What is Groundwater ? underground water that fills almost all the pores in rock and sediment -makes up 90% of the Earth’s liquid freshwater

What is Porosity? refers to the percentage of open spaces in rock or sediment

What affects Porosity? 1. sorting: amount of uniformity in size of particle in a rock or sediment -same size particles=large porosity -different size particles= small porosity 2. way particles are packed together –packed loosely= high porosity - packed tightly= low porosity

What is Permeability? how freely water passes through open spaces in rock or sediment -open spaces must be connected to be permeable !

Impermeable : rock or sediment that water cannot flow through

Groundwater Vocabulary Terms zone of saturation: layer of groundwater where all pores are full aquifer: underground body of water (underground lake); can have sediments and rock in it water table: upper surface of the zone of saturation

capillary fringe: where water is drawn up by capillary action from zone of saturation zone of aeration: zone that lies between water table and surface (remains dry except during rainfall) soil-water region: space around soil accumulates water

Ground water flow depends on permeability of aquifer and gradient of its water table. Gradient increase = velocity of ground water increase Gradient decrease = velocity of ground water decrease What affects groundwater flow?

well: a hole that is dug below the water table and fills with groundwater cone of depression: cone-shaped depression in water table around a well artesian well: well in which water flows freely with no pumping necessary cap rock: top layer of impermeable rock

Cone of Depression

spring: flow of groundwater that emerges naturally at the ground surface artesian spring: natural flow of water to the surface from an artesian formation

hot spring: hot groundwater that rises to surface before cooling

geysers: hot springs that erupt periodically

Conserving Groundwater: Sources of pollution – water dumps, underground storage tanks, agriculture and lawn fertilizers, pesticides, leaking sewage

Groundwater Contamination

Conservation – monitor levels of water tables, discourage uses of excess water, recycle, purifying used water

Results of Weathering by Groundwater hard water: water that contains large amounts of dissolved minerals –has metallic taste, soap won’t make suds, damages appliances that use water

caverns : large cave with connecting chambers

Observe an animation of cave formation.

sinkhole : depression formed when the roof of a cavern collapses

stalactite : cone-shaped calcite deposit suspended from the ceiling of a cavern

stalagmite : cone-shaped calcite deposit built up from the floor of a cavern