Lake Powell Water Supply Outlook, June 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 220 90 255
June-July115 145 86 180
Pine Ck
Fremont Lk, Abv April-July66 81 83 98
June-July46 61 80 78
New Fork
Big Piney, Nr April-July220 260 73 305
June-July133 175 69 220
Green
Fontenelle Res, Fontenelle Nr April-July590 675 93 810
June-July280 365 77 500
Big Sandy
Farson, Nr April-July36 42 81 50
June-July17 23 68 31
Green
Green River, Wy, Nr April-July595 680 93 815
June-July290 375 78 510
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July50 53 98 60
June-July13.1 16 62 23
Viva Naughton Res April-July58 62 84 70
June-July14.5 18.3 59 27
Blacks Fork
Robertson, Nr April-July59 68 76 81
June-July30 39 66 52
Ef Smiths Fork
Stateline Res, Robertson,nr April-July20 22 85 25
June-July11.6 13.3 75 16.5
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July805 910 93 1060
June-July360 465 78 615


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-July24 25 109 29
June-July4.5 5.8 67 9.4
Steamboat Springs April-July235 255 98 290
June-July70 90 76 125
Elk
Milner, Nr April-July230 260 81 295
June-July100 130 82 165
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July46 47 64 49
June-July4.2 5.5 53 7.5
Yampa
Maybell, Nr April-July670 710 76 775
June-July220 260 67 325
Little Snake
Slater, Nr April-July109 117 75 131
June-July29 37 56 51
Dixon, Nr April-July161 181 52 210
June-July45 65 48 95
Lily, Nr April-July193 220 64 250
June-July45 70 52 100
Yampa
Deerlodge Park April-July885 945 76 1030
June-July280 340 68 420
White
Meeker, Nr April-July220 235 84 255
June-July85 100 69 123
Watson, Nr April-July205 230 82 255
June-July80 105 76 130


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-July11.3 13 62 14.2
June-July3 4.7 52 5.9
Ashley Ck
Vernal, Nr April-July28 30 60 34
June-July12.5 14.5 60 18.5
West Fork Duchesne
Vat Diversion, Blo April-July11 12 65 13.7
June-July3.5 4.5 48 6.2
Duchesne
Tabiona, Nr April-July64 70 65 77
June-July30 36 60 43
Rock Ck
Upper Stillwater Res April-July52 59 80 66
June-July28 35 74 42
South Fork Rock Ck
Docs Div, Blo April-July4.2 4.8 66 5.5
June-July2.4 3 61 3.7
Rock Ck
Mountain Home, Nr April-July59 66 75 72
June-July34 41 73 47
Currant Ck
Currant Ck Res April-July8.9 9.3 47 10.1
June-July2.3 2.7 36 3.5
Strawberry
Solider Springs,nr April-July21 23 32 25
June-July6.5 8.5 35 10.5
Starvation Res, Duchesne, Nr April-July34 37 33 41
June-July11.5 14 37 18
Duchesne
Duchesne, Nr, Knight Div, Abv April-July124 135 70 146
June-July65 76 66 87
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July43 49 74 54
June-July26 32 74 37
Yellowstone
Altonah, Nr April-July43 47 77 53
June-July30 34 83 40
Whiterocks
Whiterocks, Nr April-July37 41 76 47
June-July24 28 82 34
Uinta
Neola, Nr April-July51 57 77 64
June-July36 42 84 49
Duchesne
Myton April-July155 171 52 194
June-July72 88 51 111
Randlett, Nr April-July166 185 48 220
June-July78 97 46 130


