How Coastal Processes Result in Coastal Erosion, Submersion, and Saltwater Intrusion
Summary
TLDRThis educational video delves into coastal processes, focusing on erosion, submersion, and saltwater intrusion. It explains how coastal areas, transition zones between land and sea, are shaped by natural forces like tides, waves, and currents, as well as human activities. The video outlines key processes such as abrasion, attrition, hydraulic action, and corrosion that contribute to coastal erosion. It also discusses sediment movement and coastal deposition, highlighting how waves' energy loss leads to sediment accumulation, forming new landforms. The video serves as a comprehensive guide to understanding the dynamic nature of coastlines.
Takeaways
- 🌊 **Coastal Erosion**: The process where the land is worn away by the sea, primarily through destructive waves.
- 🏖️ **Coastal Features**: Coasts have diverse features such as caves, cliffs, pitches, and mad flats, shaped by external forces like tides, waves, and currents.
- ⛰️ **Mechanical Erosion (Attrition)**: Waves cause rocks and pebbles to collide, leading to the breaking down of materials.
- 💧 **Hydraulic Action**: The force of waves drives water into cliff cracks, causing pressure that can lead to rock fragmentation.
- 🌪️ **Abrasion**: Similar to sandpaper, breaking waves with sand and debris smash against cliffs, causing erosion.
- 🌄 **Creation**: A process where waves hurl beach materials at cliffs, causing erosion.
- 🌬️ **Corrosion/Solution**: The dissolution of rocks, especially limestone, by weak acids like carbonic acid formed from dissolved carbon dioxide.
- 🏝️ **Human Impact**: Humans have built coastal features like harbors, defenses, and artificial islands, impacting natural coastal processes.
- 🌊 **Longshore Transport**: Sediments move along the coast due to waves approaching at an angle to the shoreline.
- 🏖️ **Coastal Deposition**: Occurs when waves lose energy and can no longer carry sediments, leading to sediment deposition, particularly in shallow or sheltered areas.
Q & A
What are the three dominant coastal processes discussed in the video?
-The three dominant coastal processes discussed in the video are coastal erosion, the movement of sediments along the coast, and coastal deposition.
What is coastal erosion, and how does it occur?
-Coastal erosion is the wearing away of the land by sea, caused by destructive waves. It occurs through processes such as creation, abrasion, attrition, hydraulic action, and corrosion or solution.
What is the 'sandpaper effect' mentioned in the video?
-The 'sandpaper effect' refers to abrasion, where breaking waves containing sand and large fragments smash along the cliff and wear it away.
How is attrition different from abrasion in the context of coastal erosion?
-Attrition differs from abrasion in that it involves waves causing rocks and pebbles to bump against each other, leading to the eventual breaking of the materials, whereas abrasion involves two surfaces rubbing against each other.
What is hydraulic action, and how does it contribute to coastal erosion?
-Hydraulic action is the effect of waves hitting cliff faces, forcing air into cracks in rocks. This creates pressure that can cause the rock to crack, break, and splinter, contributing to coastal erosion.
Can you explain the process of corrosion or solution in coastal erosion?
-Corrosion or solution in coastal erosion involves the dissolution of rocks, such as limestone, by weak acids like carbonic acid, which forms when carbon dioxide dissolves in water.
What is the movement of sediments along the coast, and how does it happen?
-The movement of sediments along the coast, also known as longshore transport or littoral drift, occurs when waves crash on the shore, pushing sediment up the beach and pulling it back down as the water recedes.
What is coastal deposition, and under what conditions does it occur?
-Coastal deposition is the process where waves, having lost their capacity to transport sediments, drop or deposit their sediment load. This happens in areas of shallow water, sheltered areas like bays, when there is little or no wind, and a sufficient supply of sediments.
How does the swash and backwash of waves affect coastal deposition?
-Coastal deposition occurs when the swash (waves rushing inland) is stronger than the backwash (waves rushing back to the sea), indicating that the waves are losing kinetic energy needed to transport sediments.
What are some human-built coastal features mentioned in the video?
-Some human-built coastal features mentioned in the video include harbors, coastal defenses, and artificial islands.
What effect does coastal erosion have on infrastructure along the coast?
-Coastal erosion can lead to the destruction of houses and other infrastructures along the coast, as well as the steepening of the coastal area.
Outlines
🌊 Coastal Processes and Erosion
This paragraph introduces the topic of coastal processes, focusing on erosion, submersion, and saltwater intrusion. It explains that coastal areas are transition zones between land and sea, featuring various landforms such as caves, cliffs, and beaches. External forces like tides, waves, and currents, as well as human activities, contribute to shaping these areas. The paragraph also discusses the impact of coastal erosion on infrastructure and identifies five processes that cause it: corrosion, abrasion, attrition, hydraulic action, and solution. Each process is described in detail, highlighting how they contribute to the wearing away of coastal landforms.
🌊 Sediment Movement and Coastal Deposition
The second paragraph delves into the movement of sediments along the coast, driven by wave action. It explains how sediment is pushed up the beach by waves and pulled back down as the water recedes, leading to longshore transport or drift of sand when waves approach at an angle. The paragraph also covers coastal deposition, which occurs when waves lose the energy needed to carry sediments, resulting in sediment deposition. This can happen in shallow waters, sheltered areas, or when there's a lack of wind and an ample supply of sediments. The importance of waves losing kinetic energy for deposition to occur is emphasized, and the concept of constructive waves is introduced, which are waves that can no longer transport sediments and lead to their accumulation.
