San Vicente Dam Raise

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San Vicente Dam Raise passes safety tests; re-filling begins

The San Vicente Dam Raise project added 152,000 acre-feet of water storage capacity to the reservoir – but before the expanded capacity could be used, the raised dam was required to satisfy state regulators. The California Department of Water Resources Division of Safety of Dams provided oversight during design and construction, along with post-construction safety certification.

In October, the Water Authority and the City of San Diego successfully performed an emergency release of water as a test, and the state certified the emergency release system. The state also required drilling a series of 6-inch diameter “cores” to assess the strength of the new structure.

Based on the initial core assessment results, the Water Authority was allowed to fill the reservoir 30 feet above the dam’s original elevation starting in May. The final analysis of the coring test results was being prepared for the state’s review at year’s end, moving the Water Authority closer to final certification of the dam. By June, construction of the buildings, boat ramp and parking lot for the new and improved marina also were complete.

The storage volume added by the dam raise is greater than any reservoir in the county, a vital hedge against water shortages. About one-third of the reservoir’s added capacity – 52,000 acre-feet – is for stored for emergencies. The rest is “carryover” storage designed to be filled during wet years and tapped to meet demands in dry years.

Video: San Vicente Dam Raise Dedication

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Raised dam dedicated by state and regional leaders

Approximately 200 state and local water leaders, elected officials, civic and business leaders, and community stakeholders attended a dam raise dedication ceremony at San Vicente Dam in July to celebrate the largest water storage project in San Diego County history. It was, once again, proof that the San Diego region is committed to doing what it takes to maintain a safe and reliable water supply.

The San Vicente Dam Raise Project is the largest piece and final major element of the Water Authority’s $1.5 billion Emergency Storage Project, a system of reservoirs, interconnected pipelines, and pumping stations designed to ensure a six-month supply of water for the San Diego region in case imported water deliveries are interrupted – for instance, by an earthquake.

Started in 2009, it was the tallest dam raise in the nation and the tallest in the world using a construction technique called roller-compacted concrete. Roller-compacted concrete is just as strong as conventional concrete but takes less time and water. It is placed in layers, one on top of the other, in a process that resembles road construction. The dam now stands 337 feet tall, an increase of 117 feet.