Wyoming Water Supply Outlook Report
February 2000

General
Generally, snow water equivalent (SWE) across the state is below normal -- SWE is 10 to 30 percent below average for most of the State. Precipitation for January was average to below average in the northeast and average to above average for the rest of the State. Precipitation for year-to-date is below to much below normal. Most of the reservoir levels are above average. Forecast runoff varies, but is generally from 49 to 91 percent of average. The mean of all the forecast points is 28 percent below average -- for all points in the State. The minimum yield forecast was 49 percent of average in the South Fork above Buffalo Bill and the maximum forecast was 91 percent of average at Pine Creek above Fremont Lake.

Snowpack
Snow conditions improved across the State in January, but SWE is generally below average across the State. SWE in the northwestern portion of Wyoming improved significantly, but is still about 70-90 percent of average. Northeast Wyoming SWE varies from less than 70 percent of average to about 90 percent of average. The Southeast and Southwest portions of the State generally have 70 to 90 percent of average SWE, but some areas of less than 70 percent of average SWE are included in the area.

Precipitation
January precipitation was generally good across the state except for the Northeast. The following table displays the major river basins and their departure from normal for January 2000.

BasinDeparture
from normal		BasinDeparture
from normal
Snake River +01%Upper North Platte River+32%
Yellowstone & Madison +04%Lower North Platte River+27%
Wind River +17%Little Snake River +01%
Bighorn +08%Upper Green River +08%
Shoshone & Clarks Fork +26%Lower Green River -04%
Powder & Tongue River +22%Upper Bear River +09%
Belle Fourche & Cheyenne-25%

Streams
Stream flow yield is expected to vary from below to much below average across the State. Yield from the northeast portion of Wyoming will be below average -- yield estimates vary from 50 to 87 percent of average (mean is 68%). In most cases, the southeast portion of the state will be about 70 percent of normal -- yield estimates range from 49 to 89 percent of normal. The southwest portion of Wyoming varies from 56 to 91 percent of average -- mean estimated yield for southeast Wyoming is about 74 percent of average. The northwest part of the State is expected to yield about 75 percent of normal -- yields vary from 49 to 91 percent of normal.

Reservoirs
Although several reservoirs did not report, reservoir storage for those reporting is generally above average for this time of the year. 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 JANUARY  2000


 BASIN AREA         CURRENT AS  LAST YR AS  AVERAGE AS  CURRENT AS  CURRENT AS
  RESERVIOR         % CAPACITY  % CAPACITY  % CAPACITY   % AVERAGE   % LAST YR
------------------------------------------------------------------------------
ALCOVA                    85          84          85         100         100
ANGOSTURA                 89          95          80         111          94
BELLE FOURCHE             97          94          57         171         103
BIG SANDY                                 NO REPORT
BIGHORN LAKE              69          64          62         112         109
BOYSEN                    89          96          97          91          93
BUFFALO BILL              69          69          64         108         101
BULL LAKE                 63          64          57         110          97
DEERFIELD                 98          95          84         116         103
EDEN                                      NO REPORT
FLAMING GORGE                       AVERAGE NOT ESTABLISHED
FONTENELLE                49          52          57          85          93
GLENDO                    65          80          65          99          81
GRASSY LAKE               82          85          71         115          96
GUERNSEY                  29          38          15         194          76
HEBGEN LAKE               86          82          65         131         105
JACKSON LAKE              76          72          57         134         106
KEYHOLE                   89          92          51         175          97
PACTOLA                   98          94          83         118         104
PALISADES                 88          85          75         118         103
PATHFINDER                92          87          54         169         105
PILOT BUTTE               71          71          52         136         101
SEMINOE                   82          72          46         178         113
SHADEHILL                 29          68          60          47          42
TONGUE RIVER              54           9          40         135         590
VIVA NAUGHTON RES         84          74          68         124         114
WHEATLAND #2              67          63          41         165         106
WOODRUFF NARROWS                    AVERAGE NOT ESTABLISHED
GLENDO PROJECT USERS      85          85          65         130          99
KENDRICK PROJECT          82          82          68         121         101
NORTH PLATTE PROJ         89          81          57         157         110
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