Transcript Ground Water - Mount Mansfield Union High School

Ground Water
Ground Water
• Makes up 0.397% of Earth’s Water.
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song
Ground Water Vocabulary
• Porosity
– a measure of the % of pores
(open spaces) in a material
• Permeability
– a measure of how easy it is
to force water to flow
through a porous material
More Vocab
• Aquifer– An underground formation that is capable of
transmitting H2O.
• Water Table
– the surface between the saturated zone and the
unsaturated zone (zone of aeration)
• Unsaturated Zone (Zone of Aeration)– the zone above the H2O table where all the pores
are filled with air.
• Saturation Zone (Zone of Saturation)– the zone beneath the H2O table where all the
pores are filled with H2O
How Water Tables Change
Types of Aquifers
animation
• Unconfined Aquifer– an aquifer that has a free connection upward to
the surface
• Confined Aquifer– aquifers that are isolated from the surface by an
overlying layer of impermeable material called an
AQUICLUDE or confining layer
• Aquiclude:
- Impermeable
layer
separating the
unconfined
and confined
aquifer
• Recharge
Recharge Area
– water that falls as
precipitation and
infiltrates the ground to
become groundwater.
• Recharge Area
– The area where
permeable soil allows
water to seep into the
ground.
• Discharge Area
– place where
groundwater becomes
surface water
• Spring– when groundwater simply bubbles up at the surface
of the ground. Naturally occurring
• Wells
– place where groundwater is withdrawn for use in
homes, farms, and industry. Human made
• Artesian Well– well in which H2O rises above the level it was
encountered. Must be confined and recharge must
exert enough pressure to allow H2O to flow upward
Groundwater Flow
• Ground water moves through subsurface material much like
run off
– Except a lot more slowly
– If the soil is mostly sand or gravel, it can move 5 ft/day
• Like streams and rivers, ground water moves from high areas
to low areas
• Gaining Stream– When ground water is
discharged to the surface
water.
• Losing Stream
– When water is lost from the
surface water to the ground
around it.
Water Level Declines
• Water pumped from the ground-water system causes
the water table to lower and alters the direction of
ground-water movement.
• Notice that some water that flowed to the stream no
longer does so, thereby reducing the amount of
stream flow.
Ground Water Contamination
• Piezometers– wells installed to monitor water
level and water quality
• Plume– a concentration of contaminants
that flows along the same path as
ground water
What properties of water make it unique?
• Water can dissolve more
substances in greater quantities
than any other liquid.
– However, this means that water
can be easily be contaminated
• Most groundwater
contaminates enter the system
from the surface, not at points
deep within the aquifer.
•Human activities at or near the land surface can
contaminate groundwater by moving through the
unsaturated zone to the water table.
•Then contamination can continue to move within the
saturated zone and discharge area.
Sources of groundwater
contamination include:
fertilization
•misuse of pesticides
•oil spills
•leaky landfills
•leaky septic system
•leaky underground
storage tanks
•Different chemicals react differently with different
soils.
•Contaminated groundwater may pollute surface water
•Contaminated surface water can pollute groundwater
•Water quality can vary within the aquifer
Septic System