Lake Powell Water Supply Outlook, January 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-July176 275 112 375
Pine Ck
Fremont Lk, Abv April-July70 100 102 130
New Fork
Big Piney, Nr April-July230 345 97 535
Green
Fontenelle Res, Fontenelle Nr April-July475 800 110 1220
Big Sandy
Farson, Nr April-July29 48 92 72
Green
Green River, Wy, Nr April-July475 805 110 1270
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July30 55 102 86
Viva Naughton Res April-July44 76 103 125
Blacks Fork
Robertson, Nr April-July50 82 92 115
Ef Smiths Fork
Stateline Res, Robertson,nr April-July15 24 92 32
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July600 1000 102 1690


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 26 113 36
Steamboat Springs April-July180 280 108 370
Elk
Milner, Nr April-July225 350 109 430
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July32 65 89 88
Yampa
Maybell, Nr April-July545 950 102 1200
Little Snake
Slater, Nr April-July82 145 93 196
Dixon, Nr April-July144 275 80 435
Lily, Nr April-July140 285 83 480
Yampa
Deerlodge Park April-July665 1200 97 1600
White
Meeker, Nr April-July200 295 105 355
Watson, Nr April-July215 310 111 380


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-July10.7 15 71 24
Ashley Ck
Vernal, Nr April-July20 36 72 62
West Fork Duchesne
Vat Diversion, Blo April-July9.6 16 86 24
Duchesne
Tabiona, Nr April-July60 97 90 133
Rock Ck
Upper Stillwater Res April-July50 74 100 104
South Fork Rock Ck
Docs Div, Blo April-July3.5 6.3 86 10.9
Rock Ck
Mountain Home, Nr April-July59 87 99 128
Currant Ck
Currant Ck Res April-July7.1 15.7 79 26
Strawberry
Solider Springs,nr April-July22 54 76 95
Starvation Res, Duchesne, Nr April-July43 95 85 160
Duchesne
Duchesne, Nr, Knight Div, Abv April-July118 181 93 260
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July39 58 88 87
Yellowstone
Altonah, Nr April-July38 57 93 75
Whiterocks
Whiterocks, Nr April-July25 39 72 65
Uinta
Neola, Nr April-July40 65 88 97
Duchesne
Myton April-July145 280 85 470
Randlett, Nr April-July160 310 81 540


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-July5.4 14.5 94 23
Fish Ck
Scofield, Nr, Reservoir, Abv April-July15.1 27 90 40
Price
Scofield Res, Scofield, Nr April-July19.5 37 90 56
Green
Green River, Ut April-July1640 2800 95 4200
Huntington Ck
Electric Lake April-July5.1 12.2 92 18
Power Plant, Blo April-July22 40 100 55
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July34 52 93 81
Ferron Ck
Ferron, Nr April-July24 38 100 58
Muddy Ck
Emery, Nr April-July11.6 20 101 32


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-July170 240 109 330
Willow Ck
Willow Ck Res, Granby, Nr April-July27 49 104 83
Fraser
Winter Park April-July15.4 21 108 27
Williams Fork
Williams Fork Res, Parshall, Nr April-July77 105 109 145
Muddy Ck
Wolford Mountain Reservoir April-July29 60 111 89
Blue
Dillon Res April-July154 193 118 260
Green Mtn Res April-July255 325 118 450
Colorado
Kremmling, Nr April-July675 975 113 1350
Eagle
Gypsum, Blo April-July255 365 109 525
Colorado
Dotsero, Nr April-July1080 1570 112 2200
Frying Pan
Ruedi Res, Basalt, Nr April-July105 145 104 215
Roaring Fork
Glenwood Springs April-July500 700 101 995
Colorado
Glenwood Springs, Blo April-July1600 2290 109 3250
Cameo, Nr April-July1750 2500 106 3600
Plateau Ck
Cameo, Nr April-July55 80 65 160
Colorado
Cisco, Nr April-July3300 4350 98 6500
Lake Powell, Glen Cyn Dam, At April-July4400 6500 91 9800


