Ogallala Aquifer Only 20 Years Of Water Left >>> Stuff I Didn't Know [View all]

[KittyWampus]

The Ken Burns documentary on the Dust Bowl haunted me both nights.

First night I couldn't stop thinking about how maddening it would be to have storm after storm, year after year with no end in sight.

Second night, there's the fact at the very end of the documentary where they briefly mention farmers in that area started irrigating crops, growing corn which needs more water and that there's only 20 years left of water on the aquifer they are using.

Ogallala Aquifer

Ninety-five percent of the United States' fresh water is underground. One crucial source is a huge underground reservoir, the 800-mile Ogallala aquifer which stretches from Texas to South Dakota and waters one fifth of US irrigated land.
The aquifer was formed over millions of years, but has since been cut off from its original natural sources. It is being depleted at a rate of 12 billion cubic metres a year – amounting to a total depletion to date of a volume equal to the annual flow of 18 Colorado Rivers. Some estimates say it will dry up in as little as 25 years.

http://news.bbc.co.uk/2/shared/spl/hi/world/03/world_forum/water/html/ogallala_aquifer.stm


Even more worrisome, the draining of the High Plains water account has picked up speed. The average annual depletion rate between 2000 and 2007 was more than twice that during the previous fifty years. The depletion is most severe in the southern portion of the aquifer, especially in Texas, where the water table beneath sizeable areas has dropped 100-150 feet; in smaller pockets, it has dropped more than 150 feet.

Unfortunately, that water is not coming back any time soon. The Ogallala filled slowly during the Ice Age tens of thousands of years ago. The southern portions get very little recharge today.

snip

But the Texas irrigators have already begun adapting. They have shifted from old-style flood irrigation to more efficient sprinklers. The High Plains Water District maintains that irrigation efficiency rose from 50 percent in the mid-seventies to 75 percent by 1990. Since then, more farmers have adopted low-pressure drop-line sprinklers that deliver water closer to the crops instead of spraying it high in the air. When combined with field methods that conserve water in the soil, these precision sprinklers can achieve efficiencies of 95 percent. Some cotton farmers that have installed sub-surface drip systems, which deliver water at low volumes directly to the crops’ roots, have achieved efficiencies approaching 100 percent.
http://newswatch.nationalgeographic.com/2012/02/07/texas-water-district-acts-to-slow-depletion-of-the-ogallala-aquifer/