Major Flood
16 ft
Current Water Level
Gage Height
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Streamflow
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Last Reading
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FLOOD STAGES
Know the flood categories.
Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.
Moderate Flood
11 ft
Minor Flood
9 ft
Action Stage
8 ft
What Floods at Each Level
18 ft
479th Avenue begins to flood south of Castlewood.
17 ft
Highway 22 begins to flood, as does 181st Street, and water reaches the bottom of the bridge on 459th Avenue south of Castlewood.
16 ft
The river will be about 1 mile wide and many farm buildings around Castlewood will be flooded.
15 ft
The water reaches the bottom of the bridges on Highway 22 and 181st Street.
13 ft
Major agricultural flooding begins south of Castlewood.
11 ft
Significant amounts of pasture and other agricultural lands will be flooded.
10 ft
184th Street begins to flood.
9 ft
Water overtops the culvert on 184th Street and significant agricultural flooding begins north of Castlewood.
8 ft
Minor flooding of low-lying agricultural lands along the river will begin.
Impact statements from the National Weather Service, describing what typically happens at each water level.
7-Day Water Level Chart
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Historic Crests
| Date | Stage | Flow |
|---|---|---|
| Apr 6, 1997 | 13.19 ft | 4,300 cfs |
| Mar 27, 2019 | 12.39 ft | — |
| Mar 22, 2011 | 12.29 ft | 2,270 cfs |
About This Gauge
USGS Site
NWS LID
CSWS2
River
Big Sioux River
County
Hamlin, SD
Coordinates
44.7317°N, 97.0444°W
Get Flood Alerts for Big Sioux River
StormCast monitors this gauge and sends a push notification to your phone when the water level crosses into a new flood category — even at 3 AM.
Frequently Asked Questions
What is the current water level of Big Sioux River near Castlewood?
The Big Sioux River near Castlewood gauge is maintained by USGS (site 06479525) and reports water levels every 15 minutes. Visit this page to see the latest reading updated live, or download StormCast to get push alerts when levels rise.
What is flood stage for Big Sioux River near Castlewood?
The NWS-defined flood stage for Big Sioux River near Castlewood is 9 feet. Action stage begins at 8 feet. Moderate flooding starts at 11 feet, and major flooding at 16 feet.
How do I get alerts when Big Sioux River rises?
Download StormCast free on Google Play, go to River Gauges, and add Big Sioux River near Castlewood to your watchlist. StormCast will send a push notification to your phone whenever the water level crosses into a new NWS flood category.
Where is the Big Sioux River near Castlewood gauge located?
The gauge is located in Hamlin County, South Dakota at coordinates 44.7317°N, 97.0444°W. USGS site number: 06479525. Data is provided by the U.S. Geological Survey and the National Weather Service.
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Source & Notes
Data provided by: Observations courtesy of U.S. Geological Survey
- River forecasts for this location take into account past precipitation and the precipitation amounts expected approximately 48 hours into the future from the forecast issuance time.
- Gauge reading may be affected by ice.