Friends of Farming

 San Diego County

A Short History of Developed Water

22 Jan 2016 4:07 PM | Deleted user


The history of farming in San Diego County runs hand-in-hand with the history of water development. From the building of the Old Mission Dam across the San Diego River in the late 1700’s to the anticipated delivery of desalinated water this fall, farmers not blessed with groundwater have relied on the maze of dams, aqueducts, and pipes that bring water right to the farm.  Knowing the history of the water system is important in understanding today’s water situation.

By the 1920’s all of San Diego County’s main watersheds had dams and reservoirs installed.  The military presence needed for World War II and post-war growth swelled the local population and threatened to outstrip the local water supply.  In 1947 water arrived from the Colorado River through the first of several San Diego County Water Authority (CWA) aqueducts that would connect the San Diego region to the supplies of the Metropolitan Water District of Southern California (MWD).  The aqueduct connecting to the Colorado River had been completed by MWD in 1935.

Continued growth in southern California and throughout the state meant more water was needed and in 1960 California voters authorized construction of the State Water Project, one of the largest publicly built and operated water projects in the world.  That project collects water from Northern California rivers behind dams and releases that stored water into the Sacramento/San Joaquin Delta (Delta) for pumping and delivery to urban and agricultural locations south of the Delta.  Thirteen years after voter approval the first of the State Water Project water arrived in San Diego in 1973.

Little was done between completion of the State Water Project and the California drought of 1987-1992.  That drought convinced decision makers at MWD and CWA that they needed additional sources to augment their Colorado River and State Water Project supplies.  That launched the still continuing period of local storage and supply projects, most notably MWD’s construction of the Diamond Valley Reservoir, CWA’s purchase of transfer water from the Imperial Irrigation District, and the concrete lining of canals in the Coachella and Imperial Valleys with the water saved by stemming seepage coming to MWD and CWA.

Knowing that population growth and climatic or weather change will continue to challenge water supplies, local water projects remain a top priority with the Carlsbad desalination project, expanded use of recycled water, and the future promise held by potable reuse, which is the  reintroducing treated wastewater into the potable water system, at the top of the list. 

On a statewide basis plans call for construction of additional storage to capture wet-weather flows.  Those storage projects were endorsed and partially funded by the voter approved Proposition 1 in November 2014.  Yet known is how the state will tackle vulnerabilities in the Delta that threaten the stability of supply from seismic shifts and environmental constraints.

Farming will continue in San Diego County in direct relation to the reliability of the developed water supply.  Another hiatus in supply development as occurred for 20 years between 1973 and the 1990’s could spell trouble.       

Friends of Farming San Diego County            420 South Broadway, Suite 200, Escondido, CA 92025          760-745-3023             taylor@sdfarmbureau.org

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