Agriculture in the Imperial Valley: A Tale of Two Seas

Agriculture in the Imperial Valley and the Salton Sea has a long and sordid past. The Salton Sea is located in the Imperial Valley, a region of California where the dominant economy is the production of crops. In order to create this farming oasis in the middle of the desert, 917,540 million gallons of water a year must be shunted to the Imperial Valley from the Colorado River. This is the beginning of the story of how an agriculture revolution has created and changed the largest body of water in California.

Row irrigation in Imperial Valley, Calif. 2009. Photo by Edward Burtynsky, courtesy of the Nicholas Metivier Gallery, Toronto, Howard Greenberg Gallery and Bryce Wolkowitz Gallery, New York.

The Salton Sea was originally formed in 1905 when massive rain and snowmelt overwhelmed the dams designed to contain the Colorado River and poured into the empty Salton sink. The dams were repaired quickly, but the Sea had already filled. By the 1930s water levels had noticeably dropped and most believed that the sea would naturally dry up. However, around the same time, cotton farming and the massive water shuttling began in the Imperial Valley [1], refilling the Sea with agricultural run-off.

While cotton is no longer grown in the region, irrigation run-off has remained the principle source of water for the Salton Sea. In return the Sea has provided the Imperial Valley with a more temperate climate, keeping winter temperatures optimal for year round crop growth. Today, the Imperial Valley provides 80% of the country’s winter crops, employs 50% of residents in the valley and grows a large share of the alfalfa used for cattle feed in California [2]. However these crops, particularly alfalfa, require a lot of water. This creates large amounts of irrigation run-off.

Compared to most agriculture regions in the United States the irrigation run-off that flows into the Salton Sea has considerably elevated levels of salt. Thousands of years of lake formation and evaporation cycles in the region have led to high salinity in the local soil. This means that in order to grow crops in region —most of which cannot tolerate the salt— the soil must flushed often. The run-off from this practice totals about 3 million tons of salt input into the sea annually, enough to fill about 40,000 railroad boxcars2. This salty water drains into the sea where the desert sun steals the pure water vapor and leaves behind the salt, which accumulates year over year, threatening the sea’s fish and bird populations [3].

Similarly, this irrigation run-off brings with it all the pesticides and fertilizers added to the fields, feeding algae blooms and burying chemicals at the bottom of the sea. Recent studies conducted in the Salton Sea have shown trace levels of several organic pesticides, including DDT and its derivatives, in the soil underneath the sea [4]. While sequestered in the sediment these pesticides poise little risk to the environment or human health. However, as water levels in the sea continue to drop this may change. If the sea dries up completely these pesticides and the salt will be exposed to the powerful winds that blow through the basin, kicking these chemicals up into the air, allowing them to be breathed in or to settle back down onto environmentally sensitive areas.

The sea needs agriculture as much as agriculture needs the sea. But striking a balance between health of the sea and the economic feasibility of growing crops is a difficult task to say the least. In today’s drought conditions farmers cannot afford to simply “waste” water by continuing farm practices with large irrigation run-off but without this water the sea will disappear, taking with it its’ microclimate and air quality protection. Thus this is a tale of two seas, one an invaluable resource, the other a ticking time bomb.

Written by Stacia Dudley

[1] Than, Ker. “Can California Farmers Save Water and the Dying Salton Sea?” National Geographic. National Geographic Society, 14 Feb. 2014. Web. 24 Apr. 2015.

[2] Polakovic, Gary. “Farm Runoff: Its’s An Ongoing Challenge.” Farm Runoff: Its’s An Ongoing Challenge. Accessed April 28, 2015.

[3] McClurg, Sue. “Environment and Economic Values of the Salton Sea.” Environment and Economic Values of the Salton Sea. Western Watern, Water Education Foundation, 1 Apr. 1994. Web. 24 Apr. 2015.

[4] Sapozhnikova, Yelena, Ola Bawardi, and Daniel Schlenk. “Pesticides and PCBs in Sediments and Fish from the Salton Sea, California, USA.” Chemosphere (2003): 797-809. Print.

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