 724 2002 2Platuea Ck - Cameo 30 24% 3 / 37 13.7 1977 8Colorado - Cisco 1503 34% 2 / 32 1057 2002 5Lake Powell 2063 29% 3 / 49 964 2002 3

Gunnison Basin Conditions

2012: 206 KAF (31% of average)

ESP SWS(route)

NRCSStatics

COOR %

Jan 439 460 455 450 67

Feb 467 458 465 450 67

Mar 462 447 440 450 67

April 384 340 275 330 49

May 253 227 234 230 34

Jun 201 186 238 196 29

2012: 120 KAF (41% of average)

ESP SWS(Route)

NRCSStatics

COOR %

Jan 222 230 220-245

235 80

Feb 241 225 230 225 76

Mar 225 243 250 240 81

April 196 142 184 150 51

May 149 127 170 138 47

Jun 121 115 115 115 39

San Juan Basin• Dry, but not quite as

extreme as further north

San JuanBasin Conditions

2012: 230 KAF (55 % of average)

ESP SWS NRCSStatics

COOR %

Jan 355 400 370 350 80

Feb 350 400 345 350 80

Mar 385 400 375 375 90

April 314 227 295 275 66

May 273 186 219-274 230 55

Jun 244 199 256 230 55

Forecast Evolution Plot

2012: 107 KAF (55 % of average)

Lake Powell

Lake Powell Basin Conditions

Monthly Precip-itation

Water Year Precipitation

Snow Water Equivalent

Monthly Inflow Forecast0

50

100

150Lake Powell Basin ConditionsPercent of 1981-2010 Average

As of Jan 1, 2012

As of Feb 1, 2012

As of Mar 1, 2012

As of Apr 1, 2012

As of May 1, 2012

As of Jun 1, 2012

As of Jul 1, 2012

As of Aug 1, 2012

505071%

350049%

236033%

2063 KAF29%

April Forecast

Lake PowellESP SWS raw

pref rtd NRCS rawpref rtd

COOR %

Jan 5140 60505000p

48905150p

5050 71%

Feb 5290 ---5100p

50205050p

5050 71%

Mar 5530 50005200p

52505300p

5300 74%

April 3940 15003500p

28703500p

3500 49%

May 2540 ---2360p

22602260p

2360 33%

Jun 2120 ---2010p

2010 28%

2063 KAF / 29%(#3 / 49)

1128 KAF / 38%(#4 / 108)

375 KAF / 34%(#6 / 89)

1503 KAF / 34%(#2 / 32)

2002 Obs (kaf)

% Avg Rank 2012-2002(kaf)

Green – Green River, UT 818 28% 3 310

Colorado – Cisco 1057 24% 1 446

San Juan – Bluff 0 0% 1 375

Lake Powell 964 13% 1 1099

Lower Colorado BasinVirgin:Snowpack far behind average by mid JanuarySnowpack melted out very early (order of weeks)April-June warmer than average and accelerated meltMay and June very dry (finally saw precip in July)

Salt-Verde:Generally dry for an extended period, particularly in VerdeLa Nina conditions – continued from last yearDry soil conditions entering the seasonEarly season snowpack fizzledWeighted ESP was better guidance

Phoenix dust storm

Virgin

28

WY12 Official ForecastsVirgin @ Virgin (VIRU1)

2012 AMJJ Observed = 26.5 KAF (46% AVG)

81-10 AMJJ Average = 58.1 KAF

VIRU1 Official Fcst (COORD) ErrorJan 1 45 18.5

Feb 1 32 5.5

Mar 1 32 5.5

Apr 1 28 1.5

May 1 26 -0.5

Jun 1 25 -1.5

SUMMARY:

Early months: overforecast (especially January).

As season progressed: Precip dried out; fcsts dropped.

Fcsts issued in Apr, May, June: were closest to the volume that was eventually observed.

Least Erroneous Official WY12 Fcst : May

SALT – ROOSEVELT: 2012 CBRFC-NRCS COORDINATED FORECASTSProgressive Forecast Period (Forecast Issue Date through May)

Volume in kAF

VERDE-HORSHOE: 2011 CBRFC-NRCS COORDINATED FORECASTSProgressive Forecast Period (Forecast Issue Date through May)

Volume in kAF