LOCATION.-- Lat 41°06'26", long 89°21'23" (NAD of 1927), in SW1/4 sec.15, T.13 N., R.10 E., Marshall County, Hydrologic Unit 07130001, on right bank 600 ft upstream from bridge on State Highway 18, 4.4 mi upstream from Crow Creek, 38.2 mi upstream from Peoria Lock and Dam, and at mile 196.0.

DRAINAGE AREA.-- 13,543 mi², does not include diversion from Lake Michigan through the Chicago Sanitary and Ship Canal, which has occurred since Jan. 17, 1900.

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: October 1981 to current year. Prior to October 1983, published as station number "05558900."

STAGE: Water years 1994 to current year.

SURFACE-WATER QUALITY

SEDIMENT: June 1983 to September 1986, May 1993 to September 1993.

MISCELLANEOUS: Contaminants in streambed sediments, October 1996; contaminants in fish tissue, October 1996.

GAGE.-- Water-stage recorder, phone telemeter, acoustic-velocity meter, and a crest-stage gage. Datum of gage is 425.88 ft above NGVD of 1929 (425.65 ft NAVD 1988).

REMARKS.-- Some regulation by locks and dams upstream from station at Starved Rock and downstream at Peoria.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum recorded discharge, 117,000 ft³/s, based on a stage-area and velocity rating, Feb. 23, 1997, gage height, 27.19 ft; maximum gage height, 32.02 ft, Mar. 7, 1985; minimum daily discharge, 2,240 ft³/s, Nov. 3, 2002.

SUSPENDED-SEDIMENT CONCENTRATIONS: Maximum daily mean, 324 mg/L, June 11, 1993; minimum daily mean, 19 mg/L, May 2, 1993.

SUSPENDED-SEDIMENT LOADS: Maximum daily, 52,800 tons, June 11, 1993; minimum daily, 1,600 tons, June 2, 1993.

EXTREMES OUTSIDE PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Flood of Mar. 22, 1979, reached a stage of 32.67 ft, from information by the U.S. Army Corps of Engineers, discharge, about 140,000 ft³/s, based on rating curve extended above 32.20 ft.