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Wyoming Basin Outlook Report for
BELLE FOURCHE & CHEYENNE RIVER BASINS as of March 1, 2012

Snow The Belle Fourche River Basin SWE is 114% of average at this time of year. For more information see Basin Summary of Snow Course Data at the beginning of this report. Precipitation Precipitation for last month was 210% of average or 116% of last year in the Black Hills. There were 3 reporting stations. Monthly percentages range from 84-240%. Year-to-date precipitation is 113% of average and 67% of last year s amount. Yearly percentages range from 101-125% of average. Reservoir Current reservoir storage is about 120% of average in the basin. Angostura is currently storing 97% of average (98,200 ac-ft), about 80% of capacity. Belle Fourche reservoir is storing 116% of average (130,900 ac-ft), about 73% of capacity. Deerfield reservoir is storing 113% of average (14,900 ac-ft), about 98% of capacity. Keyhole reservoir is storing 161% of average (170,200 ac-ft), about 88% of capacity. Pactola reservoir is storing 113% of average (52,200 ac-ft), about 95% of capacity. Shadehill reservoir is storing 74% of average (37,000 ac-ft), about 45% of capacity. 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 the 50% exceedance forecasts for the Apr through July period. The Deerfield Reservoir Inflow is expected to be 6,000 ac-ft (118% of average). Pactola Reservoir Inflow is expected to yield around 27,000 ac-ft (117% of average). See the following page for detailed runoff volumes.

Streamflow Forecasts

BELLE FOURCHE & CHEYENNE RIVER BASINS
Streamflow Forecasts - March 1, 2012

 <==== Drier === Future Conditions === Wetter ====> 
Forecast Pt============ Chance of Exceeding * =========== 
   Forecast90%70%50% (Most Prob)30%10%30 Yr Avg
   Period(1000AF)(1000AF)(1000AF)(% AVG.)(1000AF)(1000AF)(1000AF)

Deerfield Reservoir Inflow (2)
MAR-JUL 4.2       6.4       8.0       131       9.6       11.8       6.1      
APR-JUL 3.4       4.8       6.0       118       7.3       9.4       5.1      
Pactola Reservoir Inflow (2)
MAR-JUL 13.2       24       31       119       38       49       26      
APR-JUL 13.2       21       27       117       34       46       23      

    * 90%, 70%, 30%, and 10% chances of exceeding are the probabilities that the
       actual flow will exceed the volumes in the table.

    (1) - The values listed under the 10% and 90% Change of Exceeding are
            actually 5% and 95% exceedance levels.
    (2) - The value is natural flow - actual flow may be affected by upstream
            water management.



Reservoir Storage

BELLE FOURCHE & CHEYENNE RIVER BASINS
Reservoir Storage (1000AF) End of February

 Usable************* Usable Storage *************
Reservoir Capacity This Year Last Year Average

ANGOSTURA 122.1      98.2         108.9          101.7        
BELLE FOURCHE 178.4      130.9         157.8          113.0        
DEERFIELD 15.2      14.9         14.7          13.2        
KEYHOLE 193.8      170.2         113.3          105.9        
PACTOLA 55.0      52.2         52.9          46.0        
SHADEHILL 81.4      37.0         53.3          50.0        



Watershed Snowpack Analysis

BELLE FOURCHE & CHEYENNE RIVER BASINS
Watershed Snowpack Analysis - March 1, 2012

 Number ofThis Year as Percent of
Watershed Data Sites Last Year Normal

BELLE FOURCHE 8               79               114              

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or Write:
D. Lee Hackleman, Water Supply Specialist
Natural Resources Conservation Service
100 East B Street
Casper, WY 82601
(307) 261-6481

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