Aging Mirror Pond dam passes routine structural safety inspection

Jul 14, 2012

Bend Bulletin

Aging Mirror Pond dam passes routine structural safety inspection By Dylan J. Darling / The Bulletin

A state dam inspector examined Mirror Pond dam Friday and found no immediate causes for concern in the century-old structure just downstream of the Newport Avenue Bridge.

“For an old dam of this size, it is in a condition you would expect it to be,” said Keith Mills, dam safety officer for the Oregon Water Resources Department.

He spent about an hour on and around the dam, photographing it and taking notes. PacifiCorp, a Portland-based power company, owns the small hydroelectric dam.

The dam was due for a regular state inspection.

The dam creates Mirror Pond, the signature waterway of Bend that is subject to ongoing discussion about how to remedy its silt buildup. One of the options mentioned in the talks among stakeholders is removing the dam and reopening the river, although city officials have said draining Bend's icon is highly unlikely.

Along with creating Mirror Pond, the dam produces about one megawatt of electricity, enough power to supply about 500 homes, according to PacifiCorp.

The company plans to keep the dam, and power production, in place “as long as it is in the economic interest of our customers,” said Bob Gravely, PacifiCorp spokesman. Friday's inspection didn't reveal anything to change the company's stance.

While the federal government regulates large power dams, like the Pelton Round Butte dam complex on the Deschutes near Madras or the dams on the Columbia River, the Water Resources Department keeps tabs on small power producers and irrigation water diverters. The inspections are done every three years.

The dam was one of seven that Mills, who works out of Salem, inspected this week during a trip through Central Oregon. After finding no reasons for immediate repairs he said he will now further review his photographs and compile a report on the dam by the end of the year.

PacifiCorp is involved with both the Mirror Pond Management Board and the Mirror Pond Steering Committee, which are groups of stakeholders trying to determine what to do about silt buildup in the pond. The silt is creating ever-growing mud flats, clogging the Deschutes River as it passes through Mirror Pond.

Along with the power company, the city and the Bend Park & Recreation District, the stakeholders include neighborhood associations, watershed restoration groups and William Smith Properties, which owns the Colorado Avenue dam upstream of the pond.

In 1984 the solution was to dredge the pond at a cost of $312,000. A 2009 study estimated dredging would now cost between $2 million and $5 million. Recent discussions have centered on how to fund further study of a dredging project.

Last month an Oregon Department of Fish and Wildlife fish biologist told stakeholders that fish would benefit from the removal of the dam and the reopening of the river. City and Park & Recreation officials rebuffed the idea.

At the time, Bend City Manager Eric King said it would be hard to find support for the removal of the dam and the end of Mirror Pond.

“I think Mirror Pond is an iconic symbol of Bend,” he said.

PacifiCorp will stay involved in the larger talks and work with the stakeholders to decide how to tackle the silt situation, Gravely said.

“That's not going to be a company decision,” he said. “That is going to have to be something that the community is heavily involved in.”

— Reporter: 541-617-7812,

ddarling@bendbulletin.com

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