Bagnell Dam Floodgates Open After Flash Flooding Hits Lake Of The Ozarks

LAKE OF THE OZARKS, Mo. — Nearly nonstop rain throughout much of Saturday brought flash flooding conditions to the Lake of the Ozarks area and compelled Bagnell Dam operators to open 10 of the dam’s floodgates.

The National Weather Service says between 3 and 8 inches of rain fell across central Missouri on Saturday and into Sunday morning, and that put the Lake area under a flash flood warning through noon on Sunday.

According to Phillip Thompson, of Ameren, on Sunday morning 10 of the dam’s 12 floodgates were opened by 10 percent, with a targeted flow of 50,000 cubic feet per second (cfs). The dam is capable of passing 40,000 cfs of water without opening the floodgates.

By 4 a.m., the dam’s floodgates had surpassed the 40,000 cfs point, and by 5 a.m., the flow had reached 50,000 cfs. As a result, Osage River levels near the dam were brought up by four feet. The floodgates were closed by 10 p.m.

With the floodgates wide open, Bagnell Dam can pass 225,000 cubic feet of water per second. That converts to 1,683,116 gallons per second. The worst flood on record at the Lake of the Ozarks was in 1943. During that infamous flood, the dam was operating at 220,000 cfs.

“There were some lawsuits that came out of that,” Bagnell Dam Director of Hydro Operations Warren Witt explained, “and a court actually established criteria for how to calculate flows that the river ought to be seeing under these flood conditions.”