Nicholson Construction was recently awarded a contract for significant repair work at Grant County Public Utility District’s Wanapum Dam in Central Washington.
Water levels behind the 55-year old dam had to be lowered by 26 ft for stabilization and repairs after a 65-ft-long fracture in the dam was discovered. Because of the lowered water levels, the dam is currently operating between 50 and 60 percent of its capacity.
The combination of the fracture in the dam and the lowered water levels has prompted $1.5 million in modifications to extend the dam’s fish ladders to ensure the safe passage of the spring salmon, which will migrate through the dam at a rate of 1,200 to 1,500 fish per day at peak. In the summer run, approximately 25,000 fish will migrate through the Wanapum Dam on a daily basis at peak. Overall repairs to the dam are estimated at $61 million.
Nicholson’s repair work on the dam includes coring in the gallery to map features, drilling and installing anchors at each pier, installing uphole drains in the gallery and installing bars on the ogee.
“We’re pleased to be part of the solution for getting Wanapum Dam back up and running at full capacity,” said Matt Johnson, Regional Manager, Nicholson Construction. “We are aware of the current impacts to local fish passage and tourism and we understand how important this project is to the community.”
All repair work on the dam is expected to be complete by the end of the year.