Big Sioux River at Watertown Sioux Conifer Road, SD
River level and flood forecast · Codington County
Normal3.2 ftas of Mon 3:15 PM
The river is 5.8 ft below flood stage (9 ft).
Flow: 2 cubic feet per second (USGS).
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 | 10 ft |
| Flood stage | 9 ft |
| Action stage | 8 ft |
| Record crest (April 13, 2023) | 11.18 ft |
What floods at each level
From the National Weather Service, highest first.
- 15.5 ftThe bridge on 14th Ave NW is overtopped.
- 14 ftThe bridge on Sioux Conifer Road is overtopped.
- 12 ftSioux Conifer Road floods south of the gauge, and water reaches the bottom of the bridge at the gauge.
- 10 ftSignificant amounts of pasture land are flooded.
- 8 ftMinor lowland flooding begins, mainly upstream of the gauge.
Highest crests on record
- 11.18 ft — April 13, 2023
- 10.98 ft — March 28, 2019
- 10.29 ft — March 30, 1960
- 9.81 ft — March 15, 2010
- 9.77 ft — March 23, 2009
Recent crests: 9.15 ft (August 7, 2025) · 11.18 ft (April 13, 2023) · 9.47 ft (May 31, 2022) · 6.69 ft (April 10, 2021) · 8.9 ft (October 25, 2019)
Up and down the river, and nearby
- UpstreamBig Sioux River at Lake Kampeska, SD
- DownstreamBig Sioux River at Watertown Broadway Avenue, SD
- South Branch Tributary Mud Creek near Rauville, SD
- Lake Kampeska at Watertown Water Plant, SD
- Big Sioux River near Watertown, SD
- Mud Creek near Rauville, SD
- Willow Creek near Watertown, SD
- Big Sioux River below Watertown, SD
Not an official source. River levels, forecasts, flood stages and impacts are from the National Weather Service (WBSS2); flow from the U.S. Geological Survey. Readings are provisional. In a flood, follow your local officials and the NWS at weather.gov.