I drive across I-70 periodically between St. Louis and Denver. Something unnerving is happening to the farmland that I pass in Kansas. Sinkholes are opening, only yards from the highway.
The massive Ogallala Aquifer, an ancient underground fresh water lake that made the Plains cornucopia possible after the 1930s Dust Bowl, is located below 8 states in the High Plains, including Kansas. It stretches, at depths ranging from a few feet to 1000 feet, from Texas to South Dakota, and covers roughly 175,000 square miles. Widely exploited only since the 1940s, it has been depleted at an alarming rate since, almost entirely for farming. The problem is causing increasing concern in a number of states including Oklahoma and Texas.
The water in the Ogallala dates back 2 to 6 million years and, like oil, is an ancient and non-renewable resource. As millions of gallons are used annually, the water level declines about 2.7 feet a year. It is replenished at an estimated rate of 1/2 inch per year and has an expected life of only 25 more years.
The implications of the depletion of the Ogallala for mid-western farmland and the U.S. food supply are dire.
Sinkholes are nothing new. They have occurred for centuries around the world when soft rock dissolves underground or drainage systems go awry. Florida is known for them.
In May 1981, a large sinkhole began to develop in Winter Park , Florida. After three days, the sinkhole had swallowed a house, several cars, parts of two businesses, part of a community pool, and a section of road. …. As is often the case, this sinkhole formed during a drought period, as a result of lower groundwater levels.
What is new is that they can now be engineered with wild abandon by human activity including ground water depletion. As underground water vanishes, so does the substructure of the earth above and the land collapses, or subsides, as geologists say.
We can only wish that depletion was the only serious threat to groundwater.
Authorization for the Keystone XL pipeline, which would carry oil mined from tar sands in Canada to Texas, has not yet died the death it deserves and is being resurrected in the Senate despite President Obama’s opposition. In addition to oil, the pipeline will also carry the potential for catastrophic contamination of the Ogallala which lies below the pipeline’s path.
Other home-grown threats are alive and well. Agricultural pesticide and herbicide runoff is contaminating the aquifer, threatening production in America’s ‘bread basket’ and causing possible health problems and issues with fetal and child growth. It is subsidized to an unconscionable extent by the U.S. government’s support for corn based ethanol production. Get the story here.
The next time you fly over the Plains states, look out the airplane’s window at the pattern of large, connecting, circles on the ground, as far as the eye can see. They are the result of spigot irrigation from equipment that radiates out from the center of the field. It’s the kind of irrigation that mostly waters dry air. The size of the circles is limited by the size and reach of the sprinkler.
The water that creates this infinite-appearing checker board comes from the Ogallala aquifer, free of charge to farmers.
Back to my immediate problem: How long will I be able to drive I-70 across Kansas before the road becomes permanently impassable due to the collapse of the earth below it? Will it be safe for my next planned trip in a few months? Will I be able to get back home again if I don’t fly?
If part of an interstate over the aquifer caves, can roads anywhere along the aquifer be trusted?
And which side of an I-70 crater, east or west, do I want to be on if and when it collapses? I have no idea how a highway cave-in created by a sinkhole over the Ogallala would be fixed. Might I end up stranded on one side of the crater or the other?
Because the Ogallala runs vertically through a number of states, trying to bypass a sink with another road that circumvents the aquifer could take travellers thousands of miles out of their way. Would truck and auto traffic across the sinkhole, and the Ogallala, simply stop? Can we even get our minds around the implications of this possibility?
Maybe we could drive vertical posts that would hold a bridge. The bridge would have to be anchored to stable land on each side of the aquifer, meaning that it might have to stretch many hundreds of miles. Feasible?
Or how about a floating bridge. Can a floating bridge be created with a water level that drops several feet a year?
A puzzle without a solution. At least one that I can think of.