The city constructed the Triangle Lake Lagoon just north of the Columbia Boulevard Wastewater Treatment Plant in 1970 to store and treat solids produced during the wastewater treatment process. Environmental Services is working on a long-term lagoon reconstruction project.
The work includes dewatering parts of the lagoon, removing solids, and reconstructing and lining the lagoon system. To maintain daily plant operations, Environmental Services is completing the project in phases over several years.
Lining and leak testing the south section is complete. Environmental Services deposited dried solids in that section in summer 2014 and summer 2013 and will continue depositing dried solids in the south section for several years while work continues on the lagoon’s north section.
Columbia Slough Trail Closures
This project requires trucks to use the Columbia Slough Trail to enter and exit the work site intermittently during the summer between N Portland road and the Columbia Slough Bridge.(see map below). When traffic is expected to be heavy, the trail will close during the day for safety. The city posts signs and maintains a hotline (503-823-1993) to advise trail users of periodic closures for the duration of the lagoon reconstruction project.
In June 2015, the project contractor will use the trail to haul material to and from the site. Hauling will close the trail Monday through Friday from 7:00 a.m. until 6:00 p.m. through the end of June.
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 www.portlandonline.com/bes/odors 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