The Power of Water: Erosion
and Deposition
Curriculum outcome:311-11
Describe processes of erosion and deposition that result
from wave action and water flow.
Curriculum outcome: 209-5 & 311-11
Select and integrate information, from various print and
electronic sources, related to processes of erosion and
deposition that result from wave action and water flow
• Have you ever lifted a bucket of water or
shoveled snow? It is heavy!
• Imagine all that weight coming down on you.
• The force of water can cause a lot of damage to
plants, animals, land and buildings.
• The damage can be quick, like in floods and
avalanches or take many years, as when land is
eroded away.
• Have you ever stood on a river bank after
a storm and noticed that the water was
brownish?
• Why is the water brown?
Slipping Away: Erosion
Runoff from riverbanks and surrounding land carries
sediment (material such as gravel, sand, silt and
mud) into rivers. The process of carrying away of
soil particles by wind, water or ice is known as
erosion.
• In time, the soil (sediment) settles to the bottom.
A little bit of sediment is usually not a problem
because most river organisms can adapt, but
when you have a large amount of sediment, it
can change the habitat for plants and animals
living there.
• The process by which sediment is laid down in a
new area and builds up on the Earth's surface is
called deposition. It is the direct opposite of
erosion.
What increases erosion?
Human activities such as cutting trees, removing vegetation, and
land cultivation can increase erosion by decreasing the ability of the
soil to retain water.
• Erosion is a slow process that damages
land over time. What are two processes
that can damage land very quickly?
• Floods and Avalanches.
What is flooding?
Flooding is caused by
a large amount of
rainfall.
What is a spring flood?
A spring flood occurs when the spring thaw is rapid and is
worse in areas where riverbanks have been clear- cut.
What is a flash flood?
A flood that occurs within a few hours
(usually less than six) of heavy or
excessive rainfall.
What is an avalanche?
An avalanche is a landslide of snow.
What sets off an avalanche?
Temperature, sudden vibrations and
shearing of creeping snow masses.
Also, avalanche patrols use
explosives to cause smaller
destructive flows.
Landslide: a mass of loosened
rocks or earth that slides down a
slope or hillside.
Mudslide: landslide of
mud
Understanding Concepts
1.
What is meant by erosion?
Erosion is the carrying away of soil particles by wind
or water.
2.
What ways does nature use to prevent
erosion?
Roots trap soil and water, vegetation reduces
the force of the rain striking the ground,
preventing the rain from loosening the soil.
3.
How does the repeated freeze/thaw process cause
damage?
The freeze/thaw process can break up roads,
driveways, and concrete structures. Creating
potholes and lifting shingles on a roof.
Assignment
• Prepare a photo essay (at home) or a
series of sketches/drawings that show
erosion and deposition due to wave action
and water flow.