Belle Fourche and Cheyenne River Basins (7)
March 2001

Snow
The Belle Fourche River basin, as of March 1, is 132 percent of normal. This is 223 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 February was 113 percent of average in the Black Hills (105 percent of last February). Monthly percentages range from 87 to 145 percent. Year-to-date precipitation is 105 percent of average and 163 percent of last year's amount. Year to date percentages range from 91 to 114. 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 (90,900-acre feet). Belle Fourche reservoir is storing 137 percent of average (154,700-acre feet). Deerfield reservoir is storing 114 percent of average (15,100-acre feet). Keyhole reservoir is storing 157 percent of average (159,800-acre feet). Pactola reservoir is storing 118 percent of average (54,100-acre feet), and Shadehill reservoir is storing 79 percent of average (39,600-acre feet).

Streamflow
Streamflow forecasts for the Black Hills are not available for this month. 


==================================================================================================================================
                                              BELLE FOURCHE & CHEYENNE RIVER BASINS
                                               Streamflow Forecasts - March 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 February              |        Watershed Snowpack Analysis - March 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     90.9    113.6    101.7 |   BELLE FOURCHE               6       223       132
                                                                        |
BELLE FOURCHE                          178.4    154.7    173.6    113.0 |
                                                                        |
DEERFIELD                               15.2     15.1     14.7     13.2 |
                                                                        |
KEYHOLE                                193.8    159.8    173.5    101.9 |
                                                                        |
PACTOLA                                 55.0     54.1     54.1     46.0 |
                                                                        |
SHADEHILL                               81.4     39.6     53.5     50.0 |
                                                                        |
==================================================================================================================================
 * 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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