Construction of the massive Swan Island CSO Pump Station began in November 2002 and was completed in 2006. The facility has a pumping capacity of 100 million gallons per day (MGD), two dry weather pumps and two wet weather pumps.  Above ground, there is the Operations and Maintenance Building where the pump station controls are located. Smaller outbuildings over the shaft provide elevator access to the pump station underground. When CSO construction is finished in 2011, the pump station will pump sewage from both the West Side Big Pipe and East Side Big Pipe to the Columbia Boulevard Wastewater Treatment Plant.

Phase 2 work has already begun to add three more wet weather pumps to increase the capacity to a total of 220 MGD to handle the addition of the East Side CSO tunnel and the Portsmouth Forcemain.  It should be finished by Spring 2011.

Fun facts:

• The Portland Building would fit inside the Swan Island Pump Station shaft.

• It took almost 600 truckloads (nearly 6,000 cubic yards) of concrete for the pump station floor.

• TBM Lewis had a clearance of 40 feet to the maximum scour depth of the Willamette River at its deepest point. For most of the crossing, it was well below 40 feet deep.