Upper Colorado Water Supply Outlook, March 1, 2016

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-July115 145 175 80 195 240
Willow Ck
Willow Ck Res, Granby, Nr April-July25 35 43 91 48 67
Fraser
Winter Park April-July14.5 16.5 18 93 21 22
Williams Fork
Williams Fork Res, Parshall, Nr April-July60 73 85 89 92 115
Muddy Ck
Wolford Mountain Reservoir April-July29 35 48 89 57 70
Blue
Dillon Res April-July105 132 145 89 162 190
Green Mtn Res April-July170 210 245 89 260 325
Colorado
Kremmling, Nr April-July530 665 740 86 790 1060
Eagle
Gypsum, Blo April-July215 230 285 85 350 450
Colorado
Dotsero, Nr April-July880 1060 1200 86 1330 1760
Frying Pan
Ruedi Res, Basalt, Nr April-July90 100 125 90 145 185
Roaring Fork
Glenwood Springs April-July440 520 590 86 620 830
Colorado
Glenwood Springs, Blo April-July1350 1600 1810 86 2050 2650
Cameo, Nr April-July1500 1790 1990 84 2300 2950
Plateau Ck
Cameo, Nr April-July55 80 105 85 118 160
Colorado
Cisco, Nr April-July2800 3370 3870 87 4200 5600
Lake Powell, Glen Cyn Dam, At April-July3800 4650 5700 80 6500 8000


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-July65 74 83 84 95 115
Almont April-July100 114 127 82 145 175
East
Almont April-July104 125 135 74 150 195
Gunnison
Gunnison, Nr April-July200 240 280 76 300 410
Tomichi Ck
Gunnison April-July43 55 65 88 77 100
Lake Fork
Gateview April-July90 106 127 103 142 175
Gunnison
Blue Mesa Res April-July450 510 580 86 620 840
Morrow Point Res April-July500 560 630 85 670 890
Crystal Res April-July580 640 710 85 750 970
Muddy Ck
Paonia Res, Bardine, Nr March-June60 75 84 88 92 124
April-July59 74 83 86 91 123
Nf Gunnison
Somerset, Nr April-July195 220 245 83 275 370
Surface Ck
Cedaredge April-July8 12 13.5 80 16 20
Uncompahgre
Ridgway Res April-July75 88 97 96 106 135
Colona April-July95 117 130 95 150 200
Delta April-July70 93 106 94 121 180
Gunnison
Grand Junction, Nr April-July1000 1160 1280 86 1500 2000


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-July169 220 250 102 275 330
Mcphee Res April-July190 260 295 100 325 425
San Miguel
Placerville, Nr April-July95 120 135 105 152 188
Dolores
Cisco, Nr April-July360 500 570 101 650 880

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 406.8 123 83 484.0 146 332.0 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 8.7 105 95 9.5 115 8.2 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 76.7 123 79 78.1 125 62.4 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 42.0 95 64 45.4 103 44.2 66.0
untitled Blue
Dillon Res 236.6 108 93 244.8 112 219.3 254.0
Green Mtn Res 65.8 90 45 70.8 96 73.5 146.9
untitled Homestake Ck
Homestake Res -9999.0 135 -99 -9999.0 -99 30.7 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 68.7 101 67 78.2 115 67.9 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 12.9 97 39 15.0 113 13.2 32.9
untitled Taylor
Taylor Park Res 68.4 104 64 78.0 119 65.7 106.2
untitled Gunnison
Blue Mesa Res 558.5 116 67 546.6 113 482.2 829.5
Morrow Point Res 108.1 97 92 110.0 99 111.1 117.0
Crystal Res 16.8 107 96 16.7 106 15.8 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 1.4 29 8 1.2 25 4.7 16.7
untitled Uncompahgre
Ridgway Res 65.4 94 79 77.5 112 69.4 83.0
untitled Dolores
Mcphee Res 249.5 92 65 186.1 68 272.3 381.1
untitled
TOTAL 2027.6 108 72 2041.8 111 1872.6 2749.1
Colorado
Lake Powell 11224.5 66 46 11023.6 65 17054.6 24322.0
untitled
TOTAL 11224.5 66 46 11023.6 65 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