LOCATION.-- Lat 38°38'35", long 90°01'00" (NAD of 1927), in N1/2NW1/4 sec. 8, T.2 N., R.8 W., St. Clair County, Hydrologic Unit 07140101, on right bank at upstream side of highway bridge at Caseyville, 100 ft upstream from Penn Central Railroad bridge, 400 ft upstream from bridge on State Highway 157, and at mile 3.8.

DRAINAGE AREA.-- 22.6 mi².

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: October 1939 to September 1982.

PARTIAL RECORD: Annual maximum, water years 1983 to 1984.

SURFACE-WATER QUALITY

MISCELLANEOUS: Temperature, water years 1975-1980, 1982.

REVISED RECORDS.-- WSP 1145: 1946. WSP 1208: 1942(P). WDR IL-75-1: Drainage area.

GAGE.-- Water-stage recorder and concrete control. Datum of gage is 423.40 ft above NGVD of 1929 (levels by Corps of Engineers) (423.02 ft NAVD 1988).

REMARKS.-- Diurnal fluctuation at low flow.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 10,200 ft³/s June 15, 1957, gage height, 17.81 ft, from rating curve extended above 890 ft³/s on basis of contracted-opening measurement of peak flow; maximum gage height, 20.54 ft, Aug. 16, 1946; no flow at time in 1953-54, 1964, 1966-67, 1976-77, 1979-80.