Lake Powell Water Supply Outlook, February 1, 2013

Note: This publication is scheduled for revision. If you have feedback on content, format, or publication frequency, please contact us.
Prepared by Alcorn
NOAA, National Weather Service
Colorado Basin River Forecast Center
Salt Lake City, Utah
www.cbrfc.noaa.gov

Contents

Lake Powell Sub-Basin Summaries




*Median of forecasts within each basin.





*Median of forecasts within each basin.







*Median of forecasts within each basin.




Upper Green Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Yampa/White Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Duchesne Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Lower Green Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Upper Colorado Mainstem Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Gunnison Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Dolores Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

San Juan Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.


Upper Green Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
Green
Daniel, Nr, Warren Bridge, At April-July134 200 82 275
Pine Ck
Fremont Lk, Abv April-July58 80 82 104
New Fork
Big Piney, Nr April-July152 255 72 400
Green
Fontenelle Res, Fontenelle Nr April-July290 495 68 775
Big Sandy
Farson, Nr April-July24 37 71 60
Green
Green River, Wy, Nr April-July280 480 66 805
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July28 40 74 71
Viva Naughton Res April-July37 53 72 105
Blacks Fork
Robertson, Nr April-July41 66 74 106
Ef Smiths Fork
Stateline Res, Robertson,nr April-July12.9 18.5 71 27
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July350 640 65 1250


Yampa/White Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
Yampa
Stagecoach Rsvr, Abv April-July9.8 16.2 70 23
Steamboat Springs April-July110 172 66 245
Elk
Milner, Nr April-July146 215 67 310
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July21 45 62 63
Yampa
Maybell, Nr April-July335 590 63 900
Little Snake
Slater, Nr April-July61 95 61 149
Savery, Nr April-July100 182 53 310
Lily, Nr April-July102 185 54 320
White
Meeker, Nr April-July100 176 63 270
Watson, Nr April-July97 180 64 290


Duchesne Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
Big Brush Ck
Vernal, Nr, Red Fleet Res, Abv April-July10 13.9 66 23
Ashley Ck
Vernal, Nr April-July22 34 68 58
West Fork Duchesne
Vat Diversion, Blo April-July9.3 13.5 73 21
Duchesne
Tabiona, Nr April-July49 80 74 114
Rock Ck
Upper Stillwater Res April-July39 52 70 82
South Fork Rock Ck
Docs Div, Blo April-July3.4 5 68 7.8
Rock Ck
Mountain Home, Nr April-July48 63 72 100
Currant Ck
Currant Ck Res April-July5.7 13.6 68 23
Strawberry
Solider Springs,nr April-July19.3 40 73 65
Starvation Res, Duchesne, Nr April-July44 80 71 133
Duchesne
Duchesne, Nr, Knight Div, Abv April-July96 141 73 205
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July31 47 71 71
Yellowstone
Altonah, Nr April-July29 41 67 65
Whiterocks
Whiterocks, Nr April-July25 38 70 61
Uinta
Neola, Nr April-July32 50 68 81
Duchesne
Myton April-July83 205 62 350
Randlett, Nr April-July88 225 58 420


Lower Green Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
White
Blo Tabbyune Ck, Soldier Summit, Nr April-July5.7 11.4 74 17.2
Fish Ck
Scofield, Nr, Reservoir, Abv April-July17.4 23 77 34
Price
Scofield Res, Scofield, Nr April-July23 31 76 47
Green
Green River, Ut April-July1070 1780 60 3130
Huntington Ck
Electric Lake April-July5.4 9.1 68 17.5
Power Plant, Blo April-July22 31 78 49
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July22 37 66 57
Ferron Ck
Ferron, Nr April-July12.8 27 71 41
Muddy Ck
Emery, Nr April-July8.7 13.5 68 22


Upper Colorado Mainstem Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
Colorado
Lake Granby, Granby, Nr April-July85 140 64 230
Willow Ck
Willow Ck Res, Granby, Nr April-July17 33 70 63
Fraser
Winter Park April-July8 13.5 70 19
Williams Fork
Williams Fork Res, Parshall, Nr April-July42 68 71 105
Muddy Ck
Wolford Mountain Reservoir April-July16 37 69 59
Blue
Dillon Res April-July62 105 64 165
Green Mtn Res April-July112 180 65 285
Colorado
Kremmling, Nr April-July330 530 62 870
Eagle
Gypsum, Blo April-July122 210 63 350
Colorado
Dotsero, Nr April-July535 860 61 1350
Frying Pan
Ruedi Res, Basalt, Nr April-July50 84 60 130
Roaring Fork
Glenwood Springs April-July280 425 62 670
Colorado
Glenwood Springs, Blo April-July850 1320 63 2060
Cameo, Nr April-July950 1410 60 2300
Plateau Ck
Cameo, Nr April-July50 77 62 140
Colorado
Cisco, Nr April-July1700 2650 60 4370
Lake Powell, Glen Cyn Dam, At April-July1800 3850 54 6780


