05586100 ILLINOIS RIVER AT VALLEY CITY, IL

LOCATION.--Lat 39°42'12", long 90°38'43", in SE1/4NW1/4 sec.34, T.15 N., R.14 W., Scott County, Hydrologic Unit 07130011, on upstream side of Norfolk & Southern Corporation Railroad bridge at Flints Creek, 0.4 mi east of Valley City, 1.8 mi downstream from Mauvaise Terre Creek, and at mile 61.3.

DRAINAGE AREA.--26,743 mi2, does not include diversion from Lake Michigan through the Chicago Sanitary and Ship Canal, which has occurred since Jan. 17, 1900.

PERIOD OF RECORD.--Decemer 1974 to current year.

PERIOD OF DAILY RECORD.--
SUSPENDED SEDIMENT: Feb. 1980 to current year.

REMARKS.--Suspended-sediment samples were collected by a local observer once weekly with additional samples collected during high runoff periods.

EXTREMES FOR PERIOD OF DAILY RECORD.--
SEDIMENT CONCENTRATIONS: Maximum daily, 3,720 mg/L, Apr. 14, 1981; minimum daily, 14 mg/L, Dec. 26, 1984, July 21, 1993.
SEDIMENT LOADS: Maximum daily, 410,000 tons, June 4, 1980; minimum daily, 172 tons, Sept. 2, 1984.

EXTREMES FOR CURRENT YEAR.--
SEDIMENT CONCENTRATIONS: Maximum daily, 617 mg/L, July 21; minimum daily, 29 mg/L, Oct. 13.
SEDIMENT LOADS: Maximum daily, 98,000 tons, June 22; minimum daily, 588 tons, Oct. 13.