Lake Powell Water Supply Outlook, February 1, 2015

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




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Yampa/White Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Duchesne Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Lower Green Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Upper Colorado Mainstem Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Gunnison Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Dolores Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

San Juan Basin Conditions




Snow Water Equivalent in Percent of Median.
* 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-July190 260 106 340
Pine Ck
Fremont Lk, Abv April-July70 95 97 120
New Fork
Big Piney, Nr April-July205 320 90 470
Green
Fontenelle Res, Fontenelle Nr April-July520 725 100 1060
Big Sandy
Farson, Nr April-July26 40 77 64
Green
Green River, Wy, Nr April-July510 730 100 1100
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July31 48 89 78
Viva Naughton Res April-July45 65 88 120
Blacks Fork
Robertson, Nr April-July44 66 74 103
Ef Smiths Fork
Stateline Res, Robertson,nr April-July15 20 77 29
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July600 875 89 1520


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-July16.7 23 100 31
Steamboat Springs April-July150 230 88 315
Elk
Milner, Nr April-July200 280 88 370
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July23 49 67 67
Yampa
Maybell, Nr April-July480 740 79 1000
Little Snake
Slater, Nr April-July79 115 74 162
Dixon, Nr April-July128 205 59 330
Lily, Nr April-July122 210 61 340
Yampa
Deerlodge Park April-July605 945 76 1300
White
Meeker, Nr April-July180 240 86 325
Watson, Nr April-July180 250 89 350


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-July6.5 12.8 61 22
Ashley Ck
Vernal, Nr April-July16.2 30 60 56
West Fork Duchesne
Vat Diversion, Blo April-July7.5 12.4 67 20
Duchesne
Tabiona, Nr April-July60 83 77 115
Rock Ck
Upper Stillwater Res April-July47 62 84 93
South Fork Rock Ck
Docs Div, Blo April-July3.4 5.2 71 8.4
Rock Ck
Mountain Home, Nr April-July57 74 84 111
Currant Ck
Currant Ck Res April-July7 12 60 21
Strawberry
Solider Springs,nr April-July23 40 56 80
Starvation Res, Duchesne, Nr April-July43 72 64 128
Duchesne
Duchesne, Nr, Knight Div, Abv April-July118 155 80 215
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July38 53 80 77
Yellowstone
Altonah, Nr April-July39 51 84 71
Whiterocks
Whiterocks, Nr April-July23 36 67 61
Uinta
Neola, Nr April-July32 55 74 83
Duchesne
Myton April-July140 215 65 380
Randlett, Nr April-July150 230 60 430


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-July5.2 10.7 69 18
Fish Ck
Scofield, Nr, Reservoir, Abv April-July14.3 21 70 35
Price
Scofield Res, Scofield, Nr April-July18 28 68 48
Green
Green River, Ut April-July1600 2270 77 3500
Huntington Ck
Electric Lake April-July4.5 9 68 16
Power Plant, Blo April-July19 28 70 47
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July32 45 80 75
Ferron Ck
Ferron, Nr April-July24 34 89 54
Muddy Ck
Emery, Nr April-July12.4 18 90 28


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-July160 215 98 315
Willow Ck
Willow Ck Res, Granby, Nr April-July25 42 89 77
Fraser
Winter Park April-July14 19 98 26
Williams Fork
Williams Fork Res, Parshall, Nr April-July70 95 99 135
Muddy Ck
Wolford Mountain Reservoir April-July26 48 89 70
Blue
Dillon Res April-July140 183 112 250
Green Mtn Res April-July225 300 109 415
Colorado
Kremmling, Nr April-July630 850 99 1250
Eagle
Gypsum, Blo April-July245 320 96 475
Colorado
Dotsero, Nr April-July1000 1370 98 1930
Frying Pan
Ruedi Res, Basalt, Nr April-July98 130 94 187
Roaring Fork
Glenwood Springs April-July465 625 91 890
Colorado
Glenwood Springs, Blo April-July1470 2000 95 2800
Cameo, Nr April-July1600 2150 91 3100
Plateau Ck
Cameo, Nr April-July47 67 54 125
Colorado
Cisco, Nr April-July2650 3700 83 5600
Lake Powell, Glen Cyn Dam, At April-July3400 5200 73 8350


