Download Shoreline Erosion and Deposition Objectives

Shoreline Erosion and Deposition
Objectives
• Explain how energy from waves affects a
shoreline.
• Identify six shoreline features created by wave
erosion.
• Explain how wave deposits form beaches.
• Describe how sand moves along a beach.
I. Wave Energy
A. When waves crash into rocks over long periods
of time, the rocks are broken down into smaller and
smaller pieces until they become sand.
B. Waves usually play a major role in building up
and breaking down the shoreline. A shoreline is the
boundary between land and a body of water.
I. Wave Energy continued
C. As the wind moves across the
ocean surface, it produces ripples
called waves. The size of a wave
depends on how hard the wind is
blowing and how long the wind
blows.
D. The wind that results from
summer hurricanes and severe
winter storms produces large
waves that cause dramatic
shoreline erosion.
I. Wave Energy continued
E. Wave Trains Waves travel in
groups called wave trains.
When wave trains reach shallow
water, the bottom of the wave
drags against the sea floor,
slowing the wave down.
F. The upper part of the wave
moves more rapidly and grows
taller, and begins to curl and
break. These breaking waves
are known as surf.
G. The time interval between
breaking waves is called the
wave period.
I. Wave Energy continued
H. The Pounding Surf Tremendous energy
is released when waves break. Crashing
waves can break solid rock and throw
broken rocks back against the shore.
I. Breaking waves also wash away fine
grains of sand, which are picked up by the
waves and wear down and polish coastal
rock.
J. The process continues until rock is
broken down in smaller and smaller pieces
that eventually become sand.
II. Wave Erosion
A. Shaping a Shoreline
Wave erosion produces a
variety of features along a
shoreline. Much of the
erosion responsible for
coastal landforms takes
place during storms.
B. Sea cliffs are formed
when waves erode and
undercut rock to produce
steep slopes.
III. Wave Deposits
A. Beaches are areas of the shoreline
made up of material deposited by
waves. Some beach material is also
deposited by rivers.
B. Waves carry a variety of materials,
including sand, rock fragments, dead
coral, and shells.
C. The colors and textures of beaches
vary because the type of material
found on a beach depends on its
source.
III. Wave Deposits continued
E. Wave Angle and Sand
Movement Waves moving
at an angle to the shoreline
push water along the shore
and create longshore
currents.
F. Longshore currents move
sand in a zigzag pattern
along the beach.
III. Wave Deposits continued
G. Offshore Deposits When
waves erode material from the
shoreline, longshore currents can
transport and deposit the
material offshore, which creates
landforms in open water.
H. A sandbar is an underwater or
exposed ridge of sand, gravel, or
shell material.
I. A barrier spit is an exposed
sandbar connected to the
shoreline.