U of Texas scientist Bridget Scanlon has gotten her recent comparative study of California and high plains irrigation into PNAS. The upshot is that the arid more subtropical subregions are depleting groundwater rapidly, as we alluded have pointed out recently.
Three results of the new study are particularly striking: First, during the most recent drought in California’s Central Valley, from 2006 to 2009, farmers in the south depleted enough groundwater to fill the nation’s largest man-made reservoir, Lake Mead near Las Vegas—a level of groundwater depletion that is unsustainable at current recharge rates. Second, a third of the groundwater depletion in the High Plains occurs in just 4% of the land area. And third, the researchers project that if current trends continue some parts of the southern High Plains that currently support irrigated agriculture, mostly in the Texas Panhandle and western Kansas, will be unable to do so within a few decades.
California’s Central Valley is sometimes called the nation’s “fruit and vegetable basket.” The High Plains, which run from northwest Texas to southern Wyoming and South Dakota, are sometimes called the country’s “grain basket.” Combined, these two regions produced agricultural products worth $56 billion in 2007, accounting for much of the nation’s food production. They also account for half of all groundwater depletion in the U.S., mainly as a result of irrigating crops.
PS – Looking for a DOI or a link.