LOCATION.-- Lat 39°26'35", long 90°47'45" (NAD of 1927), in NW1/4 sec.19, T.7 S., R.3 W., Pike County, Hydrologic Unit 07110004, on left bank at highway bridge, 650 ft upstream from Spring Creek, 0.2 mi west of Nebo, 1.6 mi upstream from Illinois Central Gulf Railroad bridge, and at mile 6.8. Records include flow of Spring Creek.

DRAINAGE AREA.-- 161 mi², including that of Spring Creek.

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: October 1939 to September 1986.

SURFACE-WATER QUALITY

CHEMICAL: Water years 1978-90.

REVISED RECORDS.-- WSP 975: 1940, 1941(M), 1942. WDR IL-75-1: Drainage area.

GAGE.-- Water-stage recorder. Datum of gage is 462.56 ft above NGVD of 1929 (levels by U.S. Army Corps of Engineers) (462.19 ft NAVD 1988). Prior to Dec. 9, 1939, nonrecording gage and Dec. 9, 1939, to Apr. 11, 1979, water stage recorder at site 140 ft downstream at same datum. Apr. 12 to Sept. 26, 1979, nonrecording gage at same site and datum.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 23,500 ft³/s, Aug. 16, 1946, gage-height, 19.31 ft, from rating curve extended above 9000 ft³/s; no flow for several days in most years.

EXTREMES OUTSIDE PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Flood of Aug.16, 1916, reached a stage of 18.2 ft, from information by local residents. Discharge not determined.