LOCATION.-- Lat 40°07'55", long 89°44'08" (NAD of 1927), in NE1/4NE1/4 sec.2, T.19 N., R.6 W., Menard County, Hydrologic Unit 07130009, on downstream side of bridge on State Highway 29, 3.3 mi downstream from Pike Creek, 3.5 mi north of Greenview, and at mile 4.9.

DRAINAGE AREA.-- 1,804 mi².

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: October 1941 to current year.

STAGE: Water years 1994 to current year.

SURFACE-WATER QUALITY

CHEMICAL: Water years 1978-91.

MISCELLANEOUS: Contaminants in streambed sediments, July 1997; contaminants in fish tissue, July 1997.

REVISED RECORDS.-- WSP 1175: 1948(P). WDR IL-75-1: Drainage area.

GAGE.-- Water-stage recorder, U.S. Army Corps of Engineers satellite telemeter, and crest-stage gage. Datum of gage is 479.00 ft above NGVD of 1929 (U.S. Army Corps of Engineers bench mark) (478.68 ft NAVD 1988). Prior to Nov. 3, 1972, nonrecording gage at same site and datum.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 41,200 ft³/s, May 19, 1943, gage height, 20.50 ft, from graph based on gage readings; minimum daily discharge, 46 ft³/s, Sept. 25, 26, Oct. 12-14, 1963.

EXTREMES OUTSIDE PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Flood of July 1929 reached a stage of 20.3 ft., from floodmark, discharge unknown.