Red Rock Hydroelectric

Ames Construction retrofitted the Red Rock dam on the Des Moines River near Pella, Iowa, with a two-unit turbine generator, powerhouse, and intake structure that generates renewable, clean hydroelectric power.

Crews began installing underground support structures to prepare for powerhouse construction in August 2014. By 2016, the project’s focus progressed to constructing the powerhouse, located downstream of the dam, and the upstream intake structure. Crews built the spiral case walls, floor, and roof, along with concrete draft tubes, including the necessary embedded components for turbine-generator installation.

A major milestone was erecting the turbine generators. After the embedded items were confirmed, crews positioned the turbine runner. Assembled separately, the generator rotor included stacked steel plates made up of hundreds of pieces. The rotor was placed on the turbine/generator shaft and positioned inside of the stationary stator so that when the runner spins the rotor, the components work together to produce energy.

Throughout 2017, crews completed the center of the powerhouse, advancing to above-ground visibility. Two penstocks were constructed downstream of the dam. The downstream exterior structure of the powerhouse was enclosed. Crews then completed the electrical connections, installed support equipment, and dry tested all of the components.

After the upstream intake structure was completed and tested, crews successfully cored through the dam in October 2019 to enable water to pass through the new powerhouse. Water was delivered to the turbines in the powerhouse in the summer of 2020 to begin commissioning and testing, and a dedication ceremony in September 2020 marked the beginning of hydropower generation at the facility.

As one of the largest hydropower generators in Iowa, the retrofitted dam harnesses the power of the Des Moines River to produce electricity for thousands of homes.