PORTLAND Ore. (KPTV) – Portland\u2019s Big Pipe system reached 100% capacity Thursday morning, causing a mixture of sewage and stormwater to overflow into the Willamette River as an atmospheric river brought heavy rain to the Pacific Northwest.<\/p>\n
The Portland Bureau of Environmental Services issued a combined sewer overflow (CSO) advisory<\/a> for the Willamette River early Thursday.<\/p>\n The overflow began around 6:26 a.m. and is impacting areas downstream of the Ross Island Bridge.<\/p>\n As rain poured from Wednesday into Thursday morning, the pipe system\u2019s capacity surged from nearly 5% to 100%.<\/p>\n \u201cAt one point we had about an inch of rain in six hours, and when that happens the system overloads and does what it\u2019s designed to do: release some of that excess into the Willamette River,\u201d said Andy Kiemen, a communications representative for the Portland Bureau of Environmental Services.<\/p>\n City officials say a typical combined sewer overflow is about 80% stormwater and 20% sewage.<\/p>\n The Bureau of Environmental Services is urging people to avoid swimming, kayaking or having any contact with the water until 48 hours after the overflow stops.<\/p>\n \u201cWe\u2019re primarily concerned about the increase in bacteria levels. That\u2019s why we\u2019re advising people to stay away from the Willamette River at this time,\u201d Kiemen said.<\/p>\n The $1.4 billion Big Pipe Project, completed in 2011, built a total of 13 miles of massive underground tunnels capable of holding more than 100 million gallons of sewage and stormwater.<\/p>\n According to the city, the project has reduced overflows into the Willamette River by about 94%.<\/p>\n \u201cPrior to the Big Pipe Project, there would be combined sewage overflows an average of 50 times a year. Any time it rained more than a tenth of an inch \u2014 which in Portland happens a lot \u2014 we would be spewing billions of gallons into the Willamette River,\u201d Kiemen said.<\/p>\n