Repairs to Bend’s Mirror Pond dam complete

Repairs to Bend’s Mirror Pond dam complete

By Scott Hammers | The Bulletin

PacifiCorp has completed repairs to the Mirror Pond dam, a spokesman said Wednesday, and believes water levels in the pond should return to normal this summer.

The recent repairs were prompted by a leak in the dam that emerged in early October. Within days of the discovery of the leak — described as a basketball-sized hole below the normal waterline — Mirror Pond began dropping, exposing wide mudflats that extended through Drake Park and upstream of the Galveston Avenue Bridge.

PacifiCorp, the owner of the dam, inspected the damage and concluded the century-old dam was too damaged to warrant further repairs. In late November, the company announced it was ready to decommission it or transfer it to another entity.

In February, the utility reversed course and agreed to repair the dam.

Spokesman Bob Gravely said Wednesday that crews completed nearly all of their work Friday, driving large pieces of metal sheeting into the bedrock beneath the upstream side of the dam. Gravely said because the equipment and crews were available, PacifiCorp also added sheeting to another two of the 13 wood and rock “bays” that make up the spillway visible from the Newport Avenue Bridge.

During last fall’s inspection, the two bays added to the repair operation were found to be holding water but in danger of failing, Gravely said. Six of the 13 bays in the spillway have now been repaired using the same technique in recent years. Gravely said discussions between PacifiCorp and the Bend Park & Recreation District about the district’s possible acquisition of the dam have been temporarily suspended until the district’s inspection report is complete.

“On hold would be the wrong word, but once the Parks Department decided to do its own inspection, I think both sides agreed it would make sense to wait until both sides had their own sets of numbers and projections before continuing the talks,” he said.

Gravely said PacifiCorp repaired the dam even though officials believe the new leak was allowing too little water through to affect the level of the pond once the Deschutes River returns to full summer flows. Water running through smaller leaks in the dam tends to displace the timbers and rock inside, he said, creating larger leaks if not repaired.

“Anything I guess could still happen, but this will significantly increase the likelihood that the dam will maintain the water levels for the foreseeable future,” he said.

Source: https://www.bendbulletin.com/localstate/1928314-151/repairs-to-bends-mirror-pond-dam-complete

Central Oregon City Club hears Mirror Pond options

Repairs to leaking Bend dam underway

By Scott Hammers | The Bulletin

Three alternative solutions for the future of Mirror Pond were presented Thursday at a meeting of the City Club of Central Oregon.

The City Club invited a panel to make the case for the three possibilities under consideration by the Mirror Pond Ad Hoc Committee, a group made up of representatives of the city of Bend, the Bend Park & Recreation District and the general public.

Formed last fall primarily to look into what should be done about silt accumulating in Mirror Pond, the group’s focus has shifted with the emergence of a leak in the Mirror Pond dam, and the announcement by PacifiCorp that it is no longer economically feasible to use the dam for power generation.

Separately, PacifiCorp began repairing the leak Thursday, a process spokesman Bob Gravely said should be complete by Tuesday.

At the City Club event, Bend City Councilor and ad hoc committee member Victor Chudowsky said he and the other members of the council have committed to preserving Mirror Pond but are committed to keeping the current dam only if viable. David Blair argued for a hybrid alternative that would maintain the level of the pond, while replacing the dam with a new structure. Ryan Houston of the Upper Deschutes Watershed Council described the ecological benefits of dam removal and a free-flowing river.

Scott Wallace, chairman of the Bend Park & Recreation District Board and the Mirror Pond Ad Hoc Committee, provided a brief overview of the construction of the dam and an update on the status of an independent inspection of the dam commissioned by the two groups. He said the inspection report should be complete by early April and should include some estimates of what it would cost to repair and maintain the dam.

Chudowsky recalled how he first discovered Bend while on vacation years ago and spotted a large group of people swimming in the river near the Galveston Bridge. Mirror Pond may be an icon, he said, but it’s not just a pretty view — it’s something people use, he said, with an estimated 90,000 floaters and paddlers using the river between the Old Mill District and Drake Park each summer.

Chudowsky said removing the dam would narrow the river and quicken the current, drastically altering how locals enjoy the river today.

“Let’s remember those tens of thousands of floaters, many of them are young people, teenagers,” he said. “They don’t vote, they’re not going online to fill out questionnaires, they’re not at the City Club — they haven’t been a part of this conversation.”

Chudowsky said the city and the park district will need to carefully assess the inspection report to make sure they’re not assuming a massive liability if they choose to move ahead with acquiring the dam from PacifiCorp.

Houston said the case for removing the dam for environmental reasons isn’t particularly strong. Of the 10 dams along the Deschutes River from its source in the Cascades to the Columbia River, the Mirror Pond dam would probably rank around eighth in terms of its adverse effect on the health of the river.

The choices facing the community on Mirror Pond are really more about economics than anything else, Houston said. For 100 years, Bend residents have enjoyed the benefits of the pond created by the dam without being asked to pay for it, he said. With PacifiCorp ready to give up on the dam, residents need to decide whether preserving the pond is worth it — and how much they’re willing to pay.

With a price tag estimated at around $7 million, removing the dam would be cheaper than other alternatives that would require ongoing maintenance, Houston said, but it would radically alter the pond without providing significant environmental benefit.

