OREGON CITY, Ore. — Clackamas County broke ground on a nearly $60 million addition to the Tri-City Water Research Recovery Facility on Wednesday. The project will build a new outfall system from the facility to the Willamette River, where it will deposit treated wastewater.
The current outfall pipe was built in 1984 and is close to reaching capacity.
The current pipe is 72 inches in diameter and has a daily capacity of about 72 million gallons. The new pipe will have a 90-inch diameter, giving it a daily capacity of 108 million gallons. Once completed, the outfall pipes should give the county enough capacity to last until 2080.
The new pipe will transport the treated wastewater about 1,600 feet from where the current pipe diffuses water into the river.
The new diffuser location should be more environmentally friendly, and will contribute to fish recovery in the Willamette River, according to Clackamas County officials.
“The existing outfall is closer to the confluence of the Clackamas River. When we worked on needing a new outfall, we searched the river for a deep spot to allow for good mixing,” said Jeff Stallard, the capital program manager with Clackamas County Water Environmental Services.
The "mixing zone" must meet state water quality standards to ensure clean water for boating, swimming, fishing and aquatic resources.
The new outfall will operate without obstructing any activities on the river. Construction impacts from the projects are only expected to last a few months, officials said.
The project is projected to be completed in 2025.