Lake Powell Water Supply Outlook, February 1, 2017

Note: This publication is scheduled for revision. If you have feedback on content, format, or publication frequency, please contact us.
Prepared by CBRFC
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		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Green
Daniel, Nr, Warren Bridge, At April-July270 320 380 155 395 440
Pine Ck
Fremont Lk, Abv April-July103 115 132 135 136 152
New Fork
Big Piney, Nr April-July425 490 560 158 625 695
Green
Fontenelle Res, Fontenelle Nr April-July915 1100 1200 166 1350 1600
Big Sandy
Farson, Nr April-July55 69 75 144 82 95
Green
Green River, Wy, Nr April-July965 1160 1230 168 1400 1680
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July60 72 80 148 94 116
Viva Naughton Res April-July83 99 114 154 134 172
Blacks Fork
Robertson, Nr April-July86 96 110 124 124 155
Ef Smiths Fork
Stateline Res, Robertson,nr April-July27 30 32 123 38 43
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July1240 1460 1650 168 1830 2360


Yampa/White Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Yampa
Stagecoach Rsvr, Abv April-July16.6 18.1 23 100 26 34
Steamboat Springs April-July190 230 270 104 300 365
Elk
Milner, Nr April-July270 335 375 117 415 475
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July58 79 87 119 99 116
Yampa
Maybell, Nr April-July730 880 1030 110 1130 1370
Little Snake
Slater, Nr April-July123 150 175 112 195 230
Dixon, Nr April-July240 305 360 104 445 530
Lily, Nr April-July245 315 380 110 485 570
Yampa
Deerlodge Park April-July945 1190 1400 113 1550 1880
White
Meeker, Nr April-July215 255 290 104 315 380
Watson, Nr April-July230 270 315 113 340 430


Duchesne Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Big Brush Ck
Vernal, Nr, Red Fleet Res, Abv April-July16 21 24 114 28 35
Ashley Ck
Vernal, Nr April-July38 49 57 114 63 85
West Fork Duchesne
Vat Diversion, Blo April-July23 28 30 161 32 41
Duchesne
Tabiona, Nr April-July124 144 157 145 169 205
Rock Ck
Upper Stillwater Res April-July92 103 109 147 121 147
South Fork Rock Ck
Docs Div, Blo April-July9.5 11 12.2 167 13.7 15.1
Rock Ck
Mountain Home, Nr April-July108 122 129 147 146 181
Currant Ck
Currant Ck Res April-July24 32 35 175 38 48
Strawberry
Solider Springs,nr April-July67 92 100 141 115 142
Starvation Res, Duchesne, Nr April-July137 188 205 183 230 300
Duchesne
Duchesne, Nr, Knight Div, Abv April-July230 265 285 147 315 380
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July76 89 96 145 105 128
Yellowstone
Altonah, Nr April-July69 85 93 152 102 120
Whiterocks
Whiterocks, Nr April-July50 65 76 141 79 108
Uinta
Neola, Nr April-July76 99 113 153 119 151
Duchesne
Myton April-July410 520 550 167 640 815
Randlett, Nr April-July460 595 655 170 765 1020


Lower Green Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
White
Blo Tabbyune Ck, Soldier Summit, Nr April-July19.4 26 29 187 33 38
Fish Ck
Scofield, Nr, Reservoir, Abv April-July37 40 45 150 51 63
Price
Scofield Res, Scofield, Nr April-July51 56 63 154 72 92
Green
Green River, Ut April-July3130 3710 4070 138 4520 6030
Huntington Ck
Electric Lake April-July17.9 20 24 180 27 33
Power Plant, Blo April-July55 65 73 183 79 91
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July56 67 75 134 83 106
Ferron Ck
Ferron, Nr April-July38 47 50 132 54 73
Muddy Ck
Emery, Nr April-July19.3 26 28 141 32 40


Upper Colorado Mainstem Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Colorado
Lake Granby, Granby, Nr April-July180 220 250 114 280 365
Willow Ck
Willow Ck Res, Granby, Nr April-July43 55 65 138 85 110
Fraser
Winter Park April-July16 19 23 119 25 29
Williams Fork
Williams Fork Res, Parshall, Nr April-July85 105 115 120 130 165
Muddy Ck
Wolford Mountain Reservoir April-July35 50 62 115 75 90
Blue
Dillon Res April-July140 175 195 120 215 255
Green Mtn Res April-July240 295 330 120 360 450
Colorado
Kremmling, Nr April-July750 950 1040 121 1210 1550
Eagle
Gypsum, Blo April-July260 320 370 110 410 525
Colorado
Dotsero, Nr April-July1200 1480 1650 118 1870 2370
Frying Pan
Ruedi Res, Basalt, Nr April-July105 130 160 115 175 220
Roaring Fork
Glenwood Springs April-July600 725 800 116 860 1070
Colorado
Glenwood Springs, Blo April-July1840 2200 2450 116 2700 3500
Cameo, Nr April-July2100 2550 2780 118 3000 4000
Plateau Ck
Cameo, Nr April-July105 130 150 121 165 215
Colorado
Cisco, Nr April-July4000 5000 5500 124 6000 7550
Lake Powell, Glen Cyn Dam, At April-July6600 8300 9600 134 10500 13500


