Date: May 11, 2012

NOTES TO READER:  e, estimated; 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.  Percent of average for monthly mean discharge and reservoir contents are based on the  30-year average, water years 1981-2010.  The “normal” range is 80 to 120 percent of average.


Additional streamflow information is available at:  http://mt.water.usgs.gov/.

Recent annual water data reports for the United States can be viewed at:  http://wdr.water.usgs.gov/.

The USGS now offers a service where the user can receive updates about water conditions by subscribing to WaterAlert at:  http://water.usgs.gov/wateralert.

Monthly mean streamflows were below normal at one of eight long-term U.S. Geological Survey gaging stations in Montana, normal at one gaging station, and above normal at six gaging stations for the month of April.

Monthly mean streamflows were below normal at Rock Creek below Horse Creek, near international boundary and normal at Marias River near Shelby.

Monthly mean streamflows were above normal at:

• Yaak River near Troy
• Blackfoot River near Bonner
  
• Clark Fork at St. Regis
• Middle Fork Flathead River near West Glacier
• Yellowstone River at Corwin Springs
• Yellowstone River at Billings

Contents were normal at four of six major hydroelectric reservoirs in Montana and above normal at two of six hydroelectric reservoirs. Contents were normal at Canyon Ferry, Fort Peck, Bighorn, and Lake Koocanusa. Contents were above normal at Hungry Horse Reservoir and Flathead Lake.

Contents were normal at one and above normal at three major irrigation reservoirs in Montana. Contents were normal at Gibson Reservoir, whereas contents were above normal at Lima, Clark Canyon, and Fresno Reservoirs.

April 2012 streamflow and reservoir contents data and long-term-average values are summarized for purposes of comparison. Data in this news release are preliminary. Final data will be provided in the annual report (WDR-US-2012), Water-resources data for the United States when it becomes available in April 2013.

Station	Monthly mean discharge, in ft3/s	Average discharge, in ft3/s	Percent of average
Yaak River near Troy	3,070	1,870	164
Blackfoot River near Bonner	4,660	2,060	226
Clark Fork at St. Regis	17,620	9,240	191
Middle Fork Flathead River near West Glacier	6,610	3,210	206
Marias River near Shelby	1,130	1,100	103
Rock Creek below Horse Creek, near international boundary	14.4	93.8	15
Yellowstone River at Corwin Springs	3,190	1,560	204
Yellowstone River at Billings	5,880	4,080	144