City of Portland Bureau of Environmental Services (BES) West and Eastside CSO ‘Big Pipe’ Tunnel Projects Portland, Oregon

The CSO upgrade program, initiated in 1988, consisted of upgrading the storm and sanitary sewer systems throughout the metropolitan area including headworks, pump stations, and treatment plant projects. In 2003, The Westside CSO project was initiated which included a major revamp and new construction of shafts and a tunnel under the Willamette River to a new treatment facility the Swan Island Pump Station that could pump up to 100 million gallons per day to the to the Columbia Boulevard Treatment Plant for processing.

Upon completion of the East Side CSO project, the Swan Island Pump Station facility is scheduled to serve both the west and east side pumping to a capacity of 220 million gallons per day to the City’s primary wastewater treatment facility. It will lift sewage from 160 feet below ground to three new force mains that will empty into the existing Portsmouth and Peninsular tunnels, which will then carry sewage by gravity to the Columbia Boulevard Wastewater Treatment Plant. CMTS, Inc. was selected through an RFP process to provide construction management, inspection, and administrative personnel.

CMTS has also provided inspection services for multi-street projects which included observation of asphalt placement, overlays, concrete curbs and sidewalks, gutter replacement, installation of new sewer and storm lines ranging from 6-inch to 144-inch pipe (P.V.C., concrete, steel, H.D.P.E., ductile iron). CMTS also incorporated design review by inspectors prior to the release of bid documents for existing field conditions and constructability. The CMTS team inspected the construction of wetland and sedimentation ponds.

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