Erosion
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TEKS: conservation
Grade 3: 112.5.b11A
Grade 4: 112.6.b1B
Actually, the b1B in most grade levels
addresses conservation
Renewable/nonrenewable/inexhaustible
resources – some address
conservation and human impacts
Grade 1: 112.3.b10 A-C
Grade 3: 112.5.b11A
Grade 5: 112.7.b11C
Grade 7: 112.23.b14C (desertification, deforestation, urban
sprawl/development, ...)
Grade 8: 112.24.b14C (desertification, deforestation, urban
sprawl/development, ...)
Env Sys: 112.44c4E (desertification, deforestation, urban
sprawl/development, ...), 5C |
TEKS: erosion
takes time:
Grade 4: 112.6.b10A
Grade 5: 112.7.b11A&C
Grade 5: 112.7.b12A
Grade 6: 112.22.b14A
Grade 7: 112.23.b8A (kinetic
energy related to erosion)
Grade 7: 112.23.b14 A-C
Grade 8: 112.24.b12A rock cycle
Grade 8: 112.24.b14 A&C
Int Phys Chem: 112.42c8A
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Black Sunday: April 14, 1935, Pampa, TX. Wind erosion was a terrible
problem in the
Great Plains of the United States in the 1930's during the Dust Bowl,
and
again in the drought of the 1950's. (Larger picture)
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Wind erosion is still a problem at times in some areas in the
Great Plains, as can be seen in these photos. These were taken near
Olney, TX circa 1998. (These trees did not grow with their roots out of
the ground!) This result of erosion is called pedestaling.
 
These were taken in various places in the Texas and Oklahoma Panhandles
between 1994 and 2005.
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Wind erosion limits
visibility.
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Wind erosion can begin
with
windspeeds as low as 13 mph.
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Downdrafts before
thunderstorms
often generate wind erosion.
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Sandy soils are
particularly
susceptible to wind erosion |
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Though
wind erosion will always occur, it will probably never be as bad in the
United States as it was during the Dust Bowl because farmers are using
better technology to protect the soil. Even a small amount of residues
(leftover
plant parts) on the soil surface helps reduce erosion. Wind erosion was
not as severe in the "Filthy Fifties" due to the use of irrigation and
better management practices.
However, wind erosion like this is currently a problem in Western
China,
and in the Sahel and Sahara regions of Africa.
Link to story about April 2001 China
dust
storm
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Water can wash soil away, leaving rills (the small
finger-like areas
just larger than the pen), or it can wash away gullies that may be
deeper
and wider than a car.
(Larger picture)
(More on rills)
Water can also wash off a thin layer from the soil surface. This type
of
erosion is difficult to detect.
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When water washes soil out of one place, it leaves it
somewhere else.
The sand bar in this field was deposited after a thunderstorm that
created
runoff and erosion upslope. (Larger
picture)
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Soil that has no vegetation (plants) to protect it is the
most vulnerable
to both wind and water erosion. Soil was eroded out of the field on the
left,
and carried into the ditch beside the road. Some of the soil was left
in
the ditch after the runoff subsided.
(Larger picture)
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Erosion is not just an agricultural problem. The drainage area for this
parking lot was poorly designed, resulting in this gully, severe damage
to
the pavement, some exposed pipe. Such problems are expensive to repair.
(Larger picture)
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In urban areas, the most severe erosion problems occur during
construction
of new buildings, factories, parking lots, etc. The land is cleared of
all
vegetation, so it is unprotected from wind or water (rain). Often,
contractors
are required to take measures to limit soil loss from the site. The hay
bales
were placed in this ditch to slow the movement of water. When the water
slows
down, it loses energy, and sediments are deposited.
(Larger picture)
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This cloth barrier slows the movement of water off this construction
site.
You can see places where the soil has accumulated on the left side of
the
cloth barrier (near the chain link fence). If not for this barrier, the
soil
would have been transported off the construction site.
(Larger picture)
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Updated
06-27-2008. Copyright 2005. Clay
Robinson, Ph.D., as to
all resources: Materials may not be reproduced without Dr. Robinson's
written consent. Students are prohibited from selling (or being paid
for taking) notes or webpages during this course to or by any person or
commercial firm without the express written permission of the developer
of these pages.
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