97% contained in the oceans 3% of this water contained by landmasses (nearly all freshwater) More than 90% of freshwater on Earth in the form of polar ice caps and glaciers Remaining freshwater is groundwater Rivers, streams, lakes only small portion of Earth’s freshwater The Hydrosphere: water on and in Earth’s crust
Evaporation of ocean waters, forms clouds/precipitation, weather systems and winds move this moisture build up all over Earth Falls to land and enters ground through infiltration, becoming groundwater (solid precip. stays for longer periods of time until melting) Groundwater move through ground, returns to surface via springs, then flows back to oceans. Precipitation and Groundwater
Subsurface materials contain pores; percentage of pore space in material called porosity Range 2-3% to more than 50% (sand) Large quantity of groundwater are stored in the pore spaces of rocks and sediments Groundwater Storage: Where does the water go?
Def: depth below Earth’s surface at which groundwater completely fills all the pores of a material Upper boundary of this zone= water table Only the water in the zone of saturation is called groundwater The Zone of Saturation
Depth varies with local conditions Stream valleys groundwater close to surface; water table only few meters deep Hilltops/arid regions tens to hundreds meters deep Water table fluctuates with season and weather conditions because of its dependence on precipitation The Water Table
Flows downhill in direction of slope of the water table Moves extremely slow because the water has to travel through numerous tiny pores Ability of material to let water pass= permeability Large connected pores= high permeability (sand and gravel) Silt and clay=tiny pores=impermeable Steeper slope of water table= higher velocity of groundwater Groundwater Movement
Most groundwater flows through permeable layers known as aquifers Aquicludes: barriers to groundwater flow Aquifers
Dissolution and formation of calcium carbonate play role in formation of limestone caves Cave: natural underground opening with connection to Earth’s surface Formed when groundwater dissolves limestone Most develop in the zone of saturation just below water table Dissolution By Groundwater
Sinkhole: depression in the ground caused by the collapse of a cave or by the direct dissolution of bedrock by acidic rain or moist soil Limestone regions that have sinkholes said to have karst topography Karst Topography
Hard Water: contains high concentration of calcium, magnesium, or iron Common in limestone areas Deposits of calcium bicarbonate can clog water pipes Groundwater Deposits
Stalacites: drops of water hanging lose some carbon dioxide and deposits calcium carbonate Stalagmites: water drops splash to floor Composed of travertine: type of limestone Groundwater Deposits
Create a “travel ad” for one of the following terms from today: Karst topography Stalagmites and stalactites Aquifer Zone of saturation Your ad should include: What this term means Where it can be found What makes this term interesting Some sort of picture (with colors) to describe this term Groudwater Travel Ad
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