USGS Water-Year Summary 2024

06295000 YELLOWSTONE RIVER AT FORSYTH, MT

LOCATION - Lat 46°15'59.89", long 106°41'28.69" referenced to North American Datum of 1983, in NE 1/4 NW 1/4 NW 1/4 sec.23, T.6 N., R.40 E., Rosebud County, MT, Hydrologic Unit 10100001, on right bank 0.3 mi downstream from U.S. Highway 12 bridge, at Forsyth, and at river mile 238.2.

DRAINAGE AREA - 40,152 mi² of which 692 mi² probably is noncontributing.

REVISIONS HISTORY - Water Data Report MT-04-1: Drainage area.

SURFACE-WATER RECORDS

PERIOD OF RECORD - July 1921 to September 1923 (no winter records), October 1977 to current year. Miscellaneous discharge measurements were made in 1974 to 1976 and are available in files at the USGS Water Science Center located in Helena, Montana.

GAGE - Water-stage recorder. Elevation of gage is 2,504.62 ft, referenced to the National Geodetic Vertical Datum of 1929, from nearby elevation determined by City of Forsyth. July 1921 to March 1922, nonrecording gage on discontinued highway bridge 10 ft downstream from gage at different elevation. March 1922 to September 1923, nonrecording gage on discontinued highway bridge 10 ft downstream from gage at elevation 2 ft higher.

REMARKS - Partially regulated flow by Yellowtail Dam. Several diversions for irrigation upstream of site.

EXTREMES OUTSIDE PERIOD OF RECORD - Flood of 1918 reached a stage of about 20 ft, elevation used in 1921, information from local residents.

WATER-QUALITY RECORDS

REMARKS - Samples collected as part of the Yellowstone River Basin National Water Quality Assessment (NAWQA) Program.