Upper Colorado Water Supply Outlook, March 1, 2017

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




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.


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-July190 230 260 118 290 355
Willow Ck
Willow Ck Res, Granby, Nr April-July47 60 70 149 80 110
Fraser
Winter Park April-July18.4 21 23 119 25 29
Williams Fork
Williams Fork Res, Parshall, Nr April-July90 105 115 120 125 160
Muddy Ck
Wolford Mountain Reservoir April-July33 43 57 106 65 83
Blue
Dillon Res April-July150 175 195 120 210 235
Green Mtn Res April-July255 300 330 120 350 420
Colorado
Kremmling, Nr April-July825 1000 1060 123 1180 1490
Eagle
Gypsum, Blo April-July265 300 360 107 400 490
Colorado
Dotsero, Nr April-July1300 1520 1670 119 1770 2270
Frying Pan
Ruedi Res, Basalt, Nr April-July105 125 155 112 165 205
Roaring Fork
Glenwood Springs April-July610 690 790 114 820 990
Colorado
Glenwood Springs, Blo April-July1950 2230 2450 116 2670 3350
Cameo, Nr April-July2150 2500 2780 118 3000 3800
Plateau Ck
Cameo, Nr April-July100 125 145 117 165 200
Colorado
Cisco, Nr April-July4200 5000 5500 124 6000 7300
Lake Powell, Glen Cyn Dam, At April-July7600 9000 10400 145 11700 13800


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-July105 117 128 129 145 165
Almont April-July165 185 210 135 235 270
East
Almont April-July200 235 255 140 270 320
Gunnison
Gunnison, Nr April-July415 480 520 141 560 665
Tomichi Ck
Gunnison April-July80 96 110 149 130 170
Lake Fork
Gateview April-July104 130 145 118 165 195
Gunnison
Blue Mesa Res April-July770 870 970 144 1040 1280
Morrow Point Res April-July860 980 1060 143 1140 1370
Crystal Res April-July990 1110 1190 143 1270 1500
Muddy Ck
Paonia Res, Bardine, Nr March-June85 100 115 120 125 155
April-July85 100 115 119 125 155
Nf Gunnison
Somerset, Nr April-July260 300 345 117 380 465
Surface Ck
Cedaredge April-July14 18 21 125 24 28
Uncompahgre
Ridgway Res April-July84 107 118 117 130 160
Colona April-July110 140 158 115 175 225
Delta April-July79 120 133 118 151 205
Gunnison
Grand Junction, Nr April-July1570 1800 1950 132 2200 2700


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 340 370 151 400 475
Mcphee Res April-July330 400 440 149 475 580
San Miguel
Placerville, Nr April-July109 140 155 121 170 205
Dolores
Cisco, Nr April-July560 735 800 142 880 1090

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 398.0 120 81 406.8 123 332.0 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 8.6 105 95 8.7 105 8.2 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 73.2 117 76 76.7 123 62.4 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 50.5 114 77 42.0 95 44.2 66.0
untitled Blue
Dillon Res 218.5 100 86 236.6 108 219.3 254.0
Green Mtn Res 65.7 89 45 65.8 90 73.5 146.9
untitled Homestake Ck
Homestake Res -9999.0 -99 -99 41.2 134 30.7 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 66.1 97 65 68.7 101 67.9 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 12.8 97 39 12.9 97 13.2 32.9
untitled Taylor
Taylor Park Res 69.0 105 65 68.4 104 65.7 106.2
untitled Gunnison
Blue Mesa Res 571.4 118 69 558.5 116 482.2 829.5
Morrow Point Res 102.3 92 87 108.2 97 111.1 117.0
Crystal Res 16.0 101 91 16.8 107 15.8 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 2.5 53 15 1.4 29 4.7 16.7
untitled Uncompahgre
Ridgway Res 65.0 94 78 65.4 94 69.4 83.0
untitled Dolores
Mcphee Res 298.7 110 78 249.5 92 272.3 381.1
untitled
TOTAL 2018.3 110 73 2027.5 108 1842.0 2749.1
Colorado
Lake Powell 11217.0 66 46 11224.5 66 17054.6 24322.0
untitled
TOTAL 11217.0 66 46 11224.5 66 17054.6 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