By Mallory Pickett
Kelly Watson lives in Kentucky. She studies honeybees and pollination. She has no interest in wading into California’s water wars, in which farmers and thirsty almond crops are pitted against drought-conscious water conservation zealots.
But when the results of her latest research are published, she will likely be involved whether she wants to or not.
Watson, an assistant professor of geosciences at Eastern Kentucky University, is an expert in remote sensing. She uses satellite images to study agriculture, specifically the interactions between honeybees and industrial agriculture. At the beginning of this year she started a project with one of her graduate students, Larissa Watkins, looking at aerial photos of California almond farms. The goal was to predict how the rapid increase in almond orchards would affect demand for honeybee pollination.
But when they started processing satellite photos of California’s agricultural region taken between 2007-2014, they noticed a surprising trend.
Many areas that were classified as natural land cover—things like grasslands, wetlands and forests—were being converted to almond orchards.
“We were really shocked when we started looking at the data,” Watson says. “I was surprised this is happening in California with all the attention on the drought.”
So Watson and Watkins pivoted, deciding to put honeybees aside and instead quantify the land use changes and how they affected water use.
What they found was shocking: based on their estimates, 23,000 acres of natural land have been converted to almond farms. 16,000 of those acres were land previously classified as wetlands. Additionally, some agricultural land has been converted from lower-water crops to almonds.
Overall almond acreage increased about 14% in California between 2007-2014, so Watson says based on that number you would expect about a 14% increase in irrigation needs for almonds. But because so much land was converted from natural land or lower-water crops, the irrigation increase for the almond industry was nearly twice that. Watson and Watkins calculated that the growth of almond farms caused a 27% increase in irrigation demands for almond farms between 2007-2014—an increase that coincides with an historic drought in California, which started in 2011 and continues to plague the state.
This research, which will be presented at the Geological Association of America Annual meeting in Denver today, has yet to be peer-reviewed, and Watson is quick to qualify their results by noting that aerial images can only paint broad brush pictures of what’s going on. Individual pixels in a satellite photo cover almost 1,000 square feet, making it hard to get a detailed understanding of the landscape. The USDA and the state government verified the land classifications in Watson’s data, but wetlands are notoriously difficult to identify via satellite and it’s possible that some of what looks like wetlands in aerial photos are actually flood-irrigated farmlands.
But her preliminary results show that the soaring demand for almonds, and the ensuing boom in almond farming, has had profound impacts on California’s agricultural landscape and water use. Watson hopes the next step in her research will be a trip to California, to document land use changes from ground level.
Spending this time studying land use and irrigation has been a “side project that became very eye opening,” Watson says. But she looks forward to getting back to the honeybees.