Lower Green River Basin
March 1997

Snow
The Blacks Fork drainage snow water equivalent (SWE) is 127 percent of average, currently the lowest in the basin. Henrys Fork is about 132 percent of average. Snowpack in the Hams Fork, as of March 1, is 149 percent of average. The basin as a whole is 144 percent of average. This is 12 percent ahead of last year at this time. For more information see Basin Summary of Snow Courses at beginning of this report.

Precipitation
Precipitation was light throughout the basin during February. Precipitation ranged from 13 percent of average at Kelley RS to 54 percent of average at Rock Springs. The entire basin received 32 percent of average for the month (51 percent of last year). The basin year to date precipitation is currently 133 percent of average; sites range from 115 to 164 percent of average.

Reservoir
Fontenelle Reservoir is currently storing 119,000 acre feet; this is 69 percent of average storage. Flaming Gorge currently is storing 3,150,600 acre feet. There is no average established for Flaming Gorge. Viva Naughton did not report this month.

Streamflow
Water users can expect above average yields in the basin this season. The following forecast values are based on a 50 percent chance probability for the April to July forecast period. Yields will range from 130 percent of average for Meeks Cabin Reservoir inflow (125,000 acre feet) to 167 percent of average (110,000 acre feet) at Hams Fork near Frontier. Green River near Green River is forecast to yield 1,300,000 acre feet (145 percent of average). State Line Reservoir inflow is estimated to flow 42,000 acre feet (140 percent of average). Viva Naughton Reservoir inflow will be about 150,000 acre feet (161 percent of average). Flaming Gorge Reservoir inflow should be near 1,800,000 acre feet (151 percent of average. 

==================================================================================================================================
                                                     LOWER GREEN RIVER BASIN
                                               Streamflow Forecasts - March 1, 1997
==================================================================================================================================
                                              |  <<====== 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 R nr Green River, WY           APR-JUL      1070      1224    |     1300       145    |      1376      1528            899
                                                                    |                       |
MEEKS CABIN RESERVOIR Inflow         APR-JUL       107       118    |      125       130    |       132       143             96
                                                                    |                       |
STATE LINE RESERVOIR INFLOW          APR-JUL        33        38    |       42       140    |        46        52             30
                                                                    |                       |
HAMS FORK nr Frontier                APR-JUL        88       101    |      110       167    |       119       133             66
                                                                    |                       |
VIVA NAUGHTON RES inflow             APR-JUL       120       138    |      150       161    |       162       180             93
                                                                    |                       |
FLAMING GORGE RES INFLOW             APR-JUL      1399      1675    |     1800       151    |      1925      2201           1196
                                                                    |                       |
==================================================================================================================================
                         LOWER GREEN RIVER BASIN                        |                 LOWER GREEN RIVER BASIN
             Reservoir Storage (1000 AF) - End of February              |        Watershed Snowpack Analysis - March 1, 1997
==================================================================================================================================
                                      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    119.0    121.8    172.0 |   HAMS FORK RIVER             4       119       149
                                                                        |
FLAMING GORGE                         3749.0   3150.6   3194.4      --- |   BLACKS FORK                 5        87       127
                                                                        |
VIVA NAUGHTON RES                               NO REPORT               |   HENRYS FORK                 3       134       132
                                                                        |
                                                                        |   GREEN above Flaming Gorge  26       112       144
                                                                        |
==================================================================================================================================
 * 90%, 70%, 30%, and 10% chances of exceeding are the probabilities that the actual flow 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 flow - actual flow may be affected by upstream water management.
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