The San Diego County Water Authority started construction on the Twin Oaks Valley Road Relining Project in Fall 2022. The project is part of the Water Authority’s commitment to maintaining the critical infrastructure that supplies safe and reliable water to customers throughout the San Diego region. The project will reline about one mile of a section of underground water pipeline adjacent to North Twin Oaks Valley Road in the San Diego County unincorporated area located just north of the City of San Marcos. New steel liners will be inserted into the existing pipeline, which will prevent breaks or failures and extend the service life of the pipeline by 75 years or more. To minimize impacts, the relining will take place through access portals.

WHAT TO EXPECT:

• Nearby impacts: During construction, the nearby community may experience noise, dust and brief increases in construction traffic on N. Twin Oaks Valley Road.
• After hours work: Night and weekend work in mid-October 2022.
• Water service: Water service to nearby customers is not expected to be impacted, and planned shutdowns will be communicated well in advance to avoid any interruptions.

CURRENT CONSTRUCTION ACTIVITIES:

• Earth backfill and regrading: Construction crews will work to backfill and regrade to close the two access portals of the pipeline. This process will help provide stability and protect the new foundations for the pipes.

COMPLETED CONSTRUCTION ACTIVITIES:

• Grouting: Construction crews completed the annular space grouting, a process of filling areas around the new steel liners that have been installed within the pipeline to prevent breaks or failures in the future.
• Cement mortar lining: Construction crews completed cement mortar lining operations; a process that helps reduce any potential deterioration of the steel pipe.

PROJECT GOALS:

• Continue reliable water service: The Water Authority has undertaken this project as part of a long-term initiative to rehabilitate 82.5 miles of old and aging critical water infrastructure in San Diego County. The work will help ensure system reliability long into the future.
• Help prevent critical breaks and leaks: This project will extend the life of about 1 mile of pipeline in the area for as much as 75 years and prevent costly emergency repairs.
• Safe and efficient construction: To minimize impacts to the surrounding area, crews will work underground in portals (entry and work sites), and residents will be informed of any traffic interruptions.
• Communicate transparently: A dedicated outreach team will be available to respond to public inquiries within approximately 48 hours and provide progress updates.

LOCATION: The project traverses a rural area, adjacent to North Twin Oaks Valley Road, approximately 2 miles north of the intersection at Deer Springs Road. Construction is in the unincorporated area of San Diego County, just north of the City of San Marcos.

TIMELINE:

• 2013: Water Authority’s Capital Improvement Program is approved by the board, including 82.5 miles of critical pipe upgrades throughout San Diego County
• Spring 2022: All project designs and permits are approved, early outreach activities begin
• Mid-September 2022: Construction begins
• Mid-October 2022: Overnight work

• Mid/Late October 2022 to Early April 2023: Normal Construction
• Mid April 2023: Overnight work
• Late April 2023: Normal Construction
• Summer 2023: Estimated completion of project

SIGN UP FOR ALERTS:

To sign up for project alerts, please complete the form at the link below and select the “Twin Oaks Relining” distribution list.