Earth and Environmental Systems

What is the largest reservoir of fresh water and what is the largest reservoir of useable fresh water?
Glacial IceLargest usable reservoir: groundwater
Know the definitions of the following terms: groundwater, porosity, permeability, zone of aeration, water table, zone of saturation, infiltration, aquifer, aquiclude.
Groundwater: water in the zone of saturationPorosity: the space between solid particles of soil or rock that can be filled by fluidsPermeability: the ease with which fluids can pas through a body of soil or rockZone of Aeration: above the zone of saturationWater Table: separates zonesZone of Saturation: where the groundwater isInfiltration: movement of water from the surface to the groundAquifer: a body of soil or rock that can hold a useable amount of waterAquiclude:a body of soil that blocks the flow of water
Know how groundwater flows around a stream.
Base Flow
Know the difference between zones of recharge and discharge, and similarly the difference between gaining streams and loosing streams.
Recharge: water goes from surface to groundDischarge: ground to surface
Know Darcy’s law.
Q=KIAdischarge = permeability times hydraulic gradient times cross sectional area the groundwater is passing through
Know how you can get a perched water table, artesian well, or spring.
Perched water table created by an aquiclude lens overlying the main water table.Artesian well flows w/o pumping, created by drilling into a confined aquifer whose pressure head is above surface.Spring created by a perched water table intersecting the surface.
Know the difference between a confined and an unconfined aquifer.
Confined: rock below and above (safer)Unconfined: surface
Know the term for the shape that forms around an actively pumping well.
Cone of Depression
Know what is happening to the Ogallala aquifer.
Water table draw down, 10ft/decade
If all pumping on the Ogallala aquifer was stopped today, how long would it take for the water table to rebound to pre-pumping levels?
2000 years
Besides water table drawdown, what other problems can overpumping an aquifer cause?
Saltwater intrusion
Know the major sources of groundwater contamination.
LandfillsPesticides/fertilizersLeaking underground storage tank (#1)
Know what type of rock solution caves are formed in, the difference between stalagmites and stalactites, and how sinkholes are formed.
LimestoneStalagmite: groundStalactite: ceilingSinkholes are formed by roof of cave caving in