PORTLAND, Ore. — For the fifth time in 2021, the Big Pipe sewer system overflowed into the Willamette River.
The overflow was caused by a mix of heavy rain and snow causing the Big Pipe system to reach capacity with stormwater and sewage. The overflow began around 2 a.m. on Sunday.
When an overflow happens, it's advised that the public avoids contact with the river for 48 hours due to increased bacteria in the river.
The public can see Big Pipe levels at the new online tracker: https://www.portland.gov/bes/big-pipe-tracker.
Combined sewer overflow (CSO) is roughly 80% and 20% sewage.
The Big Pipe project was completed in 2011 and was done to help the number of CSO that occurred each year. The Big Pipe has dropped CSOs b 94% in the Willamette River and 99% in the Columbia Slough according to the Portland Bureau of Environmental Services.
