Longshore currents
are generated when a “train” of waves reach the coastline and release bursts of energy. … When a wave reaches a beach or coastline, it releases a burst of energy that generates a current, which runs parallel to the shoreline. This type of current is called a “longshore current.”
What is another name for longshore transport?
The combined effects of sediment transport within the surf zone by the longshore current and sediment movement along the beach by swash and backwash is known as longshore transport , or
littoral drift
.
What flows parallel to the shore?
A longshore current
is an ocean current that moves parallel to shore. It is caused by large swells sweeping into the shoreline at an angle and pushing water down the length of the beach in one direction.
What causes Longshores?
Longshore currents occur along a coastline. They are caused in the following way:
waves strike the shore at an angle and the water accompanying the waves tries to rush back out to sea
.
What is it called when a wave moves up a beach?
There are two different types of wave – constructive and destructive. They can affect the coastline in different ways. When a wave reaches the shore, the water that rushes up the beach is known as
the swash
.
Why do waves hit the beach at an angle?
When waves approach the beach at an angle, the
part of the wave that reaches shallow water earliest slows down the most
, allowing the part of the wave that is farther offshore to catch up. In this way the wave is refracted (bent) so that it crashes on the shore more nearly parallel to the shore.
What causes swash and backwash?
When a wave breaks, water is washed up the beach
. This is called the swash . Then the water runs back down the beach, which is called the backwash . With a constructive wave, the swash is stronger than the backwash.
What is the difference between longshore current and longshore transport?
The main difference between longshore current and longshore drift is that longshore currents are the
ocean waves that travel parallel to the beach
whereas longshore drift is the transportation of sediment materials along a coast parallel to the shoreline.
Why is longshore drift bad?
Longshore drift can
be very destructive to manmade structures
. … Longshore currents are affected by the velocity and angle of a wave. When a wave breaks at a more acute (steep) angle on a beach, encounters a steeper beach slope, or is very high, longshore currents increase in velocity.
What is a littoral current?
:
a current moving along and roughly parallel to a shore
.
Where would we find an erosional shore?
Both temporal and geographic variations may occur in each of these coastal types. Erosional coasts typically exhibit high relief and rugged topography. They tend to occur on
the leading edge of lithospheric plates
, the west coasts of both North and South America being excellent examples.
Where are longshore currents strongest?
In areas with offshore mounds of sand, known as sandbars, longshore currents are often very strong in
the trough that separates the sandbar from the beach
. Longshore currents commonly feed into rip currents, mainly those on the downwind side. Strong currents are present at some park beaches.
Where does 80 to 90 of beach sand come from?
River sediments
are the source of 80 to 90 per cent of beach sand; some beaches are built to great widths by sediments washed to the sea by episodic floods, gradually eroding until the next major flood replenishes the sand. Coastlines are constantly changing due to the action of waves, currents, and tides.
What are the two types of waves?
Waves come in two kinds,
longitudinal and transverse
. Transverse waves are like those on water, with the surface going up and down, and longitudinal waves are like of those of sound, consisting of alternating compressions and rarefactions in a medium.
Do destructive waves cause deposition?
Deposition is when
material carried by the sea is deposited or left behind on the coast
. Coastal erosion takes place with destructive waves. These destructive waves are very high in energy and are most powerful in stormy conditions.
What happens when a wave reaches the shore?
As waves come into shore, they usually reach the shore at some angle. … As a wave comes into shore,
the water ‘feels’ the bottom which slows down the wave
. So the shallower parts of the wave slow down more than the parts that are further from the shore. This makes the wave ‘bend’, which is called refraction.
