As construction concludes on a major pipeline relining project in La Mesa, the Water Authority is hosting a community meeting on May 1 to share information about a similar project this fall in Fallbrook. The Water Authority’s project team will be at the Fallbrook Library’s community room between 6 and 8 p.m. to discuss the project with residents and answer questions.
The $24 million Pipeline 5 Relining Project, expected to conclude in summer 2019, is part of the Water Authority’s program to rehabilitate prestressed concrete cylinder pipelines with steel liners to extend their service life and ensure continued system reliability. When the Fallbrook project is completed, the Water Authority will have relined more than 47 miles of the 82 miles of prestressed concrete cylinder pipeline in its system.
The Water Authority is coordinating with local water agencies to ensure the upgrades do not interrupt water service.
The Water Authority’s multi-decade effort to proactively protect the region’s water infrastructure is taking another big step with Lake Murray to Sweetwater Reservoir Relining Project that began in September 2017 to reline more than four miles of large-diameter pipeline in La Mesa.
The Lake Murray-to-Sweetwater project reinforced nearly 23,000 linear feet of the Water Authority’s Pipeline 3, including sections of 66-inch and 69-inch diameter prestressed concrete cylinder pipe. Project contactor L.H. Woods & Sons, Inc. is wrapping up construction in public street rights-of-way in La Mesa, specifically on Baltimore Drive, Nebo Drive and Spring Street. Project completion is expected by the end of summer 2018.
Prestressed concrete cylinder pipes were commonly installed between the early 1960s and the late 1980s as part of large-diameter water distribution systems worldwide. This technology, which uses a combination of concrete and steel, initially appeared to have unparalleled inner pipe strength and be highly resistant to corrosion. However, prestressed concrete cylinder pipe has not been as reliable as predicted, and the Water Authority proactively began relining sections of it to extend its service life.
Instead of removing and replacing these pipelines in their entirety, the Water Authority uses an innovative approach and excavates pipelines at access points called portals. Crews use specialized machines to insert 40-foot sections of steel liner and place them inside existing pipelines. This technique is 40 to 60 percent less costly than traditional excavation, and it results in fewer community impacts.
Pipeline relining is one facet of the Water Authority’s Asset Management Program, which assesses the health of the agency’s conveyance system using technologies such as Remote Field Eddy Current, Acoustic Fiber Optic real-time monitoring, Magnetic Flux Leakage, and Remote Field Technology.
Proactive assessments help the Water Authority avoid pipeline failures by identifying potential risks before they cause problems. To date, the Asset Management Program has saved water ratepayers more than $200 million by prioritizing repairs, avoiding unnecessary work and maximizing the service life of the region’s large-diameter water conveyance system, which includes 310 miles of pipeline ranging in diameter from 20 inches to 9 feet.