East Side Big Pipe

The East Side Big Pipe is a large sewer line and tunnel in Portland in the U.S. state of Oregon.

It is part of a combined sewer system of pipes, sumps, drains, pumps, and other infrastructure that transports sewage and stormwater run-off to the city's Columbia Boulevard Wastewater Treatment Plant.

However, the existing sewer pipes were often overwhelmed by surges of stormwater from big storms, and the resulting CSOs continued to pollute the river and the slough.

A separate project completed in 2006 centered on construction of the 3.5-mile (5.6 km) West Side CSO Tunnel and the Swan Island Pump Station.

It lies at an average of 150 feet (46 m) below the surface along the east bank of the Willamette River from the intersection of Southeast 17th Avenue and McLoughlin Boulevard to Swan Island.

In addition to the tunnel and the pipe, the project involved building seven access shafts, connecting pipelines, and the Portsmouth Forcemain, which carries sewage from the Swan Island Pump Station to the Columbia Boulevard Wastewater Treatment Plant.