The Portland Wet Weather Screening Facility Ecoroof is located at 5001 N Columbia Boulevard, Portland, OR; 503.823.2400. For more information about the City of Portland and ecoroofs, please visit the Environmental Services Ecoroof page.
The Columbia Boulevard Wastewater Treatment Plant is part of a collection and treatment system that serves more than 614,000 residential and commercial customers. The plant operates every day around the clock to manage, monitor and adjust the treatment process. Sewage pump stations and pipes convey wastewater to the facility 24 hours a day.
The Screenhouse is a 150 million gallon per day wet weather screening facility at the City of Portland?s Columbia Boulevard Wastewater Treatment plant. To accomodate the increased influent flows projected to occur due to the implementation of the Willamette River Combined-Sewer Overflow program, the facility was expanded and reroofed.
Completed on April 28, 2011, the focus of the design of this ecoroof has been the development of a system that is self-sustaining without the need for irrigation.
The Portland Wet Weather Screening Facility ecoroof was constructed in line with the City?s Green Building Policy which requires a minimum of 70% ecoroof coverage on all new and reroofed City-owned facilities when practical. The ecoroof was designed by landscape architects within the Bureau of Environmental Services.
The roof layers begin with an EPDM membrane, rigid insulation, a drainage mat and 4? of engineered soil media. Cuttings of two sedum species were broadcast at a rate of 70 pounds per 1000 square feet, and a third species was planted sporadically from 4? pots. A one inch layer of red cinder was placed over the cuttings as a mulch to retain summer moisture, eliminating soil erosion and the need for an irrigation system. River rock paths facilitate maintenance access to the skylights and add diversity.
The green components of the ecoroof cost $4.15 per square foot. The membrane and insulation are not included in this.