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

Upper Green River Basin (11)
January 2002

Snow
The Upper Green River Basin snow water equivalent (SWE), above Fontenelle Reservoir, is 88 percent of average (112 percent of last year). The Green River basin SWE above Warren Bridge is 87 percent of normal (115 percent of last year). SWE on the west side of the Upper Green River basin is about 88 percent of normal, 116 percent of this time last year. Newfork River SWE is now 90 percent of normal (96 percent of last year). Big Sandy-Eden Valley SWE is about 106 percent of average (122 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 104 percent of the December average (115 percent of last year at this time). December precipitation varied from 45 to 137 percent of average. Water year-to-date precipitation is about 97 percent of average (117 percent of last year). Year to date percentage of average ranges from 83 to 111 percent for the reporting stations.

Reservoir
Big Sandy Reservoir is currently storing 3,600 acre feet (20 percent of average) -- 71 percent of last year and 9 percent of capacity. Edan Reservoir is currently storing 480 acre feet (13 percent of average) -- 4 percent of capacity. Fontenelle Reservoir is storing 146,400 acre-feet (70 percent of average and 42 percent of the total capacity). Flaming Gorge Reservoir is currently storing 3,023,000 acre feet (98 percent of average) -- 96 percent of last year and 77 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 fifty-percent chance April through July runoff in the Upper Green River basin is forecast below average. Green River at Warren Bridge is expected to yield about 225,000 acre-feet (85 percent of normal). Pine Creek above Fremont Lake is expected to yield 88,000 acre-feet (85 percent of normal). New Fork River near Big Piney is expected to yield about 315,000 acre-feet (80 percent of normal). Fontenelle Reservoir Inflow is estimated to be 620,000 acre-feet (72 percent of average), and Big Sandy near Farson is expected to be about 49,000 acre-feet (85 percent of normal).

==================================================================================================================================
                                                     UPPER GREEN RIVER BASIN
                                               Streamflow Forecasts - January 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       142       191    |      225        85    |       259       308            265
                                                                    |                       |
Pine Creek abv Fremont Lake          APR-JUL        63        78    |       88        85    |        98       113            104
                                                                    |                       |
New Fork River nr Big Piney          APR-JUL       170       256    |      315        80    |       374       460            395
                                                                    |                       |
Fontenelle Reservoir Inflow          APR-JUL       410       530    |      620        72    |       717       874            860
                                                                    |                       |
Big Sandy River nr Farson            APR-JUL        27        40    |       49        85    |        58        71             58
                                                                    |                       |
==================================================================================================================================
                         UPPER GREEN RIVER BASIN                        |                 UPPER GREEN RIVER BASIN
             Reservoir Storage (1000 AF) - End of December              |        Watershed Snowpack Analysis - January 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      3.6      5.1     18.3 |   GREEN above Warren Bridge   4       115        87
                                                                        |
EDEN                                    11.8      0.5      ---      3.7 |   UPPER GREEN (West Side)     5       116        88
                                                                        |
FLAMING GORGE                         3749.0   2873.4   3006.0   2940.8 |   NEWFORK RIVER               2        96        90
                                                                        |
FONTENELLE                             344.8    146.4    151.9    209.7 |   BIG SANDY/EDEN VALLEY       1       122       106
                                                                        |
                                                                        |   GREEN above Fontenelle     11       112        88
                                                                        |
==================================================================================================================================
 * 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 January 2002 Basin Outlook Report Contents Page

Upper Green River Basin (11) January 2002

Upper Green River Basin (11)
January 2002