On May 13, 1912, amidst a flood of the Big Sioux River, four young men from Sioux Falls dared to take a canoe and rowboat over the Cascade Mill Dam. While two of the men, Guy Beck and Mat Yost managed to succeed, John Meehan and Will Dahl capsized. After being rescued by Beck and Yost, their rowboat was overturned by the powerful current, resulting in a terrifying cycle of the men being swept both upstream and downstream by the dam's hydraulic forces. Over 2,500 onlookers witnessed the preventable drownings.
History of Southeastern Dakota - Google Books
History of Minnehaha County, South Dakota - Google Books
Big Sioux crests at record level as flooding persists in southeast SD | sodakpb (sdpb.org)