The Willamette River Water Treatment Plant was built as a long series of buildings in a row, each joined by sections of a wall with creative stone-faced or concrete surfaces.

Despite its nearly 800-foot length and secure appearance, the facility in Wilsonville, Oregon, is widely open to the public’s view and draws people in to its operation. Varying in height to accommodate the different buildings as it slopes to the river below, the attractive wall separates the treatment facility from a public park and provides an educational portal into the plant’s operation and functions.

Strategically placed windows and openings along the wall let park users look in and see the gallery of pumps, pipes, valves and other equipment related to processes such as disinfection, clarification, sedimentation and filtration.

A look inside

An 8-foot-tall, 6-foot-wide, four-panel, tempered glass window under an overhang provides a clear and protected view into the filtration gallery. Next to it, a window-height marble inlay depicts the function of a carbon and sand filter. Similar multipanel windows reveal the finished water pumps area; others wrap around the raw water pump station.

Interpretive displays mounted with brackets behind laminated glass panels with spotlighting describe the role each component plays in water treatment. “They are like big picture windows so the public can see what’s going on in the plant,” says Kim Reid, operations manager for Veolia North America, which runs the plant under a contract. 

A flowing water feature, highlighted by a cascading pond and waterfall, complements the cast-in-place concrete wall and runs parallel to it. A 6-foot-wide concrete walkway between the wall and the water feature provides access to the wall and its portals. The walkway loops all the way around the park.   

The flow begins with a waterfall at a high point just outside the administration building and moves by gravity through a series of five landscaped ponds cascading toward the Willamette River, the plant’s water source 200 feet below. A Flygt Model 3120 submersible pump recirculates the river water from a recovery well below back to the overflow pond. 

“The water feature mimics the Willamette River with its cascades, channel and quiet ponds,” Reid says. “To many, it’s really the focal point of the park.”

Diverse materials

A variety of facades and materials add to the wall’s attractiveness. Structural brick masonry, clear anodized aluminum, cedar horizontal lap siding and the controlled growth of clinging ivy add an artistic element to the wall. Potential rain-staining of the wall is prevented by galvanized caps on the top.

The landscape of boulders, architectural stone, a variety of crushed stone and gravel, native grasses and shrubs visually blend the wall and ponds into the park. A paved trail connects a neighboring residential area with the plant and the park.

The 10-acre Willamette River Water Treatment Plant Park and the 15 mgd treatment plant were built together in 2002. The decision to build the new plant to polish river water, rather than drill more wells to meet demand, involved collaboration and community input.

The original plan was to use the entire site for the treatment plant, which is co-owned by Wilsonville’s partner in the plant — the Tualatin Valley Water District. The inclusion of the park meant reducing the plant’s footprint by using innovative and space-saving processes, such as Actiflo high-rate clarification and sedimentation (Veolia). Building the plant along the wall reduced the space required.

Part of the administration building is an open-sided meeting room used by city staff and neighborhood groups that overlooks the first waterfall on the park side of the wall. Two covered picnic areas enable park users to sit and overlook the meadows in the park and the river below.

“The wall could have been built strictly for security,” Reid says. “But rather than isolate the public from the plant, the wall draws them into its operation.”