The San Vicente Dam is a concrete gravity dam on San Vicente Creek near Lakeside and 25 km (15.5 mi) northeast of San Diego, California. The dam was built between 1941 and 1943 and created San Vicente Reservoir for the purpose of municipal water storage, flood control and recreation. Although the reservoir is fed by run-off, its main source is the First San Diego Aqueduct. In June 2009, construction to raise the height of the dam by , in order to more than double its reservoir size, commenced. It is the largest dam raise in the United States and largest roller-compacted concrete dam raise in the world. The dam raise project was originally set for the end of 2012, but was completed in early 2014. Efforts to replace the water supply pipelines and prepare the reservoir for the public will be underway until 2015–2017. History In the late 19th century, San Diego began constructing dams to help supply municipal water, mitigate drought and control floods in the San Diego River Basin. In 1928, the Metropolitan Water District of Southern California was created and charged with transferring water from the Colorado River to southern California but San Diego was excluded from the project. Construction of the Colorado River Aqueduct had begun in 1933 and was completed in 1941. However, construction on the San Vicente Dam began in 1941 with anticipation of San Diego receiving water through the Colorado River Aqueduct. San Diego residents had initially rejected proposals to build the San Vicente Dam in 1939 but after the realization of the city's growing population, voters quickly approved funding for the San Vicente Dam in 1940. Construction on the dam included pouring concrete into blocks measuring and incorporating a wide uncontrolled ogee-type spillway on the dam's downstream face. The outlet works, which release water for municipal use, connected the reservoir intake on the upstream side of the crest with San Vicente Pipelines 1 and 2 via three cast-iron pipes in diameter. In 1944, the San Diego County Water Authority (SDCWA) was formed and would soon begin construction on an aqueduct from the Colorado River Aqueduct called the San Diego Aqueduct to supply projected future water needs. Construction on the San Vicente Dam was completed in 1943 but construction on the First San Diego Aqueduct, which was supplied by the Colorado River Aqueduct, did not begin until 1945. It was not until 1947