Role of western Kansas mini-wetlands on farming, aquifer under a microscope

Two-year research project examines some of 22,000 playas

Kansas Geological Survey at the University of Kansas is embarking on a two-year study of playas that hold water during wet periods in Scott County and elsewhere to better understand their role in recharge of the underground Ogallala aquifer. (Bill Johnson/Kansas Geological Survey)

TOPEKA — New research on shallow depressions transformed into mini-wetlands by rainfall and runoff in western Kansas will examine consequences of planting crops on these patches and influence of that activity on the underground High Plains aquifer.

During wet periods these low spots in fields can hold water for weeks or months, host a variety of plants and attract eagles, swans, geese and pelicans. About four of every five of the 22,000 lagoon-like features in Kansas — called playas — have been cropped.

The Kansas Geological Survey and Kansas Biological Survey at the University of Kansas in conjunction with the University of Minnesota at Mankato and the University of Waterloo in Canada secured a $270,000 federal grant for a two-year research project. The idea is to consider the influence of farming on playas and to what degree agricultural activity altered recharge of the High Plains aquifer, also referred to as the Ogallala.

“Our study will provide information as to whether conserving or restoring playas could play a role in helping to reduce aquifer water-level declines,” said Tony Layzell, a Kansas Geological Survey assistant scientist who will oversee the project.

He said farming was known to increase playa sedimentation and diminish the volume of water these basins could hold.

“It’s possible these combined effects reduce recharge rates, thereby reducing the amount of water entering the High Plains aquifer,” Layzell said.

The U.S. Environmental Protection Agency’s investment recognized rainfall in western Kansas was insufficient to match pumping demand on the aquifer. Understanding the role of playas in recharging the aquifer could contribute to understanding of the aquifer’s health. It’s important to quality of life in especially dry regions of western Kansas because nearly all water used by cities, industry and agriculture must be pumped from the aquifer.

This research initiative was designed to focus on Groundwater Management District 1 in parts of Wallace, Greeley, Wichita, Scott and Lane counties. The Kansas Geological Survey said aquifer levels in this zone had fallen more than 10 feet in the past 25 years.

The objective is to work with landowners to study about 15 playas in the water district. The plan is to examine playas that have been farmed and not farmed as well as irrigated and not irrigated. The project would target playas of different sizes, a variety of sedimentation and a range of depths to the aquifer.

Core samples of rock and sediment is to be drilled in selected playas, the researchers said. The cores would undergo analysis of soil structure to determine how much water collected in a playa made it into the aquifer.

Layzell said anecdotal evidence suggested crop yields on cultivated playas fell below yields on non-playa farmland.

“The question is, are the costs of farming the playa greater than the potential profit for the farmers? Knowing the answer may help landowners determine whether their playa land is more valuable when left undisturbed,” he said.