USGS Water-Year Summary 2020
06479525 BIG SIOUX RIVER NEAR CASTLEWOOD, SD
LOCATION - Lat 44°43'53.7", long 97°02'39.5" referenced to North American Datum of 1927, in SW 1/4 SW 1/4 sec.26, T.115 N., R.52 W., Hamlin County, SD, Hydrologic Unit 10170202, on right bank at upstream side of bridge on State Highway 22, 3.2 mi east of intersection of U.S. Highway 81 and State Highway 22, and 1.0 mi northwest of Castlewood.
DRAINAGE AREA - 1,096 mi² of which 517 mi² probably is noncontributing. Documented runoff occurred during Water Years 1994-2002 for 213 sq mi of the usually noncontributing area.
- WDR SD-10-1: Drainage area.
PERIOD OF RECORD - October 1976 to current year.
GAGE - Water-stage recorder and crest-stage gage. Datum of gage is 1,668.47 ft above NAVD88. Prior to conversion to NAVD88 gage datum was published as 1,667.52 ft above NGVD29.
EXTREMES FOR PERIOD OF RECORD - Minimum daily discharge, 0.00 ft³/s, Dec. 30, 1976, no flow for many days in some years.