Groundwater Flashcards
How much water is located beneath Earth’s surface?
More than in lakes, rivers, reservoirs combined. Most is within a few thousand feet of the surface. Amount and depth varies.
3 basic stages of water cycle
- rain falls to earth; runs to oceans and lakes
- water evaporates
- rain falls to Earth (cycle continues)
25% water from precip. runs into oceans. 15% evaporates and falls later
4 factors that affect the amount of groundwater in an area
- amount of rain/snow
- slope of land
- type and quantity of rock
- type and quantity of plants
Permeable rock
Rock that allows water to pass through the pores between the grains (sand, gravel, sandstone)
Impermeable rock
Rocks that have pore spaces too small to allow water to pass through (granite; shale)
Permeability rate
Rate at which water can pass through a porous material like soil or rock
Infiltration Rate
Speed at which water moves through the ground to become part of the groundwater
Zone of Aeration
The regolith from Earth’s surface down to the water table where water only partially fills pores in the soil, rock, etc. This zone lies about Zone of Sat.
Zone of Saturation
Level beneath the surface of the Earth; porous soil/ rock area completely filled (saturated) with water. Zone lies below zone of A.
Water table
Top level of the Zone of Sat. Where water table intersects the surface of the Earth, a river or a lake is present
Spring
flow of groundwater that emerges naturally as a ground surface, usually where an impermeable rock layer intersects the surface of the Earth
Geyser
Network of underground water channels heated by magma. Boiling water in deeper parts of channels eventually causes an eruption at surface (like Old Faithful in Yellowstone). Many geysers occur in New Zealand because of volcanic activity
Artesian Well
When water well intersects a pressurized aquifer, water will rise in that well to same pressure. If it has a larger pressure than atmosphere, the water will form a fountain at surface of Earth
Aquifer
Porous and permeable rock unit that transports water easily and is bounded top and bottom by impermeable layers
Sinkhole
Large round depression in ground usually in limestone. Formed by action of carbonic acid at Earth’s surface or from the collapse of a cavern ceiling close to surface. Streams can disappear into one and reappear from another