Powder and Tongue River Basins (6)
January 2002

Snow
Snow water equivalent (SWE) in the Upper Tongue River drainage is 76 percent of normal (101 percent of last year). The Goose Creek drainage is 75 percent of average (95 percent of last year). Clear Creek drainage is 76 percent of normal SWE (94 percent of last year). Crazy Woman Creek is 91 percent of average (160 percent of last year). The Upper Powder River drainage is 74 percent of average (100 percent of last year). The Powder River basin snow water equivalent (SWE), in Wyoming, is about 75 percent of average (98 percent of last year). For more information see Basin Summary of Snow Courses at beginning of report.

Precipitation
December precipitation was 46 percent of average for the 10 reporting stations (50 percent of last year). Monthly percentages range from 0 to 66 percent of average. Precipitation for the year ranges from 44 to 103 percent of average at the reporting stations. Year-to-date precipitation is about 86 percent of average in the basin; this is 113 percent of last year at this time.

Reservoir
Tongue River Reservoir is currently at 92 percent of average storage for this time of year (20,700 acre feet) – the reservoir is about 26 percent of capacity (total capacity is 79,100 acre feet). Last year at this time the reservoir was storing about 34,900 acre feet – average storage is about 22,500 acre feet for this time of the year. Detailed reservoir data is shown on the following page and on the reservoir storage summary at the beginning of this report.

Streamflow
The following runoff values are for the 50 percent probability during the April through September forecast period. The estimated yield for Tongue River near Dayton is 62,000-acre feet (57 percent of normal). Middle Fork of the Powder River near Barnum is estimated to yield 8,400-acre feet (45 percent of average). The North Fork of the Powder near Hazelton should yield about 5,000 acre-feet (48 percent of normal). The estimated yield for Clear Creek near Buffalo is 14,500 acre-feet (37 percent of average). Rock Creek near Buffalo will yield about 12,000 acre-feet (50 percent of normal), and Piney Creek at Kearny should yield about 29,500 acre-feet (57 percent of average). 

==================================================================================================================================
                                                   POWDER & TONGUE RIVER BASINS
                                               Streamflow Forecasts - January 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)
====================================================================|=======================|=====================================
TONGUE RIVER nr Dayton (2)           APR-SEP        31        50    |       62        57    |        74        93            109
                                                                    |                       |
MIDDLE FORK POWDER nr Barnum         APR-SEP       0.7       5.3    |      8.4        45    |      11.5      16.1           18.7
                                                                    |                       |
NORTH FORK POWDER nr Hazelton        APR-SEP       2.4       4.0    |      5.0        48    |       6.0       7.6           10.4
                                                                    |                       |
CLEAR CREEK nr Buffalo               APR-SEP       5.8      11.0    |     14.5        37    |      18.0        23             39
                                                                    |                       |
ROCK CREEK nr Buffalo                APR-SEP       6.1       9.6    |     12.0        50    |      14.4      17.9             24
                                                                    |                       |
PINEY CREEK at Kearny                APR-SEP       4.0      19.2    |       30        57    |        40        55             52
                                                                    |                       |
==================================================================================================================================
                      POWDER & TONGUE RIVER BASINS                      |              POWDER & TONGUE RIVER BASINS
             Reservoir Storage (1000 AF) - End of December              |        Watershed Snowpack Analysis - January 1, 2002
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
TONGUE RIVER                            79.1     20.7     34.9     22.5 |   UPPER TONGUE RIVER          6       101        76
                                                                        |
                                                                        |   GOOSE CREEK                 1        95        75
                                                                        |
                                                                        |   CLEAR CREEK                 2        94        76
                                                                        |
                                                                        |   CRAZY WOMAN CREEK           1       160        91
                                                                        |
                                                                        |   UPPER POWDER RIVER          3       100        74
                                                                        |
                                                                        |   POWDER RIVER in WY          5        98        75
                                                                        |
==================================================================================================================================
 * 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.
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