MATTAWA – An examination of a cracked pillar at the Wanapum Dam is expected to take nine days.
Grant PUD hired Spokane-based Kuney-Goebel JV to investigate the pillar, which supports the dam’s spillway.
The spillway is the section of the dam which allows water to bypass the turbines and travel past the dam.
The contractor is drilling into the pillar along with using radar and sonar to discover more information about the crack, PUD spokesman Chuck Allen said.
The crack was discovered on Feb. 27 after an employee noticed a section at the top of the dam had shifted. Divers found the crack extended across the entire length of the pillar. An inspection of the dam didn’t find any other damage.
The utility, the Federal Energy Regulatory Commission and a board of independent consultants will examine the information to determine a way to fix the pillar.
The PUD is exploring an option to drill through the pillar and stringing a steel strand through the hole, Allen said. The strand would be anchored to the bedrock beneath the pillar, and held in place with a special grout.
“We’re looking at this as a possible fix,” he said. “We also have the independent board of consultants and (FERC) who will do their own analysis and make their own recommendations … Given the information we have right now, this is a possible solution.”
The PUD, along with the state Department of Ecology, is continuing to work with businesses using the water from the reservoir for irrigation. The drop in water level behind the dam stabilized it, but left some orchards without the ability to take water from the reservoir.
The two groups are working to provide technical assistance and information the orchards need before the upcoming irrigation season.