Penitencia Delivery Main & Force Main Retrofit

The objective of this project was to perform a seismic retrofit of the Penitencia Delivery Main, Penitencia Force Main, South Bay Aqueduct, and Finished Meter Vault to accommodate the creek and potentially extensive seismically-induced movements of the active Penitencia Creek Landslide over a 50-year design life.  The project included: temporary shutdown of the Penitencia Water Treatment Plant, dewatering of the existing pipelines, installation of replacement compression pipelines, site restoration, and construction of ancillary facilities.

The scope of work included the removal of existing prestressed concrete cylinder pipe (PCCP) and welded steel pipe, and replacement with earthquake-resistant ductile iron pipe and welded steel pipe. Two pipelines, with diameters of 72-inches and 66-inches, provide raw water to PWTP, and a third 60-inch pipeline conveys treated water from PWTP to the District’s water retailers. Approximately 850 feet of each pipeline was replaced. The total length of pipe replaced was approximately 2,550 feet. The earthquake-resistant ductile iron pipe used on the project is manufactured in Japan. We also installed a new control building, new flow meter and vault, new cathodic protection systems and various upgrades to existing equipment at the PWTP.