The owner, San Diego County Water Authority (SDCWA), will add 35.7m of RCC structure to the 67m high dam, or just over half the height again. Construction work is scheduled to take about three years to complete.

Final design work and engineering services during the construction phase of the project – the first major dam raise using RCC, and the largest raise of concrete dam in the US – were carried out by MWH.

The contract was awarded in late 2006, and also included project management, outlet works design, quarry design (for aggregates for the RCC), value engineering and cost estimates. In addition, the services included quality assurance and control reviews with the owner’s board of senior consultants, and coordination and permit liaison with the State of California Division of Safety of Dams.

A joint venture of Parsons and Black and Veatch will manage the project, which is to be completed by October 2012. The contract was awarded last year.

The San Vicente dam is located near Lakeside and was built in 1943.

The project is part of SDCWA’s 10-year emergency storage project to increase the amount of water available in San Diego County during emergencies, such as drought or earthquake. MWH said the project will increase reservoir storage by 187.5Mm3, or 170%, which would provide about six months of emergencies supply plus reserves for drought protection should imported water supplies by interrupted.