A Brief History of...Bagnell Dam

14, April 2010
Aerial view of Bagnell Dam. Photograph by H. L. Gamber, ca. 1937. Missouri History Museum.

Most St. Louisans probably don’t know that Lake of the Ozarks, where they head for summertime fun, is the source of their electricity. Bagnell Dam was constructed to impound water from the Osage River to produce electric power for St. Louis and other parts of Missouri. The resulting lake is now a major tourist attraction in the middle of the state. Its shoreline is even longer than the Pacific coastline of California, measuring 1,100 miles. In the article “Seeing the Lake from End to End” in the November 1932 issue of Union Electric Magazine , G. V. Williamson said, “swimming in this clean, tideless, currentless water and under our warm Missouri sun must be tried to realize that surely nowhere could this sport be more fully enjoyed.” And of course, he stated that “the Bagnell Dam is a convenient place to start a trip.”

In 1912, Ralph W. Street of Kansas City pondered the idea of damming the Osage River. He worked with partner Walter Cravens and the Missouri Hydro-Electric Power Company to begin work on Bagnell Dam in 1924. Funding problems in 1926 brought work to a halt, however. Union Electric Light and Power Company of St. Louis (now known as Ameren UE) eventually picked up the project, recommencing work in 1929.

William Bagnell. From Encyclopedia of the History of St. Louis, vol. 1., William Hyde and Howard Conard, 1899.

During the Depression, the 20,500 jobs created by the project were a boon to the area. Laborers worked 9 to 12 hours per day for 35 cents to a dollar per hour. Conversely, many lost their homes when 54,000 acres were cleared to make way for the lake. The dam’s name comes from the city of Bagnell, which was itself named for railway builder William Bagnell, who platted the town in 1883.

The dam is 148 feet tall and 2,543 feet long and boasts 12 floodgates. Six water-wheel turbines were installed, with two added in 1953. The dam was poured in 40-foot-wide blocks that are designed to slide in case of a breach. Thus, instead of a total collapse, only one or two sections would move back while the remainder of the dam would be undamaged.

The dam was finished in April 1931, and electric service began on December 24 of that year. Today Ameren uses the dam and Osage Power Plant to serve 39,000 electric customers. And scores of Missourians still head “down to the lake” every weekend in summer to enjoy the warm Missouri sun.

Detail from Shell Official Road Map of Missouri, 1929.
Detail from Shell Official Road Map of Missouri, 1932.

—Lauren Mitchell, Senior Editor