Big Sioux River at Watertown Broadway Avenue, SD
River level and flood forecast · Codington County
Normal5.0 ftas of Mon 2 PM
The river is 5.5 ft below flood stage (10.5 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 | 13.5 ft |
| Moderate flood stage | 11 ft |
| Flood stage | 10.5 ft |
| Action stage | 10 ft |
| Record crest (April 6, 1997) | 13.67 ft |
What floods at each level
From the National Weather Service, highest first.
- 18 ftThe bridge on Hwy 81 is overtopped.
- 17.5 ftThe Broadway Avenue bridge at the gauge is overtopped.
- 17 ft4th Avenue SW begins to flood near Kampeska Blvd.
- 16.5 ftBroadway Avenue begins to flood.
- 16 ftThe levees on the north side of the river upstream of the gauge are overtopped, and the gas station will begin flooding.
- 15 ftThe railroad upstream of Thunder Road begins to flood, and water reaches the bottom of the bridges on Broadway Ave and 4th Ave SW.
- 14 ftThe levee on the south side of the river upstream from the gauge is overtopped.
- 11 ftThe lower banks on both sides of the river downstream of the gauge are overtopped, and the lower lying areas along Kampeska Blvd, 4th Ave SW, and Riverside Park on Kemp Ave begin to flood.
Highest crests on record
- 13.67 ft — April 6, 1997
- 12.71 ft — April 7, 2001
- 11.97 ft — April 12, 2011
- 11.87 ft — April 13, 2023
- 11.77 ft — March 28, 2019
Recent crests: 10.85 ft (August 22, 2025) · 11.87 ft (April 13, 2023) · 10.65 ft (May 31, 2022) · 7.85 ft (April 10, 2021) · 9.58 ft (April 4, 2020)
Up and down the river, and nearby
- UpstreamBig Sioux River at Watertown Sioux Conifer Road, SD
- DownstreamBig Sioux River below Watertown, SD
- Lake Kampeska at Watertown Water Plant, SD
- Willow Creek near Watertown, SD
- South Branch Tributary Mud Creek near Rauville, SD
- Big Sioux River at Lake Kampeska, SD
- Mud Creek near Rauville, SD
- Big Sioux River near Watertown, SD
Not an official source. River levels, forecasts, flood stages and impacts are from the National Weather Service (WBWS2); flow from the U.S. Geological Survey. Readings are provisional. In a flood, follow your local officials and the NWS at weather.gov.