Project Status
Ozark Powerhouse has been unique since it was constructed because it was the first slant-shaft turbine powerhouse built by the Corps. Webber Falls, located upstream from Ozark on the Arkansas River, and Truman in Missouri, are the only other large, slant-axis installations in the Corps

Due to flaws in the origin design of these units, all have been subject to frequent failures.

"The slant-axis turbine designs were essentially vertical turbine designs oriented horizontally," said Conrad Miller, chief of Hydropower Branch. "The stresses unique to horizontal orientation caused the shafts and coupling bolts to crack repeatedly. Several engineering studies have pin-pointed the deficiencies in the original design, giving us hope that new turbines will operate more reliably with a proper design."

Ozark will be the first slant-shaft turbine powerhouse to go through a major rehabilitation. At this time, it is possible that the Webbers Falls plant rehabilitation also will be combined with the Ozark project.

Lessons learned from the Dardanelle Major Rehab Project completed in 2002 also are being applied to the work at Ozark.

A big lesson learned from Dardanelle that is being applied to the Ozark project is the need to have the powerhouse's overhead crane rehabilitated and ready before work begins.

Another lesson learned is the need to get the powerhouse staff and other people from Operations involved in the rehabilitation in the early phases.

Updated 07 July 2005:  The Crane rehab contract is underway, and the turbine replacement contract has been awarded. If all goes as planned, the turbine replacement will be complete by 2012.