With the recent heavy rains, our water supply may not be at the top of everyone’s worry list. Even so, last week the San Diego County Water Authority gave an update on the future of water in our region.
The County Water Authority was created by the Legislature in 1944. Its 24 member agencies provide about 75% of our water and serve 3.3 million people. But only 17% of our water comes from local supplies, which include the nation’s largest desalination plant at Carlsbad.11% originates in Northern California, and 72% from the Colorado River. This includes a water transfer agreement with the Imperial Irrigation District that supplies about 35% of our water.
We’ve spent billions on raising local dams, on lining the Coachella and All American Canals to eliminate seepage, on construction of the Carlsbad desalination plant, and on many other projects aimed at diversification and increased supply. While supplies are adequate for today, steps will be necessary to secure our water future.
The County Water Authority does not have a pipeline that connects directly to the Colorado River – we have to pay the Metropolitan Water District (MWD) for those deliveries, which is costly and has led to litigation. Several alternative conveyance systems are now under review. Two alignments, one along the Mexican border and another further north, would both end at the San Vicente Reservoir. A third through the Borrego area would end at the Twin Oaks Water Treatment Plant in San Marcos.
Our past diversification efforts were successful. In 1991, 95% of our water was imported from the MWD, but through diversification, only 2% will be imported from MWD by 2035. San Diego’s water future is brighter than many parts of California that haven’t been as innovative, but we can’t rest on our laurels.