LOCATION.--Lat 42°50'10", long 92°15'26" referenced to North American Datum of 1927, in NW 1/4 SW 1/4 SW 1/4 sec.27, T.93 N., R.12 W., Bremer County, IA, Hydrologic Unit 07080102, on right bank 10 ft downstream from bridge on State Highway 93, 2.0 mi north of Tripoli, 1.0 mi upstream from mouth of East Fork Wapsipinicon River, and 208 mi upstream from mouth. (map)

DRAINAGE AREA.--346 mi².

SURFACE-WATER RECORDS

PERIOD OF RECORD.--Partial-record low-flow measurement site from September 1957 to July 1977; stage-only records from May to September 2000, October 2004 to September 2006; discharge records from April 1996 to September 1998, October 2000 to September 2004, October 2006 to current year.

REVISED RECORDS.--WDR-IA-98-1: 1997 (M). WDR-US-2009: Datum.

GAGE.--Water stage recorder. Datum of gage is 986.42 ft above National Geodetic Vertical Datum of 1929.

CLIMATOLOGICAL RECORDS

PERIOD OF RECORD.--Precipitation records from April 1996 to September 1998, June 2000 to September 2008.

INSTRUMENTATION.--Tipping-bucket rain gage.

WATER-QUALITY RECORDS

PERIOD OF RECORD.--Water years 2001-2004, 2008-2009, 2012.

Advanced Hydrologic Prediction Service

National Streamflow Information Program