LOCATION.-- Lat 39°49'24", long 90°34'05" (NAD of 1927), in SE1/4 sec.21, T.16 N., R.13 W., Morgan County, Hydrologic Unit 07130011, on left bank adjacent to the crib house of Central Illinois Public Service Company in Meredosia, 0.5 mi downstream from bridge on State Highway 104, 4.2 mi upstream from McKee Creek, and at mile 71.3. This auxiliary gage is 10.0 miles upstream from the base gage Illinois River at Valley City (05586100).

DRAINAGE AREA.-- 26,029 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.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: October 1938 to September 1989. Discharge records for October 1933 to September 1938 in the reports of the Mississippi River Commission.

STAGE: October 1989 to current year.

PARTIAL RECORD: Annual maximum, water years 1921 to 1938, published as "at Beardstown".

REVISED RECORDS.-- WSP 895: 1939. WDR IL-75-1: Drainage area. WDR IL-83-2: 1979(M).

GAGE.-- Water-stage recorder, U.S. Army Corps of Engineers satellite telemeter and crest-stage gage. Datum of gage is 418.00 ft above NGVD of 1929 (levels by U.S. Army Corps of Engineers) (417.64 ft NAVD 1988). Prior to October 1938, at datum 1.89 ft. higher at Beardstown.

REMARKS.-- Occasional regulation at low flow by navigation dam at La Grange. Since Jan 17, 1900, flow has included diversion from Lake Michigan through Chicago Sanitary and Ship Canal.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 123,000 ft³/s, May 26-28, 1943; maximum gage height, 28.61 ft, May 26, 1943; minimum daily discharge, 1,330 ft³/s, Sept. 2, 1984; minimum gage height, 0.4 ft, Jan. 11-12, 1940.

EXTREMES OUTSIDE PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: At Beardstown, maximum discharge known, about 115,000 ft³/s, on Apr. 4, 1904, gage height, 20.0 ft, maximum gage height observed, 26.25 ft, Oct. 12, 1926 (discharge 105,000 ft³/s, Oct. 9, 1926); minimum discharge observed, 9,140 ft³/s, July 8-14, 1936.