Coasts

Question 1

Is the coastal system open or closed?

Answer 1

It is open because it recieves inputs from outside the system and transfers outputs away from the coast

Question 2

What are sediment cells?

Answer 2

Sediment cells are areas along the coastline and in the nearshore area where the movement of material is largely self-contained and the flows of sediment act in dynamic equilibrium

Sediment cells are often bordered by headlands

Question 3

What is dynamic equilibrium?

Answer 3

Dynamic equilibrium refers to the maintenance of a balance in a natural system, despite it being in a constant state of change.
The system has a tendency to counteract any changes imposed on the system in order to keep this balance, which is achieved by inputs and outputs constantly changing to maintain the balance.

Dynamic equilibrium in a sediment cell is where input and outputs of sediment are in a constant state of change but remain in balance.

Question 4

What are the three main coastal inputs?

Answer 4

1. Marine: waves, tides, salt spray
2. Atmospheric: sun, air pressure, wind speed and direction
3. Human: pollution, recreation, settlement, defences

Question 5

Examples of coastal outputs

Answer 5

• Ocean currents
• Riptides
• Sediment transfer
• Evaporation

Question 6

Examples of coastal stores/sinks

Answer 6

● Beaches
● Sand Dunes
● Spits
● Bars and Tombolos
● Headlands and Bays
● Nearshore Sediment
● Cliffs
● Wave-cut Notches
● Wave-cut Platforms
● Caves
● Arches
● Stacks
● Stumps
● Salt Marshes
● Tidal Flats
● Offshore Bands and Bars

Question 7

Examples of transfers/flows in the coastal system

Answer 7

● Wind-blown sand
● Mass-movement processes
● Longshore drift
● Weathering
● Erosion:
○ Hydraulic Action
○ Corrosion
○ Attrition
○ Abrasion
● Transportation:
○ Bedload
○ In suspension
○ Traction
○ In solution
● Deposition:
○ Flocculation

Question 8

What does positive feedback do?

Answer 8

It accentuates a change making the system more unstable and taking it away from dynamic equilibrium

Question 9

Example of positive feedback

Answer 9

1. People walking over sand dunes destroys vegetation growing there and causes erosion.
2. As the roots from the vegetation have been holding the sand dunes together, damaging the vegetation makes the sand dunes more susceptible to erosion. This increases the rate of erosion.
3. Eventually the sand dunes will be completely eroded leaving more of the beach open to erosion taking the beach further away from its original state.

Question 10

What does negative feedback do?

Answer 10

It bring a change back into dynamic equilibrium, making something less than it was before

Question 11

Example of negative feedback

Answer 11

1. When the destructive waves from the storm lose their energy excess sediment is deposited as an offshore bar.
2. The bar dissipates the waves energy which protects the beach from further erosion.
3. Over time the bar gets eroded instead of the beach.
4. Once the bar has gone normal conditions ensue and the system goes back to dynamic equilibrium.

Question 12

What is the littoral zone?

Answer 12

The littoral zone is the area of shoreline where land is subject to wave action. It’s subdivided into offshore, nearshore, foreshore and backshore.

Question 13

What is a spring tide?

Answer 13

The highest tide where storms reach

Question 14

What is swash?

Answer 14

When the wave moves up the beach

Question 15

What is backwash?

Answer 15

When the wave moves back down the
beach into the sea

Question 16

What are constructive waves?

Answer 16

Low energy waves with stronger swash than backwash meaning they deposit any material they were carrying. Important for the formation of beaches and other depositional processes.

Question 17

What are destructive waves?

Answer 17

High energy waves with weaker swash than backwash. The stronger backwash pulls material away from the shoreline and into the sea, resulting in erosion. They are usually steep and close together.

Question 18

How does seasonal weather affect wave type?

Answer 18

In the summer constructive waves are more common whilst in winter destructive waves are more common

Question 19

What factors affect wave energy?

Answer 19

• Strength of the Wind: As waves are caused by the wind, stronger winds also mean stronger waves.
• Duration of the Wind: If the wind is active for longer periods of time , then the energy of the
  waves will build up and increase.
• Size of the Fetch: The fetch is the distance over which the wind blows and the larger it is, the more powerful the waves will be.

Question 20

What is a current?

Answer 20

A permanent or seasonal movement of surface water

Question 21

What are rip currents?

Answer 21

Rip currents are powerful underwater currents occurring in areas close to the shoreline. They flow away from the shore

Question 22

What are the characteristics of a high-energy coastline?

