Water Authority Makes History at San Vicente Dam

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The new San Vicente Dam more than doubles the water storage capacity of the original San Vicente Reservoir.

The San Diego County Water Authority has raised San Vicente Dam 117 feet, more than doubling the storage capacity of San Vicente Reservoir. In construction since 2009, the expansion represents the single biggest increase in water storage in San Diego County’s history. It is the largest dam raise in the U.S. and the tallest roller-compacted concrete dam raise in the world. The project was completed in spring 2014.

The Water Authority used roller-compacted concrete to raise the dam because it is just as strong as conventional concrete but can be placed more efficiently. The Olivenhain Dam, constructed by the Water Authority a decade ago, is also a roller-compacted concrete dam.

San Vicente Reservoir already has a distinguished history. Constructed by the city of San Diego in 1943, it was the first reservoir in the county to receive imported water when the Water Authority’s First Aqueduct was completed in 1947. The original dam stood at 220 feet and stored up to 90,000 acre feet for use by the city of San Diego.

The reservoir expansion made possible by the dam raise provides storage for an additional 152,000 acre-feet of water.  The new storage is owned by the Water Authority, and will be used to maintain water reserves for emergencies. If an earthquake or a severe drought curtails our imported water supplies, water from San Vicente Reservoir will provide emergency supplies for the southern portion of the county.

In April 2012 the original dam was still visible behind new roller-compacted concrete, which produces a stair-stepped appearance on the downstream side of the raised dam.

Workers placed the first layer of concrete for the foundation of the dam raise in September 2011. Thanks to the efficient construction allowed by roller-compacted concrete, the new dam rose swiftly, reaching the top of the existing dam in May 2012, and its full height just four months later. Additional work will continue at the reservoir through 2015 to construct a new marina and replace a portion of the reservoir bypass pipeline.

The city of San Diego has continued to operate the San Vicente Reservoir during construction to supply its customers, and owns its original 90,000 acre-feet of storage capacity. The two agencies will share the cost of operating the expanded reservoir. The city plans to reopen San Vicente Reservoir to the public as soon as the water level reaches the new boat ramp, between late 2014 and 2017 depending on the availability of imported water and local rainfall.

The original control tower, foreground, is dwarfed by the new dam. Construction continues on the new control tower at far right.

The San Vicente Dam Raise is the largest project of the Emergency Storage Project, a system of reservoirs, interconnected pipelines, and pumping stations designed to make water available to the San Diego region in the event of an interruption in imported water deliveries.

Web Cam Shows Progress at San Vicente Dam

A web cam system at San Vicente Dam allows the public to witness progress on the world’s largest roller-compacted concrete dam raise.  Two cameras offer different views of construction activities, enabling viewers to see weeks of dam raise work compressed into a brief time-lapse video. 

Click on Topside View   or  Downstream View for two vantage points of construction.  These high-resolution photos are updated every 30 minutes, providing a current snapshot of dam raise construction. The time-lapse sequences combine these photos, illustrating the construction process.


Project Fact Sheet

San Vicente Dam Project Web Page

News Release

Birds-eye view of the dam raise project

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