Lower Green River Basin (12)
June 2000

Snow
The Blacks Fork and Henrys Fork drainage's, as of June 1, are melted out. SWE in the Hams Fork, as of June 1, is 9 percent of average (5% of last year). The basin, as a whole, is 9 percent of average (6 percent of last year). For more information see Basin Summary of Snow Courses at beginning of this report.

Precipitation
Precipitation was above average for the 3 reporting stations during May. Precipitation ranged from 67 to 110 percent of average for the month. The entire basin received 102 percent of average for the month (89 percent of last year). The basin year-to-date precipitation is currently 73 percent of average (68 percent of last year). Year to date percentages range from 69 to 78.

Reservoir
Fontenelle Reservoir is currently storing 187,100 acre feet; this is 96 percent of average (91 % of last year). Flaming Gorge did not report this month. Viva Naughton is currently storing 45,200 acre feet; this is 133 percent of average (132 % of last year).

Streamflow
Expected yields vary from 54 to 70 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 535,000-acre feet (60 percent of average). Blacks Fork near Robertson is forecast to yield 66,000-acre feet (70 percent of average). East Fork of Smiths Fork near Robertson is estimated to yield 19,800 acre-feet (66 percent of average). The estimated yield for Hams Fork near Frontier is 38,000-acre feet (58 percent of average). Viva Naughton Reservoir inflow will be about 48,000-acre feet (54 percent of average). Flaming Gorge Reservoir inflow will be about 675,000-acre feet (56 percent of average). 

==================================================================================================================================
                                                     LOWER 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 nr Green River, WY       APR-JUL       414       479    |      535        60    |       591       656            899
                                                                    |                       |
Blacks Fork nr Robertson             APR-JUL        55        61    |       66        70    |        71        78             95
                                                                    |                       |
EF of Smiths Fork nr Robertson       APR-JUL      15.0      18.8    |     19.8        66    |        21        25             30
                                                                    |                       |
Hams Fk blw Pole Ck nr Frontier      APR-JUL        28        34    |       38        58    |        43        50             66
                                                                    |                       |
Hams Fk Inflow to Viva Naughton Res  APR-JUL        29        40    |       48        54    |        56        67             89
                                                                    |                       |
Flaming Gorge Reservoir Inflow       APR-JUL       395       598    |      675        56    |       752       945           1196
                                                                    |                       |
==================================================================================================================================
                         LOWER GREEN RIVER BASIN                        |                 LOWER 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
========================================================================|=========================================================
FONTENELLE                             344.8    187.1    206.0    195.5 |   HAMS FORK RIVER             3         5         9
                                                                        |
FLAMING GORGE                                   NO REPORT               |   BLACKS FORK                 2         0         0
                                                                        |
VIVA NAUGHTON RES                       42.4     45.2     34.3     34.0 |   HENRYS FORK                 2         0         0
                                                                        |
                                                                        |   GREEN above Flaming Gorge  18         6         9
                                                                        |
==================================================================================================================================
 * 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.
To June 2000 Basin Outlook Report Contents Page