Amount and movement of groundwater governed by porosity and permeability of host.
Water Table: surface separating zones of aeration and saturation
-subdued replica of topography
-perched water table
-depth of water table: balance between recharge and discharge

Aquifer vs aquiclude

Movement of groundwater governed by
-Darcy's Law: Velocity = K(hydraulic head/distance)
-movement is very slow (= 45 feet per year)

Cone of Depression

Artesian Water System: water under pressure rises above level of aquifer
-artesian pressure surface

Groundwater "erosion": Dissolution occurs in the zone of saturation and produces caves, caverns and sinkholes
- Karst topography

Groundwater Deposition
Stalactites
Dripstone: stalagmites
Columns
Hot springs and Geysers

Groundwater Resources
- groundwater use is significant and expanding
-difficult to manage

Water law and Water Policy
East - Riparian rights
West - Prior Appropriation

Groundwater Problems
I) "Mining" of finite resource
Ex: Ogallala aquifer - High Plains -underlies - 174,000 mi2 -irrigates - 25,000 mi2 of farmland
II) Preservation of Water Quality
a) "Point" sources of pollution
-septic tanks
-municipal treatment plants
-feed lots
-landfills and dumps
-mine dumps
-industrial waste impoundments
-round salt piles
-buried fuel tanks
b) Non-point Sources
-suburban "grassed" areas
-agricultural land
-road salting
-urban "spills" (oil, gas, etc.)

1. Define porosity and permeability. Compare the porosity and permeability of clay and sand. Under what circumstances can a rock have a high porosity but not be a good aquifer?
2. Draw a completely labeled cross-section of an artesian water system. Briefly state the geologic criteria which must be satisfied before a water system can be considered artesian.
3. What is the water table? Use a labeled diagram to explain the relationship between the topography of an area and the water table. Why do flow paths of groundwater moving beneath a hill tend to turn upward toward a stream in an adjacent valley?
4. The recharge area of an important aquifer is slowly being paved over as a result of urbanization. What effects does urbanization have on the elevation of the water table? Suggest two ways of increasing infiltration in an urbanized area.
5. If it were discovered that radioactive waste from a nuclear processing plant had seeped into groundwater in the immediate vicinity of the plant, what kind of information would you want in order to predict the length of time before that waste might appear in a groundwater aquifer many kilometers away?
6. Use a completely labeled diagram to help explain how caves and caverns are formed in limestone.
7. Use a completely labeled diagram to help explain how and why saltwater encroachment takes place.
8. Draw a cross section illustrating a perched water table. Explain how a perched water table is formed.
9. Use a labeled cross section to explain how a geyser "works".

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