Date: November 4, 2008

Data in this release are preliminary. Final data will be provided in the annual report (WDR-US-2009), Water-resources data for the United States.

NOTES TO EDITOR: (1) ft3/s is an abbreviation for cubic feet per second which is the rate of discharge representing a volume of a cubic foot of water passing a given point during one second and is equivalent to 7.48 gallons per second or 448.8 gallons per minute. (2) the "normal" range is 80 to 120 percent of average.

OCTOBER STREAMFLOWS AND
RESERVOIR STORAGE MOSTLY NORMAL

At eight long-term U.S. Geological Survey gaging stations, the monthly mean streamflows for the month of October were normal at five and below normal at three. The monthly mean streamflows at the following stations were normal:

The monthly mean streamflow was below normal on the Yakk River near Troy, Middle Fork Flathead River near West Glacier, and Rock Creek below Horse Creek, near the international boundary.

Water storage remained in the normal range at five out of six major hydroelectric reservoirs in Montana: Canyon Ferry Lake, Bighorn Lake, Lake Koocanusa, Hungry Horse Reservoir, and Flathead Lake. Storage remained below normal in Fort Peck Lake.

For the month of October, water storage at four major irrigation reservoirs was normal at three and below normal at one. Storage at Lima, Gibson, and Fresno Reservoirs was normal; Clark Canyon Reservoir remained below normal.

Streamflow and reservoir data and long-term-averages are summarized for purposes of comparison.

Untitled Document
Station October monthly mean discharge, in ft3/s 1971-2000 Average discharge, in ft3/s Percent of average
Yaak River near Troy
131
178
74
Blackfoot River near Bonner
623
634
98
Clark Fork at St. Regis
3,430
3,340
103
Middle Fork Flathead River near West Glacier
694
950
73
Marias River near Shelby
291
361
81
Rock Creek below Horse Creek, near International Boundary
1.16
1.94
60
Yellowstone River at Corwin Springs
1,390
1,540
90
Yellowstone River at Billings
4,130
4,400
94

Hydroelectric reservoirs

 October contents in acre-feet Percent of capacity Percent of 1971-2000 average
Canyon Ferry Lake
1,462,000
73
85
Fort Peck Lake
10,550,000
56
64
Bighorn Lake
1,044,000
77
103
Lake Koocanusa
4,942,000
86
112
Hungry Horse reservoir
2,741,000
79
101
Flathead Lake
1,537,000
86
96

Irrigation reservoirs
Lima Reservoir
25,340
30
87
Clark Canyon Reservoir
76,570
30
61
Gibson Reservoir
29,010
30
82
Fresno Reservoir
55,780
54
103