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Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Avenue, Room 1000, Portland, OR 97204

More Contact Info

Lagoon Reconstruction

Environmental Services is working on a long-term project to reconstruct the Triangle Lake Lagoon at the Columbia Boulevard Wastewater Treatment Plant. The project includes dewatering parts of the lagoon, removing solids, reconstructing and lining the lagoon system.

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 is completing the project in phases over several years.

Lining and leak testing on the southmost section of the lagoon is complete and Environmental Services began depositing dry solids in that section in summer 2014. Work will continue on the northern section over the next few 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 a portion of the trail between the railroad tracks to the east and North Portland Road to the west (see map below). The city will post signs and maintain a hotline to advise trail users of periodic closures for the duration of the lagoon reconstruction project: 

map of Lagoon reconstruction project

Odor Advisory and Reporting

During construction, the contractor will dewater portions of the existing lagoon area to allow the solids at the bottom to dry out before removal. A slight increase in odor may be noticeable during the drying and solid removal process. The contractor will use special equipment and techniques to minimize increased odors during construction. Neighbors can subscribe to the Plant’s Odor Notification System to receive notice when maintenance and construction projects will result in odors beyond treatment plant boundaries. Go to to sign up for odor notifications, or to report an odor online.

For More Information

Contact Joe Annett at 503-823-2934.

Lagoon hotline - 503-823-1993