Wyoming Water Supply Outlook Report
January 2000

General
Generally, snow water equivalent (SWE) across the state is below normal -- SWE is 15 to 30 percent below average for most of the State. Precipitation for December was above average in the north central and northeast and below 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 74 percent of average. The mean of all the forecast points is 26 percent below average -- for all points in the State. The minimum yield forecast was 28 percent of average in the Sweetwater drainage and the maximum forecast was 87 percent of average at Shell Creek near Shell.

Snowpack
December conditions varied across the State, but SWE is generally below average across the State. The northwestern portion of Wyoming received well below normal snow accumulation. Northeast Wyoming is below normal -- they received several snow storms that missed the rest of the State. The Southeast portion of the State is much below normal and the Southwest portion is also below normal.

Precipitation
December precipitation was mixed with north central and northeast portion of the State above average and the rest below average. The following table displays the major river basins and their departure from normal for December 1999.

BasinDeparture
from normal		BasinDeparture
from normal
Snake River -27%Upper North Platte River-11%
Yellowstone & Madison -03%Lower North Platte River-20%
Wind River -49%Little Snake River -09%
Bighorn +18%Upper Green River -47%
Shoshone & Clarks Fork -03%Lower Green River -47%
Powder & Tongue River +23%Upper Bear River -43%
Belle Fourche & Cheyenne+24%

Streams
Stream flow yield is expected to be below to much below average across the State. Yield from the northeast portion of Wyoming will be below average -- yield estimates vary from 69 to 85 percent of average (mean is 74%). In most cases, the southeast portion of the state will be about 50 percent below normal -- yield estimates range from 28 to 72 percent of normal. The southwest portion of Wyoming varies from 48 to 71 percent of average -- mean estimated yield for southeast Wyoming is about 60 percent of average. The northwest part of the State is expected to yield about 30 percent less than normal -- yields vary from 38 to 87 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 DECEMBER 1999


 BASIN AREA         CURRENT AS  LAST YR AS  AVERAGE AS  CURRENT AS  CURRENT AS
  RESERVIOR         % CAPACITY  % CAPACITY  % CAPACITY   % AVERAGE   % LAST YR
------------------------------------------------------------------------------
ALCOVA                    85          85          83         102         100
ANGOSTURA                 86          91          79         109          95
BELLE FOURCHE             97          93          51         191         104
BIG SANDY                                 NO REPORT
BIGHORN LAKE              71          70          66         108         102
BOYSEN                    92         100         103          89          92
BUFFALO BILL              71          69          68         105         102
BULL LAKE                 63          65          58         108          98
DEERFIELD                 97          94          81         120         103
EDEN                                      NO REPORT
FLAMING GORGE                             NO REPORT
FONTENELLE                61          66          60         101          93
GLENDO                    55          69          55         100          79
GRASSY LAKE               80          83          69         116          97
GUERNSEY                  23          31          12         191          73
HEBGEN LAKE               91          88          65         140         104
JACKSON LAKE              75          70          56         134         107
KEYHOLE                   89          91          51         175          97
PACTOLA                   99          94          83         119         106
PALISADES                 84          86          74         113          97
PATHFINDER                91          86          50         184         107
PILOT BUTTE               73          72          49         148         101
SEMINOE                   83          74          53         156         112
SHADEHILL                 68          71          62         110          96
TONGUE RIVER                              NO REPORT
VIVA NAUGHTON RES                         NO REPORT
WHEATLAND #2                        AVERAGE NOT ESTABLISHED
WOODRUFF NARROWS                          NO REPORT


GLENDO PROJECT USERS      85          85          63         134          99
KENDRICK PROJECT          83          82          68         121         101
NORTH PLATTE PROJ         85          76          54         158         111
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