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San Vicente Dam Raise

San Vicente Dam Raise

San Vicente Dam Raise - San Diego County, California

Upgraded Facility Creates New Emergency Water Storage

The San Diego County Water Authority (SDCWA) imports up to 80% of the region’s water supply—from more than 400 miles away—and its pipelines conveying this imported water to the county cross several major fault lines. Therefore, SDCWA is increasing local storage to reduce the region’s reliance on imported water supplies and providing a more flexible conveyance system for use during emergencies. SDCWA’s project to raise San Vicente Dam is part of its water diversification strategy. Preparation for the dam raise began in 2009, and in 2010, construction began to raise San Vicente Dam in order to increase water storage. This concrete gravity dam, owned and operated by the City of San Diego, was built in 1943 near Lakeside, an unincorporated community in San Diego County.

Raising the dam adds 500 acres to the reservoir surface area and increases capacity to approximately 242,000 acre-ft

Raising the dam adds 500 acres to the reservoir surface area and increases capacity to approximately 242,000 acre-ft

In keeping with our strategic focus on infrastructure, Parsons in a joint venture (JV) is managing construction of the San Vicente Dam Raise Project. This largest component of the fourth and final phase of SDCWA's $1.5 billion Emergency Storage Project (ESP) creates new emergency water storage and pipeline connections to deliver water if a disaster disrupts the imported water supply. The ESP, which has been under development for more than a decade, is a system of reservoirs, pipelines, and other facilities that work together to store and move water around the county in the aftermath of a disaster such as an earthquake. When complete, the entire ESP system will provide more than 90,000 acre-ft of additional local water storage capacity, enough to supply the region for up to 6 months. This new emergency storage includes 52,000 acre-ft in the expanded San Vicente Reservoir. The dam raise will also create an additional 100,000 acre-ft of “carryover storage” for use in times of drought, bringing the total San Vicente Reservoir expansion to 152,000 acre-ft.

World’s Tallest Roller-Compacted Concrete Dam Raise

The San Vicente Dam Raise Project is the tallest dam raise in the United States and tallest roller-compacted concrete (RCC) dam raise in the world. This project elevates the existing 220-ft-high dam by 117 ft and more than doubles reservoir storage capacity—the largest single increase in water storage in the region’s history. When complete, the additional storage will bring the reservoir’s total capacity to 242,000 acre-ft. An acre-ft is 325,900 gallons—enough to meet the needs of two average families of four for a year.

The project will raise the existing 220-ft-high dam by 117 ft

The project will raise the existing 220-ft-high dam by 117 ft

This new water storage capacity will serve two purposes:

  • Two-thirds of the additional storage (100,000 acre-ft) will capture surplus water during wet seasons
    for use during subsequent dry years, known as carryover storage water.
  • The other third of the new reservoir capacity (52,000 acre-ft) will store water for use if an emergency cuts off the San Diego region’s imported water supply.

Building for the Future

By agreement with SDCWA, the Parsons JV provided preconstruction services through constructibility reviews, independent construction management schedules and cost estimates, and contractor prequalification. During construction, we are working with SDCWA to provide construction administration, inspection, change management, schedule monitoring, and quality assurance/control, including startup and testing support.

Additional responsibilities include:

  • Onsite testing laboratory management
  • Reports/coordination/meetings with regulators
  • Shop drawing and submittal review
  • Plan/specification interpretation and control
  • Value engineering
  • Claims management
  • Post-construction closeout

The JV incorporated sustainable practices into this project:

  • The former marina serves both as a quarry and as a temporary RCC production site.
  • Aggregates for the RCC are being mined from the existing marina’s hillsides to limit truck traffic through the community, reduce the carbon footprint of the construction activities, and ensure the aggregate is available when needed for the 24/7 operation.
  • A ¾-mile-long conveyor system transports the RCC to the dam base, eliminating several thousand truck trips to transport the RCC—a volume equivalent to that of the existing dam.

The San Vicente Dam Raise Project is one of many major Parsons projects in southern California that improve quality of life. After the dam raise is completed in 2013, refilling the reservoir will take 2 to 5 years, depending on imported water availability. Built to remain operational during a major earthquake, the dam will provide San Diego County residents with a secure water source, support our local economy, and offer enhanced recreation opportunities on the expanded reservoir.