Seymour Falls Dam Spillway Gate

Seymour Falls Dam impounds a reservoir that supplies approximately one-third of Metro Vancouver’s drinking water. The new gate had to be installed while maintaining reservoir operations and protecting both a sensitive environment and a critical regional water supply. The gate’s location complicated the coordination of construction activities and limited personnel access, which had to be closely monitored. 

The gate also had to fit the geometry of a spillway built in the early 1960s. Its custom design required careful detailing of the seals, attachment to the heavily reinforced concrete structure, and a leak-free fit with the existing spillway. 

Norda Stelo developed a custom hydraulic gate concept tailored to the existing spillway. The solution incorporated environmentally friendly hydraulic fluid, access to hoisting equipment from the bridge deck level, easy attachment to the spillway, seismic isolation from the bridge deck, and vertical installation and operation. 

The team worked with the contractor’s surveyors and used 3D laser scanning and 3D modeling to adjust the design drawings and ensure an accurate, leak-free fit between the new gate and the existing spillway.  

The new gate provides greater flexibility for annual fish migration. It also improves operational safety by reducing the need for workers to access the reservoir and spillway areas. 

The solution successfully integrated the new gate into an existing spillway structure built in the early 1960s while maintaining reservoir operations. Coordination among Metro Vancouver, the contractor and the design team minimized the required shutdown time and reduced the capital cost. 

• All the specific elements of the project that deserve to be mentioned. (Innovations, extraordinary elements, unique or ingenious solutions, etc.). 
• Design of a hydraulically actuated spillway gate integrated into an existing structure built in the early 1960s. 
• Use of 3D laser scanning and 3D modeling to achieve an accurate, leak-free fit. 
• Use of environmentally friendly hydraulic fluid. 
• Seismic isolation of the gate from the bridge deck. 

• Electrical
• Mechanical
• Structural