Water Supply and Utilization Report
Bighorn River Basin
Wyoming Area Office
This report concerns the operation of Reclamation facilities in the Shoshone and Wind/Bighorn River Basins. Reclamation defines a water year as the time period of October 1 through September 30. Water year is abbreviated in this report as W.Yr. Other organizations furnished information for the Water Supply and Utilization Report. Their cooperation is greatly appreciated.
Bighorn River Basin Inflow
July inflow was below average at Bull Lake, Boysen, and Buffalo Bill Reservoirs. Inflow to Buffalo Billand Boysen Reservoirs during July were the 4th lowest in the past 30 years.
| July Inflow |
July Historical Inflow |
Accumulated Inflow (October-July) |
|||||||
| Reservoir | W.Yr. 2007 |
30 Yr. Avg.1 |
% of Avg. |
W.Yr. 2006 |
W.Yr. 2005 |
W.Yr. 2004 |
W.Yr. 2007 |
30 Yr. Avg.1 |
% of Avg. |
|---|---|---|---|---|---|---|---|---|---|
| Bull Lake | 26.1 | 46.4 | 56 | 32.7 | 48.2 | 47.5 | 120.9 | 154.9 | 78 |
| Boysen | 32.4 | 133.5 | 24 | 29.1 | 98.1 | 110.0 | 409.1 | 827.2 | 49 |
| Buffalo Bill | 53.6 | 155.5 | 34 | 78.9 | 99.7 | 107.3 | 533.6 | 747.5 | 71 |
| 1 Average is based on the 1977-2006 period. | |||||||||
Bighorn River Basin
Reservoir Inflow
July
Bighorn River Basin Outflow
Releases from Boysen and Buffalo Bill Reservoirs were below average during July.
| July Outflow |
July Historical Outflow |
Accumulated Outflow (October-July) |
|||||||
| Reservoir | W.Yr. 2007 |
30 Yr. Avg.1 |
% of Avg. |
W.Yr. 2006 |
W.Yr. 2005 |
W.Yr. 2004 |
W.Yr. 2007 |
30 Yr. Avg.1 |
% of Avg. |
|---|---|---|---|---|---|---|---|---|---|
| Bull Lake | 51.6 | 45.7 | 113 | 46.6 | 51.8 | 9.3 | 101.6 | 104.8 | 97 |
| Boysen | 71.3 | 140.4 | 51 | 73.2 | 125.4 | 66.6 | 417.5 | 784.9 | 53 |
| Buffalo Bill | 120.6 | 172.6 | 70 | 125.1 | 132.6 | 105.0 | 419.6 | 627.5 | 67 |
| 1 Average is based on the 1977-2006 period. | |||||||||
Bighorn River Basin
Reservoir Outflow
July
Bighorn River Basin Storage
Storage at the end of July was below average at Buffalo Bill, Bull Lake, Boysen, and Pilot Butte Reservoirs. End of July storage at Boysen was the 3rd lowest in 30 years.
| Reservoir | Total Storage End of July |
End of July Historical Storage |
Total Conservation Storage Capacity |
Percent of Capacity |
||||
|---|---|---|---|---|---|---|---|---|
| W.Yr. 2007 |
30 Yr. Avg.1 |
% of Avg. |
W.Yr. 2006 |
W.Yr. 2005 |
W.Yr. 2004 |
|||
| Bull Lake | 70.4 | 127.4 | 55 | 115.3 | 146.0 | 138.1 | 152.5 | 46 |
| Boysen | 439.5 | 656.0 | 67 | 500.1 | 710.2 | 533.2 | 741.6 | 59 |
| Buffalo Bill | 555.1 | 561.72 | 99 | 590.1 | 592.6 | 521.4 | 646.6 | 86 |
| Pilot Butte | 19.9 | 25.8 | 77 | 17.0 | 25.4 | 20.6 | 33.7 | 59 |
| 1 Average is based on the 1977-2006 period. | ||||||||
| 2 This does not reflect a long term average because in 1992 the capacity of the reservoir was increased to approximately 646,565 acre-feet as a result of raising the dam. The average used here reflects data from 1993 through 2006. | ||||||||
Bighorn River Basin
Reservoir Storage
End of July
Bighorn River Basin Generation
Generation was average or greater at all powerplants except Boysen and Buffalo Bill Powerplants.
| July Gross Generation |
July Historical Generation |
Accumulated Gross Gen. (October-July) |
|||||||
| Powerplant | W.Yr. 2007 |
Avg. | % of Avg. |
W.Yr. 2006 |
W.Yr. 2005 |
W.Yr. 2004 |
W.Yr. 2007 |
Avg. | % of Avg. |
|---|---|---|---|---|---|---|---|---|---|
| Boysen1 | 5.6 | 7.8 | 72 | 5.9 | 9.8 | 5.3 | 31.3 | 55.5 | 56 |
| Pilot Butte2 | 1.1 | 0.8 | 138 | 1.1 | 1.1 | 1.0 | 2.2 | 1.9 | 116 |
| Heart Mtn.3 | 2.9 | 2.7 | 107 | 3.2 | 2.9 | 1.2 | 9.3 | 8.4 | 111 |
| Buffalo Bill3 | 9.9 | 11.6 | 85 | 10.6 | 12.2 | 9.9 | 29.0 | 51.4 | 56 |
| Shoshone3 | 2.1 | 2.2 | 95 | 2.2 | 2.2 | 2.1 | 16.8 | 16.6 | 101 |
| Spirit Mtn.4 | 3.1 | 3.2 | 97 | 3.2 | 3.3 | 3.2 | 9.6 | 8.9 | 108 |
| 1 Average is based on the 1977-2006 period. | |||||||||
| 2 Average is based on the 1990-2006 period. | |||||||||
| 3 Average is based on the 1993-2006 period. | |||||||||
| 4 Average is based on the 1995-2006 period. | |||||||||
Bighorn River Basin
Gross Generation
July
