Upper Colorado Water Supply Outlook, January 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-July97 165 75 250
Willow Ck
Willow Ck Res, Granby, Nr April-July17 38 81 67
Fraser
Winter Park April-July8 15 77 22
Williams Fork
Williams Fork Res, Parshall, Nr April-July45 75 78 112
Muddy Ck
Wolford Mountain Reservoir April-July15 40 74 70
Blue
Dillon Res April-July65 115 71 178
Green Mtn Res April-July115 200 73 315
Colorado
Kremmling, Nr April-July330 620 72 950
Eagle
Gypsum, Blo April-July130 235 70 400
Colorado
Dotsero, Nr April-July535 995 71 1580
Frying Pan
Ruedi Res, Basalt, Nr April-July50 90 65 157
Roaring Fork
Glenwood Springs April-July280 470 68 755
Colorado
Glenwood Springs, Blo April-July850 1500 71 2350
Cameo, Nr April-July950 1650 70 2640
Plateau Ck
Cameo, Nr April-July34 88 71 175
Colorado
Cisco, Nr April-July1700 2860 64 4900
Lake Powell, Glen Cyn Dam, At April-July1800 4400 61 7700


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-July47 62 63 110
Almont April-July63 90 58 158
East
Almont April-July76 115 63 215
Gunnison
Gunnison, Nr April-July152 215 58 405
Tomichi Ck
Gunnison April-July19 42 57 78
Lake Fork
Gateview April-July45 75 61 120
Gunnison
Blue Mesa Res April-July290 390 58 665
Morrow Point Res April-July320 420 57 695
Crystal Res April-July365 465 56 740
Muddy Ck
Paonia Res, Bardine, Nr March-June40 65 68 109
April-July40 66 68 111
Nf Gunnison
Somerset, Nr April-July130 192 65 290
Surface Ck
Cedaredge April-July8 12 71 23
Uncompahgre
Ridgway Res April-July41 63 62 98
Colona April-July42 69 50 130
Delta April-July27 50 44 114
Gunnison
Grand Junction, Nr April-July600 830 56 1350


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-July90 175 71 285
Mcphee Res April-July100 205 69 345
San Miguel
Placerville, Nr April-July50 90 70 150
Dolores
Cisco, Nr April-July210 390 69 720

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)

Usable
Capacity		EOM
Contents		Percent
Usable
Capacity		Last Year
EOM		Last Year
%Capacity
untitled Colorado
Lake Granby, Granby, Nr 490.3 233.3 48 412.5 84
untitled Willow Ck
Willow Ck Res, Granby, Nr 9.1 7.8 85 8.1 88
untitled Williams Fork
Williams Fork Res, Parshall, Nr 96.9 43.0 44 80.1 83
untitled Muddy Ck
Wolford Mountain Reservoir 66.0 24.7 37 58.3 88
untitled Blue
Dillon Res 254.0 178.0 70 240.8 95
Green Mtn Res 146.9 64.8 44 93.8 64
untitled Homestake Ck
Homestake Res 43.0 -9999.0 -99 22.9 53
untitled Frying Pan
Ruedi Res, Basalt, Nr 102.0 63.8 63 79.2 78
untitled Plateau Ck
Vega Res, Collbran, Nr 32.9 7.8 24 16.7 51
untitled Taylor
Taylor Park Res 106.2 56.6 53 66.7 63
untitled Gunnison
Blue Mesa Res 829.5 327.5 39 574.1 69
Morrow Point Res 117.0 106.4 91 113.0 97
Crystal Res 17.5 15.8 90 16.4 93
untitled Muddy Ck
Paonia Res, Bardine, Nr 18.5 1.3 7 0.5 3
untitled Uncompahgre
Ridgway Res 83.2 54.3 65 68.8 83
untitled Dolores
Mcphee Res 381.1 192.2 50 289.3 76
untitled
TOTAL 2794.1 1377.3 49 2141.1 77
Colorado
Lake Powell 24322.0 12707.2 52 15973.6 66
untitled
TOTAL 24322.0 12707.2 52 15973.6 66

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