1. No category

Utah Water Supply
Outlook Report
April, 2015
Bryce Canyon Snow Course, March 27, 2015
Photo by Lynn Kitchen, NRCS
Water Supply Outlook Reports
and Federal - State - Private Cooperative Snow Surveys
For more water supply and resource management information, contact: your local Natural Resources
Conservation Service Office or:
Snow Surveys
245 N Jimmy Doolittle Rd, SLC Utah, 84116. Phone (801)524-5213
Internet Address: http://www.ut.nrcs.usda.gov/snow/
How forecasts are made
Most of the annual streamflow in the western United States originates as snowfall that has accumulated in the mountains
during the winter and early spring. As the snowpack accumulates, hydrologists estimate the runoff that will occur when it
melts. Measurements of snow water equivalent at selected manual snowcourses and automated SNOTEL sites, along with
precipitation, antecedent streamflow, and indices of the El Niño / Southern Oscillation are used in statistical and
simulation models to prepare runoff forecasts. Unless otherwise specified, all forecasts are for flows that would occur
naturally without any upstream influences.
Forecasts of any kind, of course, are not perfect. Streamflow forecast uncertainty arises from three primary sources: (1)
uncertain knowledge of future weather conditions, (2) uncertainty in the forecasting procedure, and (3) errors in the data.
The forecast, therefore, must be interpreted not as a single value but rather as a range of values with specific probabilities
of occurrence. The middle of the range is expressed by the 50% exceedance probability forecast, for which there is a 50%
chance that the actual flow will be above, and a 50% chance that the actual flow will be below, this value. To describe the
expected range around this 50% value, four other forecasts are provided, two smaller values (90% and 70% exceedance
probability) and two larger values (30%, and 10% exceedance probability). For example, there is a 90% chance that the
actual flow will be more than the 90% exceedance probability forecast. The others can be interpreted similarly.
The wider the spread among these values, the more uncertain the forecast. As the season progresses, forecasts become
more accurate, primarily because a greater portion of the future weather conditions become known; this is reflected by a
narrowing of the range around the 50% exceedance probability forecast. Users should take this uncertainty into
consideration when making operational decisions by selecting forecasts corresponding to the level of risk they are willing
to assume about the amount of water to be expected. If users anticipate receiving a lesser supply of water, or if they wish
to increase their chances of having an adequate supply of water for their operations, they may want to base their decisions
on the 90% or 70% exceedance probability forecasts, or something in between. On the other hand, if users are concerned
about receiving too much water (for example, threat of flooding), they may want to base their decisions on the 30% or
10% exceedance probability forecasts, or something in between. Regardless of the forecast value users choose for
operations, they should be prepared to deal with either more or less water. (Users should remember that even if the 90%
exceedance probability forecast is used, there is still a 10% chance of receiving less than this amount.) By using the
exceedance probability information, users can easily determine the chances of receiving more or less water.
The U.S. Department of Agriculture (USDA) prohibits discrimination against its customers. If you believe you experienced discrimination when obtaining services from USDA, participating in a USDA program, or participating in a program that receives financial assistance from USDA, you may file a complaint with USDA. Information about how to file a discrimination complaint is available from the Office of the Assistant Secretary for Civil Rights. USDA prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex (including gender identity and expression), marital status, familial status, parental status, religion, sexual orientation, political beliefs, genetic information, reprisal, or because all or part of an individual’s income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) To file a complaint of discrimination, complete, sign, and mail a program discrimination complaint form, available at any USDA office location or online at www.ascr.usda.gov, or write to: USDA Office of the Assistant Secretary for Civil Rights 1400 Independence Avenue, SW. Washington, DC 20250‐9410 Or call toll free at (866) 632‐9992 (voice) to obtain additional information, the appropriate office or to request documents. Individuals who are deaf, hard of hearing, or have speech disabilities may contact USDA through the Federal Relay service at (800) 877‐8339 or (800) 845‐6136 (in Spanish). USDA is an equal opportunity provider, employer, and lender. Persons with disabilities who require alternative means for communication of program information (e.g., Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720‐2600 (voice and TDD). STATE OF UTAH GENERAL OUTLOOK
April 1, 2015
SUMMARY
An exceptionally poor water supply year – 2015 will be one that water managers will compare as
one of the worst like 2002, 1977 and 1934. Of the long term snow courses going back to the
1930’s, 2015 ranks somewhere between the worst year of record (4 sites) up to the 11th worst
year. In the last 30 years, 2015 ranks as the lowest basin average on the Weber, Provo, Tooele,
Duchesne, Price, San Rafael and the Sevier rivers. Suffice it to say – 2015 is a dead skunk. The
remaining basins, while not the lowest of the past 30 years are very close to the worst. Being
second or third lowest is pragmatically as bad as being number one. As of April 1 – the normal
peak of snowpack accumulation, Utah watersheds stand at: Bear – 56%, Weber – 37%, Provo 32%, Tooele – 18%, Duchesne – 42%, Price -41%, Upper Sevier -47%, San Pitch -44%, and
southwestern Utah -41% of normal. All low elevation sites have melted out. What little
snowpack remains will melt quickly. With low snow packs, water managers can expect the
following – 1) greatly reduced April-July flow, 2) much lower peak flows, 3) peak flows
occurring about 1 to 4 weeks earlier and 4) the bulk of flow to come in April/May as opposed to
May/June. March precipitation was below normal statewide ranging from 32% on the Provo to
68% in the southwest. The statewide average was 47% which brings the seasonal accumulation
(Oct-Mar) to 62% of average. Current soil moisture saturation levels in runoff producing areas
are well above normal due to early snow melt. Soil moisture may not have a significant impact
on runoff this year simply due to the fact that there just isn’t much snow to contribute to stream
flow. Reservoir storage is about the same as last year at 65% of capacity. General runoff
conditions are much below average across the entire state. Surface Water Supply Indices range
from 3% on the Weber, Eastern Uinta Basin and San Pitch to 42% on the Bear River. Water
managers across the state should prepare for early, short duration stream flow, a longer irrigation
season, and low stream flow volumes with low peak flows and poor runoff efficiency.
