Groundwater Flashcards
What were the freshwater usage percentages in the year 2000 for electrical generation, irrigation, and municipal water?
Electrical generation: 48%
Irrigation: 34%
Municipal water usage: 11%
What are the primary personal water usage activities?
Flushing toilets: 27%
Washing clothes: 22%
What are some ways to reduce daily water usage?
Fixing leaks
Using low-flow appliances
How does groundwater contribute to the hydrologic cycle?
It is a major component
It is stored within pores and fractures within substrate
What is the water table?
It is a subsurface boundary.
Above the water table: pores are mostly filled with air (unsaturated zone).
Below the water table: pores are filled with water (saturated zone).
What are the two general types of aquifers?
Unconfined aquifer: intersects the surface, easily contaminated
Confined aquifer: beneath an aquitard, less susceptible to pollution
What is the difference between an aquifer and an aquitard?
Aquifer: sediment or rock that can store and transmit water easily
Aquitard: impermeable or low permeability sediment or rock that hinders water flow
What is the primary source of heat for hot springs in geothermal regions?
High geothermal gradients linked to shallow magma.
What causes land subsidence when groundwater is removed?
Sediment grains compress; pore spaces collapse, leading to cracks and sinking of the land surface.
What are some sources of groundwater contamination?
Septic systems
Industrial activities
Roads and parking lots
Older sanitary landfills and waste dumps
Agriculture
Groundwater:
Water located beneath the Earth’s surface in soil pore spaces and in the fractures of rock formations.
Freshwater:
Water that contains low concentrations of dissolved salts, typically found in rivers, lakes, and groundwater.
Aquifers
Underground layers of rock or sediment that hold water and allow it to flow.
Porosity:
The percentage of void space in a rock or sediment that can hold water.
Permeability:
The ability of a rock or sediment to allow fluids to pass through it.
Cone of Depression:
A cone-shaped lowering of the water table around a well when water is being pumped out faster than it can be replenished.
Contamination:
The introduction of harmful substances into the environment, making water unsafe for consumption or use.
Water Table:
The level below the Earth’s surface at which the ground becomes saturated with water.
Land Subsidence:
The gradual sinking or settling of the Earth’s surface due to the removal of groundwater.
Ground Fissures:
Large cracks or openings in the ground caused by the removal of groundwater, leading to land instability.
Ogallala Aquifer:
One of the world’s largest aquifers, located beneath the Great Plains of the United States.
Sustainable Management:
The responsible use and conservation of water resources to meet current needs without compromising the ability of future generations to meet their own needs.
Water Law:
Legal regulations and principles governing the use, distribution, and protection of water resources.
What percentage of water on Earth is salty?
90%
By how much can daily water usage be reduced by fixing leaks and using low-flow appliances?
Up 35%
Where do streams provide great access to freshwater?
In humid climates
What happens to rainwater when it hits the ground?
It goes through a filtration process known as infiltration, which can take a long time.
What are aquifers?
Reservoirs that hold water
What are pores in the context of aquifers?
Open spaces within aquifer materials
What does porosity determine?
How much water an aquifer can hold
What does permeability refer to in the context of aquifers?
How easily water can flow through the holes in an aquifer
What is an unconfined aquifer interacting with?
The surface
What is the water table?
A line indicating where you’d draw the streams
What is a small guide used to access the aquifer?
A drill
What does “artesian” mean in the context of water?
The water was on the surface and didn’t need to be pumped out
What does the hydraulic gradient represent?
The slope of the water table