“It’s not where I would put my first $7 million, if I had $7 million to spend on river restoration on the Deschutes,” he said.

Blair said although the hybrid alternative removes the dam, the area from Drake Park upstream wouldn’t have to look like it did this winter, when the combination of low water and the leak in the dam exposed wide mud flats on both shores.

The proposal outlined by Blair would include the removal of the dam and the construction of a dam-like structure a few hundred yards upstream that would allow floaters and paddlers to pass through. Downstream, the river channel could be sculpted, possibly with a series of dropping pools, he said, while upstream, a series of sediment traps could be built to allow for easier removal of silt.

Blair said it’s been difficult to draw up a firm estimate of what the hybrid option would cost. He encouraged the park district and the ad hoc committee to consider it a serious alternative and proceed with the studies needed to compare it side-by-side with preserving the dam.

Much of the discussion on how to proceed with Mirror Pond has been bogged down with talk of water rights and other permitting issues that appear to make some alternatives impossible, Blair said. As any of the alternatives under consideration would probably require intervention by the state Legislature, the community should instead focus on what it wants, he said, and stop being “intimidated” by supposed regulatory hurdles.

“We will create a great place, no matter what,” he said.

https://www.bendbulletin.com/localstate/1904600-151/city-club-hears-options-for-mirror-pond

A close look at Bend’s Mirror Pond dam

The committee looking into what should be done with Mirror Pond got an up-close look at the leaking dam there Wednesday, joining representatives of Pacifi­Corp on a tour of the more than 100-year-old facility.

The ad hoc committee, formed last fall, includes representatives from the city of Bend, the Bend Park & Recreation District and the general public. It will weigh in on the relative merits of dredging the pond, keeping the dam, which is owned by PacifiCorp, removing the dam and other alternatives.

The group’s tour came one day before a team of consultants hired by the park district is due to arrive in Bend to inspect the dam. PacifiCorp has been lowering the level of Mirror Pond in recent days to allow for a safe inspection, but water levels should be headed back up this weekend.

Jim Figurski, the head of the park district’s efforts on Mirror Pond-related matters, said the inspection should provide a better idea of what kind of maintenance costs the city or park district would have to bear if they were to acquire the dam from Pacifi­Corp. PacifiCorp has committed to repairing a hole that opened up in the dam last fall, dropping water levels to nearly 7 feet below seasonal normals, but is looking to divest itself of the dam as a generation facility.

“Part of the analysis is what would we need to do for a 50-year or more fix, not just a 10-year fix or a near-term fix,” Figurski said.

He expects the consultants will have a complete report for the committee by the end of the month.

On the back deck of the powerhouse, members of the tour group learned Wednesday how the gates at the base of the dam can be manipulated to control how much water flows out, allowing the dam operator to maintain Mirror Pond at a consistent elevation.

They peeked into buckets of bottles, cans and old tennis balls that are scattered across the dam property, all of them retrieved from the pond above the dam with the help of a long-handled net.

Descending a ladder to a wide lawn hemmed in by the dam on the upstream side and barbed wire on the downstream side, the group examined a now rarely used gate at the north edge of the spillway, where boards can be removed to discharge ice and debris into a crudely constructed rock and concrete sluice gate.

Water seeps through several points along the concrete dam face, nourishing thick cushions of moss sprouting from the stained walls, and as suggested by the footprints dotting the mud below, a handful of raccoons and other small animals that find their way through the fences.

Mark Tallman, vice president of renewable resources for PacifiCorp, said the seepage is a cosmetic problem more than a safety issue.

“The dam is just like a drafty house, it’s just old,” he said.

Visitors donned fireproof suits before venturing inside the powerhouse, where three large generating wheels sat idle Wednesday on account of the lowered water levels. When turning, the three generators can produce enough electricity to power 300 to 400 homes.

Tallman told tour members the powerhouse is still potentially dangerous even when the generators aren’t spinning due to a live power line running across the ceiling that — under the right circumstances — can throw off high-voltage arcs. The controls for the adjacent substation are also inside the powerhouse, Tallman said, cautioning the visitors to avoid touching any of the equipment.

“It is possible, if you accidentally touch or move the wrong handle, you could put Bend in the dark,” he said.

Scott Wallace, a member of the park district board and a member of the ad hoc committee, said he expects the behind-the-scenes tour will prove useful once the engineering report is complete. Until Wednesday, Wallace said he only had a hazy idea of what went on at the Mirror Pond dam.

“I grew up in Bend, and this is the closest I’ve ever come to the powerhouse,” he said.

City Councilor and committee member Victor Chudowsky said he was impressed by the architecture of the powerhouse. If the city or the park district acquires the dam someday, it would be ideal if the powerhouse could be preserved, he said, possibly as some kind of small museum where visitors could learn about how electricity is generated and about a notable piece of Bend history.

Chudowsky said the tour confirmed much of what he already knew — that the dam is old, and in places, starting to fail. Though its days as a power generation facility may be numbered, the dam may still be the easiest and least expensive way to preserve Mirror Pond into the future, he said.

“Really, what we need to be deciding is, is this an asset or a liability, then go from there,” Chudowsky said.

— Reporter: 541-383-0387, shammers@bendbulletin.com