How Coastal Processes Result in Coastal Erosion, Submersion, and Saltwater Intrusion

Summary

This 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

00:00

🌊 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.

05:00

🌊 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.

Keywords

💡Coastal Processes

Coastal processes refer to the various natural actions that shape and change the coastal landscape. In the video, these processes include erosion, submersion, and saltwater intrusion, which are critical in understanding how coastal areas are formed and evolve over time. The video emphasizes how these processes impact the land and sea interface, leading to the formation of features like cliffs, beaches, and caves.

💡Coastal Erosion

Coastal erosion is the wearing away of land by the sea, primarily through destructive waves. It is a significant process highlighted in the video, demonstrating how the power of waves can lead to the destruction of coastal infrastructures and the steepening of coastal areas. The script mentions five common processes that cause coastal erosion, such as abrasion and corrosion, which are essential to grasp the full impact of this phenomenon.

💡Abrasion

Abrasion is a type of coastal erosion where breaking waves containing sand and large fragments smash against the cliff, wearing it away. The video describes this as the 'sandpaper effect,' illustrating how the constant action of waves can gradually erode the coastline. Abrasion is a key mechanism in the broader process of coastal erosion, contributing to the transformation of coastal landscapes.

💡Attrition

Attrition is the process where waves cause rocks and pebbles to bump against each other, leading to the eventual breaking of the materials. Unlike abrasion, where two surfaces rub against each other, attrition involves a bouncing or smashing action. The video uses this term to differentiate between the types of mechanical wear that can occur during coastal erosion.

💡Hydraulic Action

Hydraulic action is the effect of waves on the cliff faces, where fast-moving water forces air into cracks in rocks, creating pressure that can lead to the rock breaking and splintering. The video explains this process as a part of coastal erosion, showing how the power of water can cause significant changes to the coastal landscape through this mechanism.

💡Corrosion or Solution

Corrosion, also known as solution, involves the dissolution of rocks, particularly those like limestone, by weak acids such as carbonic acid formed when carbon dioxide dissolves in water. The video script points out that this process is influenced by the concentration of carbonates and other minerals in the water, which can affect the rate of rock dissolution.

💡Sediment Movement

Sediment movement along the coast is a key process discussed in the video. It occurs as waves crash on the shore, pushing sediment up the beach and then pulling it back down as the water recedes. This movement is crucial for the formation and alteration of coastal features and is influenced by the direction of wave approach and the shape of the coastline.

💡Longshore Transport

Longshore transport, also known as littoral drift, is the movement of sediments along the coast parallel to the shoreline. The video explains that this occurs when waves do not approach the beach directly but at an angle, causing the sediment to be transported along the coast. This process is a significant factor in the formation of coastal features and the distribution of sediments.

💡Coastal Deposition

Coastal deposition is the process where waves, having lost their capacity to carry sediments due to a reduction in energy, deposit their sediment load. The video describes this as a constructive process where sediments accumulate, leading to the formation of features like beaches and dunes. Deposition is emphasized as a critical process in the creation of coastal landforms.

💡Constructive Waves

Constructive waves are those that, due to a lack of energy, are unable to transport sediments and result in sediment deposition and accumulation. The video uses this term to differentiate between waves that erode and those that build up coastal features. Constructive waves are essential for understanding how certain coastal landscapes are formed and maintained.

💡Kinetic Energy

Kinetic energy is the energy of motion, and in the context of the video, it refers to the energy possessed by waves. The script explains that when waves lose their kinetic energy, they can no longer transport sediments, leading to deposition. Understanding the role of kinetic energy is crucial for comprehending how coastal processes, such as erosion and deposition, are driven by the dynamics of waves.

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