Title: Water Underground S6E3 Students will recognize the significant role of water in Earth processes.
1Water Underground S6E3 Students will recognize
the significant role of water in Earth processes.
- S6E3.a Explain that a large portion of the
Earths surface is water, consisting of oceans,
rivers, lakes, underground water, and ice.
2What you will learn in the section
- Identify and describe the location of the water
table. - Describe an aquifer.
- Explain the difference between a spring and a
well. - Explain how caves and sinkholes form as a result
of erosion and deposition.
3Match the vocabulary word to the definition.
1. Water table a. The ability of a rock or sediment to let fluids pass through its open spaces, or pores.
2. Aquifer b. The percentage of open space between individual rock particles in a rock layer.
3. Permeability c. The ground surface where water enters an aquifer.
4. Recharge zone d. A spring whose water flows from a crack in the cap rock of the aquifer.
5. Porosity e. The upper boundary of the zone of saturation.
6. Artesian spring f. A rock layer that stores groundwater and allows the flow of groundwater.
4A family lives 50 km from the nearest stream or
lake and gets water from a well. Where does the
water in the well come from?
- It comes from water stored underground.
5- Groundwater is water located within the rocks
below the Earths surface. - FYI (do not write)
- Millions of people get their water from
groundwater. - Groundwater not only is an important resource but
also plays an important role in erosion and
deposition.
6Location of Groundwater
- Water is found underground in an area between two
zones. Rainwater passes through the upper zone,
called the zone of aeration. Farther down, the
water collects in an area called the zone of
saturation. In this zone, the spaces between the
rock particles are filled with water. - The two zones meet at a boundary known as the
water table. - Rises during wet seasons and falls during dry
seasons
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8Aquifers
- The rock layer that stores groundwater and allows
the flow of groundwater is called an aquifer. - The more open spaces, or pores, between particles
in an aquifer, the more water the aquifer can
hold. - The percentage of open space between individual
rock particles in a rock layer is called
porosity.
9- If the pores of a rock layer are connected,
groundwater can flow through the rock layer. A
rocks ability to let water pass through is
called permeability. A rock that stops the flow
of water is impermeable.
10- The best aquifers usually form in permeable
materials, such as sandstone, limestone, or
layers of sand and gravel. - Some aquifers cover very large areas.
- They are important source of water for cities and
agriculture. - The ground surface where water enters an aquifer
is called the recharge zone. - The size of the recharge zone depends on how
permeable rock is at the surface.
11 Aquifer in the United States
12Aquifers in Georgia
13Springs and Wells
- Groundwater movement is determined by the slope
of the water table. Moves down slope. - If the water table reaches the Earths surface,
water will flow out from the ground and will form
a spring. - Springs are an important source of drinking
water. - Where the water table is higher than the Earths
surface, lakes will form.
14- Wells are human-made holes that are deeper than
the level of the water table. - If it is not deep enough, it will dry up when the
water table falls below the bottom of the well. - If an area has too many wells, groundwater can be
removed too rapidly which can cause the wells to
run dry.
15Artesian Springs
- A sloping layer of permeable rock sandwiched
between two layers of impermeable rock is called
an artesian formation. - The permeable rock is an aquifer and the top
layer of impermeable rock is called a cap rock. - Artesian spring is a spring whose water flows
from a crack in the cap rock of the aquifer. - These are sometimes found in deserts, where they
are the only source of water. - Most have cool water but some springs have hot
water.
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18Formation of Caves
- Water erosion creates most caves found along
coastal areas. - Waves crashing against the rock over years wears
away part of the rock forming a cave. - Inland caves are also formed by water erosion-in
particular, groundwater eroding limestone. - As the limestone dissolves, underground
passageways and caverns are formed.
19The Caves of Belize Caves Branch Cave
The Caves at Norman Island
20Sinkholes
- Sinkholes are common where the rock below the
land surface is limestone, carbonate rock, salt
beds, or rocks that can naturally be dissolved by
ground water circulating through them. - As the rock dissolves, spaces and caverns
develop underground. - Sinkholes are dramatic because the land usually
stays intact for a while until the underground
spaces just get too big. - If there is not enough support for the land above
the spaces then a sudden collapse of the land
surface can occur. - The most damage from sinkholes tends to occur in
Florida, Texas, Alabama, Missouri, Kentucky,
Tennessee, and Pennsylvania.
21Nixa, Missouri 60 feet in diameter and 75 feet
deep
Sinkhole - Guatemala 330 ft deep