Big Sioux River near Castlewood, SD
Is Big Sioux River near Castlewood, SD flooding right now?
Big Sioux River near Castlewood, SD measured 4.63 ft on 2026-09-11 01:45:00 UTC. That observation was 4.4 ft below its 9 ft flood stage. This is the latest available reading, not a guarantee of current conditions.
Gauge height
4.63 ft
Streamflow
9 cfs
Minor flooding here begins at 9 ft, with major flooding at 16 ft. The highest crest on record was 13.19 ft on Mon, Apr 7, 1997.
Streamflow outlook
Flood stages at this gauge
| Category | Stage | Current distance |
|---|---|---|
| Action | 8 ft | 3.4 ft below |
| Minor flood | 9 ft | 4.4 ft below |
| Moderate flood | 11 ft | 6.4 ft below |
| Major flood | 16 ft | 11.4 ft below |
Highest crests on record
| Stage | Date |
|---|---|
| 13.19 ft | 1997-04-07 |
| 12.39 ft | 2019-03-28 |
| 12.29 ft | 2011-03-23 |
| 12.27 ft | 2001-04-08 |
| 11.98 ft | 2010-03-15 |
Nearby gauges
| Gauge | Distance | County |
|---|---|---|
| Big Sioux River below Watertown, SD | 8.0 mi | Codington County |
| Big Sioux River at Broadway at Watertown, SD | 11.5 mi | Codington County |
| Willow Creek near Watertown, SD | 12.9 mi | Codington County |
| Big Sioux River at Watertown, SD | 15.4 mi | Codington County |
| South Branch Tributary Mud Creek near Rauville, SD | 15.6 mi | Codington County |
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Provisional data: Real-time readings are provisional and subject to revision by the USGS — sensors can be affected by ice, debris, or equipment malfunction. Do not rely on this site for decisions involving personal safety; follow official guidance from the National Weather Service and local authorities.