6.3 - Groundwater groundwater is the largest source of available fresh water for humans groundwater is stored in an aquifer movement of groundwater depends upon two main factors: porosity & permeability

porosity: percentage of a rock that consists of open spaces permeability: ability of a rock to let water pass through its open spaces (pores) for a rock to be permeable, the pores must be connected

Layers within an Aquifer zone of aeration: layer where pore spaces in the rock layer contain mostly air zone of saturation: area below zone of aeration where all the pore spaces are filled with water top of this zone marks the beginning of the water table

wells are drilled down to the water table then water is pumped to the surface

if a well is under pressure so that the water comes to the surface without any pumping, it is called an artesian well forms where the aquifer layer is between two non-permeable layers so squeezes the water out of the well

springs form when groundwater naturally comes to the surface without drilling a well if groundwater is heated by magma before coming to the surface, it is called a hot spring

geysers are hot springs that erupt at the surface, throwing steam & water into the air

karst topography: irregular surface (topography) due to groundwater chemically weathering the bedrock usually found in humid (wet) regions underlain by limestone

caverns: large cave with many smaller connecting chambers

a calcite deposit that hangs from the ceiling is called a stalactite directly below a stalactite, is another calcite build-up called a stalagmite

if a stalagmite and stalactite meet, a column will form sinkhole: circular depression at the surface that forms when rock is dissolved or a cave collapses