Construction of the Apron at St. Anthony Falls, Mississippi River

Primary Source Set
by Anna Freyberg, Public Programs Intern, Hennepin History Museum

St. Anthony Falls, the only major waterfall on the Mississippi River, is located in Minneapolis, Minnesota. While the scenic beauty of St. Anthony Falls initially drew tourists and prospective residents, the immense water power quickly overwhelmed tourism as the main function of the falls in the mid-1800s. Once this lucrative power was harnessed, sawmilling and flour milling production on the Mississippi River boomed. The construction of an apron, or a concrete overflow spillway, on the St. Anthony Falls, which was first added in the early 1870s, has played a crucial role in preserving and maintaining the functionality of the falls. The apron was first constructed in 1868 after a tunnel dug underneath the Nicollet and Hennepin Islands collapsed, threatening to destroy the falls altogether. 

After several failed attempts to alleviate the damage of the tunnel collapse with timber rafts and temporary dams, the engineer Franklin Cook worked with the U.S. Army Corps of Engineers to devise a more permanent solution to save the falls. Cook’s team received $50,000 and authorization from Congress to preserve the falls and their central contribution to the milling industries. A large timber apron was built to support the falls and prevent further erosion, while a dam at the edge of the waterfall was constructed to ensure constant water levels. The purpose of the newly installed apron was to prevent the falls from eroding and breaking up into rapids, causing them to lose their profitability. The ongoing maintenance of the apron, which could be susceptible to the harsh Minnesota weather, would become the responsibility of the Army Corps of Engineers. 

By the 1880s, the falls were running smoothly. With twenty-seven different flour mills, including Pillsbury and the Washburn-Crosby Company (later renamed General Mills) located along  the Mississippi River, Minneapolis became the nation’s top flour producer and earned the nickname “Mill City.” In 1885, the water power companies and the City of Minneapolis took responsibility for the falls’ maintenance. In the 1950s and 60s, a series of locks and dams were constructed on the Mississippi River to further secure St. Anthony Falls. 

For more information on the history of St. Anthony Falls in Minneapolis, visit the St. Anthony Falls Primary Source Set.