SAN VICENTE DAM RAISE CONCEPTUAL DESIGN

摘要

The San Diego County Water Authority (Water Authority) will be raising San Vicente Dam in San Diego County, California to increase emergency water storage, and possibly carryover storage, for the region. The existing 220-foot high concrete gravity dam will be raised by as much as 117 feet using roller compacted concrete (RCC), expanding the usable reservoir capacity by up to 152,100 acre-feet. San Vicente Dam and Reservoir are owned and operated by the City of San Diego (City) for water supply purposes. Following the dam raise, the Water Authority and City will jointly use the expanded reservoir for a variety of water supply purposes. An advanced conceptual design of the dam raise was developed during the planning/permitting phase of the project that provided three major benefits. First, key regulatory agency approvals in the areas of geologic hazards, seismic criteria, and inflow design flood were obtained that will allow the final design process to be more efficient. Second, critical coordination issues with ongoing, interdependent conveyance projects at the site were resolved early and key dam raise design parameters were agreed upon between the Water Authority and City. Third, the conceptual design data developed for the project verified the feasibility of raising the dam 117 feet. Four areas of the conceptual design process are discussed in this paper: evaluation of the condition of the existing dam, geotechnical explorations, aggregate supply source identification, and outlet works configuration. The conceptual design for this project was advanced further than traditional conceptual designs, and will help define an array of design parameters that will allow the final dam design to proceed more efficiently. The results of the conceptual design are summarized in a guide for final design, and associated technical memoranda, that form a clear handshake between the planning level and final design phases of the project.