LOCATION.--Lat 40°23'37", long 91°22'27"
referenced to North American Datum of 1927, in SE 1/4 SW 1/4 sec.30,
T.65 N., R.4 W., Lee County, IA, Hydrologic Unit 07080104, near right
bank in tailwater of dam and power plant of AmerenUE in Keokuk, 0.2
mi upstream from bridge on U.S. Highway 136, 2.7 mi upstream from Des
Moines River, and 364.2 mi upstream from Ohio River. (map)
DRAINAGE AREA.--119,000 mi2.
PERIOD OF RECORD.--Discharge records from January 1878 to current
GAGE.--Datum of gage is 477.41 ft above National Geodetic Vertical
Datum of 1929 (levels by U.S. Army Corps of Engineers). January 1,
1878, to May 1913, non-recording gage at Galland (formerly
Nashville), 8 mi upstream, with datum of gage set to low-water mark
of 1864, or 496.94 ft above Mean Sea Level, general adjustment of
COOPERATION.--Records provided by AmerenUE (formerly Union
REMARKS.--Discharge computed from records of operation of turbines
in power plant and spillway gates at dam. Minor flow regulation
caused by power plant since 1913 and navigation dams. Records for May
1913 to September 1937 adjusted for change in contents in Keokuk
Reservoir, those after September 1937 unadjusted.
PERIOD OF RECORD.--Water years 1975-1987, 2008.
PERIOD OF DAILY RECORD.--
SPECIFIC CONDUCTANCE: December 1977 to September 1981.
WATER TEMPERATURE: December 1977 to September 1981.