Project Background

The Water Authority’s First Aqueduct delivers untreated water from just south of the Riverside County/San Diego County border to San Vicente Reservoir through two large-diameter pipelines – Pipeline 1 and Pipeline 2, which are between 48 and 54 inches in diameter. Both pipelines were constructed by the federal government soon after World War II to transport the first imported water to the San Diego region. The First Aqueduct continues to be a vital part of the regional water delivery system providing untreated water service to 11 of the Water Authority’s member agencies, ensuring regional water service remains safe and reliable.

The purpose of this project is to retrofit, replace, or abandon 99 unique structures (48 structures on Pipeline 1 and 51 structures on Pipeline 2) over 21 miles of the southern portion of the First Aqueduct from Hubbard Hill in northern Escondido to the San Vicente Reservoir in Lakeside. These structures consist of blow off valves for releasing water and draining the pipeline, manway (i.e., manholes) pipeline access points, and air valves for releasing air in the pipelines. In addition, connections to existing flow control facilities are being expanded between the two pipelines to improve the aqueduct’s operational flexibility.

Blow off structures require the most complicated upgrade process. They will be demolished and reconstructed to current engineering and safety standards. Air valve and manway structures will be rehabilitated by construction of new access lids and a small portion of obsolete pipeline structures will be abandoned. The rehabilitated structures will include new piping, enhanced safety features like new ladders and standing platforms for improved confined space access, mechanical improvements, and other appurtenant upgrades. The current estimated cost is $34 million.