Tuesday, April 27, 2010

[Geology2] Time, Water Running Out for America's Biggest Aquifer

Time, Water Running Out for America's Biggest Aquifer

Dave Thier

Dave Thier Contributor

(April 21) -- In 1823, a government surveyor named Stephen Long was working to map out the Great Plains, an expanse of land acquired along with the Louisiana Purchase of 1803. He was unimpressed by what he saw. As his geographer wrote in the report that accompanied the expedition:
I do not hesitate in giving the opinion that it is almost wholly unfit for cultivation, and of course, uninhabitable by a people depending upon agriculture for their subsistence.
Long would have been shocked to see what the region looks like today -- not merely fit for cultivation, but in fact one of the most fertile and productive areas of the world. Since World War II, dramatic leaps in technology have allowed farmers to pump groundwater for irrigation and extend America's breadbasket through the entire Great Plains, transforming what Long called "The Great American Desert" into an expanse of green circles defined by the reach of central pivot irrigation systems.

But that water is not infinite, and many are becoming concerned that Great Plains agriculture is a more precarious proposition than it appears -- meaning Long's report may have been not just a description, but a prediction.
Ogallala Aquifer
Charlie Riedel, AP
A sprinkler sprays a field near Hoxie, Kan. Water for Great Plains irrigation comes from the Ogallala Aquifer, a vast underground lake that is being drained at an alarming rate.

That groundwater for irrigation comes from the Ogallala Aquifer, a massive underground lake that stretches from southern South Dakota through northern Texas, covering about 174,000 square miles. It is being drained at alarming rates, and some places have already seen what happens when local levels drop below the point where water can no longer be pumped.

"You go to areas where the aquifer has been depleted, [they] look pretty poor now," David Brauer, program manager for the U.S. Department of Agriculture's Agricultural Research Service Ogallala Aquifer Program, told AOL News. "And it only takes a few years.

"The magnitude of this is incredible," he continued. "We're talking about, for the last 20 years, 20 percent of the irrigated acreage of this nation is over the Ogallala."

For an idea of what a severe drought could do to the communities of the Great Plains, consider the Dust Bowl of the 1930s, when gigantic "black blizzards" ravaged farms and forced thousands of families to give up their land and try to make a living elsewhere.

But the implications of ceasing irrigation on the Great Plains go far beyond local communities. The farming areas fed by the Ogallala supply such large quantities of grain that any drastic changes to that economy would ripple across the world -- as seen in 2007, when fuel costs drove up corn prices and sparked a food crisis in other countries, most notably Mexico.

People have been warning about the aquifer's depletion for years, but coordinating conservation programs among farmers has proved difficult. Recently, Texas has imposed state controls on the amount of groundwater that farmers can pump, requiring 16 groundwater districts to each provide a target for an acceptable groundwater level in 50 years.

Such measures, however, are mostly designed to delay the inevitable, since the recharge rate for the Ogallala Aquifer is small enough to be considered negligible. And so, Brauer says, as a natural resource the Ogallala is comparable to a vein of coal: What you take out doesn't get put back in. "All we're doing is buying time," he says.

Buying time is important -- it will allow farmers to develop dry-farming techniques and give the biotech industry a chance to deliver on the promise of drought-resistant crops. But without groundwater irrigation, crop yields will almost certainly drop, and the local, national and global economies will have to adjust.

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