Belle Fourche and Cheyenne River Basins (7)
January 2001

Snow.
The Belle Fourche River basin, as of January 1, is 150 percent of normal. This is 243 percent of what it was last year at this time. See Basin summary of Snow Course Data at the beginning of this report for a detailed listing.

Precipitation.
Precipitation, for the month of December was 59 percent of average in the Black Hills (71 percent of last December). Monthly percentages range from 4 to 123 percent. Year-to-date precipitation is 120 percent of average and 220 percent of last year's amount. Year to date percentages range from 98 to 138. This is from the 3 reporting stations.

Reservoir.
Reservoir storage is generally above average in the basin. Angostura is currently storing 89 percent of average (85,400-acre feet). Belle Fourche reservoir is storing 146 percent of average (132,400-acre feet). Deerfield reservoir is storing 122 percent of average (15,000- acre feet). Keyhole reservoir is storing 162 percent of average (158,700-acre feet). Pactola reservoir is storing 118 percent of average (54,000-acre feet), and Shadehill reservoir is storing 82 percent of average (41,500-acre feet).

Streamflow
There was no data available to prepare streamflow forecast in this basin. 

==================================================================================================================================
                                              BELLE FOURCHE & CHEYENNE RIVER BASINS
                                               Streamflow Forecasts - January 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)
====================================================================|=======================|=====================================
                                              BELLE FOURCHE & CHEYEN|E RIVER BASINS
                                                                    |                       |
==================================================================================================================================
                  BELLE FOURCHE & CHEYENNE RIVER BASINS                 |          BELLE FOURCHE & CHEYENNE RIVER BASINS
             Reservoir Storage (1000 AF) - End of December              |        Watershed Snowpack Analysis - January 1, 2001
==================================================================================================================================
                                      Usable |  *** Usable Storage ***  |                            Number     This Year as % of
Reservoir                            Capacity|  This      Last          |   Watershed                  of       =================
                                             |  Year      Year     Avg  |                          Data Sites   Last Yr   Average
========================================================================|=========================================================
ANGOSTURA                              122.1     85.4    105.5     96.4 |   BELLE FOURCHE               3       243       150
                                                                        |
BELLE FOURCHE                          178.4    132.4    173.1     90.6 |
                                                                        |
DEERFIELD                               15.2     15.0     14.8     12.3 |
                                                                        |
KEYHOLE                                193.8    158.7    171.9     98.2 |
                                                                        |
PACTOLA                                 55.0     54.0     54.6     45.8 |
                                                                        |
SHADEHILL                               81.4     41.5     55.7     50.7 |
                                                                        |
==================================================================================================================================
 * 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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