While the Big Pipe system is named after its main features-the two giant pipes on either side of the river and one along the slough-the $1.4 billion project that spanned 20 years to build included many other engineering upgrades and additions. Overflows are now fewer, shorter, and smaller. Overflows are about 80 percent stormwater and 20 percent sewage. Smaller: The volume of overflows has decreased by about 95 percent per incident, from an average of 6 billion gallons to 297 million gallons.The last two overflows, in September this year, lasted about 10 minutes and 20 minutes each. Shorter: Overflows are now about four hours on average, down from 42 hours on average.Since completion, the average number of incidents has been 3.3 per year. Before the Big Pipe, overflows occurred about 50 times a year, often for days at a time. Fewer: Portland experienced a high of seven overflows per year (in 2017) and a low of one per year (in 20).Today, it takes about ten times that amount of rain to come close to reaching an overflow. Before the project completion in 2011, it didn’t take much rain to cause an overflow-only about one-tenth of an inch, which is a regular day of rain in Portland. Occurrences are, and that incidents are fewer, shorter, and smaller in volume. Ten years of data show overflows ranging from seven to one - down from over 50 per year before the Big Pipe In the rare event that the pipes exceed capacity and an overflow occurs, Environmental Services will issue an advisory.Įnvironmental Services’ ten years of data shows how rare those Data are updated every 15 minutes, with up to a 45-minute time delay. 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.Īn accompanying chart tracks flows during a 72-hour period. The gauge, or Big Pipe Tracker, shows a circular graphic with markers from zero to 100 percent, representing the levels of sewage and stormwater that fill two giant pipes on both sides of the Willamette River. The new Big Pipe Tracker shows the system in action, so keep refreshing your browser during rainstorms and see how the city is sending sewage to the plant and keeping it out of the river we love.” “Ten years of data show how Portlanders’ investment in the Big Pipe system is working. “Overflows are now dramatically fewer, shorter, and smaller,” said Environmental Services Director Michael Jordan. The Big Pipe Project is shorthand for an ambitious set of actions and improvements, including two giant pipes that line the east and west banks of the Willamette River in Portland, that together eliminated most combined sewer overflows, or CSOs. River recreation has soared as more people are boating, playing, swimming and enjoying the river, and for good reason – the river is cleaner.” “The Big Pipe is making a big difference for Portlanders and our relationship to the Willamette River. “On this ten-year milestone, I am pleased to bring a new tool for transparency – a way for the public to see how the system works in close to real time,” said Commissioner Mingus Mapps. The payoff, since project completion in 2011, is a healthier, cleaner river. The graphic is updated every 15 minutes, with a lag time of less than 45 minutes.Įnvironmental Services also released ten years of data showing how the project 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. This animated graphic shows Big Pipe levels during a storm last November, during a test period for the Big Pipe Tracker.

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