Regional aquifers were filled by glaciers during the last ice age, researchers say, and can't be replenished with rain and snow. "That water has been there for thousands of years, and it is rapidly being depleted," researcher Jeffrey Falke told Science Daily. "Already, streams that used to run year-round are becoming seasonal, and refuge habitats for native fishes are drying up and becoming increasingly fragmented." Pumping of regional aquifers is almost entirely done for agriculture, with about 90 percent for corn production irrigation, along with alfalfa and wheat. Depletion of the water table affects ground-water dependent grasses that support livestock grazing.
Researchers concluded that a 75 percent reduction in groundwater pumping would be needed to maintain current water-table levels and refuge pools, something that isn't "economically or politically feasible." Dryland streams in the Great Plains provide habitat for several warm-water fish species that have adapted to harsh conditions; but, "increased fragmentation of their habitats may impede their life cycle, limiting the ability of the fish to recolonize," the researchers say. (Read more)