UPDATE (March 15, 2023, 9:45 a.m.)
The Combined Sewer Overflow advisory issued on Monday expires today at 5 p.m.
During Monday’s heavy rains, the system overflowed to the Willamette River for 3.5 hours, starting around 1:35 p.m. and ending at 5 p.m.
During an overflow and for 48 hours afterward, the public is advised to avoid contact with the river because of increased bacteria in the water. The river’s water quality is safe for recreation during all other times.
A CSO is about 80 percent stormwater and 20 percent sewage. CSOs are rare and can occur during periods of heavy rain or snowfall. The public can follow the duration of this overflow by viewing the Big Pipe Tracker. The image here shows how full the system was during and after the storm.
UPDATE (March 13, 2023, 2 p.m.)
A Combined Sewer Overflow is in effect. The Big Pipe system reached 100% capacity around 1:55 p.m. and is overflowing to the Willamette River.
During an overflow and for 48 hours afterward, the public is advised to avoid contact with the river because of increased bacteria in the water. The river’s water quality is safe for recreation during all other times.
A CSO is about 80 percent stormwater and 20 percent sewage. CSOs are rare and can occur during periods of heavy rain or snowfall. The public can follow the duration of this overflow by viewing the Big Pipe Tracker.
NEWS RELEASE (March 13, 11:30 a.m.)
With today’s heavy rains, the Portland Bureau of Environmental Services reminds the public that they can monitor the Big Pipe Tracker to view in near real time how the system keeps sewage out of the Willamette River.
In the rare occasion when a combined sewer overflow may occur, the gauge also allows the public to track an incident’s start, stop, and duration.
The tracker shows the pipes are 69% full as of 11:15 a.m., and that levels are rising.
That represents the levels of sewage and stormwater that are filling two giant pipes on both sides of the Willamette River. Instead of overflowing to the river, treatment plant operators store, monitor, and direct the flow to the City’s main wastewater treatment plant in North Portland.
If an overflow is approaching or occurs, levels would be at 100%.
Ten years of data shows how the Big Pipe system is achieving its design goals of reducing overflows by 94 percent, making combined sewer overflows to the Willamette River rarer, shorter in duration, and lower in volume. The payoff, since project completion in 2011, is a healthier, cleaner river.
Follow the tracker at Big Pipe Tracker. Find out more at About Big Pipe.
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The City of Portland Bureau of Environmental Services - your sewer and stormwater utility - provides Portland residents with programs to protect water quality and public health, including wastewater collection and treatment, sewer construction and maintenance, stormwater management, and stream and watershed restoration. Portland.gov/bes