San Vicente Dam, Gravity dam in San Diego County, California, United States

San Vicente Dam is a concrete structure built across San Vicente Creek that stores water in a large reservoir for regional distribution. The installation includes pumping stations and pipeline networks that deliver water to communities throughout the area.

Construction of San Vicente Dam began in 1941, after San Diego voters approved funding in 1940, and was completed in 1943; the reservoir only began receiving Colorado River water in 1947, once the First San Diego Aqueduct was finished. Between 2009 and early 2014 the dam was raised 117 ft (36 m), from 220 ft to 337 ft, more than doubling reservoir capacity from 90,000 to 242,000 acre-feet.

The reservoir's name comes from the San Vicente valley and creek it flooded; the dam's concrete was poured in blocks 5 by 50 feet wide. The reservoir was closed to recreation during the raise and was to reopen between 2014 and 2017 once it refilled to normal levels, restoring fishing and boating.

The reservoir was closed to recreation when the dam raise began in 2009, and reopening depended on the water reaching normal levels, expected between 2014 and 2017. Replacement of the water supply pipelines continued until 2015. Check current access conditions before travelling to the site near Lakeside.

The 2014 project raised the existing structure by more than one-third without stopping the daily water supply to the region. These works demonstrate how engineers can expand older infrastructure while keeping it fully operational.