The potentiometric surface is another name for the water table. The dustbowl resulted from severe drought and poor farming practices. The Ogallala aquifer underlies the high plains of Minnesota. The water in the Ogallala aquifer entered the aquifer during the last ice age. Some hot springs are heated by the reaction of water and pyrite.
Hot springs are most common in tectonically stable areas like Warm Springs, Georgia.
About 250 million people in the US use geothermal energy. For geothermal energy to be efficient, both heat and water must be readily available. Environmentally hazardous pesticides can pollute groundwater when they are overused in agricultural areas. A nuclear-waste storage site must be isolated for 10,000 years to be considered safe by government standards. The transitional zone between the zone of aeration and the zone of saturation.