information
Microsoft CrowdStrike software outage

911 is operating as normal. Some City of Portland systems were impacted. Call 3-1-1 or 503-823-4000 to help answer questions, take non-emergency reports, or make connections with City staff.

Tryon Creek Highway 43 Culvert Replacement Project

Sewer and Stormwater
Active
Environmental Services, which manages wastewater and stormwater to protect human health and the environment, is working with the US Army Corps of Engineers to replace an undersized culvert that carries Tryon Creek under Highway 43. This project will reopen the creek to salmon and other fish species.
This project is in the early phases of design. Construction is not expected until 2025.
On this Page

Tryon Creek is one of the remaining intact free-flowing tributaries of the Lower Willamette River. About one-fifth of the watershed is park and open space, including the Tryon Creek State Natural Area. The 7‑mile stream, and its tributaries, was historically home to threatened native fish including steelhead and cutthroat trout, coho and Chinook salmon, as well as Pacific and western brook lamprey. However, an existing culvert at Highway 43 blocks fish passage under most conditions.

The Tryon Creek Highway 43 Culvert Replacement Project will replace a major fish passage barrier along Tryon Creek, where it flows under Highway 43. The existing 8-foot-wide culvert will be replaced with a 30-ft wide open-bottom arched culvert that can simulate natural stream flows. The project will restore access to 7 miles of high-quality spawning and rearing habitat in the Tryon Creek watershed that is currently blocked. 

Project Area

The project is located where Tryon Creek passes under Highway 43 near Tryon Cove Park in Lake Oswego.

Tryon Creek Culvert Replacement Project Map

What's Happening Now

Staff from Environmental Services and the US Army Corps of Engineers have started designing this important project. Initial design work will focus on identifying project criteria and evaluating the best methods for constructing the project. More information on construction schedules and impacts will be available later in the design process.

Design work will continue through 2025 and in to early 2026. Construction is not expected to begin until 2027.

Project Background

Tryon Creek is one of the last remaining intact free-flowing tributaries of the Lower Willamette River. About one-fifth of the watershed is park and open space, including the Tryon Creek State Natural Area. The 7‑mile stream, and its tributaries, were historically home to threatened native fish including steelhead and cutthroat trout, coho and Chinook salmon, as well as Pacific and western brook lamprey. However, an existing culvert under Highway 43 blocks fish passage under most conditions.

The Tryon Creek Highway 43 Culvert Replacement Project will replace the culvert where it flows under Highway 43. The existing 8-foot-wide culvert will be replaced with a 30-ft wide open-bottom arched culvert that can simulate natural stream flows. The project will restore access to high-quality spawning and rearing habitat for fish in the Tryon Creek watershed that is currently blocked. 

We Want to Hear from You

We would like to hear from you about special events, school activities, and community services in your neighborhood you think may be impacted by this project. Also, we want to know if you have any concerns related to business operations, disability or mobility issues, medical or business deliveries. Your input will help us minimize the impact to your neighborhood during construction. Construction is not expected to begin until 2025.  

Sign Up for Project Updates

Sign up for periodic email or text message updates for the Tryon Creek Highway 43 Culvert Replacement Project through our free GovDelivery subscription service. These updates are the best way to stay informed about what’s happening and what to expect. You can also sign up for bulletins on other projects and topics.