Wyoming Water Supply Outlook Report
January 1997

General
Water conditions across Wyoming are very good. December precipitation varied from above normal to much above normal. Snowpack in all the basins is above average for this time of year. Precipitation for the month of December was good across the state with all areas receiving above average amounts. Reservoir storage is looking very good across the state also. There should be no water shortages this year, if the current trend continues.

Snowpack
Snow pack over the State is above normal for this time of the year. The Powder Tongue is currently the lowest basin in percent of average SWE at 127 percent. All the other basin go up from there to a high in the Upper Yellowstone and Madison of 218 percent of average. SWE is well ahead of last year at this time. January snow water equivalent (SWE), compared to last year, varies from 22 percent to about 113 percent more than last year.

Precipitation
Basins in the state received much above average precipitation during the month. The higher altitude sites have generally received 21-93% above normal precipitation. The Powder and Tongue River basin 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 (21% above average) and Shoshone and Belle Fourche Basins (93% above normal). 

Basin                      Departure    Basin                       Departure
                           from normal                              from normal
Snake River                +66%         Upper North Platte River    +49%
Yellowstone & Madison      +87%         Lower North Platte          +51%
Wind River                 +55%         Little Snake River          +53%
Big Horn                   +25%         Upper Green River           +61%
Shoshone & Clarks Fork     +93%         Lower Green River           +65%
Powder & Tongue River      +21%         Upper Bear River            +87%
Belle Fourche & Cheyenne   +93%
Streams
All basins in the state should see average or above average runoff. Some areas in the state could see yields approaching 200 percent of average. Some high runoff might be expected in portions of Wyoming. Many areas have above to much above average runoff forecast; under the right conditions exceptionally high flows might occur in these areas. Water users should not expect any shortages during the irrigation season. The only basin that could see flows down close to average is the Powder - Tongue River basin.

Reservoirs Generally speaking, reservoir storage is above average in the state with almost all reservoirs holding more than average amounts. Most reservoirs should fill to capacity this year. Even the reservoirs that appear to be low Shadehill (87% of average), Eden (86% of average) and Fontenelle Reservoir (89% of average) should fill. See following table for further information about reservoir storage. 

                            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   DECEMBER 1996

BASIN AREA         CURRENT AS  LAST YR AS  AVERAGE AS  CURRENT AS  CURRENT AS
 RESERVOIR         % CAPACITY  % CAPACITY  % CAPACITY   % AVERAGE   % LAST YR

 ALCOVA                    84          84          83         101         100
 ANGOSTURA                 73          74          79          93          99
 BELLE FOURCHE             77          85          51         151          90
 BIG SANDY                 41          70          45          91          59
 BIGHORN LAKE              66          67          66         100          98
 BOYSEN                    93          99         103          91          95
 BUFFALO BILL              79          82          68         117          97
 BULL LAKE                 52          66          58          89          79
 DEERFIELD                101          96          81         125         105
 EDEN                      31          52          36          86          59
 ENNIS LAKE                78          77          82          95         102
 FONTENELLE                54          63          60          89          86
 GLENDO                    51          45          55          93         112
 GRASSY LAKE               84          84          69         121          99
 GUERNSEY                  26          32          12         213          79
 HEBGEN LAKE               70          68          65         107         103
 JACKSON LAKE              80          79          56         145         102
 KEYHOLE                   73          56          51         144         131
 PACTOLA                   99         101          83         118          98
 PALISADES                 89          98          74         120          90
 PATHFINDER                82          69          50         165         118
 PILOT BUTTE               75          70          49         153         108
 SEMINOE                   73          79          53         137          93
 SHADEHILL                 54          53          62          87         102
 TONGUE RIVER                              NO REPORT
 VIVA NAUGHTON RES                         NO REPORT


 GLENDO PROJECT USERS      82          86          63         129          95
 KENDRICK PROJECT          82          55          68         120         150
 NORTH PLATTE PROJ         67          88          54         124          75
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