Aquifer history goes back millions of years

By Claire Bushey

The word “aquifer” comes from two Latin words, which together mean “to bring water.” That is what the Ogallala Aquifer has done for the High Plains for nearly a century.
Named after the town of Ogallala, Neb., the aquifer covers 174,000 square miles in parts of eight states, including New Mexico and Texas. It was formed between 5 million and 20 million years ago, said Jayne Aubele, a geologist and chief of education at the New Mexico Museum of Natural History and Science. Wind and water eroded bits of rock from the Rocky Mountains and carried them east where the gravel, silt and sand built up a thick section in the plains.
The loosely consolidated debris was perfect for collecting water. Water flowed to the porous rock layer and suffused the space between the loose particles of rock.
The Ogallala is not the huge underground lake people imagine.
“The water is in all the little pore space,” Aubele said.
A hard layer of sandstone underneath the porous rock layer keeps the water from flowing deeper into the Earth, Aubele said.
Rain and snow runoff have been collecting in the Ogallala for the past several million years. But because the climate in New Mexico and Texas is semi-arid, more water is being taken out of the aquifer than is being recharged by the elements.
“It’s like taking more money out of your bank account than you put in,” Aubele said.
The thickness of the aquifer ranges from more than 1,000 feet in Nebraska to less than 20 feet in some areas of the Great Plains.
In Curry County the aquifer is being drained at a rate of 206,898 acre feet per year, according to the Office of the State Engineer. Meanwhile, the aquifer only recharges itself in the region by 50,760 acre feet annually.
An acre foot is about 326,000 gallons of water.