USGS Water-Year Summary 2021
05576000 SOUTH FORK SANGAMON RIVER NEAR ROCHESTER, IL
LOCATION - Lat 39°44'32", long 89°34'02" referenced to North American Datum of 1927, in NE 1/4 NW 1/4 sec.20, T.15 N., R.4 W., Sangamon County, IL, Hydrologic Unit 07130007, on right bank at city of Springfield dam, 100 ft. downstream from Horse Creek, 1.7 mile southwest of Rochester, and at mile 7.4. Auxiliary gage 1.2 miles downstream.
DRAINAGE AREA - 867 mi².
- WDR IL-75-1: Drainage area.
PERIOD OF RECORD -
SURFACE-WATER DISCHARGE AND STAGE
DISCHARGE: July 1949 to current.
STAGE: Water years 1994 to current.
GAGE - Water-stage recorder, U.S. Army Corps of Engineers satellite telemeter, and crest-stage gage. Datum of gage is 511.30 ft above NGVD of 1929 (510.97 ft NAVD 1988). Prior to April 6, 1966, water-stage recorder at site 2.4 mi downstream at same datum. April 29, 1975 to current, auxiliary water-stage recorder at site 1.2 mi downstream at same datum. Prior to May 19, 1950, auxiliary non-recording gage at site 6.2 mi downstream at same datum. May 19, 1950 to Apr. 29, 1975, auxiliary non-recording gage at site 1.2 mi downstream at same datum.
EXTREMES FOR PERIOD OF RECORD -
SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 24,300 ft³/s, Dec. 30, 2015, gage height, 36.66 ft., from floodmark; no flow Nov. 4-6, 1985, Sept. 9, 1987, and many days in 1988-90, 1992, and 2000.