The San Vicente Dam, Lakeside, Calif., soon will be the tallest dam of its type in the world. The San Diego County Water Authority is raising the 220-foot-tall dam an additional 117 feet. This is the last key element of the Emergency Storage Project, which will provide the San Diego region with water in the event of an emergency.
The $568 million project will be the tallest dam raise in United States history. General contractor Barnard Construction Co. Inc., Bozeman, Mont. is working with Fraco Products Ltd., St-Mathiassur-Richelieu, Quebec, and American Hydro, York, Pa. Both Fraco, which is known for its mast climbing access systems, and American Hydro, a hydrodemolition company, supplied equipment for the first phase of the project, and were also involved in the renovation of the Robert Moses Dam at Niagara Falls, N.Y.
Construction on the San Vicente Dam started in 2009 and is expected to run in multiple phases until 2012. The first phase includes removal of two to three inches of concrete from the dry side of the dam to create a bonding surface for new concrete.
To prepare for the concrete removal, mast sections were installed to the dry side of the dam, however, one obstacle was the inclining dam face. According to Tim Riley, southern California representative for Fraco, some of the mast sections needed adjustments. “The first mast section placement to the far left took four days as the dam is not quite flat as it was supposed to be; conditions changed as each 30 feet of mast was flown into place. The second layout of mast took about two days with some fine tuning of the custom shims. We installed the third mast section in one day as we built the mast on the ground and copied the shim and spacer brackets to match the second install.”
After the first three rails were installed, American Hydro fit its robot—converted from a Fraco platform to accommodate their equipment—onto the first mast section to start the concrete removal. Each mast section was moved to another area of the wall to prepare for the next section as work progressed.
The first phase of preparing the foundation finished at the end of May 2010, with the second phase scheduled for completion by the end of 2012. The rest of the project includes pipeline replacement, marina construction, and site restoration. Depending on rainfall and demand for water, the reservoir should refill and open to the public sometime between 2014 and 2017.
The dam is being built strong enough to operate in the event of a major earthquake. When finished, it will stand 337 feet tall and create a 242,000 acre-foot water reservoir—a 152,000 acre-foot increase. One acre-foot equals 325,900 gallons, about the amount of water two families of four use in one year.