Gunnison Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
Taylor
Taylor Park Res April-July38 61 62 95
Almont April-July60 90 58 145
East
Almont April-July65 115 63 175
Gunnison
Gunnison, Nr April-July140 215 58 365
Tomichi Ck
Gunnison April-July16 37 50 65
Lake Fork
Gateview April-July40 75 61 110
Gunnison
Blue Mesa Res April-July250 385 57 625
Morrow Point Res April-July280 415 56 655
Crystal Res April-July325 460 55 700
Muddy Ck
Paonia Res, Bardine, Nr March-June35 60 63 90
April-July35 59 61 90
Nf Gunnison
Somerset, Nr April-July120 192 65 285
Surface Ck
Cedaredge April-July7 12 71 19
Uncompahgre
Ridgway Res April-July40 67 66 92
Colona April-July40 76 55 120
Delta April-July25 60 53 100
Gunnison
Grand Junction, Nr April-July550 840 57 1350


Dolores Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
Dolores
Dolores April-July90 175 71 280
Mcphee Res April-July100 205 69 340
San Miguel
Placerville, Nr April-July50 90 70 140
Dolores
Cisco, Nr April-July210 390 69 650


San Juan Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
San Juan
Pagosa Springs April-July100 160 74 240
Carracas, Nr April-July175 275 72 430
Navajo Res, Archuleta, Nr April-July310 525 71 860
Farmington April-July430 750 68 1210
Bluff, Nr April-July410 750 68 1210
Rio Blanco
Pagosa Springs, Nr, Blanco Dam, Blo April-July28 40 74 61
Navajo
Chromo, Nr, Oso Div Dam, Blo April-July32 48 74 75
Piedra
Arboles, Nr April-July97 160 76 245
Los Pinos
Vallecito Res, Bayfield, Nr April-July90 150 77 225
Animas
Durango April-July185 295 71 420
Florida
Lemon Res, Durango, Nr April-July22 40 73 61
La Plata
Hesperus April-July7 16 70 25
Mancos
Mancos, Nr April-July11 22 71 36

Differences between the full period forecasts and the residual forecasts may not exactly equal the actual observed volumes due to rounding conventions (see Definitions section).

Green End of Month Reservoir Contents (kaf)

EOM
Contents		Percent
EOM
Average		Percent
Usable
Capacity		Last Year
EOM		Last Year
%Average		EOM
Average		Usable
Capacity
untitled Green
Fontenelle Res, Fontenelle Nr 165.8 110 48 164.8 110 150.1 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 7.2 43 19 22.1 133 16.6 38.3
Blacks Fork
Meeks Cabin 6.9 59 23 16.4 142 11.5 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 4.6 82 33 6.8 122 5.6 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 2980.7 98 80 3343.2 110 3050.5 3749.0
untitled Strawberry
Solider Springs,nr 897.0 122 81 972.7 132 735.5 1105.9
Starvation Res, Duchesne, Nr 135.6 98 82 153.6 111 138.8 165.3
untitled Rock Ck
Upper Stillwater Res 9.5 110 30 9.4 109 8.6 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 9.5 39 26 22.2 91 24.4 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 13.9 77 54 21.1 117 18.0 25.7
untitled Price
Scofield Res, Scofield, Nr 28.0 94 42 50.5 169 29.9 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 33.6 86 54 47.5 121 39.3 62.5
untitled Huntington Ck
Electric Lake 19.4 101 62 25.3 132 19.2 31.5
untitled
TOTAL 4311.5 101 76 4855.5 114 4247.9 5700.4


Upper Colorado End of Month Reservoir Contents (kaf)

