Lake Powell Water Supply Outlook, April 1, 2014

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-July320 370 151 420
Pine Ck
Fremont Lk, Abv April-July100 124 127 138
New Fork
Big Piney, Nr April-July390 510 144 600
Green
Fontenelle Res, Fontenelle Nr April-July950 1210 167 1440
Big Sandy
Farson, Nr April-July48 62 119 79
Green
Green River, Wy, Nr April-July950 1230 168 1480
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July50 67 124 90
Viva Naughton Res April-July68 94 127 130
Blacks Fork
Robertson, Nr April-July67 87 98 115
Ef Smiths Fork
Stateline Res, Robertson,nr April-July21 27 104 32
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July1050 1400 143 1820


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-July21 28 122 42
Steamboat Springs April-July295 360 138 440
Elk
Milner, Nr April-July360 440 138 525
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July70 95 130 118
Yampa
Maybell, Nr April-July940 1200 128 1450
Little Snake
Slater, Nr April-July150 196 126 245
Savery, Nr April-July290 390 113 515
Lily, Nr April-July300 415 120 560
Yampa
Deerlodge Park April-July1180 1550 125 1930
White
Meeker, Nr April-July205 260 93 320
Watson, Nr April-July210 270 96 340


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-July7.5 13 62 20
Ashley Ck
Vernal, Nr April-July17.5 27 54 45
West Fork Duchesne
Vat Diversion, Blo April-July9.7 13.5 73 17.5
Duchesne
Tabiona, Nr April-July70 86 80 110
Rock Ck
Upper Stillwater Res April-July58 72 97 89
South Fork Rock Ck
Docs Div, Blo April-July4.2 5.5 75 7.6
Rock Ck
Mountain Home, Nr April-July65 82 93 99
Currant Ck
Currant Ck Res April-July11.2 15 75 21
Strawberry
Solider Springs,nr April-July24 36 51 55
Starvation Res, Duchesne, Nr April-July55 72 64 100
Duchesne
Duchesne, Nr, Knight Div, Abv April-July130 166 86 200
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July48 62 94 73
Yellowstone
Altonah, Nr April-July39 54 89 69
Whiterocks
Whiterocks, Nr April-July21 30 56 50
Uinta
Neola, Nr April-July38 58 78 80
Duchesne
Myton April-July170 250 76 315
Randlett, Nr April-July185 265 69 335


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-July7.1 9.7 63 13.9
Fish Ck
Scofield, Nr, Reservoir, Abv April-July16 23 77 29
Price
Scofield Res, Scofield, Nr April-July22 31 76 40
Green
Green River, Ut April-July2700 3450 117 4400
Huntington Ck
Electric Lake April-July7.5 10.2 77 14.5
Power Plant, Blo April-July26 34 85 45
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July37 47 84 59
Ferron Ck
Ferron, Nr April-July26 34 89 43
Muddy Ck
Emery, Nr April-July10.7 16.1 81 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-July250 310 141 385
Willow Ck
Willow Ck Res, Granby, Nr April-July38 59 126 83
Fraser
Winter Park April-July23 28 144 34
Williams Fork
Williams Fork Res, Parshall, Nr April-July112 135 141 162
Muddy Ck
Wolford Mountain Reservoir April-July65 90 167 114
Blue
Dillon Res April-July205 250 153 295
Green Mtn Res April-July330 405 147 490
Colorado
Kremmling, Nr April-July1050 1260 147 1550
Eagle
Gypsum, Blo April-July300 400 119 525
Colorado
Dotsero, Nr April-July1560 1920 137 2400
Frying Pan
Ruedi Res, Basalt, Nr April-July125 160 115 210
Roaring Fork
Glenwood Springs April-July585 760 110 945
Colorado
Glenwood Springs, Blo April-July2220 2680 127 3400
Cameo, Nr April-July2300 2870 122 3680
Plateau Ck
Cameo, Nr April-July57 105 85 158
Colorado
Cisco, Nr April-July4100 5050 114 6680
Lake Powell, Glen Cyn Dam, At April-July5800 7850 110 10300


