Big Sioux River below Watertown, SD
River level and flood forecast · Codington County
Normal4.6 ftas of Mon 3:45 PM
The river is 6.4 ft below flood stage (11 ft).
The last 7 days and the forecast
NWS forecast issued Sun, Dec 31, 6 PM. Forecasts change as rain falls and as upstream water arrives.
Flood stages
| Major flood stage | 12 ft |
| Moderate flood stage | 11.5 ft |
| Flood stage | 11 ft |
| Action stage | 10 ft |
| Record crest (April 2, 1997) | 13.13 ft |
What floods at each level
From the National Weather Service, highest first.
- 14.5 ftThe bridge 1 mile north of Appleby is overtopped
- 14 ftThe bridge at the southeast corner of Watertown is overtopped
- 13.3 ftThe water reaches the bottom of the bridge 1 mile north of Appleby
- 12 ftThe water reaches the bottom of the bridge near Appleby and at the southeast corner of Watertown
- 11.7 ftWater goes over the low spot on the road 300 feet east of the gauging location
- 11 ftFlooding begins to affect significant amounts of pasture and crop land
Highest crests on record
- 13.13 ft — April 2, 1997
- 12.69 ft — April 8, 2001
- 12.56 ft — March 23, 2011
- 12.31 ft — March 28, 2019
- 12.26 ft — April 12, 2023
Recent crests: 11.68 ft (August 22, 2025) · 12.26 ft (April 12, 2023) · 8.79 ft (April 2, 2020) · 12.31 ft (March 28, 2019) · 11.49 ft (April 22, 2018)
Up and down the river, and nearby
- UpstreamBig Sioux River at Watertown Broadway Avenue, SD
- DownstreamBig Sioux River near Castlewood, SD
- Willow Creek near Watertown, SD
- South Branch Tributary Mud Creek near Rauville, SD
- Big Sioux River at Watertown Sioux Conifer Road, SD
- Lake Kampeska at Watertown Water Plant, SD
- Big Sioux River at Lake Kampeska, SD
- Mud Creek near Rauville, SD
Not an official source. River levels, forecasts, flood stages and impacts are from the National Weather Service (BSWS2); flow from the U.S. Geological Survey. Readings are provisional. In a flood, follow your local officials and the NWS at weather.gov.