Little Snake River Basin (10)
June 2001

Snow
Nearly all the SNOTEL sites have melted out in this drainage. Only one site has any snow remaining. For more information see Basin Summary of Snow Courses at beginning of this report.

Precipitation
Precipitation across the basin was below average this past month. May precipitation was 38 percent of average (42 percent of last year) for the 5 reporting stations. May precipitation ranged from 25 to 54 percent of average. The Little Snake River basin water-year-to-date precipitation is currently 73 percent of average (84 percent of last year). Year-to- date percentages range from 73 to 90 percent of average.

Streamflow
Yield from the Little Snake River basin is expected to be much below normal this year. Irrigators relying on direct diversions may experience water shortages this year. Stream yield is based on the 50 percent probability for the April through July forecast period. The Little Snake River near Slater should yield about 100,000 acre-feet (65 percent of normal). Little Snake River near Dixon is estimated to yield 210,000 acre-feet (64 percent of normal). 

==================================================================================================================================
                                                     LITTLE SNAKE RIVER BASIN
                                               Streamflow Forecasts - June 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)
====================================================================|=======================|=====================================
Little Snake River nr Slater         APR-JUL        65        85    |      100        65    |       116       142            155
                                                                    |                       |
LITTLE SNAKE R nr Dixon              APR-JUL       106       168    |      210        64    |       252       314            329
                                                                    |                       |
==================================================================================================================================
                        LITTLE SNAKE RIVER BASIN                        |                LITTLE SNAKE RIVER BASIN
             Reservoir Storage (1000 AF) - End of May                   |        Watershed Snowpack Analysis - June 1, 2001
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
                                                                        |   LITTLE SNAKE RIVER          6        95        32
                                                                        |
==================================================================================================================================
 * 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.
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