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-July2 2.1 13.5 2.4
June-July0.6 0.7 21 0.96
Fish Ck
Scofield, Nr, Reservoir, Abv April-July9.7 9.9 33 10.6
June-July2.5 2.7 28 3.4
Price
Scofield Res, Scofield, Nr April-July10.8 11.9 29 12.8
June-July2 3.1 23 4
Green
Green River, Ut April-July2040 2200 74 2680
June-July860 1020 66 1500
Huntington Ck
Electric Lake April-July5.2 5.5 41 6.3
June-July0.9 1.2 25 2
Power Plant, Blo April-July18.3 20 50 23
June-July8.5 10.7 54 13.5
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July30 32 57 34
June-July13 15.1 47 17
Ferron Ck
Ferron, Nr April-July24 26 68 29
June-July13 14.5 69 17.8
Muddy Ck
Emery, Nr April-July11.4 12.2 61 13.3
June-July6.2 7 60 8.1


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-July205 235 107 260
June-July135 166 114 190
Willow Ck
Willow Ck Res, Granby, Nr April-July36 41 87 47
June-July11 16 76 22
Fraser
Winter Park April-July17.2 20 103 23
June-July13.5 16.3 115 19
Williams Fork
Williams Fork Res, Parshall, Nr April-July89 100 104 107
June-July62 73 112 80
Muddy Ck
Wolford Mountain Reservoir April-July46 52 96 59
June-July12 18 93 25
Blue
Dillon Res April-July173 200 123 215
June-July130 157 143 170
Green Mtn Res April-July260 305 111 325
June-July185 230 125 250
Colorado
Kremmling, Nr April-July815 890 103 955
June-July510 585 111 650
Eagle
Gypsum, Blo April-July270 310 93 345
June-July175 215 100 250
Colorado
Dotsero, Nr April-July1240 1350 96 1460
June-July750 860 102 970
Frying Pan
Ruedi Res, Basalt, Nr April-July109 125 90 144
June-July75 91 102 110
Roaring Fork
Glenwood Springs April-July530 595 86 650
June-July375 440 97 495
Colorado
Glenwood Springs, Blo April-July1820 1980 94 2150
June-July1150 1310 101 1480
Cameo, Nr April-July1910 2110 89 2290
June-July1180 1380 97 1560
Plateau Ck
Cameo, Nr April-July64 75 60 85
June-July20 31 63 41
Colorado
Cisco, Nr April-July3160 3470 78 3850
June-July1790 2100 90 2480
Lake Powell, Glen Cyn Dam, At April-July4450 5000 70 6000
June-July2200 2750 73 3750


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-July75 86 87 108
June-July47 58 94 80
Almont April-July117 128 83 157
June-July75 86 91 115
East
Almont April-July114 129 71 157
May-July0 0 0 0
June-July62 77 73 105
Gunnison
Gunnison, Nr April-July245 280 76 325
June-July140 175 81 220
Tomichi Ck
Gunnison April-July58 66 89 79
June-July27 35 95 48
Lake Fork
Gateview April-July100 116 94 138
June-July72 88 109 110
Gunnison
Blue Mesa Res April-July520 570 84 670
June-July310 360 95 460
Morrow Point Res April-July565 615 83 715
June-July335 385 95 485
Crystal Res April-July625 675 81 775
June-July375 425 94 525
Muddy Ck
Paonia Res, Bardine, Nr March-June50 53 55 59
April-July31 50 52 70
June-June9 12 52 18
June-July11 14 48 20
Nf Gunnison
Somerset, Nr April-July154 165 56 187
June-July45 56 49 78
Surface Ck
Cedaredge April-July7.3 8 48 10.8
June-July1.5 2.2 29 5
Uncompahgre
Ridgway Res April-July61 73 72 85
June-July41 53 82 65
Colona April-July76 88 64 108
June-July50 62 77 82
Delta April-July69 76 67 90
June-July34 41 72 55
Gunnison
Grand Junction, Nr April-July905 1030 70 1210
June-July430 550 79 730


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-July156 171 70 205
June-July65 80 87 115
Mcphee Res April-July165 180 61 215
June-July68 83 86 120
San Miguel
Placerville, Nr April-July84 104 81 122
June-July50 70 93 88
Dolores
Cisco, Nr April-July270 295 52 355
June-July125 150 82 210


