USGS Water-Year Summary 2021
06485950 Big Sioux River at Sioux City, IA
LOCATION - Lat 42°31'28", long 96°28'48.7" referenced to North American Datum of 1927, in NE 1/4 SW 1/4 SW 1/4 sec.14, T.89 N., R.48 W., Woodbury County, IA, Hydrologic Unit 10170203, on right bank 30 ft downstream from Military Road in North Sioux City, 5.1 mi upstream from the Missouri River, and 1.0 mi east of exit 2 off of Interstate 29.
DRAINAGE AREA - 8,430 mi² of which 884 mi² probably is noncontributing. 8,430 mi² of which 884 mi² probably is noncontributing.
PERIOD OF RECORD - March 2015 to current year.
GAGE - Water-stage recorder. Datum of gage is 1,060 ft above NAVD of 1988, from topographic map.