The Mikana Dam in Barron County, Wisconsin, consists of a split-leaf gate that is operated by a hand wheel, along with an old 4-foot-diameter penstock that has a 5-foot-wide steel bulkhead at the head of the penstock.
The split leaf gate was difficult to operate with only the hand wheel, removal of the steel bulkhead required heavy equipment, and the penstock is a heavily corroded corrugated metal pipe embedded in concrete. Replacing this pipe would require significant demolition of the dam’s abutment, and the County desired an in-place repair.
Ayres evaluated several options to repair the pipe and selected a cured-in-place pipe lining. The final project included the underwater installation of a new stainless steel slide gate, the penstock lining, and installation of a motor, gear box, and controls to operate the split-leaf gate.