Advertisement

Archive for Thursday, December 3, 1998

GEOLOGISTS LOOK TO TAP POTENTIAL OF DAKOTA AQUIFER

December 3, 1998

Advertisement

Water experts with Kansas Geological Survey at KU believe the Dakota aquifer can be an important supplement to water drawn from the Ogallala formation.

Residents of western Kansas can't afford to wait until the tap runs dry before considering alternatives.

With declines in groundwater levels in the Ogallala formation, water users have started looking deeper for potential moisture sources. Staff at the Kansas Geological Survey, based at Kansas University, believe one option could be the Dakota aquifer.

Al Macfarlane, Geological Survey water specialist and co-author of a new report on the Dakota, said the Ogallala couldn't be replaced by the Dakota.

But with careful management, he said, the Dakota could be a significant source of water in some parts of the state.

"The Dakota aquifer has been used for water for more than a century in Kansas," Macfarlane said. "But it was poorly understood. Before this study, relatively little was known about the quantity and quality of water in the Dakota."

The Dakota consists of rock layers deposited about 80 million years ago during the Cretaceous Period. It's beneath the younger Ogallala formation, which was deposited in the past several million years.

Rocks of the Dakota are found in the western half of Kansas from Comanche County in the south to Washington County in the north. Some of the orange and red sandstone rock in the Dakota is visible on the surface in Ellsworth County.

In areas of the Dakota dominated by the sandstone, such as Ford and Hodgeman counties, wells drilled into the aquifer can produce as much as 1,000 gallons of water per minute. In contrast, water production is lower in sections of the Dakota composed mostly of clays and shales.

"Even over distances of only a few miles, the amount of sandstone in the aquifer can vary dramatically," Macfarlane said.

The quality of water in the Dakota is another important consideration, he said. In some parts, water from the Dakota has high salt content. That naturally salty water has moved up from older rocks beneath the Dakota.

In general, the Geological Survey's study showed the highest quality water from the Dakota was found in southwest Kansas and portions of central Kansas.

"In parts of north-central and northwestern Kansas, Dakota water is far too salty for most uses," Macfarlane said.

He said the best water in the Dakota was at the top of the aquifer. As a result, careful management -- such as spacing wells far enough apart to avoid significant water-level declines or pumping at levels that would pull up poorer-quality water -- could make the Dakota an important source of water into the future.

The Geological Survey's report on the Dakota was co-written by John Doveton and Donald Whittemore and is available to the public for a fee.

-- Tim Carpenter's phone message number is 832-7155. His e-mail address is tcarpenter@ljworld.com.

Commenting has been disabled for this item.