Upper Colorado Water Supply Outlook, May 1, 2014

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

Water Supply Forecast Discussion
Upper Colorado Mainstem Basin Conditions
Gunnison Basin Conditions
Dolores Basin Conditions
Upper Colorado Mainstem Specific Site Forecasts
Gunnison Specific Site Forecasts
Dolores Specific Site Forecasts
Reservoir Contents
Precipitation Maps
Definitions
Additional Information
Questions or Comments

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	50% Exceedance Volume	Percent Average	10% Exceedance Volume
Colorado
Lake Granby, Granby, Nr	April-July	270	320	145	370
	May-July	250	300	146	350
Willow Ck
Willow Ck Res, Granby, Nr	April-July	52	68	145	84
	May-July	43	59	137	75
Fraser
Winter Park	April-July	24	28	144	32
	May-July	23	27	145	31
Williams Fork
Williams Fork Res, Parshall, Nr	April-July	121	135	141	155
	May-July	110	124	138	144
Muddy Ck
Wolford Mountain Reservoir	April-July	78	90	167	108
	May-July	64	76	165	94
Blue
Dillon Res	April-July	220	250	153	285
	May-July	200	230	150	265
Green Mtn Res	April-July	370	405	147	465
	May-July	340	375	147	435
Colorado
Kremmling, Nr	April-July	1170	1300	151	1500
	May-July	1030	1160	148	1360
Eagle
Gypsum, Blo	April-July	335	395	118	475
	May-July	300	360	114	440
Colorado
Dotsero, Nr	April-July	1670	1940	139	2220
	May-July	1460	1730	135	2010
Frying Pan
Ruedi Res, Basalt, Nr	April-July	130	155	112	188
	May-July	117	142	109	175
Roaring Fork
Glenwood Springs	April-July	635	740	107	920
	May-July	565	670	105	850
Colorado
Glenwood Springs, Blo	April-July	2330	2700	128	3200
	May-July	2030	2400	124	2900
Cameo, Nr	April-July	2430	2950	125	3500
	May-July	2080	2600	121	3150
Plateau Ck
Cameo, Nr	April-July	67	105	85	145
	May-July	43	81	78	121
Colorado
Cisco, Nr	April-July	4250	5000	113	6000
	May-July	3590	4340	112	5340
Lake Powell, Glen Cyn Dam, At	April-July	6300	7550	105	9460
	May-July	5340	6590	108	8500

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-July	110	128	129	150
	May-July	98	116	129	138
Almont	April-July	166	200	129	235
	May-July	145	180	128	215
East
Almont	April-July	200	230	126	260
	May-July	170	200	120	230
Gunnison
Gunnison, Nr	April-July	420	470	127	545
	May-July	360	410	122	485
Tomichi Ck
Gunnison	April-July	76	92	124	116
	May-July	55	71	115	95
Lake Fork
Gateview	April-July	112	133	108	156
	May-July	101	122	105	145
Gunnison
Blue Mesa Res	April-July	780	850	126	940
	May-July	650	720	120	810
Morrow Point Res	April-July	860	930	126	1020
	May-July	715	785	121	875
Crystal Res	April-July	970	1040	125	1130
	May-July	815	885	120	975
Muddy Ck
Paonia Res, Bardine, Nr	March-June	89	95	99	116
	April-July	90	96	99	117
	May-June	63	69	100	90
	May-July	68	74	99	95
Nf Gunnison
Somerset, Nr	April-July	270	290	98	335
	May-July	210	230	96	275
Surface Ck
Cedaredge	April-July	11.1	15.1	90	19.1
	May-July	8	12	85	16
Uncompahgre
Ridgway Res	April-July	80	91	90	109
	May-July	67	78	86	96
Colona	April-July	94	114	83	148
	May-July	80	100	83	134
Delta	April-July	70	85	75	119
	May-July	56	71	76	105
Gunnison
Grand Junction, Nr	April-July	1460	1660	112	1910
	May-July	1180	1380	111	1630

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-July	169	205	84	240
	May-July	130	165	83	200
Mcphee Res	April-July	194	220	75	260
	May-July	152	177	80	220
San Miguel
Placerville, Nr	April-July	104	122	95	137
	May-July	87	105	93	120
Dolores
Cisco, Nr	April-July	365	410	73	485
	May-July	280	325	78	400

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	295.7	95	60	182.2	58	311.8	490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr	8.1	106	89	8.1	106	7.7	9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr	75.2	123	78	45.4	75	60.9	96.9
untitled Muddy Ck
Wolford Mountain Reservoir	46.3	97	70	26.9	56	47.7	66.0
untitled Blue
Dillon Res	206.4	97	81	161.8	76	213.6	254.0
Green Mtn Res	68.9	108	47	65.8	103	63.9	146.9
untitled Homestake Ck
Homestake Res	0.1	0	0	0.2	1	18.8	43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr	64.9	104	64	62.6	100	62.6	102.0
untitled Plateau Ck
Vega Res, Collbran, Nr	23.7	129	72	11.3	62	18.3	32.9
untitled Taylor
Taylor Park Res	70.3	115	66	59.2	97	61.2	106.2
untitled Gunnison
Blue Mesa Res	509.1	111	61	338.0	74	457.1	829.5
Morrow Point Res	106.1	95	91	106.5	95	111.8	117.0
Crystal Res	14.2	85	81	12.9	77	16.7	17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr	0.7	11	4	7.2	111	6.4	16.7
untitled Uncompahgre
Ridgway Res	67.3	101	81	60.4	91	66.6	83.0
untitled Dolores
Mcphee Res	223.3	69	59	197.9	61	323.0	381.1
untitled
TOTAL	1780.3	96	64	1346.6	73	1848.0	2792.1


Colorado
Lake Powell	9731.9	57	40	11422.0	67	17122.8	24322.0
untitled
TOTAL	9731.9	57	40	11422.0	67	17122.8	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:

Range		Round to
0-1.99		0.01
2.0-19.9		0.1
20-199		1.0
200-999		5.0
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