20-22 groundwater

Question 1

Porosity

Answer 1

Pores are open spaces within any sediment or rock
The total volume of open space is termed porosity
Pores can be filled with air or water

Unconsolidated material: silt and clay have greatest porosity while glacial till has the least
Consolidated material: fractured volcanic rock and limestone have the greatest porosity with unfractured mudstones and conglomerate also high

Question 2

Permeability

Answer 2

The ease of water flow due to pore interconnectedness
Highly permeable material allows water to flow readily
Water flows slowly through less permeable material
Many large and straight flow paths enhance permeability

Unconsolidated material: gravel has the greatest permeability while clay has the least
Consolidated material: limestone (with openings) has the most while unfractured igneous/metamorphic has the least

Question 3

• Understand the meaning and significance of the
  water table

Question 4

Aquifers

Answer 4

Sediment or rock that holds a lot of water and transmits it easily

Question 5

Aquitards or confining layers

Answer 5

Sediment or rock that has low permeability and porosity that hinders groundwater flow

Question 6

Confined versus unconfined aquifers

Answer 6

Confined: an aquifer beneath an aquitard. isolated from surface and less susceptible to pollution
Unconfined: an aquifer that connects with the surface. In contact with the atmosphere and more easily polluted

Question 7

Vadose zone

Answer 7

Area above the water table where pores are mostly filled with air

Question 8

Phreatic zone

Answer 8

Area beneath the water table where pores are filled with ground water