The City of Salem’s public works department hired Murraysmith to design the rehabilitation and replacement of a critical water main in their distribution system that is to be constructed in the summer of 2020. The approximately 560-foot long section of the existing 30-inch diameter welded steel water main is an important backbone of the water distribution system, providing redundancy and supply to the industrial area in the south-central neighborhood of the city.
The water main, which was installed in 1947 and identified for rehabilitation/replacement by the 2007 Water Master Plan, is reaching the end of its design life. With a portion of the water main having been repaired to address pin hole leaks in 2012, the City is invested in resolving water main deterioration before a failure results, which would release chlorinated potable water into an environmentally sensitive ecosystem. Approximately 200 feet of the water main is located in Pringle Creek, a fish habitat for listed specious of concern.
The design, utilizing CIPP lining technology and open cut construction methods, will rehabilitate and replace the ageing steel waterline in and adjacent to the creek, including a portion that runs beneath a 100-foot wide railroad bridge and associated easement. To minimize environmental impact, Murraysmith elected to use various construction techniques that will allow the project footprint to remain small. The CIPP liner had to be installed through the tricky transition from steel to ductile iron pipe, which had different internal diameters, so the Murraysmith team designed custom end connections that would transition between these pipes while providing necessary restraint and pressure rating for the rehabilitation system.