SNOWPACK
April first snow packs as measured by the NRCS SNOTEL system range from 18% of median in
the Tooele area to 56% on the Bear River watersheds. Most areas have between 30% and 45% of
normal. The entire state and indeed, west wide – have exceptionally poor snow packs.
PRECIPITATION
Mountain precipitation during March was 47% of average which brings the seasonal
accumulation (Oct-Mar) 62% of normal. Precipitation ranged from 32% on the Provo to 65%
over southeast Utah.
SOIL MOISTURE
Soil moisture is rising rapidly in response to melting snow packs but was above normal going
into the melt season. Soil moisture at lower elevations is declining quickly. Given extremely
poor snow packs across the state – above normal soil moisture may have little impact on runoff –
there just isn’t sufficient snow to generate substantial stream flow.
RESERVOIRS
Storage in 46 of Utah’s key irrigation reservoirs is at 65% of capacity compared to 64% last year.
STREAMFLOW
Snowmelt stream flows are expected to be much below average for the entire state. Forecast
stream flows range from 11% on Parleys Creek to 50% on the upper Weber. Most flows are
forecast to be in the 15% to 40% range.
SURFACE WATER SUPPLY INDEX
Surface Water Supply indexes range from 3% for the Weber, East Uintah Basin and San Pitch to
42% for the Bear River.
As this graph of the Logan River shows, in low snowpack and streamflow years, peak flows
typically occur much earlier in the runoff season and the overall hydrograph is shifted earlier as
well.
In this graph of the Sevier River in 2002 – snowmelt for various SNOTEL sites and streamflow
for the Sevier River at Hatch is shown. Note that there is basically no response to snowmelt and
that the Sevier at Hatch is nearly a flat line for the entire period. This is a very likely scenario
this year for not only the Sevier but many other streams across the state.
Previous Year % Capacity
Current % Capacity
Statewide Utah
4/1/2015
Snowpack in Utah is much below normal at 41% of normal, compared to 92% last year. Precipitation in March was much below
average at 47%, which brings the seasonal accumulation (Oct-Mar) to 62% of average. Soil moisture is at 80% compared to 62% last
year. Reservoir storage is at 65% of capacity, compared to 64% last year. Forecast streamflow volumes range from 8% to 67% of
average.
Snowpack
Soil Moisture
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
140
Statewide
120
Southwestern Utah
Percent of Average
100
Upper Sevier
Lower Sevier
80
Price Basin
60
Duchesne Basin
40
Provo Basin
Weber & Ogden…
20
Bear River Basin
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Utah
SNOTEL Current Snow Water Equivalent (SWE)
% of Normal
Raft River
Apr 01, 2015
98
Logan !
!
!
!
Snow Water
Equivalent (SWE)
Basin-wide
Percent of
1981-2010
Median
Ogden
Great
Salt Lake
Bear River
Weber
Ogden
Northeastern Uintahs
38
Salt Lake City
80
§
¦
¨
56
29
56
^
_
!
(
Duchesne River
18
TooeleVernon
42
33
!
!
!
!
Roosevelt
Provo
unavailable *
ProvoUtahJordan
<50%
50 - 69%
70 - 89%
Lower Sevier
River
90 - 109%
41
San
Pitch
Price - San Rafael
44
41
110 - 129%
130 - 149%
70
§
¦
¨
>=150%
!
!
* Data unavailable at time
of posting or measurement
is not representative at this
time of year
48
47
Beaver River
Provisional Data
Subject to Revision
15
§
¦
¨
Southwestern Utah
23
70
Dirty Devil
Upper
Sevier River
42
74
Southeastern Utah
Escalante River
St. George
!
!
0
10 20
The snow water equivalent percent of normal represents the current
snow water equivalent found at selected SNOTEL sites in or near the basin
compared to the average value for those sites on this day. Data based on
the first reading of the day (typically 00:00).
Moab
40
60
80
Miles
100
Prepared by:
USDA/NRCS National Water and Climate Center
Portland, Oregon
http://www.wcc.nrcs.usda.gov
Utah
SNOTEL Water Year (Oct 1) to Date Precipitation
% of Normal
Raft River
Apr 01, 2015
96
Logan !
!
!
!
Water Year
(Oct 1) to Date
Precipitation
Basin-wide
Percent of
1981-2010
Average
Ogden
Great
Salt Lake
Bear River
Weber
Ogden
Northeaster Uintahs
59
Salt Lake City
80
§
¦
¨
71
60
71
^
_
!
(
Duchesne River
46
TooeleVernon
unavailable *
Lower
Sevier River
70 - 89%
Roosevelt
Provo
Price - San Rafael
San
Pitch
75
90 - 109%
!
!
ProvoUtahJordan
<50%
50 - 69%
56
59
!
!
68
64
110 - 129%
130 - 149%
70
§
¦
¨
>=150%
!
!
