The City of Portland Bureau of Environmental Services is working on a long-term project to reconstruct the Triangle Lake Lagoon at the Columbia Boulevard Wastewater Treatment Plant. The lagoon is just north of the treatment plant main campus next to the Columbia Slough. In order to maintain daily plant operations, Environmental Services will complete the project in phases over several years.

Columbia Slough Trail Closures

The city’s contractor uses the Columbia Slough Trail to access the lagoon area during construction. This will intermittently close portions of the trail between the railroad tracks to the east and North Portland Road to the west (see map below). The city posts signs advising trail users of periodic closures at the following locations for the duration of the lagoon reconstruction project: 

• On the trail at the corner of North Portland Road and Marine Drive
• At the construction site entrance at the intersection of North Portland Road and the Columbia Slough Trail
• At the Columbia Slough Trailhead at Columbia Court
• At the Columbia Slough Trailhead at Denver Avenue
• On the Columbia Slough Trail east of the plant’s east entrance
• At the main plant entrance on Columbia Boulevard

For more information, visiting the project webpage at www.portlandoregon.gov/bes/lagoon