The corporation that owns Newport Avenue Dam does not expect to begin its inspection of a recently discovered leak for at least another week, a PacifiCorp spokesman said Thursday.
Spokesman Bob Gravely said the company is still working its way through regulatory matters and developing a plan for safely lowering water levels to allow inspectors access to the dam. Mirror Pond, the body of water at the heart of Bend, should remain at or near its current level — about two feet below normal, until the hole is fixed.
“I think this leak is such that with the flows as they are — and as is kind of typical for this time of year — we don’t think we can raise the water level without doing something about the leak,” Gravely said. “It is a bit like the drain in the bathtub effect; if the drain is open, you can only get so much water in the bathtub.”
PacifiCorp, a multi-state utility that operates in Oregon as Pacific Power, has patched smaller holes in the dam three times in the last five years. Past repairs were made by bolting a large piece of metal over the hole; a technique called sheet pile, Gravely said. Sheet pile is effective, he said, and a sheet pile fix would allow PacifiCorp to resume hydroelectric generation. But with the dam now more than 100 years old, continued age-related deterioration is likely, he said.
“It sounds easy enough to go fix this, but we could be right back here in eight months or a year and a half from now,” he said. “It’s the roof analogy: How long do you keep patching leaks in the roof before you take a look at (replacing) the roof.”
Gravely declined to estimate the cost of repairing the latest hole, how long it would take PacifiCorp to make the decision or complete the repairs.
Along with extensive mudflats along the river channel, the lower water has exposed the poor condition of the rock walls marking the typical high water line. Jim Figurski with the Bend Park & Recreation District said the crumbling walls present a potential safety hazard.
“We’re evaluating the conditions there and looking at it. And if there’s a decision it’s really unsafe, it’ll probably get taped off,” he said. “But, we haven’t made that determination yet. “
Figurski, who has been heading up the park district portion of the larger community conversation about silt accumulation in Mirror Pond, said nearly every proposal under consideration calls for removing most of the rock wall along the edge of Drake Park in order to create a more natural riverbank. The walls are not well built, he said. And in some locations have allowed water to seep in beneath nearby footpaths. Earlier this year, the park district tore up paver bricks along a long section of the path that had become buckled due to water seepage, Figurski said.
Although PacifiCorp’s long-term plans for the dam are still unknown, the park district has been exploring the possibility of a water rights transfer that could allow the dam to remain, even if the utility abandons power generation at the site. Figurski said although PacifiCorp’s water rights require the dam be used to produce electricity, the park district has asked state agencies about a modification that would allow the dam to remain solely for the purpose of maintaining Mirror Pond.
Source: The Bulletin ©2013