LOCATION.-- Lat 42°06'38", long 88°54'02" (NAD of 1927), in SE1/4SE1/4 sec.17, T.42 N., R.3 E., De Kalb County, Hydrologic Unit 07090006, on right bank at downstream side of bridge on Irene Road, 1.2 mi downstream from Owens Creek, 1.8 mi northeast of Fairdale, and at mile 11.0.

DRAINAGE AREA.-- 387 mi².

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: October 1939 to current year. Monthly discharge only for some periods, published in WSP 1308.

STAGE: Water years 1994 to current year.

SURFACE-WATER QUALITY

CHEMICAL: Water years 1978-81.

MISCELLANEOUS: Water years 1998 and 2002.

REVISED RECORDS.-- WSP 1508: 1940, 1942(M). WDR IL-75-1: Drainage area.

GAGE.-- Water-stage recorder, phone telemeter, and crest-stage gage. Datum of gage is 733.90 ft above NGVD of 1929 (levels by U.S. Army Corps of Engineers) (733.73 ft NAVD 1988). Prior to May 1, 1940, nonrecording gage at same site and datum. Prior to Nov. 7, 1986, water-stage recorder on left bank at upstream side of bridge at same site and datum.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 25,400 ft³/s, July 18, 1996, gage height 13.37 ft; minimum discharge, 2.1 ft³/s, Jan. 20, 1940.

EXTREMES OUTSIDE PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: A stage of 11.9 ft occurred in March 1937, from information by a local resident.