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Ch 14
Groundwater and Erosion
14.1 Water Beneath the
Surface
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Underground water that fills in the pores of
the rocks is called GROUNDWATER
This is a source of fresh water that most
people use in their homes, lawns, and for
consumption
Groundwater is very fragile and also can
be very destructive.
Rock properties
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Porosity- amount of water a rock can hold
Permeability- the ability of rocks to flow
though the spaces between a rock
Impermeable- water that cannot flow
through a material
Porosity
Sortting
Well Sorted
Large Grained
High Porosity
Well sorted
Small Grained
High Porosity
Poorly sorted
Different sizes of rocks
Low Porosity
Zones of Groundwater
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Zone of saturation
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Water table
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the upper surface of the zone of saturation
Zone of Aeration
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the lowest level where groundwater “pools”
area between the earth’s surface and groundwater
Capillary Fringe
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The region just above the water table
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Aquifer
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body of rock which
large amounts of water
can be stored
Perched water table
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water that collects on
top of impermeable
rock just above the
water table
Types of Groundwater
storage
Pollutions of groundwater
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Waste dumps leaking into water
Fertilizer leaking into water
Sewage leaking into water
Remember freshwater can be recycled
through distillation and water treatment
plants. However, if the freshwater is not
cleaned it can and does contaminate other
sources of freshwater. Once the
freshwater is gone we cannot get it back.
Questions to answer
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Amount
Porosity is the ______
of water a rock can
Hold
_______.
What are the 3 types of sorting
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How freely water passes though open spaces
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Permeability
What are the ways that groundwater can be
polluted?
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Well-Sorted Large grain, Well-Sorted Small grain,
Mixed sizes/Poorly sorted
Sewage, Fertilizer, Waste, “run off”
Where can you find a perched water table?
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Above the “main” water table or aquifer
14.2 Wells and Springs
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Well
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Artesian well
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a hole dug into the ground revealing a fresh source of
water. Water can only flow if it is pumped out
a hole dug into the ground below the water table so
that the water flows freely.
Spring
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fresh water that flows at the surface because there is
a perched water table or the ground at the surface
dips below the water table.
Ordinary vs Artesian
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Ordinary
Well needs pumping
Causes Cone of
depression around
source of pumping
Springs are because
of perched water
table or dips in
surface
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Artesian
Wells do not need
pumping
Caused by an
arrangement of
permeable and
impermeable
structures
Springs in deserts
Yellowstone National Park
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Yellow Stone National Park is one of the premier
parks when looking for Geysers, Hot Springs,
and mud pots
All of these water features are associated with
magma that is heating the water below the
earth’s surface.
These beautiful water features are a rare sight
and can only happen around areas in which hot
magma is present and hidden below the surface.
Yellowstone Images
Questions to Answer
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Where can you find an artesian spring?
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Why is an artesian well different from an
ordinary well?
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They do not need pumping, Caused by an
arrangement of permeable and impermeable
structures
In what 3 ways can heated water reach the
surface?
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Desert
Hot Spring, Mud pot, Geyser
erupt
flow
Geysers _______
but hot springs _______
Groundwater and
Chemical Weathering
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There are 2 types of fresh water that
humans can consume hard water and soft
water.
Hard water- is water that contains a lot of
dissolved minerals and material in it. Most
of them are calcium, magnesium and iron.
Soft water- is water that contains fewer
minerals and is generally preferred over
hard water.
Types of water
Things about caves
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When a cave falls in on it’s self it creates a sink
hole at the earth’s surface
Inside a cave you will find stalactites hanging
from the ceiling and stalagmites growing from
the floor.
When the roof of a cavern collapses in several
places sometimes a natural bridge is left behind
in segments that have not fallen.
Karst Topography
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Regions that have been
effected by groundwater
chemical weathering are
said to have “Karst
Topography”
There are many regions
that you can see Karst
Topography in the United
States. Florida, Kentucky,
and even Tennessee are
just some of the places
with amazing Karst
features.
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Caves- water that has
dissolved carbon in it flows
through limestone and
creates massive cave
structures.
Spelunkers- these people are
professional or experienced
cave divers. Caves can be
dry or wet. Dry caves are
gigantic caverns of majestic
rock architecture. Wet caves
are submerged underwater
and are explored with the
help of scuba gear.
Questions to Answer
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What is the effect of carbonic acid on rocks?
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What is the difference between a stalactite and a
stalagmite?
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If it comes in contact with sedimentary rocks
especially limestone, it creates caves
Stalactite is coming from the ceiling, stalagmite is on
the “floor”
Natural Bridges
Sink holes cause ____________when
multiple
sink holes fall in and only a few archways are left
Natural Bridges
that is a___________.
More Questions
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It takes a long time for polluted ground
water to become pure again because
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The Slope of the water table is called
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Ground water replenishes very slowly
Gradient
The upper surface of the zone of
saturation is called
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Zone of aeration