Also known as a confining bed.Ĭontaminant: An undesirable substance (physical, chemical, biological, or radiological) not normally present, or an unusually high concentration of a naturally occurring substance, in water, soil, or other environmental medium.ĭrawdown: The vertical distance groundwater elevation is lowered, due to the removal of groundwater.
Also know as an artesian aquifer.Ĭonfining Layer: geological material through which significant quantities of water can not move located below unconfined aquifers, above and below confined aquifers. Also called cone of drawdown.Ĭonfined aquifer: Aquifers that are wedged between layers of relatively impermeable materials and are consequently under pressure. Its trace (perimeter) on the land surface defines the zone of influence of a well. The slopes of the cone become increasingly steep the closer they are to the well. However, an aquitard may transmit appreciable water to or from adjacent aquifers.Īrea of influence: Area surrounding a pumping or recharging well within which the water table or potentiometric surface has been changed due to the well's pumping or recharge.Īrtesian Conditions: In a confined aquifer, when the water level in a well rises above the top of the aquifer.īest Management Practices (BMPs): structural, nonstructural, and managerial techniques recognized to be the most effective and practical means to reduce surface water and groundwater contamination while still allowing the productive use of resources.Ĭapillary Fringe: a zone in the soil just above the water table that remains saturated or almost saturated, because the water is drawn up against the force of gravity due to waters adhesive and cohesive forces (capillary action).Ĭone of depression: A depression in the groundwater table or potentiometric surface that has the shape of an inverted cone and develops around a well from which water is being withdrawn. Image Source: Michigan State University Extension, Water Quality Bulletin # 35, August 1991Īquitard: A saturated but poorly permeable formation that does not yield water freely to a well or a spring.
Typically is unconsolidated deposits or sandstone or limestone. Such wells can be a direct "pipeline" for introducing contamination into the groundwater.Īquiclude: A geologic formation which may contain water but does not transmit it.Īquifer/Aquifer System: A water-bearing layer(formation) of rock or sediment capable of yielding sufficient, economical quantities of water to wells. A - C D - F G - I J - L M - O P - R S - U V - ZĪbandoned Well: a well whose use has been permanently discontinued, or a well which is in such disrepair that its continued use for the purpose of obtaining groundwater is impractical or may be a health hazard.
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