groundwater fills the open spaces in rocks, sediment, and soil beneath the surface
it is an important resource for domestic, industrial, and agricultural use
What properties of earth materials allow them to absorb water?
What is the difference between porosity and permeability?
porosity- proportion of a rock or sediment that is open space (pore space), pores may contain air, water, or oil/gas
permeability-ability to allow the passage of fluid in its pore spaces (measure of the rate at which water oil, or gas can flow through a rock
What is the water table?
the top of the zone of saturation
What is the capillary fringe?
layer above the water table where some water is pulled upward by surface tension
What is the Vadose zone?
pore spaces contain mostly air
What is the zone of saturation?
pore spaces contain mostly water
How does groundwater flow?
downhill moves in response to differences in water and pressure and elevation, slope of the water table, and permeability
How fast does groundwater flow?
very slowly, as fast as 250 meters a day
a few cm a day is typical for most aquifers
What is the difference between aquifer and an aquitarde?
Aquifer- porous and permeable layer that contains groundwater
Aquitarde (aquiclude)- impermeable layer that blocks flow
Whats the difference between confined aquifer and unconfined aquifer?
Confined aquifers- water flows between two aquitardes (sandwiched in)
Unconfined aquifers- water table not covered by aquiclude or aquitarde
How do you make a water well?
made by digging or drilling into the zone of saturation. Most wells must be pumped to bring water to the surface.
What is the cone of depression?
occurs in an aquifer when groundwater is pumped from a well
What is an artesian well?
in confined aquifers water is under pressure and can rise to a level above the top of the aquifer
water wil flow naturally to the surface without pumping
What are recharge and discharge?
Recharge- the process of adding new water to the water table
Discharge- takes place when the water table intersects the ground surface (springs) or by pumping from wells
What is a spring?
water flows naturally from rock onto land surface
What aquifer does Lafayette's water come from?
What is land subsidence?
Land subsidence occurs when large amounts of ground water have been excessively withdrawn from an aquifer. The clay layers within the aquifer compactand settle, resulting in lowering the ground surface in the area from which the ground water is being pumped.
What is saltwater intrusion?
is the movement of saline water into freshwater aquifers. Most often, it is caused by ground-water pumping from coastal wells, or from construction of navigation channels or oil field canals.
What is karst topography?
Landforms created by dissolution of limestone
What are caves?
caves form as a result of dissolution of carbonate rocks
What are depostional features of caves?
stalactites-icicle-shaped mass of calcite attached to the roof of a limestone cavern
stalagmites-A mineral deposit of calcium carbonate, in shapes similar to icicles, that lie on the ground of a cave
What are sinkholes?
circular surface depressions
What are karst towers?
remains of a cave
How are hot springs and geysers formed>
Hot springs- water is circulated deep, where it is heated by magma or cooling igneous rocks
Geysers- forcefully eject water and steam because of constrictions in the plumbing system