Answer 22

High-energy coastlines are associated with more powerful waves, so occur in areas where there is a large fetch.
They typically have rocky headlands and landforms and fairly frequent destructive waves.
As a result these coastlines are often eroding as the rate of erosion exceeds the rate of deposition.

Question 23

What are the characteristics of a low-energy coastline?

Answer 23

Low-energy coastlines have less powerful waves and occur in sheltered areas where constructive waves prevail and as a result these are often fairly sandy areas .
There are landforms of deposition as the rates of deposition exceed the rates of erosion.

Question 24

What is wave refraction?

Answer 24

Wave refraction is the process by which waves turn and lose energy around a headland on uneven coastlines. The wave energy is focussed on the headlands , creating erosive features in these areas. The energy is dissipated in bays leading to the formation of features associated with lower energy environments such as beaches.

Question 25

What is the process of erosion and what types are there?

Answer 25

Erosion is a collaborative process which involves the removal of sediment from a coastline by
different types of erosion, not one type acting by itself. The main types are:

• Corrasion
• Abrasion
• Attrition
• Hydraulic action
• Solution

Question 26

What is corrasion?

Answer 26

Sand and pebbles are picked up by the sea from an offshore sediment sink or temporal store and hurled against the cliffs at high tide, causing the cliffs to be eroded.
The shape, size, weight and quantity of sediment picked up, as well as the wave speed, affects the erosive power of this process.

Question 27

What is abrasion?

Answer 27

This is the process where sediment is moved along the shoreline , causing it to be worn down over time. It is like a sandpaper effect, causing the rock to often look smooth and polished

Question 28

What is attrition?

Answer 28

Wave action cause rocks and pebbles to hit against each other , wearing each other down and so becoming round and eventually smaller. Attrition is an erosive process within the coastal environment, but has little to no effect on erosion of the coastline itself.

Question 29

What is hydraulic action?

Answer 29

As a wave crashes onto a rock or cliff face, air is forced into cracks, joints and faults within the rock. The high pressure causes the cracks to force apart and widen when the wave retreats and the air expands

Question 30

What is solution/corrosion?

Answer 30

The mildly acidic seawater can cause alkaline rock such as limestone to be eroded and is very similar to the process of carbonation weathering

Question 31

What factors affect erosion?

Answer 31

• Waves
• Subaerial processes (weathering and mass movement) e.g. landslides
  weaken cliffs. Rock fragments as a result of these processes may lead to increased
  corrasion and abrasion
• Rock type
• Faults in the rock
• Beaches beaches will decrease effects of erosion

Question 32

What is transportation and what are the 4 main types?

Answer 32

Coastal transportation is responsible for transferring sediment within a sediment cell and between
other sediment cells. The four main processes of transportation are:

● Traction
● Saltation
● Suspension
● Solution

Question 33

What is traction?

Answer 33

Large, heavy sediment rolls along the sea bed pushed by currents (like a tractor wheel)

Question 34

What is saltation?

Answer 34

Smaller sediment bounces along the sea bed, being pushed by currents . The sediment is too heavy to be picked up by the flow of the water

Question 35

What is suspension?

Answer 35

Small sediment is carried within the flow of the water. The Hjulström curve shows how greater velocities of water are able to suspend larger and heavier pieces
of sediment

Question 36

What is solution? (transportation)

Answer 36

Dissolved material is carried within the water, potentially in a chemical form. This method of transportation is an important part of carbonation weathering

Question 37

Describe the process of longshore drift

Answer 37

1. Waves hit the beach at an angle determined by the direction of the prevailing wind
2. The waves push sediment in this direction and up the beach in the swash
3. Due to gravity, the wave then carries sediment back down the beach in the backwash
4. This moves sediment along the beach over time

Question 38

What is deposition?

Answer 38

Deposition occurs when sediment becomes too heavy for the water to carry, or if the wave loses energy. Deposition tends to be a gradual and continuous process, so a wave won’t release all its sediment at the same time

Question 39

What is flocculation?

Answer 39

This is an important process in salt and tidal marshes. Clay particles clump together and then sink due to their high density

Question 40

What is weathering and what are the types?

