Pipeline Upgrade Prepares for Seawater Desalination

Pipeline Upgrade Prepares for Seawater Desalination
The San Diego County Water Authority is relining an existing large drinking water pipeline in San Marcos in preparation for a new, drought-proof water supply from the coast: seawater desalination. Most of the construction for the Pipeline 3 Desalination Relining Project will take place underground inside the pipeline, but some work above ground will impact local City streets. Pipeline relining will not interrupt water service to nearby homes or businesses. 

Construction will be ongoing through May 2015. Crews will enter the pipe by excavating access sites or “portals” along the pipeline in the Water Authority’s easement. At the portals, workers will remove approximately 40 feet of existing pipe to gain access to the interior of the pipe and to install relining materials.

Five portals are within the City boundary (click to view map). Portal 15 is located at the intersection of Descanso Avenue and Pawnee Street immediately east of Rancho Santa Fe Road and south of Highway 78. The Descanso-Pawnee intersection has been closed for construction. All businesses in the area remain accessible via adjacent streets.

Portals 11-14 are within the Water Authority’s easement in off-City street sites north of Highway 78. These portals will not require street closures. Ten additional portals north of City boundary extend to the Water Authority’s Twin Oaks Valley Water Treatment Plant.

Sound walls will be temporarily placed around portals where they are needed to reduce noise impacts to residents and businesses, and to comply with environmental regulations. Nearby residents and businesses will see construction traffic approaching and departing the portal sites through May 2015. Upon completion, the work areas will be restored to their previous condition.

Pipeline 3 is being relined to accommodate pressurized flows from the Carlsbad Desalination Project, which is now in construction. The upgraded Pipeline 3 will convey desalinated seawater northward to the Water Authority’s regional facilities in Twin Oaks Valley. From there, this new supply will blend with imported water to enhance the reliability of our region’s water supply. A new east-west pipeline is under construction to connect the desalination plant in Carlsbad to Pipeline 3 in San Marcos.

For more information about the Pipeline 3 Desalination Relining project, please contact the Water Authority’s project information line at 877 682-9283, ext 7005 or email CIPinfo@sdcwa.org. Water Authority staff will respond within one business day.

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