Mercer Island Sewer Line and Pump Station #4 Replacement

November , 2009

The sewer line on the northwest corner of Mercer Island was installed in the mid-1950s, and was constructed of asbestos-cement (AC) material. The line suffered ongoing pipeline deterioration, capacity deficiencies, and other operation and maintenance problems. Manson Construction was awarded the contract to replace this portion of the sewer line with cast iron pipe and selected Global to provide the diving services. The project extended over a two-year period and involved the replacement of over 7,000 feet of pipe with 32 side sewer connections.

Global worked closely with Manson during all aspects of the project, including: installing both gravity and force main pipes, aligning and connecting the side sewer piping, assisting with hand dredging under docks and in tight areas where the derrick cannot access, and making the physical transition from the existing line to the new piping.