Starting Monday, the company that owns Newport Avenue Dam will lower the water level a couple of inches per hour until it is low enough to investigate a recently discovered leak in the dam.
PacifiCorp discovered a leak in the dam Oct. 2, and Mirror Pond dropped by roughly 2 feet in the days that followed, turning much of the area into mudflats. The pond then rebounded briefly as water managers upstream adjusted flows in the Deschutes River to prepare for the end of irrigation season. The water level has since receded a second time, stabilizing around 2 feet below its typical winter level.
PacifiCorp plans to draw down the water even further starting Monday, to get a better look at the damaged area. How far the water will drop this week is unclear; workers will lower it until they can get a good look at the problem. The drawdown will likely take two to three days.
Though the inspection is this week, any repairs to the dam will probably happen later, which could mean water levels fall for a fourth time. In the past, dam operators have found and repaired three seemingly similar leaks in the last five years by bolting large sheets of metal to the more than 100-year-old wooden dam.
This is how Mirror Pond looked in March in a satellite photo taken when its level was approximately 2 feet higher. The silt buildup that is at the heart of the debate of whether to dredge Mirror Pond, partially dredge it, remove the dam and let the river run its natural course, or do nothing.
Contrast the March photo with aerial photos of the river as it is today.