StormCast — Weather & Emergency Alerts

Big Sioux River near Castlewood
South Dakota — Water Level & Flood Stage

Located in Hamlin County, South Dakota on the Big Sioux River. Live water level data from USGS gauge 06479525, updated every 15 minutes.

Current Water Level

Gage Height

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Streamflow

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Last Reading

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Flood Stages

Major Flood

16 ft

Moderate Flood

11 ft

Minor Flood

9 ft

Action Stage

8 ft

Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.

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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View Official NWS Hydrograph →

Historic Crests

Date Stage Flow
Apr 6, 199713.19 ft4,300 cfs
Apr 6, 199713.19 ft4,300 cfs
Mar 27, 201912.39 ft
Mar 27, 201912.39 ft
Mar 22, 201112.29 ft2,270 cfs

About This Gauge

USGS Site

06479525

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.

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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 — even when your screen is off.

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