While the West Side CSO tunnel is under construction to reduce sewage into the Willamette river, the 9.15 km East Side CSO tunnel is under design. Currently, the planned interior diameter of the tunnel is approximately 6.7 m while the outer diameter of the tunnel is approximately 7.6 m. The final size of the tunnel and the liner are still being evaluated and have not been finalised yet. The tunnel is planned to be excavated through the use of a pressure face TBM to maintain face stability and minimise ground losses in the soft ground conditions. Two types of closed face TBMs were identified for potential use on this project: slurry face and earth pressure balance machines. It is currently assumed that two TBMs would be used to complete the project. The two TBMs that are being used for the West Side CSO tunnel would not be used on the East Side due to their different diameters. The lining is expected to consist of bolted precast reinforced concrete segments. The mucking-out technique has not yet been evaluated and will be dependent on the selected tunnelling equipment. Options for discharge and transport of excavated material include conveyor, truck, barge and/or rail. The five shortlisted JVs are Bouygues / Traylor / J.F. Shea; Flatiron / Wayss & Freytag / Fluor; Impregilo / S.A. Healy / Obayashi; ESCSO Tunnel Constructors which consists of Morgan Est, Arup and Soletanche Bachy; and Kiewit / Bilfinger Berger. A Notice to Proceed to begin construction of the project is anticipated to be issued to the selected contractor in January of 2006. It is currently estimated that tunnelling would begin on May 2007 and end on July 2010. More in E-News Weekly 40/2004. Visit www.portlandonline.com/cso 40/04.The City of Portland will negotiate with a JV of Kiewit and Bilfinger Berger for a contract to build the East Side Big Pipe. Construction will start in 2006 on the final project in the city's combined sewer overflows (CSOs). The East Side Big Pipe will be a 9 km 6.5 m-diameter tunnel to capture sewage and stormwater on the east side of the Willamette River and carry it to the wastewater treatment plant. The Portland City Council will consider approving the pre-construction contract in late March. Construction is estimated to cost approximately USD500 million and will be finished in 2011. Visit www.portlandonline.com/cso, www.kiewit.com/eastsidecso and www.bilfinger.de 06/05.