COASTAL PROCESSES
Part 1
LESSON OBJECTIVES: By the end of the
lesson, students should be able to :
(i) Identify the ways waves apply their energy.
(ii) Describe the coastal erosional processes.
THE ENERGY OF WAVES
Waves posses a great deal of energy . The
energy of waves can be applied in three (3)
ways .The ways are :
• Erosion
• Transportation
• Deposition
IMAGE OF COASTAL EROSION
IMAGE OF COASTAL EROSION
IMAGE OF COASTAL EROSION
Erosion by waves
Erosion is the wearing away of the coast by the action of
waves. There are four (4) ways or processes of wave
erosion .They are:
 Hydraulic Action: As a wave breaks against a cliff, it traps
air that is compressed into cracks in the rock, causing
blocks to be loosened and broken away over time.
 Corrasion or Abrasion: The moving water bombards the
cliff with rock fragments (sand, pebbles, and boulders) and
drags others backwards and forwards over rock surfaces,
wearing them away. This is a very powerful type of
erosion, especially during storms.
Erosion by waves
 Corrosion (solution): The sea water dissolves soluble
materials from the rock .This happens along limestone
and chalk coasts when calcium carbonate is dissolved.
 Attrition: Rocks and boulders already eroded from the
coast are knocked together, and slowly worn into
smaller and rounder pieces. Boulders with rough
surface become smooth through the process of
attrition.
 NB: The more powerful waves, the more energy they
have. The softer the rock, the faster erosion will be.
END OF PRESENTATION
THANK YOU
HOMEWORK
14-09-2022
(1) Identify the 3 ways waves apply their energy.
[3]
(2) Describe the following processes of wave
erosion:
(a) Hydraulic Action
[3]
(b) Abrasion
[3]
(3) State another term for ‘Abrasion’
[1]