USGS Water-Year Summary 2024

06601200 Missouri River at Decatur, NE

LOCATION - Lat 42°00'28.2", long 96°14'34.5" referenced to North American Datum of 1983, in NE 1/4 SW 1/4 sec.36, T.24 N., R.10 E., Monona County, IA, Hydrologic Unit 10230001, on right bank 500 ft upstream from bridge on State Highway 175 in Decatur, and 691.0 mi upstream from mouth.

DRAINAGE AREA - 316,200 mi².

SURFACE-WATER RECORDS

PERIOD OF RECORD - Periodic streamflow measurements from March 1956 to October 1987. Discharge records from October 1987 to current year.

GAGE -

Water-stage recorder.

Datum of gage is 1,010.56 ft above North American Vertical Datum of 1988 (U.S. Army Corps of Engineers).

From Feb. 17, 1975, to Aug. 1, 2016, datum of gage was 1,010.00 ft above National Geodetic Vertical Datum of 1929, supplementary adjustment of 1954.

Prior to Feb. 17, 1975, datum of gage was 1,030.00 ft above National Geodetic Vertical Datum of 1929.

REMARKS - Accuracy of records is discussed in the annual Station Analysis archived at the USGS IA Water Science Center. Flow regulated by upstream main-stem reservoirs. Fort Randall Dam was completed in July 1952, with storage beginning in December 1952. Gavins Point Dam was completed in July 1955, with storage beginning in December 1955.

WATER-QUALITY RECORDS

PERIOD OF RECORD - Water years 1974-1981.

PERIOD OF DAILY RECORD -
SPECIFIC CONDUCTANCE: March to November 2006, April to November 2007.
WATER TEMPERATURE: March to November 2006, April to November 2007, October 2011 to current year.
DISSOLVED OXYGEN: March to November 2006, April to November 2007.
pH: March to November 2006, April to November 2007.
TURBIDITY: March to November 2006, April to November 2007.