* Data unavailable at time
of posting or measurement
is not representative at this
time of year
55
Beaver River
Provisional Data
Subject to Revision
15
§
¦
¨
67
68
81
Upper
Sevier River
Moab
Dirty Devil
Southwestern Utah
59
75
Southeastern Utah
Escalante River
St. George
!
!
0
10 20
The water year to date precipitation percent of normal represents the
accumulated precipitation found at selected SNOTEL sites in or near the basin
compared to the average value for those sites on this day. Data based on
the first reading of the day (typically 00:00).
40
60
80
Miles
100
Prepared by:
USDA/NRCS National Water and Climate Center
Portland, Oregon
http://www.wcc.nrcs.usda.gov
Utah streamflow
and reservoir
forecast points
#
*
Percent normal
#
*
#
*
#
*
#
*
#
*
#
*
#
*
#
*
< 50%
#
*
Forecast points
50 - 69%
5
Cities
70 - 89%
Rivers
90 - 109%
Highways
Ü
110 - 129%
130 - 149%
0
> 150%
no % avail.
15 30
60
90
120
Miles
SNOTEL Current Snow Water Equivalent (SWE) Records
Apr 02, 2015
NOTE: Until further notice,
record calculations are based
on period of record through water
year 2012; water years 2013
and 2014 are not analyzed.
Current Snow
Water (SWE)
Equivalent
Records
New High
Near High
Non-Record
New Low
Near Low
snow free
Analysis includes sites with more
than 20 years of historical data.
"Near" record means that one other year
of the period of record is more extreme.
Provisional Data
Subject to Revision
Prepared by:
USDA/NRCS National Water and Climate Center
Portland, Oregon
http://www.wcc.nrcs.usda.gov
Previous Year % Capacity
Current % Capacity
Bear River Basin
4/1/2015
Snowpack in the Bear River Basin is much below normal at 56% of normal, compared to 120% last year. Precipitation in March was
much below average at 50%, which brings the seasonal accumulation (Oct-Mar) to 71% of average. Soil moisture is at 88% compared
to 67% last year. Reservoir storage is at 48% of capacity, compared to 46% last year. Forecast streamflow volumes range from 10% to
67% of average. The surface water supply index is 42% for the Bear River, 14% for the Woodruff Narrows, 4% for the Little Bear.
Soil Moisture
Snowpack
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
140
WOODRUFF CREEK
120
WOODRUFF
NARROWS
Percent of Average
100
80
PORCUPINE
60
40
HYRUM
20
BEAR LAKE
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Bear River
*
^
583.77
#
KAF
^
18.00
Storage + Forecast
KAF
^
601.77
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Bear River Surface Water Supply Index
1800
1600
Thousand Acre Feet
1400
1200
1000
800
600
400
200
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
42
-0.69
07, 10, 90, 14
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Little Bear
*
^
14.10
#
KAF
^
8.00
Storage + Forecast
KAF
^
22.10
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Little Bear Surface Water Supply Index
140
Thousand Acre Feet
120
100
80
60
40
20
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
4
-3.82
13, 14, 03, 01
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Woodruff Narrows
*
#
^
50.93
KAF
^
40.00
Storage + Forecast
KAF
^
90.93
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Woodruff Narrows Surface Water Supply Index
300
Thousand Acre Feet
250
200
150
100
50
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
14
-3.01
04, 13, 03, 90
Bear basin
!
(
!
(
!
(
!
(
!
(
!
(
!
(
#
*!
(
#
*
§
¨
¦
15
!
(
!
(
!
(
!
(!
(!
(
§
¨
¦
84
!
(
5#
*
Tremonton5
Logan
#
*
#
*
#
*
!
(
!
(
!
(
§
¨
¦
!
(
#
*
15
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
!
(
#
*
< 50%
5 Evanston
5 Ogden
§
¨
¦
50 - 69%
84
§
¨
¦
80
70 - 89%
!
(
#
*
90 - 109%
!
(!
(
110 - 129%
!
(
130 - 149%
V
U
> 150%
150
!
(
no % avail.
SNOTEL sites
Forecast points
Rivers
Highways
5
Cities
Ü
0
5 10
20
30
40
Miles
Raft River Basin
4/1/2015
Snowpack in the Raft River Basin is near normal at 98% of normal, compared to 114% last year. Precipitation in March was much
below average at 48%, which brings the seasonal accumulation (Oct-Mar) to 97% of average. Soil moisture is at 78% compared to 30%
last year. The forecast streamflow volume for Dunn Creek is 28% of average.
Snowpack
Soil Moisture
120%
Snow Water Equivalent Index
Saturation, volume %
100%
80%
60%
40%
20%
0%
Calculated using soil moisture content at 2, 8, and 20-inch depths.
Max
Min
Avg
WY 2015
2005-Current
Precipitation
200
180
160
Percent of Average
140
120
100
80
60
40
20
0
Monthly
Year-to-Date
WY 2015
Avg
Raft basin
V
U
16
V
U
42
V
U
30
!
(
#
*
5
V
U
Park Valley
30
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
< 50%
50 - 69%
70 - 89%
!
(
#
*
SNOTEL sites
Forecast points
90 - 109%
Rivers
110 - 129%
Highways
130 - 149%
5
Cities
> 150%
no % avail.
