Upper Bear River Basin (13)
April 1999

Snow
Snow water equivalent (SWE), at snow courses in the Bear River above the Idaho State Line, is 95 percent of average (107 percent of last year). SWE for the Bear River in Utah is estimated to be 85 percent of average; that is about 100 percent of last year at this time. SWE in the Wyoming portion of the Bear River drainage (Smiths and Thomas Forks) is estimated at 101 percent of average (113 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 91 percent of average for the 2 reporting stations; this is 58 percent of the previous March. The monthly percentages range from 86 to 96 percent of average. The year-to-date precipitation, for the basin, is 102 percent of average; this is 106 percent of last year's amount. Year-to-date percentages range from 101 to 111 percent of average.

Reservoir
Woodruff Narrows reservoir is currently storing 57,300 acre feet compared to 46,000 acre feet this time last year. There is no average established for Woodruff Narrows. The total capacity of the reservoir is 57,300 acre-feet.

Streamflow
The 50 percent chance stream flow yields are expected to be below average in the Bear River drainage. The Bear River near the Utah-Wyoming State Line is expected to yield about 110,000 acre feet; that is 93 percent of average for the April through September period. The Thomas Fork drainage is estimated to yield 32,000 acre-feet or 89 percent of normal for the April-September period. The 50 percent chance yield for Smiths Fork near Border is about 105,000 acre-feet (83 percent of normal) for the April-September period. The Bear River near Woodruff is expected to yield about 120,000 acre-feet, about 81 percent of normal for the April-July period. 

==================================================================================================================================
                                                      UPPER BEAR RIVER BASIN
                                               Streamflow Forecasts - April 1, 1999
==================================================================================================================================
                                              |  <<====== 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        82        98    |      110        93    |       124       147            118
                                                                    |                       |
THOMAS FK nr WY-ID State Line (Disc. APR-SEP      19.9        26    |       32        89    |        39        52             36
                                                                    |                       |
Bear R nr UT-WY State Line           APR-SEP        82        95    |      105        83    |       116       134            126
                                                                    |                       |
BEAR R nr Woodruff, UT               APR-JUL        72        98    |      120        81    |       147       199            149
                                                                    |                       |
==================================================================================================================================
                         UPPER BEAR RIVER BASIN                         |                 UPPER BEAR RIVER BASIN
             Reservoir Storage (1000 AF) - End of March                 |        Watershed Snowpack Analysis - April 1, 1999
==================================================================================================================================
                                      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     57.3     46.0      --- |   UPPER BEAR RIVER in Utah    5       100        85
                                                                        |
                                                                        |   SMITHS & THOMAS FORKS       4       113       101
                                                                        |
                                                                        |   BEAR RIVER abv ID line      9       107        95
                                                                        |
==================================================================================================================================
 * 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.
(D) - The operational measurement of flow at this point has been discountinued.
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