Frog Pond, Advance Road development will tax existing infrastructure

by: JOSH KULLA - The existing sewer pump station at Memorial Park once had to have sandbags placed around it to avoid failure. Finding a site for a new wastewater pump station in Wilsonville’s Memorial Park is proving slightly more difficult than first expected.

Despite several public discussions on the matter involving the Wilsonville City Council, city public works staff and wastewater consultants, finding consensus on where to build a new lift station to serve existing and future residential growth has proven elusive.

A number of possible sites for the station have been considered, but none have garnered consensus among councilors tasked with making a final decision. As a result, city staff recently added several more options to the list.

Adding to the urgency of the project is the city’s desire to build the pump station concurrently with the planned overhaul of Memorial Park’s parking lot, which is slated to begin after Labor Day.

“We heard ideas for alternative locations, and we wanted to bring back a little more information,” Community Development Director Nancy Kraushaar told city councilors at a July 15 meeting.

According to City Engineer Michael Ward, the existing Memorial Park pump station was built in 1993 to feed the Boeckman Creek sewer line. It falls within the 100-year floodplain and, in 1996, city public works crews were forced to sandbag the station to prevent failure.

Computer modeling indicates the pump station will be near capacity with the build-out of the Frog Pond area and construction of future planned Advance Road schools. Taken together, staff anticipates reconstruction of a new pump station being necessary in two to five years.

A replacement pump station will cost anywhere from $1.4 to $2.5 million, depending on the location chosen. A plan with three suggested sites was first brought before the council in April.

Site A would be just uphill and to the north of the existing pump station, which currently sits next to the intersection of Memorial Drive and the parking lot of Memorial Park. Site B would see the pump station placed between the roadway and the north side of the park’s tennis courts. Site C places the pump station on the western edge of the park next to an existing fence separating the Daydream Ranch neighborhood from park property.

At a July 15 council work session, Kraushaar placed several more options in front of the council. They include a potential site next to the Stein-Boozier barn, which sits at the edge of Murase Plaza, as well as a site at the decommissioned Nike Well next to the city-operated community garden off Rose Lane.

Kraushaar said both new options are feasible but considerably more expensive to engineer and build. Both would require significantly deeper drilling, known as a trenchless bore, to accomplish.

“The first, the barn site, would require a 50-foot deep pump station, which is quite deep,” consultant Michael Carr said. “It’s feasible, but it’s not the easiest.”

Complicating matters even further is the city’s ongoing construction of a new wastewater treatment plant. Any new pump station sending wastewater to that treatment plant must first be ensured the latter is operational.

Kraushaar said it is best at this point to make mechanical improvements to the current pump station to squeeze more life out of the structure. This will allow the city to complete its updated parks master plan, a document that will lay out preferred locations for infrastructure such as the pump station.

For now, Kraashaur said, the city plans to maximize existing capacity, review its wastewater capacity requirements, identify a final site and begin design work.

“I would like to coordinate this with the parks master plan update,” she said. “But we’ve found that mechanical improvements can help get us through this with less of a need to act quickly. That will give us about six to nine months leeway, and at that point action will probably be needed from the council.”

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