New 1991-2020 Averages being used this year.
Great Water Supply Outlook, June 1, 2022

Great Water Supply Outlook, June 1, 2022

Note: This publication is scheduled for revision. If you have feedback on content, format, or publication frequency, please contact us.
Prepared by Patrick Kormos
NOAA, National Weather Service
Colorado Basin River Forecast Center
Salt Lake City, Utah
www.cbrfc.noaa.gov

Contents

Great Summary






*Median of forecasts within each basin.


Bear Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Weber Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Six Creeks Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Utah Lake Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.


Bear 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
Bear
Utah April-July68 75 82 75 87 100
June-July23 30 37 59 42 55
Woodruff Narrows Rsvr, Abv April-July61 67 77 71 79 90
June-July7.2 12.9 23 45 25 36
Stewart Dam * April-July17 18.6 19.5 12 22 34
June-July2.1 3.7 4.6 6 7.4 18.7
Smiths Fork
Border, Nr April-July42 47 56 64 57 65
June-July16.5 22 31 63 32 40
Logan
Logan, Nr, State Dam, Abv April-July47 51 57 54 61 65
June-July17.8 22 28 49 32 36
Blacksmith Fork
Hyrum, Nr, Upnl Dam, Abv April-July14.8 17 19.2 52 20 21
June-July3.1 5.3 7.5 53 8.3 9.6
Little Bear
Paradise April-July11.5 12.6 13.8 35 14.5 17
June-July1.3 2.4 3.6 38 4.3 6.8

*Regulated Forecast, i.e. Observed flow uncorrected for upstream diversion.

Weber 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
Weber
Oakley, Nr April-July69 75 85 77 87 95
June-July17.2 23 33 56 35 43
Rockport Res, Wanship, Nr April-July66 72 79 69 81 91
June-July12.9 18.9 26 47 28 38
Coalville, Nr April-July64 72 81 68 82 88
June-July7.7 15.7 25 45 26 32
Chalk Ck
Coalville April-July17.1 18.9 21 60 23 25
June-July2.2 4 5.7 43 8.1 10.1
Weber
Echo Reservoir, Echo, At April-July78 87 98 64 100 107
June-July9.5 18.7 29 44 31 38
Lost Ck
Lost Ck Reservoir, Croyden, Nr April-July5.8 6 6.5 51 7 7.5
June-July0.42 0.62 1.2 37 1.6 2.1
East Canyon Ck
East Canyon Reservoir, Morgan, Nr April-July9.5 10.2 11.8 51 12.1 15
June-July0.53 1.2 2.8 41 3.1 6
Weber
Gateway April-July127 140 154 56 164 195
June-July7.8 21 35 38 45 76
Sf Ogden
Huntsville, Nr April-July27 28 31 60 32 37
June-July3.2 3.8 6.9 53 8.1 13.1
Ogden
Pineview Reservoir, Ogden, Nr April-July45 47 50 46 55 63
June-July2.5 4.8 7.4 32 12.5 21


Six Creeks 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
Little Cottonwood Ck
Salt Lake City, Nr April-July19.7 22 25 74 26 27
June-July8.4 10.6 13.2 60 14.7 15.2
Big Cottonwood Ck
Salt Lake City, Nr April-July18 19 21 62 23 26
June-July7.8 8.8 10.6 60 12.8 15.8
Mill Ck
Salt Lake City, Nr April-July2.8 2.9 3.2 62 3.4 3.9
June-July1.5 1.7 1.9 71 2.1 2.6
Dell Fk
Little Dell Reservoir April-July1.7 1.8 1.9 44 2 2.7
June-July0.16 0.26 0.38 28 0.5 1.2
Lambs Ck
Salt Lake City, Nr April-July1.7 2 2.2 51 2.3 2.8
June-July0.29 0.57 0.79 34 0.86 1.4
Parleys Ck
Salt Lake City, Nr April-July4.6 4.9 5.4 47 5.6 7.1
June-July0.5 0.79 1.3 27 1.5 3
Red Butte Ck
Ft Douglas, At, Salt Lake City, Nr April-July0.54 0.58 0.63 40 0.7 0.85
June-July0.08 0.12 0.17 35 0.24 0.39
City Ck
Salt Lake City, Nr April-July2.6 3.2 3.3 51 3.5 4
June-July0.93 1.5 1.7 54 1.8 2.3
S Willow Ck
Grantsville, Nr April-July0.8 0.87 1 35 1.1 1.1
June-July0.25 0.32 0.49 30 0.52 0.59


Utah Lake 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
Spanish Fork
Castilla, Nr April-July19.5 22 24 44 25 27
June-July1.5 4 6.5 35 6.8 9
Provo
Woodland, Nr April-July66 74 84 88 86 90
June-July11.1 18.8 29 64 31 35
Hailstone, Nr April-July65 73 83 78 85 89
June-July12.4 19.9 30 63 32 36
Deer Ck Reservoir April-July69 76 89 75 92 96
June-July4.5 11 24 48 27 31
American Fork
American Fork, Nr, Up Pwrplnt, Abv April-July6.3 8.4 10.2 41 10.9 12.4
June-July1.9 4 5.8 36 6.5 8
West Canyon Ck
Cedar Fort, Nr April-July0 0.01 0.04 2 0.06 0.12
June-July0 0.01 0.04 5 0.06 0.12
Salt Ck
Nephi Powerplant Div, Blo April-July3.1 3.2 3.7 47 3.8 4.3
June-July0.53 0.65 1.1 35 1.2 1.8
Jordan
Utah Lake, Provo, Nr April-July131 150 167 78 172 185
June-July8 27 44 35 49 62

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).

Great 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 Bear
Woodruff Narrows Reservoir, Woodruff, Nr 39.0 83 70 14.6 31 47.1 55.8
untitled Bear River
Bear Lake, Nr Lifton 726.0 87 56 923.4 111 829.8 1302.0
untitled Little Bear
Hyrum Reservoir 14.5 99 95 13.3 91 14.6 15.3
untitled Weber
Rockport Res, Wanship, Nr 58.7 116 106 33.5 66 50.5 55.2
Echo Reservoir, Echo, At 60.4 94 82 33.1 51 64.4 73.9
untitled Lost Ck
Lost Ck Reservoir, Croyden, Nr 15.1 82 67 15.7 86 18.4 22.5
untitled East Canyon Ck
East Canyon Reservoir, Morgan, Nr 38.5 84 78 36.9 81 45.6 49.5
untitled Sf Ogden
Causey Reservoir 7.1 100 100 7.0 100 7.0 7.1
untitled Ogden
Pineview Res, Ogden, Nr 72.2 72 66 60.2 60 99.7 110.1
untitled Provo
Jordanelle Reservoir 220.0 85 69 228.6 88 258.7 320.3
Deer Ck Reservoir 126.3 97 84 119.9 92 130.6 149.7
untitled Dell Fk
Little Dell Reservoir 11.9 -99 58 12.2 -99 -9999.0 20.5
untitled Jordan
Utah Lake, Provo, Nr 507.6 60 58 625.3 74 844.2 870.9
untitled
TOTAL 1885.4 78 62 2111.6 88 2410.4 3052.8

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 1991-2020 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: Patrick Kormos