Precipitation
February precipitation was 80 percent of the monthly average (71
percent of last year). Sites ranged from 50 to 293 percent of
average for the month. Year-to-date precipitation is 69 percent of
normal; that is 76 percent of last year at this time. Year to date
percentages, from the 13 reporting stations, range from 61 to 168.
Reservoir
Boysen Reservoir is currently storing 434,500-acre feet (78 percent
of average). Bighorn Lake is now at 104 percent of average (842,400-
acre feet). Boysen is currently storing 82 percent of last year at
this time and Big Horn Lake is storing 90 percent of last year's
volume.
Streamflow
The 50 percent chance April through September runoff is anticipated
to be below normal. The Boysen Reservoir inflow is forecast to yield
370,000 acre feet (46 percent of average); the Greybull River nr
Meeteese should yield 85,000 acre feet (42 percent of average); Shell
Creek near Shell should yield 49,000 acre feet (65 percent of
average) and the Bighorn River at Kane should yield 505,000 acre feet
(45 percent of average).
================================================================================================================================== BIGHORN RIVER BASIN 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) ====================================================================|=======================|===================================== BOYSEN RESERVOIR Inflow (2) APR-SEP 227 307 | 370 46 | 500 692 809 | | GREYBULL RIVER nr Meeteetse APR-SEP 70 78 | 85 42 | 99 119 201 | | SHELL CREEK nr Shell APR-SEP 42 46 | 49 65 | 54 60 75 | | BIGHORN RIVER at Kane (2) APR-SEP 292 416 | 505 45 | 693 971 1124 | | ================================================================================================================================== BIGHORN RIVER BASIN | BIGHORN RIVER BASIN 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 ========================================================================|========================================================= BOYSEN 596.0 434.5 527.3 555.2 | NOWOOD RIVER 5 61 50 | BIGHORN LAKE 1356.0 842.4 935.3 810.4 | GREYBULL RIVER 2 86 51 | | SHELL CREEK 4 62 60 | | BIGHORN (Boysen-Bighorn) 11 64 55 | ================================================================================================================================== * 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.