LOCATION.-- Lat 39°50'35", long 89°32'50" (NAD of 1927), in NW1/4NE1/4 sec.16, T.16 N., R.4 W., Sangamon County, Hydrologic Unit 07130008, at right abutment on former U.S. Highway 36 bridge in Riverton, 2.2 mi downstream from Sugar Creek, 5.6 mi upstream from Fancy Creek, and at mile 83.1.

DRAINAGE AREA.-- 2,618 mi².

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: February 1908 to September 1912, August 1914 to September 1956, and January 1986 to current year.

STAGE: Water years 1994 to current year.

PARTIAL RECORD: Annual maximum, water years 1957-85.

SURFACE-WATER QUALITY

CHEMICAL: Water years 1978-91.

MISCELLANEOUS: Water years 1998 and 2002.

REVISED RECORDS.-- WSP 1208: 1908-9, 1921-22, 1926-27, 1947. WDR IL-75-1: Drainage area.

GAGE.-- Water-stage recorder, U.S. Army Corps of Engineers satellite telemeter, and crest-stage gage. Datum of gage is 508.38 ft above NGVD of 1929 (508.06 ft NAVD 1988). Prior to Aug. 14, 1934, chain gage on old Wabash Railway bridge (currently Norfolk and Western Railway bridge), 1,450 ft downstream, at datum 5.61 ft lower.

REMARKS.-- Some regulation by municipal reservoirs at Decatur (since 1922) and at Springfield (since 1934).

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 68,700 ft³/s, May 19, 1943, gage height, 31.52 ft, from graph based on gage readings; minimum daily, 3.0 ft³/s, Oct. 3-15, 1914.

EXTREMES OUTSIDE PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: The high water of 1883 reached a stage of approximately 32 ft with respect to the gage at the old Wabash Railway bridge. The high water of 1875 is said to have been about one-half foot lower.