Grant PUD close to completing repair work at Priest Rapids Dam

EPHRATA — The water levels behind Priest Rapids Dam, lowered in response to leaks discovered in March, could be raised back to normal operating levels before the end of the year. Repair work should be completed within the next month, said Rich Wallen, director of power production for the Grant County PUD.

“We’ll do some more drilling for instrumentation install, but drilling for drainage is complete,” Wallen said in answer to a question from PUD commissioner Terry Brewer.

Utility district officials discovered the problem when drilling test holes, a precautionary measure after a crack was discovered at Wanapum Dam in 2014. The test revealed some leaking, and prompted more testing.

“To date about 230 of those core samples have been drilled,” Wallen said. The leaks were “much more isolated to (spillway supports) 17, 18 and 19, but some small indications throughout.”

During the next month PUD and contractor crews will be installing instruments “that will help better monitor any spillway or monolith movements,” he said.

“We’re really hopeful that once we get that instrumentation installed we’ll be able to work back to FERC (the Federal Energy Regulatory Commission) and raise the operating pool back to normal operating band (water level).”

Cheryl Schweizer can be reached via email at education@columbiabasinherald.com.