The U.S. Geological Survey has recorded the highest streamflow in the Big Sioux River since record keeping began in 1929.
A USGS streamgage on the river in Akron, Iowa, recorded a record stage of 25.46 feet on Thursday. The streamflow is operating at approximately 108,000 cubic feet per second. The previous record of 80,800 cfs was in 1969.
The current flooding has a 0.5 to 1 percent change of occurring each year.
USGS field crews are measuring the flooding throughout the state. The data is being used by the National Weather Service, U.S. Army Corps of Engineers, state and local agencies.
The USGS is also distributing rapid deployment gages to monitor areas where streamgages do not exist. There are 144 USGS-operated streamgages in South Dakota.
Residents near the Big Sioux River can receive instant alerts via email or text message about water conditions from the USGS’s WaterAlert system.