February 2002 Water Supply Outlook - Upper Bear River Basin (13)

Upper Bear River Basin (13)
February 2002

Snow
Snow water equivalent (SWE), at snow courses in the Bear River above the Idaho State line, is 83 percent of average (130 percent of last year). SWE for the Bear River in Utah is estimated to be 81 percent of average; that is about 116 percent of last year at this time. SWE in the Wyoming portion of the Bear River drainage (Smiths and Thomas Forks) is estimated at 83 percent of average (135 percent of last year at this time.). See the Basin Summary of Snow Course Data at the beginning of this report for more detailed information.

Precipitation
Precipitation for last month was 50 percent of average for the 2 reporting stations. The year-to-date precipitation, for the basin, is 78 percent of average; this is 119 percent of last year's amount.

Reservoir
Woodruff Narrows reservoir is currently storing 4,000 acre feet (7 percent of capacity). Normally, the reservoir is storing 44 percent of capacity at this time of the year. Current storage is 16 percent of average, and 14 percent of last year's amount.

Streamflow
The following is based on the 50 percent chance stream flow yields are for the April through September period. Smiths Fork near Border is estimated to yield 91,000 acre-feet (77 percent of normal), and Thomas Fork drainage near the Idaho-Wyoming state line is much below average. Bear River above the Utah-Wyoming State Line is expected to yield about 100,000 acre feet ( 80 percent of average), The Bear River near Woodruff is expected to yield about 118,000 acre-feet (about 77 percent of normal).


==================================================================================================================================
                                                      UPPER BEAR 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)
====================================================================|=======================|=====================================
SMITHS FK nr Border, WY              APR-SEP        62        78    |       91        77    |       107       134            118
                                                                    |                       |
Bear R nr UT-WY State Line           APR-SEP        72        88    |      100        80    |       114       139            125
                                                                    |                       |
BEAR R nr Woodruff, UT               APR-SEP        63        92    |      118        77    |       152       220            154
                                                                    |                       |
==================================================================================================================================
                         UPPER BEAR RIVER BASIN                         |                 UPPER BEAR 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
========================================================================|=========================================================
WOODRUFF NARROWS                        57.3      4.0      8.0     25.2 |   UPPER BEAR RIVER in Utah    5       116        81
                                                                        |
                                                                        |   SMITHS & THOMAS FORKS       4       135        83
                                                                        |
                                                                        |   BEAR RIVER abv ID line      7       130        83
                                                                        |
                                                                        |   NORTHWEST                  76       155        79
                                                                        |
                                                                        |   NORTHEST                   21        86        67
                                                                        |
                                                                        |   SOUTHEAST                  34        78        61
                                                                        |
                                                                        |   SOUTHWEST                  30       112        76
                                                                        |
==================================================================================================================================
 * 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 Bear River Basin (13) February 2002

Upper Bear River Basin (13)
February 2002