The Des Moines River, the largest river in central Iowa , has a history of too much or too little water, depending on the season. Major floods occurred on the Des Moines River in 1851, 1903, 1935, 1938 and 1944. Following these floods, the Committee on Commerce of the United States.
Senate authorized a study of the Des Moines River in the interest of providing additional flood protection for the city of Des Moines. The Des Moines local flood protection project was authorized by Congress on December 22, 1944. In 1958, after investigating nine sites, six on the Des Moines River, two on the Raccoon, and one on the South Raccoon, Congress authorized construction of Saylorville Lake by the U.S. Army of Engineers at a site about 11 miles upstream from the city of Des Moines.
The principal purpose of the Saylorville project is to provide additional storage to supplement the flood control capacity of Lake Red Rock downstream and help reduce flood crests on the Des Moines and Mississippi Rivers. Saylorville Lake, acting in conjunction with the completed local protection works of the city of Des Moines, also provides flood protection for the city.