Ü
0 1.5 3
6
9
12
Miles
Weber & Ogden River Basins
4/1/2015
Snowpack in the Weber & Ogden River Basins is much below normal at 37% of normal, compared to 100% last year. Precipitation in
March was much below average at 45%, which brings the seasonal accumulation (Oct-Mar) to 59% of average. Soil moisture is at 83%
compared to 66% last year. Reservoir storage is at 57% of capacity, compared to 50% last year. Forecast streamflow volumes range
from 14% to 50% of average. The surface water supply index is 11% for the Ogden River, 3% for the Weber River.
Snowpack
Soil Moisture
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
120
SMITH AND
MOREHOUSE
100
Percent of Average
Calculated using soil moisture content at 2, 8, and 20-inch depths.
ROCKPORT
ECHO
80
LOST CREEK
60
EAST CANYON
40
CAUSEY
PINEVIEW
20
WILLARD BAY
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Ogden River
*
^
77.94
#
KAF
^
Storage + Forecast
KAF
16.00
^
93.94
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Ogden River Surface Water Supply Index
400
350
Thousand Acre Feet
300
250
200
150
100
50
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
11
-3.24
88, 03, 13, 87
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Weber River
*
^
232.33
#
KAF
Storage + Forecast
^
KAF
54.00
^
286.33
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Weber River Surface Water Supply Index
1200
Thousand Acre Feet
1000
800
600
400
200
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
3
-3.94
13, 04, 03, 07
Weber-Ogden basin
!
(
!
(
(
!!
(
!
(
!
(
5
#
*
*
#
#
*
Ogden
§
¨
¦
!
(
80
!
(
#
*
#
*
5 Layton
!
(
!
(
!
#
* (
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
!
(
#
*
#
*
!
(
< 50%
!
(
!
(
50 - 69%
70 - 89%
§
¨
¦
80
90 - 109%
!
( #
*
110 - 129%
§
¨
¦
130 - 149%
15
!
(
> 150%
no % avail.
SNOTEL sites
Forecast points
Highways
Cities
Ü
0 2.5 5
10
15
(
#
*!
#
*
!
(
!
(
Rivers
5
#
*
*
#
#
*
20
Miles
!
(
Provo & Jordan River Basins
4/1/2015
Snowpack in the Provo & Jordan River Basins is much below normal at 32% of normal, compared to 88% last year. Precipitation in
March was much below average at 41%, which brings the seasonal accumulation (Oct-Mar) to 59% of average. Soil moisture is at 86%
compared to 70% last year. Reservoir storage is at 71% of capacity, compared to 73% last year. Forecast streamflow volumes range
from 11% to 48% of average. The surface water supply index is 14% for the Provo River.
Soil Moisture
Snowpack
100%
40
35
80%
Saturation, volume %
25
20
15
10
60%
40%
20%
5
0%
0
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
140
UTAH LAKE
120
100
Percent of Average
Snow Water Equivalent Index
30
JORDANELLE
80
DEER CREEK
60
40
UPPER STILLWATER
20
STRAWBERRY
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Provo River
*
^
920.40
#
KAF
^
28.00
Storage + Forecast
KAF
^
948.40
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Provo River Surface Water Supply Index
1600
1400
Thousand Acre Feet
1200
1000
800
600
400
200
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
14
-3.03
04, 03, 14, 02
(
!
(!
#
*
#
* !
(
*
Salt Lake City 5 #
#
*
#
*
§
¨
¦
80
!
(
#
*
!
(
!
(
#
*
5
Heber City
#
* (
!
#
*
#
*
!
(
!
(
5Provo
!
(
#
*
§
¨
¦
15
!
(
!
(
!
(
#
*
5 Nephi
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
< 50%
50 - 69%
70 - 89%
!
(
#
*
SNOTEL sites
Forecast points
90 - 109%
Rivers
110 - 129%
Highways
130 - 149%
> 150%
no % avail.
5
Cities
Ü
0 2.5 5
!
(
!
(
!
(
#
*
#
*
!
(
Provo-Utah LakeJordan basin
10
15
20
Miles
Tooele & Vernon Creek Basins
4/1/2015
Snowpack in the Tooele & Vernon Creek Basins is much below normal at 18% of normal, compared to 82% last year. Precipitation in
March was much below average at 32%, which brings the seasonal accumulation (Oct-Mar) to 47% of average. Soil moisture is at 62%
compared to 51% last year. Reservoir storage is at 50% of capacity, compared to 62% last year. Forecast streamflow volumes range
from 16% to 22% of average.
Snowpack
Soil Moisture
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
140
120
VERNON CREEK
Percent of Average
100
80
SETTLEMENT
CANYON
60
40
GRANTSVILLE
20
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Salt Lake City
§
¨
¦
80
Tooele 5
§
¨
¦
*
!
(#
15
!
(
!
(
TooeleVernon basin
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
!
(
#
*
50 - 69%
#
*
70 - 89%
!
(
90 - 109%
110 - 129%
130 - 149%
> 150%
no % avail.
SNOTEL sites
Rivers
Highways
5
5 Vernon
< 50%
Forecast points
Cities
0 2.5 5
Ü
5
10
15
20
Miles
Northeastern Uintah Basin
4/1/2015
Snowpack in the Northeastern Uintah Basin is much below normal at 26% of normal, compared to 97% last year. Precipitation in
March was much below average at 35%, which brings the seasonal accumulation (Oct-Mar) to 60% of average. Soil moisture is at 84%
compared to 60% last year. Reservoir storage is at 84% of capacity, compared to 77% last year. Forecast streamflow volumes range
from 51% to 63% of average. The surface water supply index is 24% for the Blacks Fork, 24% for the Smiths Creek.
