Water reintroduced into tailrace as Red Rock Hydroelectric Project construction continues

Oct 05, 2018

Water reintroduced into tailrace  as Red Rock Hydroelectric Project construction continues

Recent high water levels at the Red Rock Dam have slowed construction work on the upstream side of the dam, but work continues to progress well on the downstream side. The exterior structure of the powerhouse is complete and water is now being reintroduced into the tailrace. The tailrace is the channel that carries water from the turbines, out of the powerhouse, and directs it back into the Des Moines River.  

Crews began pumping water into the tailrace Oct. 4 in preparation for removal of the temporary cofferdam. The cofferdam was among the initial components installed in 2015 to keep water out of the construction site, allowing for work on dry land. The tailrace will be flooded to the same level as the Des Moines River, which flows on the opposite side of the cofferdam. This will stabilize water levels, equalize water pressure, and minimize any disturbances to the river or to the dike when the cofferdam is removed. It is expected to take about three days to flood the tailrace. 

Heavy gates, known as stop logs, have been installed between the turbines in the powerhouse and the tailrace. The stop logs are used to stop the flow of water during maintenance of the turbines. Once the tailrace is flooded, the stop logs will be tested for leaks and certified as water-tight before the cofferdam is removed.

Improvements also have been added to the North Tailwater Recreation Area, which is a popular spot for fishing enthusiasts. Two new fishing access walkways and a stairway have been constructed along the tailrace that will provide access for fishermen in most water conditions. The walkways are designed to accommodate water levels resulting from both high and low water releases by the U.S. Army Corps of Engineers.

Construction of the Red Rock Hydroelectric Project was approximately 83 percent complete at the end of August. Project completion, along with reopening of the North Tailwater Recreation Area and other recreation features, is expected in the first half of 2020.

“Missouri River Energy Services (MRES) extends our sincere thanks to the residents and businesses in the Pella and Knoxville region for your kind understanding and patience as this project has moved forward,” said MRES Director of Member Services and Communications Joni Livingston.

MRES serves 61 member municipally owned utilities in the states of Iowa, Minnesota, North Dakota, and South Dakota. The Red Rock Hydroelectric Project, when operational, will produce enough electricity to serve about 18,000 homes and it will be the second largest hydroelectric facility in the State of Iowa.

For more information about the Red Rock Hydroelectric Project, visit the project website at or contact Joni Livingston at Missouri River Energy Services, phone 605-261-3637 or email: