About the Project
The Tryon Creek Wastewater Treatment Plant is more than 60 years old and in need of replacement to address structural issues, seismic vulnerability, and water quality. Lake Oswego, with Portland’s support, is planning to build a new, environmentally sustainable wastewater treatment facility to replace the old plant.
Replacing the aging Tryon Creek wastewater treatment plant is one of the largest capital investments in the City of Lake Oswego’s history. This project will ensure safe, reliable wastewater treatment for generations to come, protect public health and the environment, and reduce the risk of more costly emergency repairs.
Tryon Creek Plant Background
The Tryon Creek Wastewater Treatment Plant (TCWTP) was built in 1964 and is owned and operated by the Portland Bureau of Environmental Service (BES). It is strategically located at the confluence of Tryon Creek and the Willamette River in Lake Oswego. The plant treats wastewater collected from parts of southwest Portland, unincorporated areas of Multnomah and Clackamas counties, and the City of Lake Oswego. Treated wastewater is discharged to the Willamette River via an outfall system.
Currently, wastewater treatment operations and maintenance costs are split between Portland and Lake Oswego. On average, Lake Oswego contributes approximately 70 percent of the flow volume. Lake Oswego also pays approximately 70 percent of the cost of operating the plant, in line with its usage. Both cities are planning to build a new plant that will be owned by Lake Oswego.
Project Overview
The existing Tryon Creek Wastewater Treatment Plant is more than 60 years old and has reached the end of its useful life.
The plant needs significant investments to continue to reliably meet more stringent Oregon Department of Environmental Quality (ODEQ) permit requirements and protect the plant from natural disasters.
The City of Lake Oswego, with the City of Portland’s support, is planning to replace the aging Tryon Creek plant with an environmentally sustainable wastewater treatment facility. Replacement is more cost-effective than continual repairs or upgrades that will not fully meet the Oregon DEQ standards of today.
The treatment plant is critical public health infrastructure that protects homes, businesses, and the environment.
The project is:
- Necessary to replace aging critical infrastructure
- Required to maintain safe, reliable wastewater treatment and improved water quality regulatory compliance
- A long-term investment protecting public health
- The most responsible financial approach to avoid increased costs later
Project Benefits
A new, wastewater treatment facility will produce cleaner water, be earthquake and flood resilient, and ensure reliable wastewater treatment for generations to come.
Additional benefits include:
- Proven, reliable treatment technology
- Reduced risk of failures and sewer overflows
- Protects public health and the Willamette River
- Improved odor and noise control
- More attractive, neighborhood-compatible design
- More energy efficient and climate resilient
- Higher quality treated water
- Lower long-term maintenance and emergency repair costs
- Smaller footprint that supports the Foothills District Plan
- Capacity to serve future community needs
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You can also email lowastewaterfacility@lakeoswego.city