An Expensive Way to Ease California's Drought: Desalinization Plants

With the middle of April approaching, there is no significant precipitation in the forecast for California in the coming ten days, and there is a good chance that the California rainy season is at least 95% over. As wunderground's weather historian, Christopher C. Burt, documents in his April 3 California Drought Update, the California rainy season lasts from October to mid-April, and typically only 10 - 15% of the rainy season precipitation falls after April 1. While enough precipitation fell over the past two months to prevent the current rainy season from hitting record low precipitation levels, the 2013 - 2014 rainy season was the third consecutive poor rainy season, leaving California in a dire drought situation. The winter of 2013 - 2014 had the most severe winter drought conditions since record keeping began in 1895, and California faces a long, dry summer with a Sierra snowpack that is only 33% of normal. The April 3, 2014 Drought Monitor is showing that 99.8% of California is in drought, with 95% of the state in Severe, Extreme, or Exceptional drought.


Figure 1. Predicted precipitation for the 7-day period ending at 8pm EDT Sunday, April 13, 2014. No significant rain is expected to fall in California in the coming week. Image credit: NOAA/HPC.

Ways to Ease California's Drought
There is only one major river in the Southwest, the Colorado River, and in most years the flow in the river is far less than the amount of water allocated to stockholders drawing water from the great river. Over 30 million people depend on the Colorado River for their water, including much of Southern California, and the river irrigates farmland that produces 15% of the nation's food. Two major studies, one by the U.S. Bureau of Reclamation in 2012, and one by the non-profit Pacific Institute in 2013, laid out five major ways that the Colorado River basin can get more water. As I outlined in Part 1 and 2 of this series last month, two ways to get more water for the thirsty Southwest are through conservation measures and cloud seeding. A much more expensive way--typically costing 2 to 20 times more than conservation techniques--is to make fresh water out of salt water using a desalinization plant.


Figure 2. Arizona's Yuma Desalting Plant, used to treat saline agricultural runoff and create fresh water. Image credit: U.S. Bureau of Reclamation.

Desalinization Plants
Fresh water can be wrung out of the ocean by forcing it through filtration membranes used in the reverse osmosis process. The high pressures needed consume a lot of energy--even more energy than it takes to pump water from Northern California rivers to Los Angeles over a 2000'-high mountain obstacle. Desalinized water provides less than 1% of California's fresh water, and costs nearly double what water imported from Northern California rivers and the Colorado River costs. However, given that desalinized water is "drought-proof", there are efforts to greatly expand the creation of fresh water from the sea. The $734 million Carlsbad Desalination Project in San Diego County, California, scheduled to be completed in 2016, will generate about 56,000 acre-feet annually, at a projected cost of $2135 per acre-foot. This largest desalinization plant in the U.S. is projected to meet 7 percent of San Diego County’s demand in 2020, and will push up the typical home's water bill by $5 to $7 a month, according to the San Diego Water Authority. A sister plant has been proposed near Los Angeles. California currently has six operational desalinization plants, with three others that are partially or fully idled due to their high cost of operation. remains unused and has been partially dismantled, because the city found cheaper sources of water.

I’ll discuss several other ways California can get more water in future blogs posts in the coming weeks.

Jeff Masters