The Bend City Council in Oregon adopted the Outback Facility Plan in May, a wide-ranging roadmap for upgrading the Water Filtration Facility (WFF) that supplies most of the city’s drinking water. The centerpiece of the plan is a new surface-water pretreatment system, with officials describing it and other near-term improvements as an estimated $60 million investment intended to keep the plant running through natural disasters and drought.
The plan looks well beyond the city’s immediate needs, laying out a roadmap that considers infrastructure through 2045 and the years that follow. Rather than focusing on a single fix, it approaches the Outback site west of Bend as a long-term water-supply campus that could grow and adapt over time.
The site already anchors much of the city’s system, housing the WFF and seven active groundwater wells. Under the plan, it would gradually take on a wider role, with new facilities added in stages as funding allows and as conditions warrant.
At the heart of the plan is a new water pretreatment system, built ahead of the plant’s existing membrane filters to add a layer of protection the facility does not have today. The setup would pair a pre-sedimentation pond with a plate-settler facility, both housed in a new pretreatment building.
The plan notes that water drawn from Bridge Creek is usually clean enough to skip pretreatment altogether. The concern is what happens during extreme events. Wildfire and heavy seasonal rain can send debris and sediment into the supply, with past runoff having pushed it high enough to overwhelm the membranes and take the plant offline, leaving the city to lean on its groundwater wells. The new system is designed to ease that strain, clearing out solids before filtration so the plant can keep running.
The plan estimates the pretreatment work at about $48 million. Of that, about $33.7 million covers the building and its treatment systems, while about $14.4 million goes toward site and civil improvements.
Those figures run higher than a 2020 study had projected. The plan attributes the increase to inflation along with a few design changes. Among them are an added treatment channel for backup and a shift toward a full operations building rather than a simpler structure.
The plan also calls for a small hydropower system that would generate electricity from the city’s existing water pipeline. Water flows about 1,000 feet downhill under heavy pressure on its way to the plant, with that energy currently bled off and lost. Under the plan, a turbine would capture it instead, powering the plant and producing about 1.3 megawatts.
Beyond offsetting energy costs, the plan notes the turbine system could lower the city’s carbon emissions and, under one design, keep the plant running on its own power during an outage. The turbine cost estimates range from about $7.6 million to $10.6 million.
Beyond the pretreatment and hydropower work, the plan outlines a broader set of improvements for the site. They include on-site generation of the chemicals used to disinfect the water, drying beds to handle treatment residuals, reservoir replacement and repairs, expanded groundwater wells and new piping. The plan also reserves space for a future system to treat per- and polyfluoroalkyl substances (PFAS) should the contaminants ever turn up in the supply.
Most of those projects are not slated for the near term. The plan stages them as midterm needs or holds them in reserve, to be advanced only as aging equipment, demand or new regulations call for them.
The pretreatment system and hydropower facility sit at the front of the line, with design slated for 2027 and construction the following year. Coordinating the two projects is meant to limit disruption at the site.
Much of the plan’s timeline hinges on land the city does not yet own. The improvements depend in part on a pending transfer of 48 acres of Deschutes National Forest land next to the filtration facility, which the city is seeking under the Townsite Act.
Photo by Jos van Ouwerkerk from Pexels
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