The San Diego County Water Authority Board of Directors today certified the enironmental impact report to raise San Vicente Dam by 117 feet. The $568 million project, to be built on top of the existing San Vicente Dam in Lakeside, will expand the reservoir to hold an additional 52,000 acre-feet of water for use during emergencies and another 100,000 acre-feet of water to supplement imported supplies during dry periods.
“Raising San Vicente Dam will significantly enhance our water supply reliability,” said Water Authority Board Chair Fern Steiner. “As we face increased challenges to our water supplies, we not only must diversify our water supply portfolio, we must also improve our infrastucture to reliably store and deliver water to our region.”
Construction is scheduled to begin in early 2009 and to be completed in late 2012. This project will be the largest dam raise in the United States and the largest in the world using roller compacted concrete.
The raising of the San Vicente Dam has two key components: emergency storage and carryover storage. The raising of San Vicente Dam is the fourth phase of the Water Authority’s approximately $1.2 billion Emergency Storage Project. The ESP will provide up to six months of water if a natural disaster such as an earthquake cuts off the region’s imported water supplies. It achieves this through 20,000 acre-feet of water storage in Lake Hodges, 18,000 acre-feet in the Olivenhain Reservoir, as well as 52,000 acre-feet in San Vicente Reservoir, providing a total of 90,000 acre-feet of water for use during emergencies.
In addition to emergency storage capacity, San Vicente will hold 100,000 acre-feet of water for carryover storage. Carryover storage allows the Water Authority to store water during wet periods for use during subsequent dry years. In total, the additional 152,000 acre-feet of water in San Vicente could meet 40 percent of San Diego County’s needs for a year.
The city of San Diego, which owns the San Vicente Dam and Reservoir, has begun lowering the reservoir’s water level in preparation for the project. Fishing and water recreation at the reservoir will be allowed starting May 1, 2008 through the summer. Fishing will be allowed on Thursday and Friday, and water sports will be permitted Friday through Sunday. To assure public safety, the reservoir will be closed to all recreation when the water level drops below the boat launch at the reservoir’s marina. It will remain closed during dam construction. The reservoir will reopen to recreation between 2014 and 2017, when the water level reaches the boat launch at the reservoir’s new, expanded marina.
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