Overview
Ballard was contracted by the City of Pasco, Washington for the design-build of the Butterfield Water Treatment Plant renovations and repairs. This included review of engineering and constructability plans, preparation of installation drawings, flow analysis, and the procurement of an engineered schedule to avoid intake shutdowns.

Scope of Work
Ballard removed four existing sluice gates in the intake structure, plugging two of them, and installing two new valves. HDPE intake lines and two fourteen-million gallons per day stainless steel intake screens were also installed within this process. This project required dredging of the existing river bottom for placement of the 32,000-pound concrete anchors. Once the piping install was complete, Ballard placed forty cubic yards of river rock to anchor the piping in place. Included in the intake screen installation was the complete renovation of the pumps, controls, and mechanical system of the Butterfield Water Treatment Plant.

Challenges and Solutions
The installation was performed by divers in extremely cold weather, high velocity, and unpredictable current conditions. Preassembly of the pipe and concrete anchors reduced the construction schedule and maximized the diver’s efforts underwater.

Results
The intake structure and mechanical system renovations handled by Ballard within this design-build provided Butterfield Water Treatment Plant with a more reliable and efficient intake than the dated system that was removed. The expert dive team and surface support completed the retrofit according to the engineered schedule to mitigate the intake interruptions throughout the construction process.