LOCATION.--Lat 40°43'40", long 91°57'34" referenced to North American Datum of 1927, in NE 1/4 SE 1/4 SW 1/4 sec.36, T.69 N., R.10 W., Van Buren County, IA, Hydrologic Unit 07100009, on left bank on downstream side of bridge on State Highway 1 in Keosauqua, 4.0 mi downstream from Chequest Creek, and 49.3 mi upstream from mouth. (map)

DRAINAGE AREA.--14,038 mi².

SURFACE-WATER RECORDS

PERIOD OF RECORD.--Discharge records from May 1903 to July 1906, April to December 1910, August 1911 to current year. Prior to April 1918, monthly mean discharge for some periods published in WSP 1308.

REVISED RECORDS.--WSP 525: 1913-20. WSP 1438: Drainage area. WSP 1508: 1903, 1905-06, 1915-18 (M), 1922 (M), 1924-26 (M), 1932-34 (M), 1937, 1942 (M).

GAGE.--Water-stage recorder. Datum of gage is 547.36 ft above National Geodetic Vertical Datum of 1929. Prior to December 25, 1933, non-recording gage, and December 25, 1933, to September 30, 1972, water-stage recorder, both at same site at datum 10.00 ft higher.

REMARKS.--Prior to December 21, 1958, and since November 30, 1960, minor diurnal fluctuations during periods of low and medium flows due to operations of power plant located 43.3 mi upstream. Flow regulated by Lake Red Rock (station 05488100), 91.0 mi upstream, since March 12, 1969.

WATER-QUALITY RECORDS

PERIOD OF RECORD.--Water years 2004 to current year.

Advanced Hydrologic Prediction Service

U.S. Army Corps of Engineers - Rock Island District