The Big Pipe Project, which was completed in 2011 at a cost of $1.4 billion, according to the Bureau of Environmental Services, is designed to prevent combined sewer overflows (CSOs).

The Big Pipe Project, completed in 2011, was a $1.4 billion initiative aimed at reducing CSOs. Since its completion, the number of overflows has decreased by 94 percent to the Willamette River and ...