Snowpack
Snowpack over the State is above normal to much above normal for this time of
the year. Some basins are stil at record levels. The Powder-Tongue River
drainage currently has the lowest percentage of average SWE (123 percent); all
the other basins go up from there with a high of 155 percent of average in the
upper Yellowstone and Madison drainage. SWE is well ahead of last year at this
time. March (SWE), compared to last year, varies from the same to about 30
percent more than last year.
Precipitation
Many basins in the state received below average precipitation during the month.
The higher altitude sites have generally received above normal precipitation.
The Powder and Tongue River basin has received the lowest precipitation in the
state so far this water year (Oct - Sep). The entire State has above normal
year-to-date precipitation. The extremes are Powder - Tongue (13% above
average) and the Belle Fourche Basin (59% above normal).
Basin Departure Basin Departure
from normal from normal
Snake River +37% Upper North Platte River +23%
Yellowstone & Madison +57% Lower North Platte +26%
Wind River +28% Little Snake River +16%
Big Horn +17% Upper Green River +21%
Shoshone & Clarks Fork +56% Lower Green River +24%
Powder & Tongue River +13% Upper Bear River +39%
Belle Fourche & Cheyenne +59%
Streams,
Even though March precipitation was generally below average, all basins in the
state should see average or above average runoff -- in some cases there will be
much above average yield if it quit snowing entirely. Record SWE is being
recorded in some portions of the state (generally the northern portion); high
runoff might be expected in those portions of Wyoming. Under the right
conditions exceptionally high flows could occur in the areas with record snow
levels. Water users should not expect any shortages during the irrigation
season.
Reservoirs
Reservoir storage varies from well below to well above average. Generally
speaking, reservoir storage in the portions of the State that expects large
amounts of runoff have been lowered to below average volumes. Most reservoirs
should fill to capacity this year. Some reservoirs are currently being drawn
down in anticipation of excessive flows during the runoff season. See
following table for further information about reservoir storage. Major
Reservoirs in Wyoming
B A S I N W I D E
R E S E R V O I R S U M M A R Y
FOR THE END OF MARCH 1997
BASIN AREA CURRENT AS LAST YR AS AVERAGE AS CURRENT AS CURRENT AS
RESERVOIR % CAPACITY % CAPACITY % CAPACITY % AVERAGE % LAST YR
--------------------------------------------------------------------------------
ALCOVA 85 85 88 97 100
ANGOSTURA 99 91 90 110 108
BELLE FOURCHE 96 102 73 131 95
BIG SANDY 70 0 52 134 0
BIGHORN LAKE 56 58 59 95 97
BOYSEN 77 90 89 86 85
BUFFALO BILL 66 73 56 118 90
BULL LAKE 54 65 55 98 83
DEERFIELD 96 97 89 108 99
EDEN 52 52 40 130 100
ENNIS LAKE 69 72 81 85 95
FONTENELLE 35 28 46 77 124
GLENDO 95 77 83 115 124
GRASSY LAKE 88 88 74 120 100
GUERNSEY 63 55 47 133 114
HEBGEN LAKE 62 68 65 95 92
JACKSON LAKE 65 74 56 117 88
KEYHOLE 94 76 56 169 123
PACTOLA 97 98 85 114 99
PALISADES 28 49 72 39 58
PATHFINDER 89 84 61 146 106
PILOT BUTTE 74 71 68 109 105
SEMINOE 63 65 36 174 97
SHADEHILL 103 79 78 132 130
TONGUE RIVER 38 59 53 71 64
VIVA NAUGHTON RES NO REPORT
GLENDO PROJECT USERS 92 92 69 132 100
KENDRICK PROJECT 77 54 68 114 142
NORTH PLATTE PROJ 86 102 64 136 85
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