In August, the San Diego County Water Authority will begin relining more than three miles of large-diameter water pipeline underneath parts of Mission Trails Regional Park and several major streets in eastern San Diego and western La Mesa. The project is part of a $786 million effort, over multiple decades, to extend the service life of 82 miles of pipelines in San Diego County that deliver the majority of the region’s water supply.
On Wednesday July 25, the Water Authority will host an open house for residents, businesses, and community leaders to learn more about the pipeline relining program and the construction details of this specific project, called the Mission Trails to Lake Murray Relining Project. The open house will be held from 5 to 7 p.m. at the San Carlos Branch Library at 7265 Jackson Drive, San Diego.
“This project is an important part of our commitment to ensuring our regional water system will continue to deliver a safe and reliable water supply to sustain the region’s 3.1 million residents and $186 billion economy,” Water Authority Director of Engineering Bill Rose said. “Relining projects are a cost-effective alternative to completely replacing entire sections of pipeline, and they have less construction impact to surrounding communities. This open house is a great opportunity for the public to ask questions and learn more about the project.”
The Mission Trails to Lake Murray Relining Project will reline approximately three miles of pipeline beginning immediately south of State Route 52 in Mission Trails Regional Park east of Tierrasanta. The relining will extend south to Lake Murray underneath Jackson Drive in the community of San Carlos. The project also will reline approximately a half-mile of another pipeline along Lake Shore Drive, south of Jackson Drive in San Carlos and into La Mesa.
Construction crews will conduct most of the work underground, inside the pipe. They will establish 11 portals along the project’s length to access the pipe. Large wooden sound walls will be temporarily placed at portals as needed to comply with environmental regulations and ease noise impacts to residents.
Five of the portals will be in Jackson Drive and one will be in Lake Shore Drive. The project will not require the closure of these streets, but safety barriers around the portals will reduce the number of available traffic lanes.
The Water Authority’s Pipeline Relining Program aims to replace sections of Pre-Stressed Concrete Cylinder Pipe (PCCP), which were installed during the early 1960s to the late 1980s. Made from steel and concrete reinforced with steel wiring, PCCP was widely considered state-of-the-art technology at the time. However, water users have found PCCP to be less reliable than previously thought. In response, the Water Authority launched the Pipeline Relining Program to reinforce these pipes around the County with steel liners, a process that costs 40 to 60 percent less than replacing the pipelines and is less disruptive to the environment and surrounding communities.
Through the program, relining projects are scheduled based on the pipeline’s age and evidence of wear gathered by round-the-clock monitoring systems. To date, the Water Authority has relined approximately 30 miles of PCCP.
More information about this project can be found at the project web page at, www.sdcwa.org/mission-trails-lake-murray-pipeline-relining. More information about the Pipeline Relining Program, including photos and videos, can be found at www.sdcwa.org/pipeline-relining.