LOCATION.-- Lat 41°36'51", long 87°43'46" (NAD of 1927), in SE1/4NW1/4 sec.15, T.36 N., R.13 E., Cook County, Hydrologic Unit 07120003, on right bank at downstream side of bridge on Kilbourn Avenue in Oak Forest, and at mile 5.9.

DRAINAGE AREA.-- 12.6 mi².

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: October 1950 to current year. Prior to October 1974, records published with those for streams in the St. Lawrence River basin (WSP 1307, 1727, 1911, 2111, WDR-IL 1971-74).

STAGE: Water years 1994 to current year.

REVISED RECORDS.-- WSP 1337: 1951-53: WSP 1911: Drainage area.

GAGE.-- Water-stage recorder and phone telemeter. Datum of gage is 620.41 ft above NGVD of 1929 (Cook County Highway Department bench mark) (620.10 ft

NAVD 1988).

REMARKS.-- Diurnal fluctuation at low flow caused by small industrial plants upstream. Retention pond 1.0 mi upstream detains water during periods of heavy runoff and gradually releases water during recessions. Flow bypassed gage from Nov. 21, 1962, to Mar. 2, 1963, due to diversion 1.0 mi upstream.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 627 ft³/s, Apr. 22, 1973, gage height, 7.67 ft; maximum gage height, 9.00 ft, July 13, 1957, discharge, 550 ft³/s; no flow at times in most years.