Pacific Power agrees to fix Mirror Pond dam leak

PacifiCorp announced Tuesday it will reinforce a section of the company’s dam in downtown Bend to address a leak in one of the structure’s wooden panels that developed in October last fall.

The installation of steel sheet pile upstream of a leaking panel is planned to begin in April, at an estimated cost of $250,000.

The company stopped generating power at the dam after the leak was discovered. In November, the utility announced it had decided it is not cost-effective to rebuild the entire facility to generate power for current and future generations of customers across its six-state territory.

PacifiCorp has since been in formal discussions with Bend Parks and Recreation and the city of Bend regarding a potential transfer of the dam to a local entity for the purpose of maintaining the Mirror Pond impoundment.

“Though the dam remains safe, we fully understand the community’s concern about the potential for low water levels during summer recreation months,” said Mark Tallman, PacifiCorp’s vice president for renewable resources.

“It’s possible Mirror Pond would have remained full this summer without this fix, but in our view, this is the right action to take at this time.” Tallman said. “This reinforcement is also anticipated to restore hydro generation for the year, and should provide the community with more certainty about the structure and Mirror Pond during the summer season and going forward.”

The company used the sheet pile technique previously to address similar leaks in other wooden panels, known as bays, most recently in 2008 and 2009, said utility spokesman Bob Gravely.

The reinforcement work involves driving long pieces of interlocking steel sheets into the river bed to create steel facing on the upstream side of the leaking panel.

“This action will also facilitate further discussions with community leaders to determine if an agreement can be reached that enables PacifiCorp to clearly demonstrate that placing the dam under local control is better for all our customers than dam removal or other alternatives,” Tallman said.

Gravely said the reinforcement work is “very similar” to the two projects done a few years ago.

“For one, we went ahead and reinforced a few adjoining wooden bays because it was clear they were deteriorating,” he said. “For the other, we reinforced one panel — just like we will do with this one.”

In the utility’s announcement, Scott Bolton, PacifiCorp’s vice president for community and government relations, said, “The company is very committed to trying to find the best possible outcome regarding this facility that balances the community’s priorities for Mirror Pond and our regulatory obligations.”

“That includes taking steps like this reinforcement as part of our community commitment, and our support of efforts by community leaders to preserve Mirror Pond’s future,” Bolton added.

“We are hopeful an agreement can be reached that allows this to happen and also protects the interest of our rate-paying customers in Bend and throughout our six-state service area,” the utility official said.

The Mirror Pond Ad-Hoc Committee meets at 1 p.m. Wednesday at the Bend Parks and Rec headquarters.