Returning the Wanapum Dam to working order as quickly and safely as possible
When a crack was discovered at the Wanapum Dam Spillway the project owner, Grant County Public Utility District, immediately consulted with the Federal Energy Regulatory Commission (FERC), lowered the reservoir, and sought out help.
By drilling through the spillway, the team determined the extent and orientation of the crack. The solution? Post-Tensioned Anchors (PTAs) to repair the cracked monolith and mitigate the potential for further cracks. However, the drilling needed to be extremely precise to avoid hitting critical features.
To return the dam to working order as quickly and safely as possible, the first remedial action was to drill vertical drains that provided pressure relief for the lift joints. More than 100 lift-joint drains were installed in the spillway monoliths and then the PTA installation was sequenced to allow an intermediate pool raise, returning the fish ladders to normal operations. All while protecting culturally sensitive sites along the reservoir shoreline.
Through cooperation between the District, our team, construction contractors, and regulators, operations were back in full swing in just over a year after discovery of the crack.
At a Glance
- Award
- Engineering News Record (ENR) - Northwest's Best Project of the Year, Energy/Industry category, 2015
Gregory Rollins, Vice President, Energy
Always try to take the high road, no matter how difficult. It takes longer sometimes, but doing the right thing ultimately pays off.
Christina Brueckman, Senior Associate, Geological Engineer
Our projects are not cookie cutter designs—our dams group pushes boundaries on creativity and technology.
We’re better together
-
Become a client
Partner with us today to change how tomorrow looks. You’re exactly what’s needed to help us make it happen in your community.
-
Design your career
Work with passionate people who are experts in their field. Our teams love what they do and are driven by how their work makes an impact on the communities they serve.