Big Sioux River at Lake Poinsett Inlet/Outlet
South Dakota — Water Level & Flood Stage
Located in Hamlin County, South Dakota on the Big Sioux River. Live water level data from USGS, updated every 15 minutes.
Current Water Level
Gage Height
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Streamflow
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Last Reading
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This is an NWS forecast point (LID: PONS2). Live data may be limited. View on NWS AHPS →
Flood Stages
Major Flood
1657 ft
Moderate Flood
1655 ft
Minor Flood
1654 ft
Action Stage
1651.5 ft
Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.
What Floods at Each Level
1658 ft
The Highway 28 bridge on the north side of the lake is overtopped.
1657 ft
Highway 81 on the west side of Lake Poinsett begins to flood, as does Highway 28 on the north and east side of the lake, and the Highway 28 bridge at the inlet/outlet begins to flood.
1655 ft
Homes along the north side of the lake begin to flood, and water will begin overflowing 459th Avenue.
1654 ft
Boat docks and yards along the lake begin to flood.
1651.5 ft
Lake Poinsett is considered full
1650.5 ft
Lake outlet elevation
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 4, 2011 | 1657.6 ft | — |
| Apr 4, 2011 | 1657.6 ft | — |
| Apr 21, 2019 | 1657 ft | — |
| Apr 21, 2019 | 1657 ft | — |
| Jul 16, 2010 | 1656.44 ft | — |
About This Gauge
NWS LID
PONS2
River
Big Sioux River
County
Hamlin, SD
Coordinates
44.5961°N, 97.0275°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 at Lake Poinsett Inlet/Outlet?
The Big Sioux River at Lake Poinsett Inlet/Outlet gauge is maintained by USGS 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 at Lake Poinsett Inlet/Outlet?
The NWS-defined flood stage for Big Sioux River at Lake Poinsett Inlet/Outlet is 1654 feet. Action stage begins at 1651.5 feet. Moderate flooding starts at 1655 feet, and major flooding at 1657 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 at Lake Poinsett Inlet/Outlet 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 at Lake Poinsett Inlet/Outlet gauge located?
The gauge is located in Hamlin County, South Dakota at coordinates 44.5961°N, 97.0275°W. 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 South Dakota DANR
- Gauge reading may be affected by ice.