Lower Green River Basin (12)
February 2001

Snow
The Lower Green, as of February 1, is below average. SWE in the Hams Fork, as of February 1, is 64 percent of average (84% of last year). Blacks Fork SWE is currently 79 percent of average (86 percent of last year). The Henry's fork SWE is currently 125 percent of average (125 percent of last year). The basin, as a whole, is 60 percent of average (74 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 January. Precipitation ranged from 14 to 20 percent of average for the month. The entire basin received 16 percent of average for the month (17 percent of last year). The basin year-to-date precipitation is currently 55 percent of average (98 percent of last year). Year to date percentages range from 52 to 62.

Reservoir
Fontenelle Reservoir is currently storing 120,400 acre feet; this is 61 percent of average (72 % of last year). Flaming Gorge is currently storing 2,992,000 acre feet. There is no average established for Flaming Gorge. Viva Naughton did not report this month.

Streamflow
Expected yields vary from 54 to 84 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 630,000-acre feet (70 percent of average). Blacks Fork near Robertson is forecast to yield 80,000-acre feet (84 percent of average). East Fork of Smiths Fork near Robertson is estimated to yield 24,000 acre-feet (80 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 875,000-acre feet (73 percent of average). 
==================================================================================================================================
                                                     LOWER GREEN RIVER BASIN
                                               Streamflow Forecasts - February 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       368       524    |      630        70    |       736       892            899
                                                                    |                       |
Blacks Fork nr Robertson             APR-JUL        50        68    |       80        84    |        92       110             95
                                                                    |                       |
EF of Smiths Fork nr Robertson       APR-JUL      17.9        21    |       24        80    |        27        32             30
                                                                    |                       |
Hams Fk blw Pole Ck nr Frontier      APR-JUL        20        30    |       38        58    |        47        62             66
                                                                    |                       |
Hams Fk Inflow to Viva Naughton Res  APR-JUL      19.6        33    |       48        54    |        63        85             89
                                                                    |                       |
Flaming Gorge Reservoir Inflow       APR-JUL       508       727    |      875        73    |      1023      1242           1196
                                                                    |                       |
==================================================================================================================================
                         LOWER GREEN RIVER BASIN                        |                 LOWER GREEN RIVER BASIN
             Reservoir Storage (1000 AF) - End of January               |        Watershed Snowpack Analysis - February 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    120.4    167.6    196.2 |   HAMS FORK RIVER             4        84        64
                                                                        |
FLAMING GORGE                         3749.0   2992.0   3226.0      --- |   BLACKS FORK                 2        86        79
                                                                        |
VIVA NAUGHTON RES                               NO REPORT               |   HENRYS FORK                 2       125       125
                                                                        |
                                                                        |   GREEN above Flaming Gorge  22        78        64
                                                                        |
==================================================================================================================================
 * 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 February 2001 Basin Outlook Report Contents page