LOCATION.-- Lat 40°35'12", long 89°16'42" (NAD of 1927), in NW1/4NE1/4 sec. 36, T.25 N., R.2 W., Tazewell County, Hydrologic Unit 07130004, at Rocky Ford bridge, 0.5 mi upstream from Rock Creek, 0.8 mi upstream from Hollands Creek, 4.5 mi southwest of Congerville, and at mile 53.7.

DRAINAGE AREA.-- 776 mi².

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: July 1983 to September 1986, (from station 05567500-- Mackinaw River near Congerville).

SURFACE-WATER QUALITY

CHEMICAL: Water years 1978-91.

SEDIMENT: July 1983 to September 1986.

EXTREMES FOR PERIOD OF RECORD.--

SUSPENDED-SEDIMENT CONCENTRATIONS: Maximum daily mean, 4,720 mg/L Mar. 28, 1985; minimum daily mean, 1 mg/L Jan. 26 to Feb. 17, 1985.

SUSPENDED-SEDIMENT LOADS: Maximum daily, 96,400 tons Feb. 23, 1985; minimum daily, 0.26 ton Feb. 13-17, 1985.