Streamflow
The following runoff values are for the 50 percent probability during
the May through September forecast period. The estimated yield for
Tongue River near Dayton is 96,000 acre-feet (88 percent of normal).
Water users on the Middle Fork near Barnum should have a yield near
15,900 acre-feet (90 percent of normal). The North Fork of the Powder
near Hazelton should yield about 10,500 acre-feet (111 percent of
normal). The estimated yield for Clear Creek near Buffalo is 36,000
acre-feet (97 percent of average). Rock Creek near Buffalo will yield
about 24,500 acre-feet (107 percent of normal), and Piney Creek at
Kearny should yield about 48,500 acre-feet (103 percent of average).
================================================================================================================================== POWDER & TONGUE RIVER BASINS Streamflow Forecasts - May 1, 1999 ================================================================================================================================== | <<====== 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) MAY-SEP 72 86 | 96 88 | 106 120 109 | | MIDDLE FORK POWDER nr Barnum MAY-SEP 10.3 13.7 | 15.9 90 | 18.1 22 17.7 | | NORTH FORK POWDER nr Hazelton MAY-SEP 8.00 9.49 | 10.50 111 | 11.51 13.00 9.50 | | CLEAR CREEK nr Buffalo MAY-SEP 29 33 | 36 97 | 39 43 37 | | ROCK CREEK nr Buffalo MAY-SEP 19.1 22 | 25 107 | 27 30 23 | | PINEY CREEK at Kearny MAY-SEP 24 39 | 49 103 | 58 73 47 | | ================================================================================================================================== POWDER & TONGUE RIVER BASINS | POWDER & TONGUE RIVER BASINS Reservoir Storage (1000 AF) - End of April | Watershed Snowpack Analysis - May 1, 1999 ================================================================================================================================== Usable | *** Usable Storage *** | Number This Year as % of Reservoir Capacity| This Last | Watershed of ================= | Year Year Avg | Data Sites Last Yr Average ========================================================================|========================================================= TONGUE RIVER 68.0 27.3 10.0 36.6 | UPPER TONGUE RIVER 9 102 98 | | GOOSE CREEK 3 97 93 | | CLEAR CREEK 4 84 105 | | CRAZY WOMAN CREEK 3 93 127 | | UPPER POWDER RIVER 4 108 108 | | POWDER RIVER in WY 8 95 106 | ================================================================================================================================== * 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.