Upper Colorado Water Supply Outlook, April 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-July145 175 195 89 210 255
Willow Ck
Willow Ck Res, Granby, Nr April-July35 46 54 115 60 75
Fraser
Winter Park April-July17 19 21 108 23 25
Williams Fork
Williams Fork Res, Parshall, Nr April-July70 85 95 99 100 120
Muddy Ck
Wolford Mountain Reservoir April-July37 45 55 102 65 77
Blue
Dillon Res April-July120 140 155 95 168 200
Green Mtn Res April-July200 230 255 93 280 335
Colorado
Kremmling, Nr April-July650 740 820 95 900 1100
Eagle
Gypsum, Blo April-July220 255 295 88 335 415
Colorado
Dotsero, Nr April-July1020 1140 1300 93 1390 1760
Frying Pan
Ruedi Res, Basalt, Nr April-July84 105 117 84 127 165
Roaring Fork
Glenwood Springs April-July400 495 550 80 590 735
Colorado
Glenwood Springs, Blo April-July1480 1690 1870 89 2020 2540
Cameo, Nr April-July1630 1850 2060 87 2220 2800
Plateau Ck
Cameo, Nr April-July60 85 100 81 110 150
Colorado
Cisco, Nr April-July2900 3400 3700 83 4020 5170
Lake Powell, Glen Cyn Dam, At April-July3850 4750 5300 74 6160 7650


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 71 76 77 85 100
Almont April-July95 107 115 74 128 158
East
Almont April-July100 117 128 70 141 178
Gunnison
Gunnison, Nr April-July210 235 265 72 300 380
Tomichi Ck
Gunnison April-July37 47 57 77 69 83
Lake Fork
Gateview April-July87 100 115 93 130 155
Gunnison
Blue Mesa Res April-July420 465 515 76 590 730
Morrow Point Res April-July465 510 560 76 635 775
Crystal Res April-July545 590 640 77 715 855
Muddy Ck
Paonia Res, Bardine, Nr March-June54 62 70 73 83 95
April-June49 57 65 71 78 90
April-July54 61 69 71 82 94
Nf Gunnison
Somerset, Nr April-July170 200 225 76 255 300
Surface Ck
Cedaredge April-July8.5 11 13.5 80 15.5 19
Uncompahgre
Ridgway Res April-July74 84 92 91 105 125
Colona April-July85 104 120 88 140 170
Delta April-July66 78 96 85 117 145
Gunnison
Grand Junction, Nr April-July940 1050 1150 78 1300 1580


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-July170 195 220 90 255 280
Mcphee Res April-July200 220 255 86 295 325
San Miguel
Placerville, Nr April-July95 106 120 94 132 150
Dolores
Cisco, Nr April-July360 405 470 83 535 610

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