LOCATION.-- Lat 39°45'50", long 89°33'43" (NAD of 1927), in NW1/4SE1/4 sec.8, T.15 N., R.4 W., Sangamon County, Hydrologic Unit 07130007, on right bank at upstream side of bridge on West Main Road, 1.7 mi northwest of Rochester, 3.4 mi upstream from Black Branch, 1.2 mi downstream from Horse Creek, and at mile 6.2. Gage is used as an auxiliary gage to the base gage (05576000) 1.2 mi upstream.

DRAINAGE AREA.-- 870 mi².

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

STAGE: October 1993 to current.

SURFACE-WATER QUALITY

CHEMICAL: Water years 1978 to 1991. Additional chemical data for water years 1972-77 are published in Water-Resources Investigations 78-23 and 79-24 as site EO 01.

MISCELLANEOUS: Temperature, water year 1977.

REVISED RECORDS.-- WDR IL-79-2: Drainage area.

GAGE.--Water-stage recorder and crest-stage gage. Datum of gage is 511.30 ft above NGVD of 1929 (510.98 ft NAVD 1988). Prior to May 19, 1950, non-recording gage 5 miles downstream at same datum. May 19, 1950 to April 29, 1975, non-recording gage at current site and datum.

REMARKS.-- Beginning April 14, 1955, occasional regulation due to diversion for Springfield's public water supply at dam 1.2 miles upstream. Pumpage from Lake Taylorville into stream generally occurs during the fall upstream from the dam. Water discharges for surface-water quality data were determined from South Fork Sangamon River near Rochester (station 05576000).