California water agency advances dam raise project

A California water agency and the Corps of Engineers called for comments until Nov. 9 on the second stage of a two-stage plan to increase the height of the 220-foot-tall San Vicente Dam by 117 feet.

San Diego County Water Authority and the Corps are preparing an environmental impact statement assessing a plan to raise the height of the concrete gravity dam by 63 feet beyond that of an already approved 54-foot dam raise. Comments were solicited on the environmental issues to be considered.

The new proposal would provide 100,000 acre-feet of carryover storage at San Vicente Reservoir. The EIS also is to evaluate an alternative to build a new dam and reservoir in Moosa Valley near Valley Center, Calif.

The project is to employ roller-compacted concrete, making San Vicente the world’s first major raise of a concrete dam using RCC, officials said.

The water authority and the Corps will prepare a draft environmental impact report/environmental impact statement that includes results of public scoping and technical studies. The parties anticipate completing the draft in the spring of 2007, at which time it will be circulated for public review and comment. A final EIR will be considered by the water authority board, while the Corps is to sign a record of decision for the EIS.

Raising San Vicente Dam by the initial 54 feet would provide about 52,100 acre-feet of emergency storage capacity over the present capacity of 90,000 acre-feet. That work is part of an $834 million Emergency Storage Project the water authority approved in 1996 to provide local water storage for emergency needs within its service area. SDCWA is a public agency that serves the San Diego region as a wholesale supplier of water from the Colorado River and northern California.

The Emergency Storage Project includes several phases, including: construction of 318-foot-tall Olivenhain Dam, completed in 2003; a pipeline connecting Olivenhain Reservoir to the water authority’s second aqueduct, completed in 2002; a pipeline connecting Olivenhain Reservoir with Lake Hodges; the 54-foot raising of San Vicente Dam; a pipeline connecting San Vicente Reservoir to the second aqueduct; five new pump stations; and related facilities. The project also includes plans for a 40-MW pumped-storage plant, the Olivenhain-Hodges Pumped-Storage project (No. 12473), which is scheduled for completion and operation by January 2008.

SDCWA names engineer, construction manager

SDCWA awarded a $19.5 million professional services contract in July to MWH Global Inc. for design and engineering services of the San Vicente Dam raise project. Design work is to be completed in June 2009 and support services, including bidding, construction, and refilling of the reservoir are to be completed in September 2014.

The water authority also awarded a contract to Parsons Brinckerhoff to provide construction management and inspection services for coordinating three construction contracts for a new pump station, surge control facilities, and a large pipeline.

SDCWA has considered submitting a preliminary permit application to the Federal Energy Regulatory Commission for permission to study a pumped-storage project that would use San Vicente Reservoir as a lower reservoir.

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