Gunnison Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Taylor
Taylor Park Res April-July99 115 128 129 145 165
Almont April-July157 188 210 135 230 265
East
Almont April-July185 220 245 135 260 315
Gunnison
Gunnison, Nr April-July380 460 510 138 560 660
Tomichi Ck
Gunnison April-July75 92 105 142 120 170
Lake Fork
Gateview April-July109 128 150 122 167 195
Gunnison
Blue Mesa Res April-July690 820 925 137 990 1250
Morrow Point Res April-July785 915 1020 138 1090 1350
Crystal Res April-July915 1050 1150 138 1220 1480
Muddy Ck
Paonia Res, Bardine, Nr March-June95 110 118 123 133 167
April-July96 111 119 123 134 168
Nf Gunnison
Somerset, Nr April-July285 325 355 120 380 480
Surface Ck
Cedaredge April-July15 18 21 125 25 31
Uncompahgre
Ridgway Res April-July85 110 118 117 126 160
Colona April-July114 142 158 115 171 225
Delta April-July82 120 133 118 145 200
Gunnison
Grand Junction, Nr April-July1480 1720 1920 130 1980 2650


Dolores Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Dolores
Dolores April-July280 335 370 151 400 475
Mcphee Res April-July320 395 440 149 480 570
San Miguel
Placerville, Nr April-July109 142 155 121 173 210
Dolores
Cisco, Nr April-July550 720 800 142 900 1110


San Juan Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
San Juan
Pagosa Springs April-July200 235 255 119 280 340
Carracas, Nr April-July355 405 455 120 510 620
Navajo Res, Archuleta, Nr April-July640 755 880 120 1000 1230
Farmington April-July990 1190 1360 124 1520 1850
Bluff, Nr April-July1030 1210 1370 125 1580 1930
Rio Blanco
Pagosa Springs, Nr, Blanco Dam, Blo April-July54 59 67 124 78 87
Navajo
Chromo, Nr, Oso Div Dam, Blo April-July61 67 77 118 90 101
Piedra
Arboles, Nr April-July185 215 245 117 285 350
Los Pinos
Vallecito Res, Bayfield, Nr April-July180 210 235 121 260 300
Animas
Durango April-July400 480 515 124 590 640
Florida
Lemon Res, Durango, Nr April-July48 57 65 118 74 86
La Plata
Hesperus April-July25 29 33 143 37 42
Mancos
Mancos, Nr April-July30 38 43 139 51 60

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 184.2 123 53 170.0 113 150.1 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 23.5 142 61 19.7 119 16.6 38.3
Blacks Fork
Meeks Cabin 11.2 97 38 7.0 60 11.5 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 6.4 114 46 6.0 107 5.6 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 3087.3 101 82 3162.8 104 3050.5 3749.0
untitled Strawberry
Solider Springs,nr 775.8 118 70 792.1 120 659.9 1105.9
Starvation Res, Duchesne, Nr 142.2 102 86 150.6 108 138.8 165.3
untitled Rock Ck
Upper Stillwater Res 15.1 175 48 11.1 128 8.6 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 24.7 101 68 21.5 88 24.4 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 21.4 118 83 16.1 89 18.0 25.7
untitled Price
Scofield Res, Scofield, Nr 14.5 49 22 10.9 37 29.9 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 30.4 77 49 36.8 94 39.3 62.5
untitled Huntington Ck
Electric Lake 16.1 84 51 17.0 89 19.2 31.5
untitled
TOTAL 4352.8 104 76 4421.6 106 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 424.3 120 87 436.9 124 352.2 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 8.2 104 91 8.3 104 8.0 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 74.4 117 77 78.0 122 63.8 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 50.7 114 77 42.6 95 44.6 66.0
untitled Blue
Dillon Res 224.0 100 88 236.9 106 223.2 254.0
Green Mtn Res 67.2 83 46 67.9 84 81.1 146.9
untitled Homestake Ck
Homestake Res -9999.0 -99 -99 41.3 129 31.9 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 67.8 94 67 70.3 97 72.4 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 11.9 95 36 12.1 96 12.6 32.9
untitled Taylor
Taylor Park Res 69.5 104 65 69.7 104 66.9 106.2
untitled Gunnison
Blue Mesa Res 586.6 114 71 590.1 115 514.6 829.5
Morrow Point Res 111.7 100 95 109.6 98 111.4 117.0
Crystal Res 16.2 105 92 15.6 102 15.3 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 1.6 38 10 1.1 26 4.2 16.7
untitled Uncompahgre
Ridgway Res 63.8 92 77 63.5 92 69.2 83.0
untitled Dolores
Mcphee Res 294.4 109 77 246.3 91 270.9 381.1
untitled
TOTAL 2072.4 108 75 2090.0 108 1910.6 2749.1
Colorado
Lake Powell 11359.3 66 47 11426.7 66 17338.2 24322.0
untitled
TOTAL 11359.3 66 47 11426.7 66 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 76.2 120 61 86.4 136 63.5 125.4
untitled San Juan
Navajo Res, Archuleta, Nr 1339.1 104 79 1404.7 109 1292.2 1696.0
untitled Florida
Lemon Res, Durango, Nr 21.0 100 53 21.5 103 21.0 39.8
untitled
TOTAL 1436.3 104 77 1512.6 110 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