Snowpack
Soil Moisture
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
120
Percent of Average
100
MEEKS CABIN
80
60
STATELINE
40
20
FLAMING GORGE
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Blacks Fork
*
^
26.29
#
KAF
^
45.00
Storage + Forecast
KAF
^
71.29
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Blacks Fork Surface Water Supply Index
200
180
Thousand Acre Feet
160
140
120
100
80
60
40
20
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
24
-2.15
00, 12, 89, 13
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Smiths Fork
*
^
8.86
#
KAF
Storage + Forecast
^
KAF
15.00
^
23.86
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Smiths Fork Surface Water Supply Index
80
70
Thousand Acre Feet
60
50
40
30
20
10
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
24
-2.21
07, 89, 03, 06
Northeastern Utah
#
*
Manila5
#
*
!
(
!
(
!
(
!
(
!
(
!
(
!
(
!
(
#
*
V
U
44
!
(
£
¤
191
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
!
(
#
*
< 50%
50 - 69%
70 - 89%
90 - 109%
110 - 129%
130 - 149%
> 150%
no % avail.
SNOTEL sites
Forecast points
Rivers
Highways
5
Ü
Cities
0 2.254.5
9
!
(
13.5
18
Miles
Duchesne River Basin
4/1/2015
Snowpack in the Duchesne River Basin is much below average at 40% of normal, compared to 91% last year. Precipitation in March
was much below average at 45%, which brings the seasonal accumulation (Oct-Mar) to 56% of average. Soil moisture is at 76%
compared to 44% last year. Reservoir storage is at 78% of capacity, compared to 76% last year. Forecast streamflow volumes range
from 17% to 55% of average. The surface water supply index is 19% for the Western Uintahs, 3% for the Eastern Uintahs.
Soil Moisture
Snowpack
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
120
STRAWBERRY
Percent of Average
100
CURRANT CREEK
MOON LAKE
80
STARVATION
60
UPPER STILLWATER
40
BIG SAND WASH
RED FLEET
20
STEINAKER
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Eastern Uintah
*
#
^
31.00
KAF
Storage + Forecast
^
KAF
22.90
^
53.90
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Eastern Uintah Surface Water Supply Index
200
180
Thousand Acre Feet
160
140
120
100
80
60
40
20
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
3
-3.94
14, 02, 13, 89
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Western Uintah
*
#
^
195.47
KAF
Storage + Forecast
^
KAF
40.00
^
235.47
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Western Uintah Surface Water Supply Index
400
350
Thousand Acre Feet
300
250
200
150
100
50
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
19
-2.55
03, 12, 04, 07
Duchesne basin
£
¤
191
!
(
!
(
!
(
!
(
!
(
!
(
#
*
!
(
£
¤
* !
(
!
(#
#
(
* !
#
*
#
*
!
(#
*
!
(
#
*
5
Duchesne
!
(
£
¤
191
Percent normal
< 50%
!
(
#
*
50 - 69%
70 - 89%
SNOTEL sites
Forecast points
90 - 109%
Rivers
110 - 129%
Highways
5
130 - 149%
Cities
> 150%
no % avail.
Ü
5
10
20
30
£
¤
5
#
*
*
##
*
40
Miles
#
*
Vernal 5
Roosevelt
*
!#
(
0
#
*
#
*
40
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
(
#
*!
#
*
40
*
#
Lower Sevier River Basin
4/1/2015
Snowpack in the Lower Sevier River Basin is much below normal at 41% of normal, compared to 71% last year. Precipitation in March
was much below average at 38%, which brings the seasonal accumulation (Oct-Mar) to 75% of average. Soil moisture is at 74%
compared to 59% last year. Reservoir storage is at 50% of capacity, compared to 59% last year. Forecast streamflow volumes range
from 18% to 25% of average. The surface water supply index is 11% for the Lower Sevier.
Soil Moisture
Snowpack
120%
Snow Water Equivalent Index
Saturation, volume %
100%
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
220
200
180
Percent of Average
160
140
120
SEVIER BRIDGE
100
80
60
40
20
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Lower Sevier
*
^
117.10
#
KAF
^
Storage + Forecast
KAF
25.00
^
142.10
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Lower Sevier Surface Water Supply Index
900
800
Thousand Acre Feet
700
600
500
400
300
200
100
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
11
-3.24
03, 92, 02, 94
Lower Sevier
basin
§
¨
¦
15
5 Nephi
#
*
!
(
*!
#
(
5 Delta
Fillmore
5
!
(
§
¨
¦
15
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
< 50%
50 - 69%
70 - 89%
!
(
#
*
SNOTEL sites
Forecast points
90 - 109%
Rivers
110 - 129%
Highways
130 - 149%
> 150%
5
Cities
Ü
0 2.5 5
no % avail.
10
15
20
Miles
Upper Sevier River Basin
4/1/2015
Snowpack in the Upper Sevier River Basin is much below normal at 47% of normal, compared to 69% last year. Precipitation in March
was much below average at 58%, which brings the seasonal accumulation (Oct-Mar) to 67% of average. Soil moisture is at 78%
compared to 65% last year. Reservoir storage is at 61% of capacity, compared to 82% last year. Forecast streamflow volumes range
from 15% to 43% of average. The surface water supply index is 8% for the Upper Sevier.
