Upper Bear River Basin (13)
April 2001

Snow
Snow water equivalent (SWE), at snow courses in the Bear River above the Idaho State line, is 57 percent of average (68 percent of last year). SWE for the Bear River in Utah is estimated to be 60 percent of average; that is about 69 percent of last year at this time. SWE in the Wyoming portion of the Bear River drainage (Smiths and Thomas Forks) is estimated at 58 percent of average (69 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 the month of March was 65 percent of average for the 2 reporting stations; this is 71 percent of the previous March. The year-to- date precipitation, for the basin, is 66 percent of average; this is 85 percent of last year's amount.

Reservoir
Woodruff Narrows reservoir did not report this month.

Streamflow
The following 50 percent chance stream flow yields are for the April through September period. Smiths Fork near Border is estimated to yield 52,000 acre-feet (44 percent of normal), and Thomas Fork drainage near the Idaho- Wyoming state line is estimated to yield 7,200 acre-feet or 20 percent of normal. Bear River near the Utah-Wyoming State Line is expected to yield about 60,000 acre feet (48 percent of average), The Bear River near Woodruff is expected to yield about 68,000 acre-feet (about 44 percent of normal). 

==================================================================================================================================
                                                      UPPER BEAR RIVER BASIN
                                               Streamflow Forecasts - April 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)
====================================================================|=======================|=====================================
SMITHS FK nr Border, WY              APR-SEP        39        46    |       52        44    |        59        70            118
                                                                    |                       |
THOMAS FK nr WY-ID State Line (Disc. APR-SEP       4.5       5.9    |      7.2        20    |       8.7      11.6             36
                                                                    |                       |
Bear R nr UT-WY State Line           APR-SEP        47        54    |       60        48    |        66        77            126
                                                                    |                       |
BEAR R nr Woodruff, UT               APR-SEP        40        55    |       68        44    |        84       114            154
                                                                    |                       |
==================================================================================================================================
                         UPPER BEAR RIVER BASIN                         |                 UPPER BEAR RIVER BASIN
             Reservoir Storage (1000 AF) - End of March                 |        Watershed Snowpack Analysis - April 1, 2001
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
WOODRUFF NARROWS                                NO REPORT               |   UPPER BEAR RIVER in Utah    7        69        60
                                                                        |
                                                                        |   SMITHS & THOMAS FORKS       4        69        58
                                                                        |
                                                                        |   BEAR RIVER abv ID line      9        68        57
                                                                        |
                                                                        |   NORTHWEST                  77        63        54
                                                                        |
                                                                        |   NORTHEST                   19        92        73
                                                                        |
                                                                        |   SOUTHEAST                  37        85        75
                                                                        |
                                                                        |   SOUTHWEST                  35        74        65
                                                                        |
==================================================================================================================================
 * 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 April 2001 Basin Outlook Report Contents Page