The Flume

It was a big event in San Diego. How big? On the front page of the San Diego Union on February 22, 1889, Washington’s Birthday was bumped four columns over by an article on the dedication of the San Diego Flume.

The flume was a massive irrigation project that damned the waters of the San Diego River at the base of the Cuyamaca Mountains, then relayed that water through a network of 35 miles of wooden chutes, climbing atop hundreds of trestles and down through excavated tunnels, winding through the El Cajon Valley to be impounded in another reservoir in La Mesa, from which pipes carried the water to the city of San Diego.

Here’s a photo from the 1908 book History of San Diego: 1542-1908 by William E. Smythe showing a delegation of officials in flat-bottom boats riding the flume as part of the dedication ceremony. The bearded man sitting on the far right in front is then-California Governor Robert Waterman.

Access to a steady water supply was crucial to San Diego City and County. Up until the mid-nineteenth century, San Diego County farmers and ranchers practiced water management individually by digging wells, creating earthen dams to form local reservoirs, and keeping careful track of rainfall. The last half of the century saw growing collective action within and between individual communities, private companies and public efforts at the county and state level to promote irrigation and other conservation programs. The city of San Diego’s first water company was formed in 1873. The San Diego Flume Company was founded in 1886. Other water companies and irrigation districts began to form throughout the county, like the Escondido Mutual Water Company and the Vista Irrigation District, formed in 1904 and 1923 respectively. Local, county and state water management efforts became more intertwined with the creation of the Metropolitan Water District (MWD) of Southern California in 1928 and the California State Water Project (SWP) in 1960.

The MWD brought a steady supply of Colorado River water to San Diego County, while the SWP linked our water systems to the reservoirs of northern California.

These efforts along with aging infrastructure made the flume system obsolete by the 1930s and led to its abandonment. But remnants of the old trestles and tunnels can still be seen in parts of the county.