Snowpack
Soil Moisture
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
160
140
PANGUITCH LAKE
Percent of Average
120
100
80
OTTER CREEK
60
40
PIUTE
20
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Upper Sevier
*
^
80.39
#
KAF
^
Storage + Forecast
KAF
26.00
^
106.39
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Upper Sevier Surface Water Supply Index
350
Thousand Acre Feet
300
250
200
150
100
50
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
8
-3.47
04, 91, 90, 92
Upper Sevier basin
!
(
Fillmore 5
#
*
!
(
70
!
(
!
(
!
(
5 Richfield
#
*
!
(
!
(
!
(
!
(
#
*
Beaver 5
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
#
*#
*
< 50%
!
(
§
¨
¦
50 - 69%
15
!
(
70 - 89%
90 - 109%
!
(
110 - 129%
130 - 149%
!
(
> 150%
#
*
!
(
no % avail.
!
(
!
(
#
*
SNOTEL sites
Forecast points
Rivers
Highways
5
Ü
Cities
0
5
10
20
30
40
Miles
!
(
§
¨
¦
San Pitch River Basin
4/1/2015
Snowpack in the San Pitch River Basin is much below normal at 44% of normal, compared to 90% last year. Precipitation in March was
much below average at 32%, which brings the seasonal accumulation (Oct-Mar) to 68% of average. Soil moisture is at 82% compared
to 66% last year. Reservoir storage is at 11% of capacity, compared to 24% last year. The forecast streamflow volume for Manti Creek
is 39% of average. The surface water supply index is 3% for the San Pitch.
Snowpack
Soil Moisture
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
200
180
160
Percent of Average
140
120
GUNNISON
RESERVOIR
100
80
60
40
20
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
San Pitch
*
^
2.28
#
KAF
Storage + Forecast
^
6.50
KAF
^
8.78
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
San Pitch Surface Water Supply Index
70
Thousand Acre Feet
60
50
40
30
20
10
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
3
-3.94
02, 13, 14, 03
San Pitch basin
!
(
!
(
Mt. Pleasant 5
!
(
£
¤
89
Ephraim 5
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
!
(
#
*
!
(
< 50%
50 - 69%
*
#
!
(
70 - 89%
90 - 109%
110 - 129%
#
*
130 - 149%
5
!
(
Gunnison
> 150%
no % avail.
SNOTEL sites
!
(
Forecast points
Rivers
Highways
5
Ü
Cities
0
2.5
5
10
15
20
Miles
!
(
(
!
(!
Price & San Rafael Basins
4/1/2015
Snowpack in the Price & San Rafael Basins is much below normal at 41% of normal, compared to 88% last year. Precipitation in March
was much below average at 45%, which brings the seasonal accumulation (Oct-Mar) to 64% of average. Soil moisture is at 83%
compared to 63% last year. Reservoir storage is at 50% of capacity, compared to 45% last year. Forecast streamflow volumes range
from 8% to 46% of average. The surface water supply index is 6% for the Price River, 8% for Joe's Valley, 6% for Ferron Creek.
Snowpack
Soil Moisture
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
180
SCOFIELD
160
Percent of Average
140
MILLER FLAT
120
100
CLEVELAND LAKE
80
HUNTINGTON
NORTH
60
MILLSITE
40
20
JOES VALLEY
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Price River
*
^
14.55
#
KAF
^
7.00
Storage + Forecast
KAF
^
21.55
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Price River Surface Water Supply Index
160
140
Thousand Acre Feet
120
100
80
60
40
20
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
6
-3.7
92, 04, 02, 94
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Ferron Creek
*
^
10.84
#
KAF
^
Storage + Forecast
KAF
12.00
^
22.84
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Ferron Creek Surface Water Supply Index
120
Thousand Acre Feet
100
80
60
40
20
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
6
-3.7
13, 02, 90, 12
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Joe's Valley
*
^
41.63
#
KAF
^
20.00
Storage + Forecast
KAF
^
61.63
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Joe's Valley Surface Water Supply Index
200
180
Thousand Acre Feet
160
140
120
100
80
60
40
20
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
8
-3.47
13, 02, 90, 03
Price-San Rafael
!
(
basin
#
*
#
!
(
#
*
!
(
!
(
!
(
5 Price
!
(
!
(
!
(
#
*
#
*
Castle Dale
5
!
(!
(
#
*
5
#
*Green River
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
!
(
#
*
< 50%
§
¨
¦
70
50 - 69%
70 - 89%
90 - 109%
110 - 129%
130 - 149%
> 150%
no % avail.
SNOTEL sites
Forecast points
Rivers
Highways
5
Ü
Cities
0
5
10
20
30
40
Miles
Southeastern Utah Basin
4/1/2015
Snowpack in the Southeastern Utah Basin is much below normal at 22% of normal, compared to 55% last year. Precipitation in March
was much below average at 65%, which brings the seasonal accumulation (Oct-Mar) to 68% of average. Soil moisture is at 79%
compared to 75% last year. Reservoir storage is at 65% of capacity, compared to 53% last year. Forecast streamflow volumes range
from 18% to 61% of average. The surface water supply index is 21% for Moab.
Snowpack
Soil Moisture
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
140
120
Percent of Average
100
80
KEN'S LAKE
60
40
20
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Moab
*
^
1.50
#
KAF
Storage + Forecast
^
2.00
KAF
^
3.50
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Moab Surface Water Supply Index
14
Thousand Acre Feet
12
10
8
6
4
2
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
21
-2.44
12, 89, 04, 09
Vernal
5
Southeastern Utah
5 Price
£
¤
6
!
(
Green River 5
§
¨
¦
70
#
*
Moab
5
#
*!
!
