Unit 1: 48-inch Force Main reliability improvements Project
Unit 1 included several interesting aspects of pipeline construction. The installation required relocation of several exiting utilities including an asbestos cement (ACP) water line, some electrical utilities and the conversion of an existing sewer force main to a gravity sewer.
The new force main was constructed of High Density Polyethylene (HDPE) heat fusion bonded material. Approximately 1,000 lineal feet was installed by traditional open cut construction in the middle of a local city street requiring extensive traffic control. The remaining approximately 2,200 lineal feet crossed existing waterways and sensitive US Fish & Wildlife habitats. This required the pipeline to be installed via microtunneling in order to minimize impacts to these sensitive areas. The tunneling work included deep shaft excavations and shoring, installation of a 72-in. diameter steel casing in which the new HDPE pipeline was inserted.
One final element included the installation of two (2) 3-in. HDPE fiber optic (FO) conduits with pull boxes at strategic locations along the entire alignment. These FO conduits will be used in the future to install FO cables for communication between the outlying pump stations and the main treatment facility.
All of this work required significant and constant public outreach along with detailed mitigation measures to ensure habitats were not impacted.
Silicon Valley Clean Water (SVCW)