Upper Green River Basin (11)
June 2000

Snow
The Upper Green River Basin snow water equivalent (SWE), above Fontenelle Reservoir, is 11 percent of average (7 percent of last year). The Green River basin SWE above Warren Bridge is 0 percent of normal (0 percent of last year). SWE on the west side of the Upper Green River basin is about 12 percent of normal, 9 percent of this time last year. Newfork River SWE is now 0 percent of normal (0 percent of last year). Big Sandy-Eden Valley SWE is about 0 percent of average (0 percent of last 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 100 percent of the May average (90 percent of last year at this time). May precipitation varied from 73 to 119 percent of average. Water year-to-date precipitation is about 74 percent of average (71 percent of last year). Year to date percentage of average ranges from 67 to 87 for the reporting stations.

Reservoir
Data for Big Sandy Reservoir, Eden Reservoir, and Flaming Gorge were not reported this month. Fontenelle Reservoir is storing 187,100 acre-feet (96 percent of average and 30 percent of the total capacity). There is no average 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 well below average. Green River at Warren Bridge is expected to yield about 200,000 acre-feet (75 percent of normal). Pine Creek above Fremont Lake is expected to yield 80,000 acre-feet (77 percent of normal). New Fork River near Big Piney is expected to yield about 235,000 acre-feet (61 percent of normal). Fontenelle Reservoir Inflow is estimated to be 525,000 acre-feet (62 percent of average), and Big Sandy near Farson is expected to be about 38,000 acre-feet (67 percent of normal). 

==================================================================================================================================
                                                     UPPER GREEN RIVER BASIN
                                               Streamflow Forecasts - June 1, 2000
==================================================================================================================================
                                              |  <<====== 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       165       186    |      200        75    |       214       235            266
                                                                    |                       |
Pine Creek abv Fremont Lake          APR-JUL        69        75    |       80        77    |        85        92            104
                                     JUN-JUL        38        48    |       54        64    |        61        70             85
                                                                    |                       |
New Fork River nr Big Piney          APR-JUL       142       209    |      235        61    |       261       323            385
                                                                    |                       |
Fontenelle Reservoir Inflow          APR-JUL       331       485    |      525        62    |       566       722            849
                                                                    |                       |
Big Sandy River nr Farson            APR-JUL        26        35    |       38        67    |        41        50             57
                                                                    |                       |
==================================================================================================================================
                         UPPER GREEN RIVER BASIN                        |                 UPPER GREEN RIVER BASIN
             Reservoir Storage (1000 AF) - End of May                   |        Watershed Snowpack Analysis - June 1, 2000
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
BIG SANDY                                       NO REPORT               |   GREEN above Warren Bridge   4         0         0
                                                                        |
EDEN                                            NO REPORT               |   UPPER GREEN (West Side)     5         9        12
                                                                        |
FLAMING GORGE                                   NO REPORT               |   NEWFORK RIVER               2         0         0
                                                                        |
FONTENELLE                             344.8    187.1    206.0    195.5 |   BIG SANDY/EDEN VALLEY       1         0         0
                                                                        |
                                                                        |   GREEN above Fontenelle     11         7        11
                                                                        |
==================================================================================================================================
 * 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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