Groundwater

Hydrosphere

The water on and in the earth's crust, including oceans and freshwater sources.

Infiltration

The process by which precipitation trickles into the ground and becomes groundwater.

Porosity

A measure, in percent, of the amount of pore space in a material.

Permeability

The connection between pores that determines how easily water can flow through a material.

Aquifer

A geologic formation that can store and transmit groundwater, often composed of permeable rock or sediment.

Aquiclude

Barriers to groundwater flow that restrict water movement.

Aquatard

A semi-permeable or impermeable geologic layer that impedes vertical movement of groundwater.

Perched water table

A small aquifer that temporarily contains water above the main water table.

Spring

A natural discharge of groundwater on the earth's surface.

Carbonic Acid

Acid formed when carbon dioxide gas combines with water; contributes to limestone erosion.

Cave

A natural underground opening big enough for a person, generally formed by the dissolution of calcite.

Karst topography

Surface features produced by the dissolution of limestone, characterized by sinkholes and underground drainage.

Hard water

Water with a high mineral content, particularly calcium and magnesium.

Water softeners

Devices used to remove hard minerals like calcium and magnesium from water.

Draw down

The difference between the original water table level and the level after pumping.

Recharge area

The land area that supplies infiltrating water to an aquifer.

Artesian well

A well in which groundwater rises to the surface without the need for pumping due to pressure.

Geyser

An explosive hot spring that erupts periodically as water vaporizes.

Subsidence

The sinking of land that occurs when surface water is removed from pore space.

Salt Intrusion

The movement of saltwater into freshwater aquifers, often due to over pumping.