Upper Green River Basin (11)
June 2001

Snow
Snow has mostly melted from the SNOTEL sites in this basin. Only three of the eleven sites report any snow, and those sites are well below average for this time of the year. For more information see the Basin Summary of Snow Courses at the beginning of this report.

Precipitation
The 11 reporting precipitation sites in the basin were 111 percent of the May average (191 percent of last year at this time). May precipitation varied from 59 to 178 percent of average. Water year-to-date precipitation is about 88 percent of average (63 percent of last year). Year to date percentage of average ranges from 56 to 75 percent for the reporting stations.

Reservoir
Usable storage in Big Sandy Reservoir is 19,600 acre-feet (69 percent of average and 51 percent of the total capacity). Eden Reservoir water level is 2,800 acre-feet (36 percent of average and 24 percent of the total capacity). Usable storage in Fontenelle Reservoir is 158,500 acre feet (81 percent of average and 46 percent of capacity. Flaming Gorge Reservoir is currently storing 3,041,200 acre feet -- 81 percent of capacity. No average has been established for Flaming Gorge. Detailed reservoir data is shown on the following page and on the reservoir storage summary at the beginning of this report.

Streamflow
The fifty-percent chance April through July runoff in the Upper Green River basin is forecast much below average. Irrigators without a storage facility may experience water shortage. Green River at Warren Bridge is expected to yield about 155,000 acre-feet (58 percent of normal). Pine Creek above Fremont Lake is expected to yield 65,000 acre-feet (63 percent of normal). New Fork River near Big Piney is expected to yield about 225,000 acre-feet (58 percent of normal). Fontenelle Reservoir Inflow is estimated to be 335,000 acre-feet (40 percent of average), and Big Sandy near Farson is expected to be about 32,000 acre-feet (56 percent of normal). 

==================================================================================================================================
                                                     UPPER GREEN RIVER BASIN
                                               Streamflow Forecasts - June 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 at Warren Bridge         APR-JUL       120       141    |      155        58    |       169       190            266
                                                                    |                       |
Pine Creek abv Fremont Lake          APR-JUL        52        60    |       65        63    |        70        78            104
                                     JUN-JUL        36        41    |       45        53    |        52        61             85
                                                                    |                       |
New Fork River nr Big Piney          APR-JUL       160       199    |      225        58    |       251       290            385
                                                                    |                       |
Fontenelle Reservoir Inflow          APR-JUL       260       303    |      335        40    |       368       420            849
                                                                    |                       |
Big Sandy River nr Farson            APR-JUL        24        29    |       32        56    |        35        40             57
                                                                    |                       |
==================================================================================================================================
                         UPPER GREEN RIVER BASIN                        |                 UPPER GREEN RIVER BASIN
             Reservoir Storage (1000 AF) - End of May                   |        Watershed Snowpack Analysis - June 1, 2001
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
BIG SANDY                               38.3     19.6     33.1     28.3 |   GREEN above Warren Bridge   4         0         0
                                                                        |
EDEN                                    11.8      2.8      5.3      7.8 |   UPPER GREEN (West Side)     5         0         0
                                                                        |
FLAMING GORGE                                   NO REPORT               |   NEWFORK RIVER               2         0         0
                                                                        |
FONTENELLE                             344.8    158.5    187.1    195.5 |   BIG SANDY/EDEN VALLEY       1         0         0
                                                                        |
                                                                        |   GREEN above Fontenelle     11         0         0
                                                                        |
==================================================================================================================================
 * 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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