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-July70 93 94 125
Almont April-July98 145 94 200
East
Almont April-July95 140 77 205
Gunnison
Gunnison, Nr April-July220 310 84 440
Tomichi Ck
Gunnison April-July47 74 100 105
Lake Fork
Gateview April-July88 123 100 160
Gunnison
Blue Mesa Res April-July420 620 92 900
Morrow Point Res April-July475 675 91 955
Crystal Res April-July555 755 90 1040
Muddy Ck
Paonia Res, Bardine, Nr March-June52 63 66 105
April-July53 64 66 106
Nf Gunnison
Somerset, Nr April-July160 215 73 320
Surface Ck
Cedaredge April-July5 9.5 57 16.2
Uncompahgre
Ridgway Res April-July65 91 90 129
Colona April-July85 118 86 186
Delta April-July60 90 80 165
Gunnison
Grand Junction, Nr April-July850 1220 82 1830


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-July120 185 76 260
Mcphee Res April-July120 210 71 310
San Miguel
Placerville, Nr April-July80 110 86 150
Dolores
Cisco, Nr April-July250 380 67 580


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-July73 120 56 190
Carracas, Nr April-July125 196 52 330
Navajo Res, Archuleta, Nr April-July240 400 54 660
Farmington April-July350 640 58 1050
Bluff, Nr April-July380 610 55 1000
Rio Blanco
Pagosa Springs, Nr, Blanco Dam, Blo April-July18 32 59 50
Navajo
Chromo, Nr, Oso Div Dam, Blo April-July22 36 55 58
Piedra
Arboles, Nr April-July85 130 62 200
Los Pinos
Vallecito Res, Bayfield, Nr April-July95 145 75 210
Animas
Durango April-July200 315 76 425
Florida
Lemon Res, Durango, Nr April-July22 39 71 60
La Plata
Hesperus April-July9 15 65 23
Mancos
Mancos, Nr April-July10 19 61 30

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 232.7 155 67 162.7 108 150.1 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 21.5 130 56 9.2 56 16.6 38.3
Blacks Fork
Meeks Cabin 22.6 196 76 13.1 114 11.5 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 8.5 153 62 6.8 122 5.6 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 3232.9 106 86 2847.2 93 3050.5 3749.0
untitled Strawberry
Solider Springs,nr 837.6 127 76 830.2 126 659.9 1105.9
Starvation Res, Duchesne, Nr 146.8 106 89 148.0 107 138.8 165.3
untitled Rock Ck
Upper Stillwater Res 14.2 164 45 9.9 115 8.6 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 30.6 125 84 23.2 95 24.4 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 11.3 63 44 10.7 59 18.0 25.7
untitled Price
Scofield Res, Scofield, Nr 12.3 41 19 14.5 48 29.9 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 40.7 104 65 30.1 77 39.3 62.5
untitled Huntington Ck
Electric Lake 18.8 98 60 17.0 89 19.2 31.5
untitled
TOTAL 4630.6 111 81 4122.6 99 4172.4 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 496.9 141 101 350.1 99 352.2 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 8.9 112 98 8.7 110 8.0 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 78.5 123 81 76.0 119 63.8 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 45.6 102 69 43.7 98 44.6 66.0
untitled Blue
Dillon Res 250.1 112 98 239.7 107 223.2 254.0
Green Mtn Res 75.0 93 51 82.3 102 81.1 146.9
untitled Homestake Ck
Homestake Res -9999.0 -99 -99 0.8 2 31.9 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 81.5 113 80 79.8 110 72.4 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 14.5 115 44 15.7 125 12.6 32.9
untitled Taylor
Taylor Park Res 78.9 118 74 71.4 107 66.9 106.2
untitled Gunnison
Blue Mesa Res 546.5 106 66 388.8 76 514.6 829.5
Morrow Point Res 110.4 99 94 107.9 97 111.4 117.0
Crystal Res 14.9 97 85 15.0 98 15.3 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 0.7 18 4 0.5 13 4.2 16.7
untitled Uncompahgre
Ridgway Res 77.0 111 93 73.8 107 69.2 83.0
untitled Dolores
Mcphee Res 183.6 68 48 184.5 68 270.9 381.1
untitled
TOTAL 2063.1 108 75 1738.8 90 1910.6 2749.1
Colorado
Lake Powell 11145.9 64 46 9827.7 57 17338.2 24322.0
untitled
TOTAL 11145.9 64 46 9827.7 57 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 97.2 153 78 95.8 151 63.5 125.4
untitled San Juan
Navajo Res, Archuleta, Nr 1090.7 83 64 963.2 74 1310.4 1696.0
untitled Florida
Lemon Res, Durango, Nr 21.8 104 55 17.0 82 20.9 39.8
untitled
TOTAL 1209.7 87 65 1076.0 77 1394.7 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