USGS Water-Year Summary 2021
05595700 BIG MUDDY RIVER NEAR MT. VERNON, IL
LOCATION - Lat 38°18'35", long 88°59'18" referenced to North American Datum of 1983, in SE 1/4 NW 1/4 sec.33, T.2 S., R.2 E., Jefferson County, IL, Hydrologic Unit 07140106, on left bank at downstream side of bridge on State Highway 15, 0.5 mi downstream from Harper Creek, 4.7 mi west of Mt. Vernon, 8.9 mi downstream from Snow Creek, and at mile 133.2.
DRAINAGE AREA - 71.9 mi².
PERIOD OF RECORD -
STAGE: October 1979 to current. Gage-height record for February 1965 to September 1979
available in files of U.S. Army Corps of Engineers.
CHEMICAL: Water years 1978-90.
GAGE - Water-stage recorder, U.S. Army Corps of Engineers satellite telemeter, and crest-stage gage. Datum of gage is 425.00 ft above NGVD of 1929 (levels by U.S. Army Corps of Engineers) (424.64 ft NAVD 1988).
EXTREMES FOR PERIOD OF RECORD - STAGE: Maximum gage height, 12.04 ft, Nov.14, 1993; minimum, -0.03 ft, on Oct, 17, 2020.