PacifiCorp moves up Mirror Pond dam repairs

A large construction crane and materials needed to perform a planned reinforcement of the company’s dam in downtown Bend will be in place in time for the work to be completed next week, ahead of schedule, PacifiCorp officials said Tuesday.

Addressing a leak in one of the structure’s wooden panels, which developed in October, had been planned for April.

The timeframe has been moved up due to the company securing necessary permitting more quickly than anticipated and the availability of the crane and contract work crews. No change in either the leak or overall condition of the dam has been detected, officials said.

“Nothing has changed with the dam,” said Mark Tallman, PacifiCorp’s vice president for renewable resources. “This is simply an occasion where permitting and contractor availability has allowed us to move up planned work, and we want to take advantage of an opportunity to get this done.”

The work involves driving long pieces of interlocking steel sheets, known as “sheet pile”, into the river bed to create steel facing on the upstream side of the leaking panel. The method was successfully used in 2008 and 2009 to reinforce other sections of the dam.

The crane is en route to Bend and will be assembled in the parking lot on the south side of the river across from the Bend dam and powerhouse, in a safe, restricted work area.

The actual installation of sheet pile is planned to begin as soon as Friday, and be completed by the end of next week.

The company will not need to lower Mirror Pond water levels to accommodate the work, officials said.

PacifiCorp has said it wants to hand over the more than century-old dam to another entity as it is no longer cost-effective to operate to generate power. The city, park district and community have been involved in discussions with the utility over how to proceed, complicating an already-lengthy process that began with a need to remove silt that periodically builds up in the well-known pond