(
(
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
< 50%
50 - 69%
70 - 89%
5 Monticello
!
(*
!#
(
90 - 109%
110 - 129%
130 - 149%
> 150%
no % avail.
#
*
!
(
#
*
SNOTEL sites
Forecast points
Rivers
Highways
5
Ü
Cities
0 5 10
20
30
40
Miles
Dirty Devil Basin
4/1/2015
Snowpack in the Dirty Devil Basin is below normal at 70% of normal, compared to 99% last year. Precipitation in March was much
below average at 53%, which brings the seasonal accumulation (Oct-Mar) to 81% of average. Soil moisture is at 68% compared to 45%
last year. Forecast streamflow volumes range from 44% to 48% of average.
Snowpack
Soil Moisture
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
Precipitation
220
200
180
Percent of Average
160
140
120
100
80
60
40
20
0
Monthly
Year-to-Date
WY 2015
Avg
Dirty Devil basin
!
(
#
*
§
¨
¦
70
!
(
#
*
!
(
Hanksville
Torrey
5
!
(
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
!
(
#
*
< 50%
50 - 69%
70 - 89%
90 - 109%
110 - 129%
130 - 149%
> 150%
no % avail.
SNOTEL sites
Forecast points
Rivers
Highways
5
Ü
Cities
0
5
10
20
30
40
Miles
5
Escalante River Basin
4/1/2015
Snowpack in the Escalante River Basin is below normal at 74% of normal, compared to 86% last year. Precipitation in March was much
below average at 66%, which brings the seasonal accumulation (Oct-Mar) to 75% of average. Soil moisture is at 61% compared to 63%
last year. The forecast streamflow volume for Pine Creek is 59% of average.
Snowpack
Soil Moisture
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Calculated using soil moisture content at 2, 8, and 20-inch depths.
Max
Min
Avg
WY 2015
2005-Current
Precipitation
160
140
Percent of Average
120
100
80
60
40
20
0
Monthly
Year-to-Date
WY 2015
Avg
!
(
Escalante basin
V
U
12
!
(
5 Boulder
#
*
!
(
Escalante
5
£
¤
89
#
*
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
< 50%
50 - 69%
70 - 89%
!
(
#
*
SNOTEL sites
Forecast points
90 - 109%
Rivers
110 - 129%
Highways
130 - 149%
> 150%
5
Cities
Ü
0 2.5 5
no % avail.
10
15
20
Miles
Beaver River Basin
4/1/2015
Snowpack in the Beaver River Basin is much below normal at 48% of normal, compared to 85% last year. Precipitation in March was
much below average at 56%, which brings the seasonal accumulation (Oct-Mar) to 55% of average. Soil moisture is at 46% compared
to 42% last year. Reservoir storage is at 50% of capacity, compared to 57% last year. The forecast streamflow volume for the Beaver
River is 30% of average. The surface water supply index is 6% for the Beaver River.
Snowpack
Soil Moisture
80%
Snow Water Equivalent Index
Saturation, volume %
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
120
Percent of Average
100
80
MINERSVILLE
RESERVOIR
60
40
20
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Beaver River
*
^
11.72
#
KAF
^
Storage + Forecast
KAF
7.70
^
19.42
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Beaver River Surface Water Supply Index
100
90
Thousand Acre Feet
80
70
60
50
40
30
20
10
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
6
-3.7
02, 04, 90, 03
Beaver basin
§
¨
¦
15
§
¨
¦
70
Milford
5
Beaver 5
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
< 50%
50 - 69%
70 - 89%
!
(
#
*
SNOTEL sites
Forecast points
90 - 109%
Rivers
110 - 129%
Highways
130 - 149%
> 150%
no % avail.
5
Cities
0 1.5 3
Ü
6
9
12
Miles
#
*
!
(
!
(
Previous Year % Capacity
Current % Capacity
Southwestern Utah Basin
4/1/2015
Snowpack in the Southwestern Utah Basin is much below normal at 41% of normal, compared to 46% last year. Precipitation in March
was much below average at 68%, which brings the seasonal accumulation (Oct-Mar) to 59% of average. Soil moisture is at 69%
compared to 63% last year. Reservoir storage is at 45% of capacity, compared to 39% last year. Forecast streamflow volumes range
from 22% to 45% of average. The surface water supply index is 12% for the Virgin River.
Snowpack
Soil Moisture
100%
Snow Water Equivalent Index
Saturation, volume %
80%
60%
40%
20%
0%
Max
Min
Avg
WY 2015
Calculated using soil moisture content at 2, 8, and 20-inch depths.
2005-Current
WY 2015
Avg
Reservoir Storage
Precipitation
120
QUAIL CREEK
100
Percent of Average
SAND HOLLOW
80
GUNLOCK
60
KOLOB
UPPER ENTERPRISE
40
LOWER ENTERPRISE
20
LAKE POWELL
0
Monthly
Year-to-Date
Previous Year % Capacity
Current % Capacity
Surface Water Supply Index
April 1, 2015
Basin or Region
Mar EOM* Storage APR-JUL Forecast
KAF
Virgin River
*
^
32.86
#
KAF
^
19.50
Storage + Forecast
KAF
^
52.36
^
EOM, end of month; SWSI, Surface Water Supply Index; KAF, thousand acre-feet.
Virgin River Surface Water Supply Index
300
Thousand Acre Feet
250
200
150
100
50
0
Water Year
Storage (KAF)
Streamflow (KAF)
Percentile SWSI#
Years with similiar SWSI
%
12
-3.21
91, 03, 14, 13
Southwestern Utah
§
¨
¦
15
!
