Stantec, a sustainable design and engineering company, has completed the Priest Rapids Right Embankment Improvement Project in Mattawa, Washington, US.  

The infrastructure initiative has been carried out in partnership with Grant County Public Utility District No. 2 (Grant PUD) and IMCO General Construction. 

It will improve the dam’s safety and seismic resilience. It is now capable of withstanding a 7.1-magnitude earthquake. 

Priest Rapids Dam stores water for a hydroelectric powerhouse with a capacity of 950MW. Gradually, its right embankment started raising concerns about seismic stability. 

To address these issues, Grant PUD launched the improvement project. 

Grant PUD power production senior manager Dale Campbell said: “Completion of the Priest Rapids Right Embankment Improvement Project enhances the protection and preservation of the Wanapum people’s culture who live immediately downstream of the dam. 

“This investment in Priest Rapids Dam is strategically critical for our customers as it reduces Grant PUD[']s public safety and financial risk for the foreseeable future.” 

The new dam segment has been built using roller-compacted concrete.

Stantec's team designed and constructed a new downstream replacement dam, mitigating liquefaction risks associated with the existing foundation. 

Despite the project's complexity, Stantec completed the work a month ahead of schedule.  

Stantec Energy & Resources executive vice-president Mario Finis said: “We are thrilled to have successfully completed the Priest Rapids Right Embankment Improvement Project ahead of schedule. 

“Our collaboration with Grant PUD exemplifies our commitment to dam safety and community resilience. The project’s success was the result of a strong partnership spanning years of planning and dedication.” 

Recently, Stantec also announced the commencement of construction at the Bull Run filtration facility in Portland, Oregon.