Upper Colorado Water Supply Outlook, June 1, 2013

Note: This publication is scheduled for revision. If you have feedback on content, format, or publication frequency, please contact us.
Prepared by Brenda Alcorn, Greg Smith
NOAA, National Weather Service
Colorado Basin River Forecast Center
Salt Lake City, Utah
www.cbrfc.noaa.gov

Contents

Upper Colorado Summary




*Median of forecasts within each basin.


Upper Colorado Mainstem Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Gunnison Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Dolores Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.


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-July185 205 93 230
June-July110 130 90 155
Willow Ck
Willow Ck Res, Granby, Nr April-July47 51 109 58
June-July14 18 86 25
Fraser
Winter Park April-July15.2 17.2 89 19.2
June-July11 13 92 15
Williams Fork
Williams Fork Res, Parshall, Nr April-July82 88 92 96
June-July50 56 86 64
Muddy Ck
Wolford Mountain Reservoir April-July38 44 81 46
June-July10 16 83 18
Blue
Dillon Res April-July134 149 91 164
June-July90 105 95 120
Green Mtn Res April-July220 245 89 280
June-July140 165 90 200
Colorado
Kremmling, Nr April-July695 785 91 870
June-July360 450 86 535
Eagle
Gypsum, Blo April-July183 215 64 240
June-July95 125 58 150
Colorado
Dotsero, Nr April-July1050 1170 84 1280
June-July535 650 77 760
Frying Pan
Ruedi Res, Basalt, Nr April-July80 95 68 105
June-July47 62 70 72
Roaring Fork
Glenwood Springs April-July405 465 67 505
June-July250 310 68 350
Colorado
Glenwood Springs, Blo April-July1500 1660 79 1820
June-July800 965 74 1120
Cameo, Nr April-July1550 1740 74 1920
June-July830 1020 72 1200
Plateau Ck
Cameo, Nr April-July53 61 49 71
June-July7 15 31 25
Colorado
Cisco, Nr April-July2260 2570 58 2810
June-July1000 1300 56 1550
Lake Powell, Glen Cyn Dam, At April-July2480 3000 42 3480
June-July1000 1520 40 2000


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-July61 69 70 77
June-July34 42 68 50
Almont April-July87 98 63 106
June-July46 57 61 65
East
Almont April-July102 110 60 118
May-July0 0 0 0
June-July52 60 57 68
Gunnison
Gunnison, Nr April-July185 210 57 235
June-July98 123 57 148
Tomichi Ck
Gunnison April-July16 19 26 23
June-July7 9 24 13
Lake Fork
Gateview April-July63 68 55 73
June-July30 35 43 45
Gunnison
Blue Mesa Res April-July330 370 55 400
June-July154 194 51 225
Morrow Point Res April-July360 400 54 430
June-July165 205 51 235
Crystal Res April-July395 435 52 465
June-July180 220 49 250
Muddy Ck
Paonia Res, Bardine, Nr March-June35 37 39 38
April-July35 37 38 40
June-June7 9 39 10
June-July9.5 11.2 39 14
Nf Gunnison
Somerset, Nr April-July151 169 57 180
June-July52 69 61 80
Surface Ck
Cedaredge April-July4.8 5.4 32 6.9
June-July1.2 1.8 24 3.3
Uncompahgre
Ridgway Res April-July44 51 50 59
June-July19 27 42 35
Colona April-July46 54 39 63
June-July15 23 28 32
Delta April-July33 38 34 44
June-July5 10 17.5 16
Gunnison
Grand Junction, Nr April-July585 650 44 710
June-July190 255 37 315


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-July75 90 37 115
June-July10 27 29 40
Mcphee Res April-July80 95 32 120
June-July10 28 29 45
San Miguel
Placerville, Nr April-July47 65 51 77
June-July15 33 44 45
Dolores
Cisco, Nr April-July127 147 26 190
June-July20 40 22 70

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).

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 272.3 75 56 426.1 117 363.6 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 10.0 112 109 8.2 93 8.9 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 71.1 97 73 91.9 126 73.0 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 49.3 82 75 66.1 110 59.9 66.0
untitled Blue
Dillon Res 193.8 83 76 243.2 105 232.7 254.0
Green Mtn Res 95.1 106 65 102.4 114 89.8 146.9
untitled Homestake Ck
Homestake Res 5.0 20 12 0.3 1 24.8 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 74.7 96 73 85.2 109 78.0 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 28.2 92 86 30.6 99 30.8 32.9
untitled Taylor
Taylor Park Res 73.6 99 69 80.5 108 74.7 106.2
untitled Gunnison
Blue Mesa Res 398.5 69 48 526.7 92 575.3 829.5
Morrow Point Res 112.2 99 96 112.3 99 113.2 117.0
Crystal Res 12.6 75 72 14.9 89 16.7 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 15.6 99 93 15.4 99 15.7 16.7
untitled Uncompahgre
Ridgway Res 72.8 103 88 75.1 106 70.7 83.0
untitled Dolores
Mcphee Res 215.6 62 57 338.2 97 347.8 381.1
untitled
TOTAL 1700.3 78 61 2217.2 102 2175.6 2792.1
Colorado
Lake Powell 11696.7 64 48 15631.9 86 18186.3 24322.0
untitled
TOTAL 11696.7 64 48 15631.9 86 18186.3 24322.0

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


Hydrologist: Brenda Alcorn, Greg Smith