Canada
United States
Belgium
France
Ireland
Netherlands
United Kingdom
Austria
Czechia
Germany
Poland
Slovenia
Switzerland
Italy
Spain
Türkiye
Denmark
Finland
Norway
SwedenBig Sioux River near Castlewood water level
River gauge, Big Sioux River, South Dakota, United States
Right now
Below flood stage
Water level
- Flow
- 25.0 cfs
History
20252026
What this means
The gauge at Big Sioux River near Castlewood reads 4.80 ft, a normal level.
It is 4.20 ft below the flood stage of 9.00 ft. On the same day last year the reading was 5.66 ft, a difference of −0.86 ft.
It has barely moved over the past 24 hours. Over the past 30 days it has moved between 4.71 ft and 4.88 ft.
Fall is often low-water season on rivers, until steadier rain returns.
Judged against the official flood stage for this gauge. How to read levels
Key numbers
- Same day last year
- 5.66 ft−0.86 ft
- Lowest and highest in 30 days
- 4.71 ft – 4.88 ft
- Lowest and highest in 12 months
- 4.60 ft – 9.00 ft
- Highest on record
- 13.19 ftApril 7, 1997
What the stage means on the water
A normal level is usually prime time for floating and wade fishing, as long as the weather holds upstream.
The National Weather Service puts flood stage for this gauge at 9.00 ft, still 4.20 ft away.
What happens at each level
- 18.00 ft
- 479th Avenue begins to flood south of Castlewood.
- 17.00 ft
- Highway 22 begins to flood, as does 181st Street, and water reaches the bottom of the bridge on 459th Avenue south of Castlewood.
- 16.00 ft
- The river will be about 1 mile wide and many farm buildings around Castlewood will be flooded.
- 15.00 ft
- The water reaches the bottom of the bridges on Highway 22 and 181st Street.
- 13.00 ft
- Major agricultural flooding begins south of Castlewood.
- 11.00 ft
- Significant amounts of pasture and other agricultural lands will be flooded.
- 10.00 ft
- 184th Street begins to flood.
- 9.00 ft
- Water overtops the culvert on 184th Street and significant agricultural flooding begins north of Castlewood.
- 8.00 ft
- Minor flooding of low-lying agricultural lands along the river will begin.
- 4.80 ft
- Right now
Impact statements from the U.S. National Weather Service.
Highest crests on record
Chance of at least minor flooding in October to December: 14 %.
| Rank | Level | Date |
|---|---|---|
| 1 | 13.19 ft | April 7, 1997 |
| 2 | 12.39 ft | March 28, 2019 |
| 3 | 12.29 ft | March 23, 2011 |
| 4 | 12.27 ft | April 8, 2001 |
| 5 | 11.98 ft | March 15, 2010 |
| 6 | 11.73 ft | March 30, 1986 |
| 7 | 11.65 ft | March 14, 1996 |
| 8 | 11.64 ft | April 13, 2023 |
| 9 | 11.44 ft | July 29, 2025 |
| 10 | 11.39 ft | March 28, 1993 |
Weather at the gauge
The forecast is not available right now.