Answer 40

Weathering is the breaking down of rocks in situ (where they are). It is caused by day-to-day changes in the atmosphere such as temperature and precipitation. The types of weathering are:

• Mechanical
• Biological
• Chemical
• Onion-skin

Question 41

What is mechanical weathering? + examples

Answer 41

The breakdown of rocks due to exertion of physical forces without any chemical changes taking place

● Freeze-thaw: Water enters cracks in rocks and then the water freezes overnight during the winter. As it freezes, water expands by around 10% in volume which increases the pressure acting on a rock, causing cracks to develop. Over time these cracks grow, weakening the cliff making is more vulnerable to other processes of erosion

● Salt Crystallisation: As seawater enters cracks then evaporates, salt is left behind. Salt crystals will grow over time, exerting pressure on the rock, which forces the cracks to widen. Salt can also corrode ferrous (materials that contains iron) rock due to chemical reactions

● Wetting and Drying: Rocks such as clay expand when wet and then contract again when
they are drying. The frequent cycles of wetting and drying at the coast can cause these
rocks and cliffs to break up

● Onion-skin: * During the day the sun heats up the surface of the rock, causing the rock to expand. During the night the rock cools down and contracts. As the rock expands and contracts over and over again small pieces of surface rock begin to fall and flake off

Question 42

What is scree?

Answer 42

Frost-shattered pieces of rock

Question 43

What is biological weathering? + examples

Answer 43

The breakdown of rocks by organic activity

• Piddocks (shellfish that bore into rocks)
• Seaweed and algae secretes chemicals capable of promoting solution
• Plant roots can get into tiny cracks and open them up further
• Decaying plant roots produce acid which chemically eats away at rocks
• Burrowing animals such as Puffins

Question 44

What is chemical weathering? + examples

Answer 44

The breakdown of rocks through chemical reactions

• Acid rain: nitrogen and sulphur oxide produce much more acidic rain that can rapidly chemically dissolve rocks
• Carbonation: carbon dioxide gas dissolves into rain to form weak carbonic acid. This very slowly eats away at certain rocks like chalk and limestone
• Oxidation: when rocks are broken down by oxygen in the air. It makes them go a rusty colour. Rocks which contain iron are prone to this

Question 45

What is mass movement and what are the four categories?

Answer 45

Mass movement is the movement of material down a slope under the influence of gravity. The four categories are:

• Creeps
• Flows
• Slides
• Falls
• Slumps

e.g. rockfall, landslide, landslip

Question 46

Explain the process of caves -> arches -> stacks -> stumps

Answer 46

● Initially, faults in the headland are eroded by hydraulic action and abrasion to create small caves
● Marine erosion widens faults in the base of the headland , widening over time to create a cave
● The cave will widen due to marine erosion and sub-aerial processes, eroding through to the other side of the headland, creating an arch
● The arch continues to widen until it is unable to support itself, falling under its own weight through mass movement, leaving a stack as one side of the arch becomes detached from the mainland
● With marine erosion attacking the base of the stack, eventually the stack will collapse into a stump
● A wave-cut platform will be left afterwards

Question 47

How do blowholes form?

Answer 47

A blowhole is formed as sea caves grow landwards and upwards into vertical shafts and expose themselves towards the surface, which can result in blasts of water from the top of the blowhole is the gemoetry of the cave and state of the weather are appropriate

Question 48

What is a bay?

Answer 48

A bay is a crescent-shaped indentation in the coastline found between two headlands. It usually has a beach which is composed of sand or shingle (soft rock)

For example, Swanage

Question 49

What is a headland?

Answer 49

A headland is a cliff that sticks out into the sea, so it is surrounded by water on three sides. Headlands are composed of hard rock such as granite, chalk or limestone, which are resistant to erosion

For example, Durlstone Head

Question 50

How are headlands and bays formed?

Answer 50

Bays and headlands are formed on discordant coastlines when there is a section of soft rock between hard rock on a coast line. The soft rock and hard rock have differential erosion with the soft rock eroding faster to the waves therefore the hard rock cliff stick out, creating headlands

Question 51

What is a concordant coastline?

Answer 51

A coastline where the geology is parallel

Question 52

What is a discordant coastline?

Answer 52

A coastline where the geology is perpendicular. Features such as headlands and bays will be sene here

Question 53

Swash-aligned vs drift-aligned beaches

Answer 53

Swash-aligned:
Waves break perpendicular to coast so there is limited longshore drift. Sediment doesn’t travel far along the beach. Wave refraction may reduce the speed of high energy waves, leading to the formation of a shingle beach with larger sediment

Swash aligned beaches are more influenced by constructive wave patterns, which are also important for building up large beaches. In contrast, drift aligned coasts bring in waves at an angle to the shoreline and so therefore, the waves tend to transport sediment down the coast, keeping beaches relatively narrow.