Mindmap
Keywords
💡Coastal Processes
💡Coastal Erosion
💡Abrasion
💡Attrition
💡Hydraulic Action
💡Corrosion or Solution
💡Sediment Movement
💡Longshore Transport
💡Coastal Deposition
💡Constructive Waves
💡Kinetic Energy
Highlights
Coastal processes result in erosion, submersion, and saltwater intrusion.
Coastal areas are transition zones between land and sea, also known as coasts or coastlines.
Coasts feature various formations like caves, cliffs, pitches, and sand flats.
External forces such as tides, waves, and water currents shape coastal features.
Glaciers and lava flows can also alter coastal landscapes.
Human activities like building harbors and coastal defenses impact coastal features.
Coastal erosion is caused by destructive waves and mechanical wear of bedrock.
Attrition is the process where rocks and pebbles break due to wave impact.
Hydraulic action describes the force of water on cliffs, causing rock to crack and break.
Corrosion or solution is the dissolution of rocks by weak acids, affecting rocks like limestone.
Sediment movement along the coast occurs due to wave action pushing and pulling sediments.
Longshore transport or littoral drift happens when waves approach the beach at an angle.
Coastal deposition occurs when waves lose energy and can no longer carry sediments.
Constructive waves lead to sediment deposition and accumulation.
Deposition is more likely in shallow water, sheltered areas, and when there's a strong swash and sufficient sediment supply.
Waves must lose kinetic energy for coastal deposition to take place.
Transcripts
in this video we are going to talk about
how coastal processes result in coastal
erosion submersion and salt water
intrusion these are the specific
learning outcomes
now i want you to study these two maps
pay particular attention to the outlines
of the continents
these outlines of the islands are called
coastal areas
coastal areas are transition areas
between land and sea these are sometimes
called as coasts or coastlines
coasts have many different features such
as caves and cliffs pitches and mad
flats
external forces such as tides waves and
water currents flow
shape the land to form these coastal
features
some coasts are also changed by the flow
of glaciers which are huge rivers of ice
and lava from volcanoes
humans have also built coastal features
such as harbors coastal defenses and
artificial islands
these pictures show the effect of
coastal erosion leading to the
destruction of houses and other
infrastructures along the coast and the
steepening of the coastal area
now there are three dominant coastal
processes
the first one is coastal erosion coastal
erosion based on the name itself is the
wearing away of the land by sea and this
is done by destructive waves
there are five common processes that
cause coastal erosion first is what we
call creation
creation is a process of erosion which
refers to the strictly mechanical wear
of bedrock by moving directly and other
materials during their migration
downslope under the influence of gravity
and the further transportation of
erosional agencies
such as running water moving ice or wind
in simple words
when waves pick up beach materials such
as stones and hurl them at the base of
the cliff correction happens
creation looks like this and it is a
serious problem
next is what we call coastal abrasion or
just abrasion
abrasion occurs as breaking waves which
contain sand and large fragments smash
along the cliff and wear it away
it is also referred to as the sand paper
effect and it looks like this
as you can see the waves carry the large
fragments and destroy the coast
now there is another thing called
attrition
attrition is the process when waves bump
rocks and pebbles
against each other leading to the
eventual breaking of the materials
here it is basically the waves that
cause the damage
just to clarify the difference between
the two
abrasion and nutrition
abrasion is when two surfaces rub
against each other and attrition is
where they bounce or smash against each
other
the next process is called the hydraulic
action
okay still under the coastal erosion
it is simply the effect of waves as the
heat cliff faces
when fast moving water strikes river
banks and large rocks
air is forced into the cracks
this puts great pressure on the
surrounding rock which can progressively
cracked
breaks and splinter this is followed by
sudden decompression which can happen
with explosive force
here the released air simply blows away
pieces of rocks
cracks are gradually widened so that
subsequent waves compress more air
which increases the explosive force of
its release
and last under coastal erosion we have
the corrosion or solution
this involves dissolution by weak acids
such as carbon dioxide in the atmosphere
so when carbon dioxide is dissolved in
water
it turns into a weak acid called the
carbonic acid
now several rocks such as limestone
are vulnerable to this acidic water and
will dissolve into it
you have to remember that the rate of
the solution is affected by the
concentration of carbonates and other
minerals in the water
so as it increases the solution becomes
slower
the next coastal process is the movement
of sediments along the coast
as wave crashes on the shore the water
pushes sediment up the beach
and then pulls it back down the beach as
the water slides back down
if the waves do not come in parallel to
the beach
longshore transport or what we call
literal drift of sand occurs
last we have the coastal deposition
so when waves lose their capacity to
carry or transport sediments because of
reduction in energy they can and will
drop or deposit its sediment load
okay
so waves that do not have the capacity
to transport sediments and which results
to sediment deposition and accumulation
are called constructive waves
you have to remember that deposition
happens when the swash
or the waves that rushes inland
is stronger than the backwash or the
waves rushing back to the sea
deposition can occur as waves enter
areas of shallow water
sheltered areas like coast and bay
little or no wind and there is a
sufficient supply of sediments now
it must be emphasized that the waves
lose kinetic energy to transport the
sediment load for coastal deposition to
happen
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