Prineville built a 120-acre wetland instead of a new wastewater plant; the Oregon system cost $7.7 million and saved the city $54 million versus conventional treatment

Prineville, Oregon, is a high-desert town of roughly 11,000 people, tucked into a valley near the Ochoco National Forest. Population growth began outpacing the town's wastewater capacity around 2004 and 2005, and that pressure only grew when Facebook opened its first Prineville data center in April 2011, with Apple following later, according to the USDA Rural Development news release. The town's existing wastewater facility, constructed back in 1960 for a town of only 3,000 people, couldn't keep up. According to the EPA's Clean Water State Revolving Fund case study on this project, constructing a conventional plant would have cost the city $62 million. Instead, the town built a wetland.

Why a swamp made more sense than a treatment plant

Conventional wastewater treatment plants rely on pumps, chemicals, and mechanical systems that are expensive to build and even pricier to expand as a city grows. The USDA release explains that the city laid new sewer lines, built a new pump station, and upgraded its existing lagoon system with the help of a $4 million USDA Rural Development loan and a $1 million grant through the agency's Water and Waste Disposal Program. The wetland was part of this treatment system.

How the Crooked River Wetlands actually works

Rather than sending the wastewater through another treatment facility, Prineville uses a wetland to do the rest of the work. Water treated in Prineville's lagoons passes through a 120-acre artificial wetland before discharge into the Crooked River. As the water passes through vegetation, soil, and open water, it cools and sheds sediment. The EPA case study says the cooler water helps salmon and other native species downstream, something concrete tanks would not achieve. The city council voted in January 2011 to pursue the wetland complex over a traditional mechanical plant; project design later got underway in 2012 with the help of $280,000 from the Oregon Watershed Enhancement Board and $75,000 from the Pelton Fund, according to the City of Prineville's project page.

The price tag that changed everything

The EPA case study puts the wetland's construction cost at $7.7 million compared to the conventional plant that would have cost $62 million, a $54 million savings that the city did not need to borrow or recover through utility bills. The savings were also felt immediately by residents. According to the city's figures, the development charge for the sewage system fell from $9,147 per household to $3,875 per household. The wastewater rate remained constant, and the city maintained its competitiveness despite continued growth.

More than a treatment system

Not only was the issue of sewage handled, but the wetland became an open park for everyone. According to the case study conducted by the EPA, the project resulted in the creation of more than 5.4 miles of hiking and walking trails, with 3.25 miles being paved throughout the year and over two miles of riparian restoration in the Crooked River. The city’s project page also explains that school children from the community designed educational kiosks that can be found throughout the park, with the EPA case study citing around 500 students visiting the park.

Recognition and what other cities can learn

The groundbreaking took place on Earth Day, April 22, 2016, while the grand opening came a year later, on April 22, 2017. Since then, the project has received national recognition. EPA's PISCES program has recognized it as one of the best water-related projects in the nation. Additionally, the National Association of Clean Water Agencies has given the project a National Environmental Achievement Award in the Operations and Environmental Performance Category in 2019. The Prineville project offers a useful model for other fast-growing small towns weighing expensive plant expansions against more creative options. This approach probably won’t work everywhere, depending as it does on land availability, suitable soils and the right regulatory conditions. But it shows us that sometimes the most modern solution in infrastructure isn’t more machines; it is letting the river do what it was meant to do.