(
Cedar City
5#
*
!
(
!
(
!
(!
(
!
(
!
(
!
( !
(
!
(!
(
(
#
*!
#
*
5
#
*
Hurricane
St. George 5
Percent normal
"
)
"
)
"
)
"
)
"
)
"
)
"
)
"
)
< 50%
50 - 69%
70 - 89%
!
(
#
*
SNOTEL sites
Forecast points
90 - 109%
Rivers
110 - 129%
Highways
130 - 149%
> 150%
no % avail.
5
Cities
0 2.5 5
Ü
10
15
20
Miles
Surface Water Supply Index
April 1, 2015
*
Basin or Region
Bear River
Woodruff Narrows
Little Bear
Ogden River
Weber River
Provo River
Western Uintah
Eastern Uintah
Blacks Fork
Smiths Fork
Price River
Joe's Valley
Ferron Creek
Moab
Upper Sevier
San Pitch
Lower Sevier
Beaver River
Virgin River
Mar EOM
Storage
KAF ^
583.8
50.9
14.1
77.9
232.3
920.4
195.5
31.0
26.3
8.9
14.6
41.6
10.8
1.5
80.4
2.3
117.1
11.7
32.9
APR-JUL Forecast
Storage + Forecast
Percentile
KAF ^
KAF ^
%
18.0
40.0
8.0
16.0
54.0
28.0
40.0
22.9
45.0
15.0
7.0
20.0
12.0
2.0
26.0
6.5
25.0
7.7
19.5
601.8
90.9
22.1
93.9
286.3
948.4
235.5
53.9
71.3
23.9
21.6
61.6
22.8
3.5
106.4
8.8
142.1
19.4
52.4
42
14
4
11
3
14
19
3
24
24
6
8
6
21
8
3
11
6
12
SWSI #
Years with similiar
SWSI
‐0.69
‐3.01
‐3.82
‐3.24
‐3.94
‐3.03
‐2.55
‐3.94
‐2.15
‐2.21
‐3.7
‐3.47
‐3.7
‐2.44
‐3.47
‐3.94
‐3.24
‐3.7
‐3.21
07, 10, 90, 14
04, 13, 03, 90
13, 14, 03, 01
88, 03, 13, 87
13, 04, 03, 07
04, 03, 14, 02
03, 12, 04, 07
14, 02, 13, 89
00, 12, 89, 13
07, 89, 03, 06
92, 04, 02, 94
13, 02, 90, 03
13, 02, 90, 12
12, 89, 04, 09
04, 91, 90, 92
02, 13, 14, 03
03, 92, 02, 94
02, 04, 90, 03
91, 03, 14, 13
*EOM, end of month; # SWSI, surface water supply index; ^KAF, thousand acre‐feet.
What is a Surface Water Supply Index?
The Surface Water Supply Index (SWSI) is a predictive indicator of total surface water availability within a watershed for the spring and summer water use seasons. The index is calculated by combining pre‐runoff reservoir storage (carryover) with forecasts of spring and summer streamflow which are based on current snowpack and other hydrologic variables. SWSI values are scaled from +4.1 (abundant supply) to ‐4.1 (extremely dry) with a value of zero (0) indicating median water supply as compared to historical analysis. SWSI's are calculated in this fashion to be consistent with other hydroclimatic indicators such as the Palmer Drought Index and the Precipitation index. Utah Snow Surveys has also chosen to display the SWSI value as well as a PERCENT CHANCE OF NON‐EXCEEDANCE. While this is a cumbersome name, it has the simplest application. It can be best thought of as a scale of 1 to 99 with 1 being the drought of record (driest possible conditions) and 99 being the flood of record (wettest possible conditions) and a value of 50 representing average conditions. This rating scale is a percentile rating as well, for example a SWSI of 75% means that this years water supply is greater than 75% of all historical events and that only 25% of the time has it been exceeded. Conversely a SWSI of 10% means that 90% of historical events have been greater than this one and that only 10% have had less total water supply. This scale is comparable between basins: a SWSI of 50% means the same relative ranking on watershed A as it does on watershed B, which may not be strictly true of the +4 to ‐4 scale. For more information on the SWSI go to: www.ut.nrcs.usda.gov/snow/ on the water supply page. The entire period of historical record for reservoir storage and streamflow is available.
Issued by
Released by
Jason Weller
Chief
Natural Resources Conservation Service
U.S. Department of Agriculture
David Brown
State Conservationist
Natural Resources Conservation Service
Salt Lake City, Utah
Prepared by
Snow Survey Staff
Randall Julander, Supervisor
Troy Brosten, Assistant Supervisor
Beau Uriona, Hydrologist
Jordan Clayton, Hydrologist
Jeffrey O’Connell, Hydrologist
Bob Nault, Electronics Technician
Kent Sutcliffe, Soil Scientist
YOU MAY OBTAIN THIS PRODUCT AS WELL AS CURENT SNOW, PRECIPITATION,
TEMPERATURE AND SOIL MOISTURE, RESERVOIR, SURFACE WATER SUPPLY INDEX, AND
OTHER DATA BY VISITING OUR WEB SITE @: http://www.ut.nrcs.usda.gov/snow/
Snow Survey, NRCS, USDA
245 North Jimmy Doolittle Road
Salt Lake City, UT 84116
(801) 524-5213
Utah Climate and
Water Report
Natural Resources Conservation Service
Salt Lake City, UT