February 2002 Water Supply Outlook - Upper Green River Basin (11)

Upper Green River Basin (11)
February 2002

Snow
The Upper Green River Basin snow water equivalent (SWE), above Fontenelle Reservoir, is 82 percent of average (132 percent of last year). The Green River basin SWE above Warren Bridge is 84 percent of normal (138 percent of last year). SWE on the west side of the Upper Green River basin is about 80 percent of normal, 137 percent of this time last year. Newfork River SWE is now 84 percent of normal (109 percent of last year). Big Sandy-Eden Valley SWE is about 89 percent of average (131 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 60 percent of last month's average . Precipitation varied from 46 to 79 percent of average. Water year-to-date precipitation is about 87 percent of average (134 percent of last year). Year to date percentage of average ranges from 79 to 95 percent for the reporting stations.

Reservoir
Big Sandy Reservoir is currently storing 3,100 acre feet (17 percent of average) -- 14 percent of last year and 8 percent of capacity. Eden Reservoir is currently storing 480 acre feet (15 percent of average) -- 4 percent of capacity. Fontenelle Reservoir is storing 141,200 acre-feet (77 percent of average and 41 percent of the total capacity). Flaming Gorge Reservoir is currently storing 2,854,100 acre feet (96 percent of average) -- 95 percent of last year and 72 percent of capacity. Detailed reservoir data is shown on the following page and on the reservoir storage summary at the beginning of this report.

Streamflow The following forecast is based on the fifty-percent chance April through July runoff in the Upper Green River basin. Runoff is forecast to be below average. Green River at Warren Bridge is expected to yield about 215,000 acre-feet (81 percent of normal). Pine Creek above Fremont Lake is expected to yield 82,000 acre-feet (79 percent of normal). New Fork River near Big Piney is expected to yield about 290,000 acre-feet (73 percent of normal). Fontenelle Reservoir Inflow is estimated to be 590,000 acre-feet (69 percent of average), and Big Sandy near Farson is expected to be about 46,000 acre-feet (79 percent of normal).

==================================================================================================================================
                                                     UPPER GREEN RIVER BASIN
                                               Streamflow Forecasts - February 1, 2002
==================================================================================================================================
                                              |  <<====== 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       154       190    |      215        81    |       240       276            265
                                                                    |                       |
Pine Creek abv Fremont Lake          APR-JUL        64        75    |       82        79    |        89       100            104
                                                                    |                       |
New Fork River nr Big Piney          APR-JUL       166       240    |      290        73    |       340       414            395
                                                                    |                       |
Fontenelle Reservoir Inflow          APR-JUL       418       517    |      590        69    |       668       792            860
                                                                    |                       |
Big Sandy River nr Farson            APR-JUL        28        39    |       46        79    |        53        64             58
                                                                    |                       |
==================================================================================================================================
                         UPPER GREEN RIVER BASIN                        |                 UPPER GREEN RIVER BASIN
             Reservoir Storage (1000 AF) - End of January               |        Watershed Snowpack Analysis - February 1, 2002
==================================================================================================================================
                                      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      3.1      5.5     18.6 |   GREEN above Warren Bridge   4       140        84
                                                                        |
EDEN                                    11.8      0.5      ---      3.2 |   UPPER GREEN (West Side)     7       137        80
                                                                        |
FLAMING GORGE                         3749.0   2854.1   2992.0   2966.0 |   NEW FORK RIVER              3       109        84
                                                                        |
FONTENELLE                             344.8    141.2    120.4    182.2 |   BIG SANDY/EDEN VALLEY       1       131        89
                                                                        |
                                                                        |   GREEN above Fontenelle     14       132        82
                                                                        |
==================================================================================================================================
 * 90%, 70%, 30%, and 10% chances of exceeding are the probabilities that the actual volume will exceed the volumes in the table.

(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 2002 Basin Outlook Report Contents Page

Upper Green River Basin (11) February 2002

Upper Green River Basin (11)
February 2002