The Ogallala and other aquifers around the globe are threatened by overuse and insufficient recharging.
Photo from Fotolia/InTheSkies
This map shows irrigated areas in blue; the darker the color, the heavier the irrigation.
Photo Courtesy of the Institute on the Environment, University of Minnesota, and Esri
The colors in the aquifers show the health of the body of water. The closer to red, the worse the condition of the aquifer.
Photo from Nature