Salt Buildup Growing In CA Central Valley; 88,000 Acres In One District Already "Retired"
In much of California’s flat, sunny San Joaquin Valley, canals deliver the irrigation water that has made the state an agricultural powerhouse, supplying one-third of vegetables and two-thirds of fruit and nuts eaten in the United States. But along the west side of the valley, some fields are sprouting not crops, but solar panels. The water that made this agricultural land productive also spelled its doom. Because most water contains salt, irrigating adds salt to soil over time, especially in arid and semi-arid places with little rainfall and poor drainage.
“Anytime you use water, you leave salt behind,” said Jeanne Chilcott, environmental program manager for the Central Valley Regional Water Quality Control Board. “The salt moves where the water goes.” An agency that allocates water to farmers in Fresno and Kings counties in central California, Westlands Water District, has retired 88,000 acres because the soil is now too saline to grow food. The district is buying the tainted land from farmers, reallocating their water rights to other growers, and then selling the land for other purposes such as solar farms. “We have about a dozen solar projects that are somewhere in the works,” said Gayle Holman, public affairs representative for Westlands.
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Yet salt in the San Joaquin Valley continues to increase, especially during drought years. That’s because, during droughts, California’s farms and cities rely on groundwater for up to 60 percent of their freshwater supply, up from 35 percent in non-drought years, and groundwater tends to be saltier than river water. People have been using groundwater faster than it naturally replenishes, dropping water levels deeper underground. Pumping groundwater near the coast can leave a vacuum, sucking in increased seawater, Grattan said. Affected coastal areas include Salinas to Monterey to Oxnard to Lompoc, he said. Climate scientists predict the future will bring more frequent, intense droughts to the semi-arid state.
Also, many growers in the San Joaquin rely on imported water from the Sacramento-San Joaquin Delta, which is saltier in drought years when lower river flows don’t push back ocean tides as much, Grattan said. “More salt is coming into the valley than leaving it,” said Daniel Cozad, executive director of CV-SALTS (Central Valley Salinity Alternatives for Long-term Sustainability), a collaboration of stakeholders studying possible solutions to salt and nitrate problems.
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http://www.environmentalhealthnews.org/ehs/news/2017/march/in-california-salt-taints-soil-threatening-food-security