Work continues on Wanapum Dam spillway

BEVERLY - Grant PUD and its contractors continue to work on the 800-foot-long Wanapum Dam spillway to prepare for final reinforcing repairs required after discovery of damage this spring.

Various types of drilling are underway, according to Public Information officer Thomas Stredwick. Crews prepare for repairs expected to be approved by the Federal Energy Regulatory Commission (FERC).

This drilling work is the most time-intensive phase of the repair process, Stredwick said. Holes are being drilled throughout the spillway in anticipation of installation of high strength cables (known as tendons) from the top of the dam into the bedrock below.

Repairs will also likely include additional reinforcing anchor bars in the upstream and downstream sides of the spillway. Thousands of pages of technical data outlining repair plans require the FERC approval prior to being implemented.

All repairs will occur over the summer allowing the utility to increase the river elevation in the fourth quarter of 2014, Stredwick said. He added that costs are still on the track of the original $61 million estimate.

According to Stredwick, fish passage modifications to both of the dam's ladders have proven effective. They have allowed the PUD to suspend the trap and haul operation for migrating adult fish.

More than 23,500 spring Chinook adults have migrated upstream successfully. Spiral flumes have been added to the existing fish ladders in anticipation of the record-breaking sockeye, summer and fall Chinook runs. As of June 22, more than 7,000 sockeye and 13,000 summer Chinook have been counted passing Priest Rapids Dam.

Excavation and pile-driving work is near completion on both the Vantage and Frenchman Coulee boat launches, Stredwick said. The improved sites will be available to the public by the 2015 Memorial Day weekend.

Current low-river conditions have allowed the utility to expedite these projects at a decreased cost to customers.

The 38-mile stretch of shoreline from above Wanapum Dam to below Rock Island Dam will continue to be closed as a precaution for public safety and to protect culturally-sensitive sites. The shoreline will remain closed until repairs to Wanapum Dam are in place.

While there may be some portions of the shoreline that appear safe, the velocity of water moving through the narrow river channel, and sandy banks creates hazardous conditions for the public, Stredwick said.

Wanapum Dam remains stable and is operating at approximately 50 percent capacity.