In case we need another example of the disturbing ramifications of extreme drought for our future water security, we can look to recent news out of northwest Texas.
The High Plains Water District, based in Lubbock, recently reported that the 2011-12 drought drove groundwater levels in its sixteen-county service area to drop an average of 2.56 feet (0.78 meters) – the largest annual decline recorded in the last 25 years and more than triple the annual average for the last decade.
The lesson: as droughts intensify, our depletion of groundwater will pick up speed.
The recent Texas drought was indeed severe. Lubbock’s rainfall for 2011 amounted to a meager 5.86 inches compared to its long-term annual average of 18 inches.
Besides setting the stage for a record-breaking fire season, the drought forced farmers to pump more groundwater to make up for the rainfall deficit. Without the extra pumping, the drought would have decimated their crops.
Farmers in the District draw from the Ogallala Aquifer, a vast underground water reserve that supplies portions of eight states and waters 27 percent of the nation’s irrigated cropland. Since much of the aquifer gets little recharge from rainfall today, rising rates of pumping have led to steady depletion. According to the U.S. Geological Survey, a volume of groundwater equivalent to two-thirds of the water held in Lake Erie has been depleted from the Ogallala since 1940.
Because large-scale irrigation began earlier in northwest Texas and replenishment rates there are less than in other areas supplied by the Ogallala, the region has suffered the heaviest declines. Water tables have dropped 100-150 feet in sizeable areas, and even more in smaller pockets.
But this year’s decline was exceptional. It warns the world that as droughts become more frequent, particularly in arid crop-producing regions, groundwater reserves will be depleted even faster than in recent decades, threatening not only water but food supplies.
California farmers similarly hastened the depletion of Central Valley aquifers during the drought years of 2006 through 2010, to compensate for both less rainfall and cutbacks in surface water. And farmers in India have turned more and more to groundwater as surface supplies get less reliable.
Hope on the High Plains
My hat goes off, though, to the High Plains Water District (HPWD) for deciding to measure and monitor what’s happening to the water beneath it. Few places in the world dependent on groundwater bother to do so, which means we’re flying blind into the future of water stress. We can’t manage what we don’t monitor and measure. Keeping our heads in the sand only guarantees ugly surprises down the road.
And manage is what the HPWD is attempting to do. A few months ago I wrote about the District’s new rule that places a limit or cap on the volume of groundwater farmers can pump from beneath their land, a limit that gets gradually stricter. The rule sets the 2016 pumping volume at 29 percent below 2012 levels.
Not surprisingly, farmers are not pleased with – and have threatened lawsuits over — the restrictions. They say the rule interferes with their right to pump as much water from beneath their land as they want to. Both Texas law and a February 2012 opinion by the Texas Supreme Court affirm that farmers do indeed own the groundwater beneath their property, but also that conservation districts like the HPCD can regulate pumping rates.
In response to the outcry and threat of legal action, the HPCD decided in late February to delay enforcement of the new rule until 2014.
But what the HPWD is attempting, and what is needed in other groundwater-dependent areas threatened by long-term depletion, is sound planning and management. By law, groundwater may be privately owned, but in reality it is a shared resource. Just as many straws in a water glass will empty the glass faster if there’s no limit on the amount allowed per straw, so will an aquifer dry out faster if there’s no limit on the volume pumped per well.
The District’s goal is to ensure that at least half as much water remains in the Ogallala in 2060 as it contained in 2010. While such “planned depletion” is still an unsustainable use of water, it slows the depletion down by promoting wiser choices about what crops to grow and how to grow them. And it motivates investments in irrigation efficiency, enabling farmers to get more crop per drop.
Without question, weighing concern for future generations against that of our own, and balancing private rights with the public good is difficult – especially during hard times. But pulling our heads out of the sand and coming up with realistic solutions to achieve the best balance we can is crucial.
It seems to me the Texas High Plains Water District is attempting to do just that.
Sandra Postel is director of the Global Water Policy Project and lead water expert for National Geographic’s Freshwater Initiative. She is the author of several acclaimed books, including the award-winning Last Oasis, a Pew Scholar in Conservation and the Environment, and one of the “Scientific American 50.”
*Note: Upon a re-read the day after publication, I edited the phrase describing farmer’s sentiments about the ruling to better reflect my understanding.