Hyperbaric Projects
Projects > Portland Kiewit- Bilfinger Berger J/V - CSO
Project Date: 2010

Ballard Diving & Hyperbaric Services is a division of Ballard Marine Construction:

BDHS was awarded the diving and hyperbaric support services for the East Side Combined Sewer Overflow (CSO) Tunnel Project. This system conveys captured flows from Southeast Portland to a pump station on Swan Island, travelling under a busy industrial area along the Willamette River. The main tunnel was constructed at a depth ranging from 30 – 48 meters and finished, is approximately 9,144 meters long with a finished inside diameter of 6.7 meters.

Multiple slurry wall launch and recovery shafts were constructed for this project. We provided personnel and equipment to construct the tremie slabs in each of the shafts. This work included working in up to 115 feet of water to install heavy rebar, water stop systems, clear blockout panels, break and remove concrete, dredging and material excavation, etc.


With rain occurring about 100 days a year in Portland, wastewater volumes often exceed the city's sewer system capacity, resulting in untreated overflows into the Willamette River. The East Side Combined Sewer Overflow (CSO) project was part of a massive tunnel construction program that will virtually eliminate combined sewer overflows into the river.

The Kiewit-led joint venture of Kiewit-Bilfinger-Berger (KBB) completed Phase 1 of the East Side CSO project, a $1.5 million Preconstruction Services contract. Phase 1 included design review and assist, a cost estimate and schedule, and development of project-specific programs such as safety, quality and subcontracting plans.

Based on KBB's exemplary performance during Phase 1, the team was awarded the $381 million Phase 2 contract, the single largest component of Portland's CSO program. Referred to as "the Big Pipe," Phase 2 is the largest public works contract ever awarded by the City of Portland.

Portland CSO Website  
Portland's Bureau of Environmental Services
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