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 122 57 145
June-July30 42 44 65
Carracas, Nr April-July205 215 57 245
June-July65 77 49 105
Navajo Res, Archuleta, Nr April-July370 405 55 470
June-July110 145 50 210
Farmington April-July555 605 55 785
June-July200 250 53 430
Bluff, Nr April-July505 580 53 745
June-July160 235 52 400
Rio Blanco
Pagosa Springs, Nr, Blanco Dam, Blo April-July30 33 61 42
June-July8 11 48 20
Navajo
Chromo, Nr, Oso Div Dam, Blo April-July31 34 52 42
June-July11 14 47 22
Piedra
Arboles, Nr April-July132 140 67 156
June-July46 54 73 70
Los Pinos
Vallecito Res, Bayfield, Nr April-July122 135 70 174
June-July60 73 74 112
Animas
Durango April-July290 315 76 370
June-July165 190 86 245
Florida
Lemon Res, Durango, Nr April-July27 32 58 40
June-July12 17 63 25
La Plata
Hesperus April-July8.7 10.7 47 12.7
June-July3 5 59 7
Mancos
Mancos, Nr April-July13 16 52 18
June-July4 7 67 9

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 297.8 182 86 186.4 114 164.0 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 35.0 119 91 24.3 83 29.4 38.3
Blacks Fork
Meeks Cabin 30.3 122 102 30.4 122 24.9 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 14.0 124 101 14.2 126 11.3 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 3197.7 104 85 3185.0 104 3071.5 3749.0
untitled Strawberry
Solider Springs,nr 849.9 119 77 870.6 122 716.0 1105.9
Starvation Res, Duchesne, Nr 163.6 106 99 158.3 102 154.8 165.3
untitled Rock Ck
Upper Stillwater Res 21.0 134 67 19.8 126 15.7 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 32.0 112 88 30.5 107 28.6 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 18.3 78 71 13.6 58 23.4 25.7
untitled Price
Scofield Res, Scofield, Nr 18.5 38 28 26.1 54 48.5 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 48.8 95 78 51.4 100 51.6 62.5
untitled Huntington Ck
Electric Lake 20.9 88 66 23.1 97 23.8 31.5
untitled
TOTAL 4747.7 109 83 4633.9 106 4363.6 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 505.2 139 103 383.2 105 363.6 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 7.4 83 82 10.1 113 8.9 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 86.3 118 89 91.9 126 73.0 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 52.5 88 80 68.4 114 59.9 66.0
untitled Blue
Dillon Res 224.8 97 88 202.9 87 232.7 254.0
Green Mtn Res 111.4 124 76 98.6 110 89.8 146.9
untitled Homestake Ck
Homestake Res 24.7 100 58 1.4 6 24.8 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 84.3 108 83 81.0 104 78.0 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 32.3 105 98 34.4 112 30.8 32.9
untitled Taylor
Taylor Park Res 90.5 121 85 74.1 99 74.7 106.2
untitled Gunnison
Blue Mesa Res 652.8 113 79 675.6 117 575.3 829.5
Morrow Point Res 111.6 99 95 111.1 98 113.2 117.0
Crystal Res 16.7 100 95 18.7 112 16.7 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 15.6 100 94 14.5 92 15.7 16.7
untitled Uncompahgre
Ridgway Res 72.3 102 87 60.9 86 70.7 83.0
untitled Dolores
Mcphee Res 264.8 76 69 270.0 78 347.8 381.1
untitled
TOTAL 2353.5 108 84 2197.0 101 2175.6 2792.1
Colorado
Lake Powell 11491.5 63 47 10764.5 59 18186.3 24322.0
untitled
TOTAL 11491.5 63 47 10764.5 59 18186.3 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 119.9 119 96 121.6 121 100.5 125.4
untitled San Juan
Navajo Res, Archuleta, Nr 1266.5 89 75 1142.1 80 1429.7 1696.0
untitled Florida
Lemon Res, Durango, Nr 34.2 107 86 33.0 103 32.1 39.8
untitled
TOTAL 1420.6 91 76 1296.7 83 1562.3 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