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 100 101 150
Almont April-July110 157 101 245
East
Almont April-July112 165 91 265
Gunnison
Gunnison, Nr April-July230 350 95 580
Tomichi Ck
Gunnison April-July50 81 109 130
Lake Fork
Gateview April-July91 132 107 175
Gunnison
Blue Mesa Res April-July480 690 102 1000
Morrow Point Res April-July540 750 101 1060
Crystal Res April-July630 840 101 1150
Muddy Ck
Paonia Res, Bardine, Nr March-June45 77 80 110
April-July46 77 79 115
Nf Gunnison
Somerset, Nr April-July160 245 83 330
Surface Ck
Cedaredge April-July6 11 65 20
Uncompahgre
Ridgway Res April-July66 102 101 145
Colona April-July90 138 101 200
Delta April-July60 112 99 175
Gunnison
Grand Junction, Nr April-July1000 1400 95 2090


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-July115 220 90 330
Mcphee Res April-July135 255 86 410
San Miguel
Placerville, Nr April-July75 127 99 180
Dolores
Cisco, Nr April-July176 485 86 820


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-July80 138 64 210
Carracas, Nr April-July140 235 62 370
Navajo Res, Archuleta, Nr April-July250 450 61 750
Farmington April-July400 730 66 1200
Bluff, Nr April-July380 720 65 1220
Rio Blanco
Pagosa Springs, Nr, Blanco Dam, Blo April-July22 35 65 55
Navajo
Chromo, Nr, Oso Div Dam, Blo April-July24 37 57 61
Piedra
Arboles, Nr April-July85 148 70 230
Los Pinos
Vallecito Res, Bayfield, Nr April-July112 160 82 230
Animas
Durango April-July225 350 84 480
Florida
Lemon Res, Durango, Nr April-July27 42 76 68
La Plata
Hesperus April-July9 18.5 80 27
Mancos
Mancos, Nr April-July11 22 71 37

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 265.1 151 77 195.1 111 175.3 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 20.6 133 54 8.7 56 15.5 38.3
Blacks Fork
Meeks Cabin 21.0 203 70 11.6 112 10.3 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 8.4 145 60 6.5 112 5.8 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 3261.5 105 87 2833.6 92 3094.9 3749.0
untitled Strawberry
Solider Springs,nr 839.0 127 76 831.2 126 659.7 1105.9
Starvation Res, Duchesne, Nr 141.8 106 86 140.0 104 134.1 165.3
untitled Rock Ck
Upper Stillwater Res 13.3 127 42 9.4 91 10.4 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 28.7 128 78 21.4 96 22.4 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 10.6 60 41 10.1 58 17.5 25.7
untitled Price
Scofield Res, Scofield, Nr 12.4 44 19 13.8 49 28.5 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 40.3 101 64 29.3 74 39.7 62.5
untitled Huntington Ck
Electric Lake 19.3 98 61 17.1 87 19.6 31.5
untitled
TOTAL 4681.7 111 82 4127.9 97 4233.8 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 518.6 138 106 379.6 101 375.1 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 8.3 109 91 8.2 107 7.6 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 79.8 120 82 75.0 113 66.5 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 46.1 102 70 43.8 97 45.1 66.0
untitled Blue
Dillon Res 250.9 111 99 241.5 106 226.9 254.0
Green Mtn Res 79.5 88 54 90.4 101 89.8 146.9
untitled Homestake Ck
Homestake Res -9999.0 -99 -99 0.7 2 32.9 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 85.0 111 83 83.1 108 76.8 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 13.9 116 42 14.9 125 12.0 32.9
untitled Taylor
Taylor Park Res 79.4 117 75 71.4 105 68.1 106.2
untitled Gunnison
Blue Mesa Res 574.4 104 69 380.9 69 549.9 829.5
Morrow Point Res 111.9 100 96 107.3 96 111.6 117.0
Crystal Res 15.1 98 86 16.0 104 15.4 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 0.7 17 4 0.5 11 4.2 16.7
untitled Uncompahgre
Ridgway Res 76.4 111 92 72.7 106 68.8 83.0
untitled Dolores
Mcphee Res 181.3 67 48 182.4 68 270.1 381.1
untitled
TOTAL 2121.4 107 77 1768.2 87 1987.9 2749.1
Colorado
Lake Powell 11536.7 65 47 10323.8 58 17744.8 24322.0
untitled
TOTAL 11536.7 65 47 10323.8 58 17744.8 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 95.6 154 76 92.6 149 62.1 125.4
untitled San Juan
Navajo Res, Archuleta, Nr 1090.7 81 64 965.0 72 1341.1 1696.0
untitled Florida
Lemon Res, Durango, Nr 21.5 104 54 16.8 81 20.7 39.8
untitled
TOTAL 1207.8 85 65 1074.4 75 1423.8 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