Nov. 22, 2018. Repairs to the Newport Avenue Dam in downtown Bend are now complete. Aiming to fix a small leak that was discovered on Oct. 10, construction crews started work on Nov. 13 and they finished this Wednesday, the day before Thanksgiving.
Pacific Power, which owns and operates the 108-year-old dam, says that the leak “posed no safety risk and does not impact the structural integrity of the dam,” but that it made it difficult to maintain normal water levels for Mirror Pond. As for the source of the seepage, the utility company blames an old wooden panel that was installed 25 years ago to seal an outlet that is no longer used.
It’s not all that difficult to picture a leak forming here and there, especially when looking at the wooden structure from the downstream side. Some of the boards are rotten, others washed away for good. But, dilapidated as it may look, the dam has become an integral part of the landscape.
Built in 1910 by the Bend Water, Light and Power Company, it was the town’s initial source of electricity and the first project of its kind in Central Oregon. It still produces hydropower, but not much. Of the six hydroelectric power plants operated by PacifCorp (Pacific Power’s parent company), the output of Newport Ave. Dam is negligible, providing about one-tenth of one percent of the whole system’s power potential. The dam’s real benefit—perhaps it’s only benefit, some would argue—is that it backs up a stretch of the Deschutes River to form Mirror Pond, one of the most emblematic landmarks of downtown Bend.
Of course the iconic shallow pond faces the same problem as any other man-made urban reservoir: siltation. A century and more of silt continues to build on top of itself, making the pond shallower each year. The City Council has brought up the idea of dredging it, perhaps redesigning it. Pacific Power has even considered ditching the pond altogether. Why? Because the aging dam that impounds it tends to leak.
First in 2008, then in 2009, 2013 and 2014, and now again in 2018, the wooden face of the dam continues to show its age, springing leaks as seeping sunspots and dripping wrinkles are exposed. Playing the part of plastic surgeon, Pacific Power has continued to update and overhaul the structure. Their strategy over years has been to cover up these blemishes with interlocking steel sheets, known as “sheet pile”. And so far, the utility company says, that technique has worked.
In order to properly install the sheet pile, the utility first lowered the level of Mirror Pond by about three feet and assembled a large crane on site. Workers then used the crane to install the long, interlocking pieces of steel on the upstream side of the structure, effectively shielding the weakened wood from the river’s perpetual attempts to slip through.
Tom Gauntt, a spokesman for Pacific Power, says that the utility took all the necessary steps to secure state-issued permits for the project, and that they did not expect it to have any serious environmental impacts on either Mirror Pond or the stretch of river downstream. “There is a third-party inspector monitoring turbidity and all of that,” Gauntt says, “and during re-fill, they’ll have a biologist on site to watch for any fish strandings.”
The utility company is confident that this will be the last repair of its kind on the dam because, as Gauntt told the Bend Bulletin last week, “this is the last section of dam that hasn’t had [the sheet pile] installed.”
Gauntt says that construction workers finished installing the sheet pile ahead of schedule on Wednesday, and that Pacific Power will start re-filling the pond next Monday after the long holiday weekend.
