Lower Green River Basin (12)
January 2001

Snow
The Blacks Fork and Henrys Fork drainage's, as of January 1, are just below average. SWE in the Hams Fork, as of January 1, is 93 percent of average (183% of last year). Blacks Fork SWE is currently 97 percent of average (150 percent of last year). The basin, as a whole, is 85 percent of average (145 percent of last year). For more information see Basin Summary of Snow Courses at beginning of this report.

Precipitation
Precipitation was below average for the 3 reporting stations during December. Precipitation ranged from 48 to 100 percent of average for the month. The entire basin received 73 percent of average for the month (139 percent of last year). The basin year-to-date precipitation is currently 73 percent of average (191 percent of last year). Year to date percentages range from 67 to 83.

Reservoir
Fontenelle Reservoir is currently storing 151,900 acre feet; this is 73 percent of average (72 % of last year). Flaming Gorge is currently storing 3,006,000 acre feet. There is no average established for Flaming Gorge. Viva Naughton is currently storing 32,200 acre feet; this is 110 percent of average.

Streamflow
Expected yields vary from 85 to 100 percent of average across the basin. The following forecast values are based on a 50 percent chance probability for the April through July forecast period. Green River near Green River is forecast to yield about 765,000-acre feet (85 percent of average). Blacks Fork near Robertson is forecast to yield 94,000-acre feet (99 percent of average). East Fork of Smiths Fork near Robertson is estimated to yield 30,000 acre-feet (100 percent of average). The estimated yield for Hams Fork near Frontier is 60,000- acre feet (91 percent of average). Viva Naughton Reservoir inflow will be about 80,000-acre feet (90 percent of average). Flaming Gorge Reservoir inflow will be about 1,060,000-acre feet (89 percent of average). 

==================================================================================================================================
                                                     LOWER GREEN RIVER BASIN
                                               Streamflow Forecasts - January 1, 2001
==================================================================================================================================
                                              |  <<====== Drier ======  Future Conditions  =======  Wetter =====>>  |             
                                              |                                                                     |
  Forecast Point                     Forecast |  ==================== Chance Of Exceeding * ======================  |
                                      Period  |    90%       70%    |  50% (Most Probable)  |      30%       10%    |  30-Yr Avg.
                                              | (1000AF)  (1000AF)  |   (1000AF)  (% AVG.)  |    (1000AF)  (1000AF) |    (1000AF)
====================================================================|=======================|=====================================
Green River nr Green River, WY       APR-JUL       457       640    |      765        85    |       890      1073            899
                                                                    |                       |
Blacks Fork nr Robertson             APR-JUL        63        81    |       94        99    |       107       125             95
                                                                    |                       |
EF of Smiths Fork nr Robertson       APR-JUL        22        27    |       30       100    |        34        41             30
                                                                    |                       |
Hams Fk blw Pole Ck nr Frontier      APR-JUL        37        50    |       60        91    |        71        89             66
                                                                    |                       |
Hams Fk Inflow to Viva Naughton Res  APR-JUL        37        63    |       80        90    |        97       123             89
                                                                    |                       |
Flaming Gorge Reservoir Inflow       APR-JUL       634       888    |     1060        89    |      1232      1486           1196
                                                                    |                       |
==================================================================================================================================
                         LOWER GREEN RIVER BASIN                        |                 LOWER GREEN RIVER BASIN
             Reservoir Storage (1000 AF) - End of December              |        Watershed Snowpack Analysis - January 1, 2001
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
FONTENELLE                             344.8    151.9    210.4    208.3 |   HAMS FORK RIVER             3       183        93
                                                                        |
FLAMING GORGE                         3749.0   3006.0   3269.0      --- |   BLACKS FORK                 2       150        97
                                                                        |
VIVA NAUGHTON RES                       42.4     32.2      ---     29.3 |   HENRYS FORK                 2       152       131
                                                                        |
                                                                        |   GREEN above Flaming Gorge  18       154        90
                                                                        |
==================================================================================================================================
 * 90%, 70%, 30%, and 10% chances of exceeding are the probabilities that the actual volume will exceed the volumes in the table.

The average is computed for the 1961-1990 base period.

(1) - The values listed under the 10% and 90% Chance of Exceeding are actually 5% and 95% exceedance levels.                  
(2) - The value is natural volume - actual volume may be affected by upstream water management.
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