LOCATION.-- Lat 41°30'54", long 88°04'24" (NAD of 1927), in NE1/4SW1/4 sec.15, T.35 N., R.10 E., Will County, Hydrologic Unit 07120004, on left bank at downstream side of Richards Street bridge in Joliet, 0.6 mi downstream from Spring Creek, and at mile 1.6.

DRAINAGE AREA.-- 107.48 mi².

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: October 1944 to current year.

STAGE: Water years 1994 to current year.

SURFACE-WATER QUALITY

CHEMICAL: Water years 1979-91.

REVISED RECORDS.-- WDR IL-91-2: 1981(M).

GAGE.-- Water-stage recorder, phone telemeter, and crest-stage gage. Datum of gage is 506.00 ft above NGVD of 1929. Prior to Oct. 9, 1946, nonrecording gage at site 0.3 mi upstream at datum 21.00 ft higher. Oct. 9, 1946, to Sept. 30, 1974, at site 0.3 miles upstream at datum 21.00 ft higher. Oct. 1, 1974 to Sept. 30, 2003, at site 0.3 miles upstream at datum 20.00 ft higher.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 17,300 ft³/s, June 13, 1981, gage height, 14.90 ft, from rating curve extended above 6,300 ft³/s, site and datum then in use; maximum gage height, 16.82 ft, June 12, 2004, present site and datum (discharge 4,630 ft³/s); minimum, 0.5 ft³/s, Aug. 9, 16, 19, 1964.