LOCATION.-- Lat 41°54'10", long 89°41'46" (NAD of 1927), in SW1/4SE1/4 sec.9, T.22 N., R.7 E., Whiteside County, Hydrologic Unit 07090005, on left bank 50 ft upstream from bridge on County Road 2200 N, 2 mi northwest of Penrose, 2.2 mi downstream from Buffalo Creek, 5 mi upstream from Sugar Creek, and at mile 17.5.

DRAINAGE AREA.-- 146 mi².

PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE

DISCHARGE: October 1939 to current year.

STAGE: Water years 1994 to current year.

SURFACE-WATER QUALITY

CHEMICAL: Water years 1979-91.

REVISED RECORDS.-- WSP 925: 1940. WSP 955: 1941. WSP 1175: 1941(P), 1948(P). WSP 1308: 1950(M). WDR IL-72-1: Drainage area.

GAGE.-- Water-stage recorder and phone telemeter. Datum of gage is 657.85 ft above NGVD of 1929 (levels by U.S. Army Corps of Engineers). Prior to Apr. 6, 1940, nonrecording gage at same site and datum.

EXTREMES FOR PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 7,330 ft³/s, June 4, 2002, gage height, 17.42 ft; maximum gage height, 17.75 ft, Jan. 5, 1946; minimum discharge, 1.9 ft³/s, Jan. 3, 1976, result of freezeup.

EXTREMES OUTSIDE PERIOD OF RECORD.--

SURFACE-WATER DISCHARGE AND STAGE: Flood of June 1938 reached a stage of 19.6 ft, from U.S. Army Corps of Engineers high-water mark.