US Army Corps of Engineers
Rock Island District

About Us

 History

A series of floods took place on the Des Moines River in 1851, 1859, 1903, 1944, 1947, and 1954. In 1938 and 1944, Flood Control Acts were passed which led to a lengthy study of nine sites on the Des Moines River. Two of the sites studied were chosen for the construction of dams: Red Rock and Saylorville.
Construction of the Red Rock Dam began in 1960, and the dam was finished in 1969. The primary purpose of the dam is to reduce flood damage along the Des Moines River below the dam, as well as along the Mississippi River further downstream.

A Price to Pay for Security

The Red Rock project cost a total of 88 million dollars. This amount was divided three ways. Approximately one-third was spent to purchase land around the site. Another third was spent to relocate 96 miles of the Wabash Railroad, 42 miles of highway, 2 miles of gas lines, 225 miles of electric lines, and 8 cemeteries. The final third was used to construct Red Rock Dam. The project was costly to build but has paid for itself many times over. By protecting property, lives, and crops, an estimated 449 million dollars had been saved during 1969 to 1999.

The Des Moines River Basin

The Des Moines River Basin begins in Minnesota and extends through Iowa to the Mississippi River. The runoff from over 12,000 square miles of land drains from this basin into the Des Moines River above Lake Red Rock. The Des Moines River joins the Mississippi River at Keokuk, Iowa.
Saylorville Dam and Red Rock Dam work together to provide flood control on the Des Moines River and Mississippi River.

The Control Structure

While the earthen segments make up most of the dam, the control structure is where the action is. Each part of the structure has a specific and important function.

The "Stilling Basin" functions to still the river water as it flows out of the dam. Slowing the water decreases bank erosion. To slow the water, large concrete blocks called "baffles" were placed in the basin. There are 25 baffles, each the size of a passenger van, lined up in two rows in the basin.

The "Sluice Gates," located inside the control structure, empty into the stilling basin. There are 14 hydraulically- operated sluice gates. Each is five feet wide and nine feet tall. These gates are used when outflow is less than 38,000 cubic feet per second.

Unlike some dams, Red Rock has a "controlled" spillway through the use of the "Tainter Gates." Each gate is 41 feet wide and 45 feet tall. These high outflow gates are used only during high water conditions.