Map
Other gauges on the Big Sioux River
| Gauge | Level | Compared with normal | 24 hours | Distance |
|---|---|---|---|---|
| Big Sioux River near FlorenceRiver gauge, Big Sioux River | 3.05 ft | Normal | −0.01 ft | 32 mi |
| Big Sioux River near WatertownRiver gauge, Big Sioux River | 3.80 ft | Very low | −0.02 ft | 20 mi |
| Big Sioux River at Lake Kampeska near WatertownRiver gauge, Big Sioux River | 18.54 ft | Below flood stage | ±0 | 16 mi |
| Big Sioux River at WatertownRiver gauge, Big Sioux River | 3.15 ft | Below flood stage | +0.01 ft | 15 mi |
| Big Sioux River at Broadway at WatertownRiver gauge, Big Sioux River | 5.03 ft | Below flood stage | −0.04 ft | 11 mi |
| Big Sioux River below WatertownRiver gauge, Big Sioux River | 4.47 ft | Below flood stage | ±0 | 8 mi |
| Big Sioux River near BruceRiver gauge, Big Sioux River | 3.11 ft | Below flood stage | −0.02 ft | 20 mi |
| Big Sioux River near BrookingsRiver gauge, Big Sioux River | 2.27 ft | Below flood stage | −0.03 ft | 41 mi |
| Big Sioux River near Dell RapidsRiver gauge, Big Sioux River | 3.23 ft | Below flood stage | −0.01 ft | 67 mi |
| Big Sioux River below Diversion at Sioux FallsRiver gauge, Big Sioux River | 3.12 ft | Below flood stage | −0.01 ft | 81 mi |
| Big Sioux River at Sioux FallsRiver gauge, Big Sioux River | 1.49 ft | Below flood stage | +0.01 ft | 86 mi |
| Big Sioux River at North Cliff Ave at Sioux FallsRiver gauge, Big Sioux River | 5.08 ft | Below flood stage | +0.01 ft | 82 mi |
Nearby gauges
| Gauge | Level | Compared with normal | 24 hours | Distance |
|---|---|---|---|---|
| Willow Creek near WatertownRiver gauge, Willow Creek | 5.65 ft | Below flood stage | −0.06 ft | 13 mi |
| Lake Kampeska at Water Plant at WatertownLake, Lake Kampeska | 17.42 ft | Normal | ±0 | 15 mi |
| South Branch Tributary Mud Creek near RauvilleRiver gauge, South Branch Tributary Mud Creek | 0.21 ft | Below flood stage | −0.07 ft | 16 mi |
| Mud Creek near RauvilleRiver gauge, Mud Creek | 7.63 ft | Below flood stage | ±0 | 19 mi |
Questions and answers
Is the Big Sioux River near Castlewood higher than last year?
No, it is 0.86 ft lower than on the same day last year, when the reading was 5.66 ft.
What is flood stage for the Big Sioux River near Castlewood?
The official flood stage is 9.00 ft. The level is currently 4.20 ft below it.
Is gage height the same as water depth?
No. Gage height is measured from a fixed reference point chosen by the agency, so a reading of 10 ft does not mean the river is 10 ft deep.
What is the water level of Big Sioux River near Castlewood today?
On Oct 20, 2026, 06:45 PM CDT, the water level was 4.80 ft. Steady over the last 24 hours.
Is Big Sioux River near Castlewood rising or falling?
Steady over the last 24 hours. Steady over the last 7 days.
Is the level of Big Sioux River near Castlewood normal?
Below flood stage. Judged against the official flood stage for this gauge.
What is the highest water level ever recorded at Big Sioux River near Castlewood?
The highest level on record is 13.19 ft on April 7, 1997.
For specialists
Station codes, datum, parameters, data quality and downloads
- Operator
- U.S. Geological Survey
- Station code
usgs:06479525(Agency page)- Coordinates
44.73158, -97.04431(WGS84)- Vertical datum
- NAVD88
- Update interval
- every 15 minutes
- Licence
- Public domain. Data: U.S. Geological Survey (USGS), provisional data subject to revision
Published series
| Parameter | Last value | Time (UTC) | Quality |
|---|---|---|---|
| Water level | 4.80 ft | 2026-10-20 23:45 | Provisional |
| Flow | 25.0 cfs | 2026-10-20 23:45 | Provisional |
Download
Embed this gauge
Add a live card for this gauge to your website. It updates on its own and links back here.
How to cite
U.S. Geological Survey: Big Sioux River near Castlewood (usgs:06479525). Accessed October 21, 2026 via Nivelmap, https://nivelmap.com/en/united-states/south-dakota/big-sioux-river-near-castlewood
How we check values
Each reading is stored as published. We hold back values that jump faster than physically plausible and show the measurement time with every value.
Readings are provisional, can be delayed or wrong and are not a flood warning. Read the disclaimer