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Inspiration, Wonder, and...Wastewater Treatment

The story of Oregon’s Fernhill Wetlands: how sewage lagoons were transformed into a valuable resource that provides wildlife habitat and recreational opportunities as it cools and cleans water that is discharged into the Tualatin River.

By Katie Bohren

Bordered by three mountain ranges, and veined with rivers and creeks, Oregon’s Willamette Valley is very much alive. Its woodlands, grasslands, wetlands, and riparian and aquatic habitats are home to a rich variety of species. This includes humans, as the area is also the state’s most densely populated region. In the northern portion of the Valley, near the confluence of Gales Creek and the Tualatin River is a unique place that is demonstrating how an integrated water strategy can address a human challenge and support the needs other members of the biological community.

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Great blue heron (Ardea hernias), Fernhill Wetlands

Great blue heron (Ardea hernias), Fernhill Wetlands

Fernhill Wetlands, located in the city of Forest Grove, is a popular spot for hikers, birdwatchers, and nature lovers. Visitors walking the trails of Fernhill Wetlands may see up to 200 species of birds, including bald eagles, great blue herons, and white egrets amidst the native wetland vegetation. But there’s something else they see. Something you might not expect: the treatment of wastewater from the surrounding communities. Wastewater that ultimately ends up in the Tualatin River.

Owned and operated by Clean Water Services, an Oregon utility service, Fernhill Wetlands is a promising solution for cleaning water while providing loads of other ecological, recreational, and educational benefits. The creation of Fernhill Wetlands did not happen overnight, and it is not complete. It began with an ambitious vision that is in the process of being realized.

“One of the goals is to bring people back to the water and to understand how we are all connected to the Tualatin River,” said Diane Taniguchi-Dennis, Deputy General Manager at Clean Water Services.

Biohabitats has been helping Clean Water Services achieve that goal by transforming three former sewage lagoons into a rich mosaic of riparian wetlands that will improve the ecological function of this section of the Tualatin River floodplain. The new “South Wetlands” are a natural treatment system that cools treated effluent from the Forest Grove wastewater treatment facility through a series of emergent wetland cells before discharging to the Tualatin River.

Together the woody and herbaceous wetland cells, along with a lake, provide open water, mudflat, emergent marsh, scrub-shrub, and upland habitat, making Fernhill Wetlands an important stopover site in the Pacific Flyway. They also improve the ecological function of this section of the Tualatin River floodplain and create a natural connection from the treatment plant to the watershed.

Winter at the Fernhill Wetlands

Winter at the Fernhill Wetlands

In terms of water quality, the wetlands will reduce the temperature of the treated wastewater flowing into the Tualatin River, and serve to regenerate the complex systems of life and nutrients that exist in healthy waters. This will allow Clean Water Services to discharge treated wastewater to the Tualatin River year round, where they currently only discharge during winter months due to regulatory limits.  During warm summer months, wastewater is currently pumped 17 miles to an advanced wastewater treatment facility before being discharged to the Tualatin River.  The treatment wetlands allow the District to reduce its energy and carbon footprint, while treating wastewater in a more natural and less expensive manner than expanding a wastewater treatment facility.

The design team preparing to break ground.

The design team preparing to break ground

The design had to accommodate the diurnal variation in the discharge of treated water into the wetland system.A system of hydraulic control structures is included in the design to provide District staff the ability to manipulate water levels in the wetland cells to more closely mimic typical seasonal variations and operational flexibility.

“Fernhill is a place of inspiration and wonder, a place to experience the beauty and grace of nature. Together we are creating a legacy for our community, for water, for the environment, and for future generations,” said Taniguchi-Dennis.

By creating a wetland system that provides benefits in water quality, wildlife habitat and recreation, Clean Water Services is making a long-term investment in the health and resilience of the Tualatin River.

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