Corvallis Wastewater Treatment Wetland

View of the treatment wetland from above, with the Willamette River and Downtown Corvallis in the background.

For the past several months, GreenWorks has been working for the City of Corvallis as part of a multi-disciplinary team led by Kennedy/Jenks Consultants to develop a schematic design for a 30-acre treatment wetland on the banks of the Willamette River directly across from the city’s downtown.   The design combines wastewater treatment using the cleansing abilities of plants and micro-organisms, with trails, overlooks, interpretive displays, and other public open space amenities.

Seven to ten million gallons of Class B wastewater will be piped every day from the nearby Corvallis Wastewater Reclamation Plant to the wetland site. At the wetland, the wastewater will be distributed into a series of emergent marsh wetlands before infiltrating through a rocky sub-layer back to the river.  During this infiltration process the primary role of the wetland is to cool the wastewater.  In order to preserve fish habitat, all Oregon municipalities discharging wastewater to natural bodies of water are required by the DEQ to adhere to certain Total Maximum Daily Load (TMDL) temperature limits.

On August 7th, the design was presented to Corvallis city officials and the general public.   GreenWorks generated a series of 3D visualizations to convey the design intent where wastewater treatment and public open space intertwine.  Further sessions with city and county review boards are scheduled for the near future.

View from the northern end of the wetland, where wastewater from the Corvallis Wastewater Reclamation Plant emerges and is distributed into the wetland over a dramatic waterfall cascade

View from the raised gabion overlook in the middle of the wetland, with the emergent marsh on the right, infiltration pond on the left, and distribution waterfall in the distance.

Process diagram showing wastewater treatment train from inflow into the wetlands all the way to infiltration and outfall in the Willamette River

 

 

 

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