EOM
Contents		Percent
EOM
Average		Percent
Usable
Capacity		Last Year
EOM		Last Year
%Average		EOM
Average		Usable
Capacity
untitled Colorado
Lake Granby, Granby, Nr 250.5 71 51 444.4 126 352.2 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 8.1 101 89 8.6 108 8.0 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 42.6 67 44 80.1 126 63.8 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 24.3 54 37 58.1 130 44.6 66.0
untitled Blue
Dillon Res 172.1 77 68 242.7 109 223.2 254.0
Green Mtn Res 61.9 76 42 87.1 108 81.1 146.9
untitled Homestake Ck
Homestake Res -9999.0 -99 -99 7.7 24 31.9 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 62.9 87 62 76.1 105 72.4 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 8.1 64 25 17.0 135 12.6 32.9
untitled Taylor
Taylor Park Res 56.6 85 53 65.8 98 66.9 106.2
untitled Gunnison
Blue Mesa Res 328.2 64 40 545.2 106 514.6 829.5
Morrow Point Res 105.1 94 90 113.5 102 111.4 117.0
Crystal Res 15.3 99 87 16.5 107 15.3 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 1.4 32 8 0.6 14 4.2 16.7
untitled Uncompahgre
Ridgway Res 54.8 79 66 68.3 99 69.2 83.0
untitled Dolores
Mcphee Res 190.6 70 50 287.9 106 270.9 381.1
untitled
TOTAL 1382.4 72 50 2119.6 109 1910.6 2749.1
Colorado
Lake Powell 12176.8 70 50 15641.2 90 17338.2 24322.0
untitled
TOTAL 12176.8 70 50 15641.2 90 17338.2 24322.0


San Juan End of Month Reservoir Contents (kaf)

EOM
Contents		Percent
EOM
Average		Percent
Usable
Capacity		Last Year
EOM		Last Year
%Average		EOM
Average		Usable
Capacity
untitled Los Pinos
Vallecito Res, Bayfield, Nr 45.8 72 37 76.4 120 63.5 125.4
untitled San Juan
Navajo Res, Archuleta, Nr 937.6 73 55 1284.9 99 1292.2 1696.0
untitled Florida
Lemon Res, Durango, Nr 7.8 37 20 14.0 67 21.0 39.8
untitled
TOTAL 991.2 72 53 1375.3 100 1376.7 1861.2

Precipitation Maps




Definitions

10% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 10% chance of being exceeded. Previously referred to as "Reasonable Maximum Forecast".

50% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 50% chance of being exceeded. Previously referred to as "Most Probable Forecast".

90% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 90% chance of being exceeded. Previously referred to as "Reasonable Minimum Forecast".

Acre-Foot (af): The volume equal to one acre covered one foot deep (43,560 cubic feet). See kaf below.

Average: The arithmetic mean. The sum of the values divided by the number of values. Values from 1981-2010 are used for this publication.

Categories: Much Above Average=Greater than 130%, Above Average=111-130%, Near Average=90-110%, Below Average=70-89%, Much Below Average=Less than 70%.

CBRFC: Colorado Basin River Forecast Center.

Forecast Period: The period from April 1 through July 31, unless otherwise noted.

kaf: Thousand Acre-Feet. See Acre-Foot above.

Inflow: The volume of water that flows into a reservoir or lake.

Median: The middle value of an ordered set of values. Half of the values are higher and half of the values are lower. When the set contains an even number of values the median is the average of the two middle numbers.

NOAA: National Oceanic and Atomospheric Administration.

NWS: National Weather Service.

Rounding Conventions:
RangeRound to
0-1.990.01
2.0-19.90.1
20-1991.0
200-9995.0
1000+3 significant digits


Streamflow: The volume of water that flows past a specific stream site.

Water Year: The 12-month period, October 1 through September 30. The water year is designated by the calendar year in which it ends. Thus, the year ending September 30, 2008, is called the "2008 water year."


Additional Information

Water supply forecasts take into consideration present hydrometeorological conditions and use average basin temperatures and precipitation for the forecast period. As the forecast season progresses, a greater portion of the future hydrologic and climatic uncertainty becomes known and monthly forecasts become more accurate. For more information on the tools we use, consult Water Supply Forecasting Tools.

Volume forecasts represent adjusted flows; that is, observed flows with upstream water use taken into account. Adjusted flows will closely approximate natural or unimpaired flows. However, not all upstream diversions or impoundments are measured or quantifiable. For specific adjustments used with each forecast point, consult the Guide to Water Supply Forecasting.

The Water Supply Outlook is issued monthly January through May by the Colorado Basin River Forecast Center. It represents a coordinated effort between the National Weather Service, Natural Resources Conservation Service, Bureau of Reclamation, U.S. Geological Survey and local water district managers.

Note: Data used in this report are provisional and are subject to revision.

For more information, or to be included on the mailing list, please contact:

Colorado Basin River Forecast Center
2242 W North Temple
Salt Lake City, UT 84116
(801) 524-5130
www.cbrfc.noaa.gov