LOCATION.--Lat 41°06'11.5", long 91°03'48.7" referenced to North American Datum of 1983, in SW 1/4 SW 1/4 SW 1/4 sec.23, T.73 N., R.2 W., Louisa County, IA, Hydrologic Unit 07080209, on left bank 10 ft downstream from bridge on State Highway 99, 0.7 mi west of Oakville, 1.7 mi downstream from Smith Creek, and 5.3 mi upstream from mouth. (map)

DRAINAGE AREA.--12,630 mi².

SURFACE-WATER RECORDS

PERIOD OF RECORD.--Discharge records from April 2009 to current year.

GAGE.--Water-stage recorder. Datum of gage is 535.64 ft above National Geodetic Vertical Datum of 1929.

REMARKS.--Flow regulated by Coralville Lake (station 05453510), 77.2 mi upstream, since September 17, 1958.

Advanced Hydrologic Prediction Service

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