This document discusses different types of erosion and deposition. It begins with definitions of erosion as the movement of sediment from one place to another, and deposition as dropped sediment. It then examines several specific types of erosion in more detail: - Stream bank erosion occurs along streams and rivers due to running water and burrowing animals. Planting vegetation or using concrete mats can help control this type of erosion. - Topsoil erosion involves the wearing away of the top layer of soil by water, wind, and gravity. Farming practices like no-till, contour plowing, and cover crops can prevent this type of erosion, which is important because topsoil contains nutrients and takes a long time to form. -

1. January 18, 2013 Q-2 Pg.
Daily Goal: We will be able to articulate the
difference between erosion and deposition. We
will demonstrate how geographical features
influence deposition.
Homework: Study for Thursday and
Friday’s mastery quiz! Enjoy your long
weekend!
Science Starter:
1.What is deposition?
2.What factors might determine why sediment builds
up in one area and not in another?
3.What is the difference between weathering, erosion,
and deposition?

2. Review Questions…
We’ve been talking about weathering, erosion and the impact of human
actions.
Identify as mechanical or chemical weathering:
n Acid rain slowly wears down a statue.
1. A rock rolls down a hill and cracks in half.
2. A tree root grows into a rock, breaking it into small
pieces.
3. Oxygen in the atmosphere reacts with iron in rocks
creating a rusty color.

3. Major types of erosion
1. Stream bank
2. Topsoil
3. Coastal

4. What words do we need to know to be
able to speak like scholars about
this subject?
***Write this in your glossary***
Erosion – the process in which sediment
is picked up and moved from one place to
another
Deposition – when sediment that is
being transported gets dropped in a
location

5. I. Stream bank erosion is the movement
of sediment from the sides of streams or
rivers.
 Stream bank erosion is caused by running
water and burrowing animals (like nutria).

6. What are ways we could stop
stream bank erosion?
Does it seem like a natural type
of erosion?
So, humans don’t do ALL the
damage.

7. Methods to control stream bank
erosion:
The roots of the
plants hold soil back!
Manmade nets and
mats also hold back
and keep it from
washing away!
1. Planting plants
on the edge of a
stream or river.
2. Placing concrete
mats, netting or
logs on the sides of
a stream.

8. III. Coastal Erosion is the
movement of soil and sediment from
coastal areas.
Land + Ocean meeting = the coast

9. What causes coastal erosion--
humans or nature??
All the grass is gone!!

10. BOTH!
Erosion caused
by Nature
1. Subsidence: when
land sinks as
sediments compact
2. Hurricanes and
storms
3. Sea level rise
Erosion caused
by Humans
1. Building levees
2. Oil field canals
3. Oil & gas production:
causes increased
subsidence

11. II. Topsoil
Erosion is the
wearing away of
the top layer of soil
due to water runoff
or rainfall, wind
and gravity.

12. What exactly is topsoil??
 Topsoil is the upper, outermost layer of
soil.
 Usually 2-8 inches deep.
 It contains most of soil’s living matter and
nutrients.
 This is where plant roots grow!

13. Methods to prevent topsoil
erosion:
1. No-till farming: soil is not tilled (stirred) and
dead plant material builds up and covers the
surface of the land
2. Contour plowing: farmers plow in curved
rows, parallel to the curve of the land
3. Terracing: farmers cut steps into steep
hillsides
4. Cover-crops & Crop Rotation: certain
crops are good for restoring the natural
balance of nutrients in the soil and preventing
erosion

14. Human impact: It might seem like fun, but
when you’re done, you’ve destroyed the
earth a little bit…
4-wheeler tracks
Climbing
and ‘surfing’
on sand
dunes in
Namibia.

15. WHAT DO YOU THINK?
Why is it important to prevent
erosion of topsoil?
Why do farmers work so hard to
make sure their soil is good?

16. We know the earth has been here for a
long time… and things happen slowly.
It takes approximately 100 years for one
inch of topsoil to be created through the
weathering and erosion of rocks.
There are 25 billion tons of topsoil lost each
year due to erosion!
We need topsoil to grow crops
so we have food to eat.

17. Let’s try it out!
 You will need:
 1 clear box filled ¼of the way full with sand
 1 straw
 2 rocks

18. What is soil?
What is it made of?
What’s in it?

19. Soil is a mixture of pieces of rock,
organic matter, air and water.

20. Rock fragments (pieces) can be:
Sand
Silt
Clay

21. Humus is
the organic part of soil;
decaying plant and animal
matter, such as leaves, roots
and dead animals.

23. Soil is made
in layers,
which are
called
horizons.
 The layers of soil
are made of
different types of
sediment and
nutrients.

24. There are 3 horizons (A, B, C)
that form a soil profile.
SOIL
HORIZO
N
LAYER ORGANI
C
MATTER
COLOR NUTRIENT
S
A
Horizon
Topsoil High Darkest High
B
Horizon
Subsoil Low Lighter Low
C
Horizon
Weathered
Bedrock
Low Lightest Low
**Fill in the whole chart!**

25. The layers!
A Horizon
B Horizon
C Horizon
Bed rock

26. WHAT IS THAT???
In Louisiana there is NO C Horizon.
So, there is NO bedrock layer
under the soil.

27. What is a possible effect?
Meaning, what happens
because there is not bedrock
under the soil in Louisiana?

28. Exit Slip
1. Which layer of soil is most important for
growing crops?
2. Which layer of soil contains humus?
3. Which layer of soil is made up of
partially broken bedrock?
4. What is humus?
a. Parent rock c. Bedrock
b. Plants and animals d. Horizon B
A Horizon
B Horizon
C Horizon