LOCATION.-- Lat 41°55'52", long 88°45'35" (NAD of 1983), in SW1/4NE1/4 sec.22, T.40 N., R.4 E., De Kalb County, Hydrologic Unit 07090006, on left bank 100 ft downstream from bridge on State Highway 38 in De Kalb, and at mile 48.5.

DRAINAGE AREA.-- 77.7 mi².

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: July 1925 to October 1933, October 1979 to current year.

STAGE: Water years 1995 to current year.

SURFACE-WATER QUALITY

SEDIMENT: October 1979 to September 1981.

REVISED RECORDS.-- WDR IL-80-1: Drainage area.

GAGE.-- Water-stage recorder, phone telemeter, and crest stage gage. Datum of gage is 831.88 ft above NGVD of 1929 (831.74 ft NAVD 1988). Mar. 23, 1980, to Sept. 30, 1983, at datum 3.0 ft higher. Oct. 1, 1979, to Mar. 22, 1980, nonrecording gage at same site at datum 3.0 ft higher. Prior to Sept. 30, 1933, nonrecording gage at same site at datum 3.40 ft higher.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 3,500 ft³/s, July 2, 1983, gage height, 15.80 ft; present datum; no flow, at times in several years.

SUSPENDED-SEDIMENT CONCENTRATIONS: Maximum daily mean, 1,650 mg/L June 13, 1981; minimum daily mean, 10 mg/L Mar. 9, 1980.

SUSPENDED-SEDIMENT LOADS: Maximum daily, 3,070 tons June 13, 1981; minimum daily, 0.04 ton Oct. 15, 1979.