USGS Water-Year Summary 2024
05469000 HENDERSON CREEK NEAR OQUAWKA, IL
LOCATION - Lat 41°00'05.13", long 90°51'15.51" referenced to North American Datum of 1983, in SE 1/4 NE 1/4 SW 1/4 sec.28, T.12 N., R.4 W., Henderson County, IL, Hydrologic Unit 07080104, downstream side of bridge on State Highway 94, 1 mi. south of Bald Bluff, 6.5 mi. northeast of Oquawka, and at mile 20.8.
DRAINAGE AREA - 432 mi².
REVISIONS HISTORY - WSP 1208: 1939, 1942-43, 1948. WSP 1308: 1935-38(M), 1941(M). WDR IL-75-1: Drainage area.
Revisions: Gage datum was updated to 540.64 ft NAVD88 on January 3, 2023, as determined by a GNSS Level II survey. Gage datum was previously published as 541.21 ft NGVD29 (540.99 ft NAVD88) from levels.
SURFACE-WATER RECORDS
PERIOD OF RECORD -
SURFACE-WATER DISCHARGE AND STAGE
DISCHARGE: October 1934 to September 1996. October 1997 to current. Prior to October
  1938, published as Henderson River. Monthly discharge only for some periods, published
in WSP 1308.
STAGE: Water years 1994-1996, 1998 to current.
SURFACE-WATER QUALITY
CHEMICAL: Water years 1978 to 1991. Additional chemical data for water years 1972-77 are
published in Water-Resources Investigations 78-23 and 79-24 as site LD 02.
SEDIMENT: April 1978 to September 1981.
GAGE - Water-stage recorder, U.S. Army Corps of Engineers satellite telemeter, and crest-stage gage. Datum of gage is 540.64 ft above North American Vertical Datum of 1988. Prior to Mar. 4, 1941, nonrecording gage at same site and datum.
EXTREMES OUTSIDE PERIOD OF RECORD -
SURFACE-WATER DISCHARGE AND STAGE:
Flood of June 1924 reached a stage of 27.8 ft, from flood profile, and an estimated discharge of 20,000 ft³/s.
EXTREMES FOR PERIOD OF RECORD -
SURFACE-WATER DISCHARGE AND STAGE:
Maximum discharge, 34,600 ft³/s, July 8, 1982, gage height, 31.05 ft; maximum gage height, 32.65 ft, July 25, 1993, discharge 30,800 ft³/s; minimum daily observed, 1.7 ft³/s, Sept. 22, 23, 1940.
SUSPENDED-SEDIMENT CONCENTRATIONS:
Maximum daily mean, 7,070 mg/L May 27, 1981; minimum daily mean, 6 mg/L Feb. 10, 11, 1981.
SUSPENDED-SEDIMENT LOADS: Maximum daily, 33,900 tons Apr. 14, 1981; minimum daily, 0.87 tons Feb. 2-4, 1980.