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-July100 120 121 146
Almont April-July158 195 126 245
East
Almont April-July180 215 118 265
Gunnison
Gunnison, Nr April-July390 465 126 585
Tomichi Ck
Gunnison April-July70 92 124 130
Lake Fork
Gateview April-July105 133 108 170
Gunnison
Blue Mesa Res April-July690 850 126 1120
Morrow Point Res April-July770 930 126 1200
Crystal Res April-July890 1050 126 1320
Muddy Ck
Paonia Res, Bardine, Nr March-June62 96 100 130
April-June62 96 105 130
April-July66 101 104 134
Nf Gunnison
Somerset, Nr April-July235 300 102 385
Surface Ck
Cedaredge April-July11.5 15.5 92 21
Uncompahgre
Ridgway Res April-July70 91 90 123
Colona April-July90 119 87 174
Delta April-July68 94 83 155
Gunnison
Grand Junction, Nr April-July1200 1640 111 2150


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-July190 235 96 320
Mcphee Res April-July200 250 85 350
San Miguel
Placerville, Nr April-July105 130 102 170
Dolores
Cisco, Nr April-July350 480 85 650


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-July110 147 68 180
Carracas, Nr April-July190 255 67 320
Navajo Res, Archuleta, Nr April-July370 510 69 660
Farmington April-July600 850 77 1150
Bluff, Nr April-July600 830 75 1100
Rio Blanco
Pagosa Springs, Nr, Blanco Dam, Blo April-July25 37 69 48
Navajo
Chromo, Nr, Oso Div Dam, Blo April-July30 40 62 55
Piedra
Arboles, Nr April-July115 155 74 205
Los Pinos
Vallecito Res, Bayfield, Nr April-July126 175 90 230
Animas
Durango April-July320 400 96 520
Florida
Lemon Res, Durango, Nr April-July29 45 82 68
La Plata
Hesperus April-July9.5 15 65 21
Mancos
Mancos, Nr April-July11 18 58 25

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 121.3 100 35 128.8 106 121.7 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 11.5 59 30 9.2 47 19.6 38.3
Blacks Fork
Meeks Cabin 15.8 118 53 8.5 63 13.4 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 7.4 134 53 4.9 89 5.5 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 2916.9 97 78 2986.3 99 3021.3 3749.0
untitled Strawberry
Solider Springs,nr 839.1 126 76 895.4 135 663.7 1105.9
Starvation Res, Duchesne, Nr 162.1 108 98 156.0 104 149.7 165.3
untitled Rock Ck
Upper Stillwater Res 3.4 76 11 9.0 202 4.5 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 26.0 95 71 11.8 43 27.3 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 11.9 62 46 14.8 78 19.0 25.7
untitled Price
Scofield Res, Scofield, Nr 17.7 57 27 30.5 99 30.9 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 32.2 80 52 33.9 85 40.0 62.5
untitled Huntington Ck
Electric Lake 16.9 92 54 19.0 104 18.3 31.5
untitled
TOTAL 4182.1 101 73 4308.2 104 4134.9 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 295.7 95 60 182.2 58 311.8 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 8.1 106 89 8.1 106 7.7 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 75.2 123 78 45.4 75 60.9 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 46.3 97 70 26.9 56 47.7 66.0
untitled Blue
Dillon Res 206.4 97 81 161.8 76 213.6 254.0
Green Mtn Res 68.9 108 47 65.8 103 63.9 146.9
untitled Homestake Ck
Homestake Res 0.1 0 0 0.2 1 18.8 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 64.9 104 64 62.6 100 62.6 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 23.7 129 72 11.3 62 18.3 32.9
untitled Taylor
Taylor Park Res 70.3 115 66 59.2 97 61.2 106.2
untitled Gunnison
Blue Mesa Res 509.1 111 61 338.0 74 457.1 829.5
Morrow Point Res 106.1 95 91 106.5 95 111.8 117.0
Crystal Res 14.2 85 81 12.9 77 16.7 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 0.7 11 4 7.2 111 6.4 16.7
untitled Uncompahgre
Ridgway Res 67.3 101 81 60.4 91 66.6 83.0
untitled Dolores
Mcphee Res 223.3 69 59 197.9 61 323.0 381.1
untitled
TOTAL 1780.3 96 64 1346.6 73 1848.0 2792.1
Colorado
Lake Powell 9731.9 57 40 11422.0 67 17122.8 24322.0
untitled
TOTAL 9731.9 57 40 11422.0 67 17122.8 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 105.8 143 84 62.7 85 74.0 125.4
untitled San Juan
Navajo Res, Archuleta, Nr 1052.7 77 62 928.4 68 1361.0 1696.0
untitled Florida
Lemon Res, Durango, Nr 24.7 103 62 11.2 46 24.1 39.8
untitled
TOTAL 1183.2 81 64 1002.3 69 1459.0 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