Pipeline 3 Relining Lake Murray to Sweetwater Reservoir

Location:

La Mesa, CA

Value:

$28.6 million

Completion:

Summer 2018

Owner:

San Diego County Water Authority

Contractor:

L.H. Woods & Sons, Inc.

Butier Engineering, Inc. provided construction management services for the Pipeline 3 Relining project as a sub-consultant to Richard Brady & Associates. The 4.3 miles of relined pipeline extends from Lake Murray in the north to Sweetwater Reservoir in the south. It serves the Helix Water District and Sweetwater Authority and traverses portions of Baltimore Drive and Spring Street in La Mesa and the unincorporated communities of Spring Valley and La Presa.

The project rehabilitated 23,000 linear feet of 66- to 69-inch diameter prestressed concrete cylinder pipe (PCCP) that was constructed in 1959. Instead of trenching and removing the old pipe, crews excavated 13 entry portals (25- by 60-feet) that were spaced 525 to 2,500 feet apart at strategic points; inserting new steel liners into the pipeline using a specially designed cart; welding the new steel liners into place; inserting grout into the annular space between the new liner and existing pipeline; and applying a cement mortar lining to the new steel liner. When the pipe installation was complete, the portals were backfilled, the streets repaved, and the pipeline was put back in service.

Project Benefits

• Extended Life — Pipeline’s service will be extended by 75 years or more, ensuring water system reliability 
• Least Impact — Relining process has the least impact on the community and the environment
• Cost Effective — Method is half the cost of a conventional replacement project, which would include replacing the pipeline in its entirety

Project Challenges

• Traffic Impacts — Spring Street and Baltimore Drive reduced from two lanes down to one lane of traffic in each direction in areas adjacent to the access portals
• Community / Residential Impacts — Work at several locations was conducted during nighttime hours and large wooden sound walls were temporarily placed to ease noise impacts
• Stakeholder Coordination — Coordination with 12 agencies and entities to ensure project was completed smoothly and on time
• Public Outreach — Project updates provided by posting signs, distributing fliers and door hangers, mailing construction notices, conducting tent events and open houses, performing presentations at business events, and having information booths at community events