Final effluent from SVCW's treatment plant is pumped from the main structure and discharged into the San Francisco Bay through a diffuser near the San Mateo Bridge. The original pipe between the main structure and the levee was built in 1980 and found to be irreparably leaking in March 2015.
Diver investigations of the old concrete pipe joints identified varying degrees of gaps beyond what would be expected normally, making it difficult to identify a single specific leaking joint. The location of the pipe was extremely challenging and delicate, and required the segment to be bypassed. Additionally, work was further complicated by the presence of young bay mud substrate that requires a cofferdam shoring system.
The repair replaced the entire length of reinforced concrete pipe from the main treatment structure to the levee with a new, continuous fused section of 63-inch High-density Polyethylene (HDPE) pipe. Using an approach to bring a new pipeline onto the treatment plant property shortened the length of the project and significantly reduced its overall cost.