Southern First Aqueduct Facilities Improvement

Project Background

The First Aqueduct delivers both treated and untreated water to 11 water agencies countywide, transporting up to 120 million gallons of water per day to the San Diego region.

After more than 7 decades of safe operations, the Southern First Aqueduct Facilities Improvement Project will renovate portions of two major pipelines that were built by the federal government in the late 1940s and 50s.

Funding for the $66 million effort comes from water bills across the region as part of the Water Authority’s Capital Improvement Program. When complete, the project will extend the lifespan of these vital historic pipelines by at least 50 years to ensure continued delivery of safe and reliable water supplies for the region.

Your Water Bill at Work

The three-and-a-half-year project is one of the most extensive maintenance efforts in the agency’s history.

Stretching 21-miles, the project starts north of Escondido and east of Interstate 15 and continues south to Slaughterhouse Canyon on the west and ends at the San Vicente Reservoir in Lakeside. Along the way the work crosses Escondido, Poway, Rancho Bernardo and parts of unincorporated San Diego County.

A total of 99 structures will be rehabilitated during the project. These structures contain blow-off valves for releasing water and draining the pipeline, pipeline access points, or air valves for releasing and letting air into the pipelines.

Connections to existing flow-control facilities are also being expanded between the two water pipelines to improve operational flexibility and maintain delivery to member agencies during construction.

This critical project will ensure that the First Aqueduct will continue to be a vital part of the regional water delivery system for decades to come.

 

Project Status: Current

Construction is divided into two phases, each one focusing on one of two parallel pipelines. Each pipeline is being shut down, inspected, and rehabilitated separately. This way, the Water Authority can ensure that one pipeline is always in service and avoid interruptions in water delivery to the Water Authority’s retail water agencies.

Phase I of construction began in spring 2024 and is ending in February 2025. Phase II of construction is due to begin in early March 2025 and is expected to continue through summer 2026.

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