Bighorn River Basin (4)
June 2000

Snow
Snowpack in this basin is well below average for this time of year. The Nowood and Greybull river drainage's are melted out. Shell Creek SWE is 61 percent of average (47 percent of last year). The basin SWE, as a whole, is currently 49 percent of average (33 percent of last year). For more information see Basin Summary of Snow Courses at beginning of report.

Precipitation
May precipitation was 100 percent of the monthly average (76 percent of last year). Sites ranged from 58 to 136 percent of average for the month. Year-to-date precipitation is 93 percent of normal; that is 72 percent of last year at this time. Year to date percentages, from the 14 reporting stations, range from 56 to 111.

Reservoir
Boysen Reservoir is currently storing 542,900-acre feet (99 percent of average). Bighorn Lake is now at 111 percent of average (947,600- acre feet). Boysen is currently storing 111 percent of last year at this time and Big Horn Lake is storing 104 percent of last year's volume.

Streamflow
The 50 percent chance June through September runoff is anticipated to be well below normal. The Boysen Reservoir inflow is forecast to yield 355,000 acre feet (58 percent of average); the Greybull River nr Meeteese should yield 60,000 acre feet (36 percent of average); Shell Creek near Shell should yield 45,000 acre feet (82 percent of average) and the Bighorn River at Kane should yield 475,000 acre feet (59 percent of average). 

==================================================================================================================================
                                                       BIGHORN RIVER BASIN
                                               Streamflow Forecasts - June 1, 2000
==================================================================================================================================
                                              |  <<====== 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)
====================================================================|=======================|=====================================
BOYSEN RESERVOIR Inflow (2)          JUN-SEP       148       271    |      355        58    |       439       562            609
                                                                    |                       |
GREYBULL RIVER nr Meeteetse          JUN-SEP        49        55    |       60        36    |        65        71            167
                                                                    |                       |
SHELL CREEK nr Shell                 JUN-SEP        35        41    |       45        82    |        49        55             55
                                                                    |                       |
BIGHORN RIVER at Kane (2)            JUN-SEP       227       324    |      475        59    |       626       722            811
                                                                    |                       |
==================================================================================================================================
                           BIGHORN RIVER BASIN                          |                   BIGHORN RIVER BASIN
             Reservoir Storage (1000 AF) - End of May                   |        Watershed Snowpack Analysis - June 1, 2000
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
BOYSEN                                 596.0    542.9    490.4    546.4 |   NOWOOD RIVER                2         0         0
                                                                        |
BIGHORN LAKE                          1356.0    947.6    911.5    855.6 |   GREYBULL RIVER              2         0         0
                                                                        |
                                                                        |   SHELL CREEK                 3        47        61
                                                                        |
                                                                        |   BIGHORN (Boysen-Bighorn)    7        33        49
                                                                        |
==================================================================================================================================
 * 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.


	SHOSHONE & CLARKS FORK RIVER BASINS as of June 1, 2000
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