Glossary

A B C D E F G H I J L M N O P Q R S T U W
  • alluvial aquifer

    An aquifer formed by material laid down by physical processes in a river channel or on a floodplain.

  • alluvial plain

    A level, gently sloping, or slightly undulating land surface produced by extensive deposition of alluvium, usually adjacent to a river that periodically overflows its banks.

  • alluvium

    Unconsolidated clay, silt, sand, or gravel deposited during recent geologic time by running water in the bed of a stream or on its floodplain.

  • anhydrite

    A mineral usually associated with gypsum and of nearly the same chemical composition. Anhydrite is distinguished from gypsum in that it lacks water, as its name implies.

  • aquifer

    A geologic formation (or one or more geologic formations) that is porous enough and permeable enough to transmit water at a rate sufficient to feed a spring or a well. Sandstone beds and the Ogallala Formation are some of the best water-producing layers in Kansas and are used extensively for private and municipal water supplies.

  • arid

    Said of a climate characterized by dryness, variously defined as rainfall insufficient for plant life; less than 10 inches (254 mm) of annual rainfall.

  • artesian aquifer

    An aquifer in which groundwater is confined under pressure significantly greater than atmospheric pressure. This pressure, called artesian pressure, is generally due to the weight of water at higher levels in the same zone and is sufficient to cause water to rise above the level of the aquifer in a well or natural fissure. An artesian aquifer is bounded above and below by confining beds of less permeable rock. Synonym: confined aquifer.