1. Water Beneath the Surface
Chapter 6.3

2. Distribution of Water Underground
Much of the water in soil seeps downward until it reaches the zone of saturation
The zone of saturation is the area where water fills all of the open spaces in sediment and rock
Groundwater is water below Earth’s surface within the zone of saturation
The water table is the upper level of the saturation zone of groundwater
The zone of aeration is the area above the water table where the soil, sediment, and rock are not saturated with water

3. Movement of Water Underground
Groundwater moves by twisting and turning through interconnected small openings
The groundwater moves more slowly when the pore spaces are smaller
Porosity is the percentage of pore spaces in rock
Determines how much groundwater can be stored
Permeability is the ability to transmit water through connected pore spaces
Aquifers are permeable rock layers or sediments that transmit groundwater freely

4. Features Associated with Subsurface Water – page 172

5. Water Beneath the Surface
A spring forms whenever the water table intersects the ground surface
Hot Springs have water that is 6–9ºC warmer than the mean air temperature
Water is heated by cooling of igneous rock
Geysers are hot springs that ejects water
Water turns to steam and erupts

6. Geyser Eruption Cycle

7. Water Beneath the Surface
A well is a hole bored into the zone of saturation
An artesian well is any formation in which groundwater rises on its own under pressure
Pumping can cause a lowering of the water table
Pumping can form a cone of depression in the water table

8. Cone of Depression

9. Environmental Problems
Groundwater is being threatened by overuse and contamination
In some regions, the amount of water available to recharge an aquifer is less than the amount being withdrawn
Common sources of groundwater pollution are sewage from septic tanks, farm wastes, and inadequate or broken sewers

10. Caverns A cavern is a naturally formed underground chamber
Erosion forms most caverns at or below the water table in the zone of saturation
Travertine (sedimentary rock) is a form of limestone that is deposited by hot springs or as a cave deposit
Also known as dripstone

11. Cavern Characteristics
Formed from calcite deposited as dripping water evaporates
Formed in the zone of aeration
Common features include stalactites (hanging from the ceiling) and stalagmites (growing upward from the ground)

12. Karst Topography
Formed by dissolving rock at, or near, Earth’s surface
Common features include
Sinkholes are surface depressions
Sinkholes form when bedrock dissolves and caverns collapse
Caves and caverns
Area lacks good surface drainage

13. Sinkhole Formed