Drift-aligned:
Waves approach at an angle, so longshore drift causes the sediment to travel far along the beach, which may lead to the formation of a spit at the end of a beach.
Generally larger sediment is found at the start of the beach and weathered sediment moves further down the beach through longshore drift, becoming smaller as it does, so the end of the beach is likely to contain smaller sediment

Question 54

What is a spit?

Answer 54

This is a long narrow strip of land which is formed when longshore drift causes the beach to extend out to sea, usually due to a change in direction of the coastline.
This sediment projection can create a salt marsh due to the sheltered, saline environment where water flow speed is lower, allowing deposition of finer sediments to occur.
The length of the spit depends on any changing currents or rivers, which will prevent sediment from being deposited .
This means a spit can never extend across an estuary.
A change in wind direction or wave direction can cause the end of the spit to curve

Question 55

What is a barrier beach?

Answer 55

A barrier beach occurs when a beach or spit extends across a bay to join two headlands .
This traps water behind it leading to the formation of a brackish lagoon which is separated from the sea.
As well as forming from present day processes, some barrier beaches may have formed due to rising sea levels after the last glacial period , when meltwater from glaciers deposited sediment in the coastal zone. If a barrier beach becomes separated from the mainland, it becomes a barrier island. T
hey are common in areas with low tidal ranges

Question 56

What are tombolos?

Answer 56

A tombolo is a bar or beach that connects the mainland to an offshore island and is formed due to wave refraction off the coastal island reducing wave velocity , leading to deposition of sediments.
They may be covered at high tide if they are low lying.

Question 57

What is an offshore bar?

Answer 57

An offshore region where sand is deposited , as the waves don’t have enough energy to carry the sediment to shore.

They can be formed when the wave breaks early, instantly depositing its sediment as a loose-sediment offshore bar. They may also be formed as a result of backwash from destructive waves removing sediment from a beach.

Offshore bars may absorb wave energy, reducing erosion in some areas.

Question 58

Describe the formation of sand dunes

Answer 58

1. Sand accumulates against a feature and builds upper beach height
2. Wind speed drops behind accumulation resulting in more sand deposition
3. Marram grass colonises embryo dunes stabilising further dune migration
4. Marram leaves further reduce wind speed and capture more blown sand. Decaying plants add humus
5. Microclimate and soil conditions change allowing colonisation by additional species

Question 59

What are the types of dunes and descriptions of each?

Answer 59

• Embryo dunes: Upper beach area where sand starts to accumulate around a small obstacle (driftwood, wooden peg, ridge of shingle)
• Yellow dunes: – As more sand accumulates and the dune growns, vegetation may develop on the upper and back dune surfaces, which stabilises the dune.
• Grey dunes: – Sand develops into soil with lots of moisture and nutrients, as vegetation dies, enabling more varied plant growth and giving it a greyer colour
• Dune slacks: The water table rises closer to the surface, or water is trapped between hollows between dunes during storms, allowing the development of moisture-loving plants (e.g. willow grass)
• Heath and woodland: Sandy soils develop as there is a greater nutrients content, allowing for less brackish plants to thrive. Trees will also grow (willow, birch, oak trees) with the coastal woodland becoming a natural windbreak to the mainland behind

Question 60

Describe the formation of estuarine mudflats and salt marshes

Answer 60

Salt marshes tend to develop in sheltered areas such as behind a spit where there are no strong tides or currents to prevent sediment deposition and accumulation. As most of the sediment is small, this leads to a build up of mud via flocculation, which over time builds up until it is above the water level. Pioneer plants colonise this area, leading to more sediment becoming trapped. A meadow is formed as sections of the salt marsh rise above the high tide level, leading to the climatic climax of the vegetation succession

Question 61

What are the reasons for current sea level rise?

Answer 61

• Thermal expansion (as ocean water warms, it expands)
• Increased melting of land-based ice
• Human-induced global warming (1.7mm per year sea level rise)

Question 62

What is isostatic change?

Answer 62

Isostatic change occurs when the land rises or falls relative to the sea and is a localised change caused by a growing or declining ice sheet.

Isostatic sea level change is often a result of isostatic subsidence (glaciers weigh down the land beneath, and so the land subsides). When the glaciers melted, this has lead to isostatic recovery and the coastline to rebound and rise again in the areas that were covered by ice.

In the UK, Scotland and the north-west of England are rising at around 1.5mm per year as they were previously covered by glaciers, but the land in the south-east subsides at around 1mm a year as the ice was thinner and so there was less pressure on the crust

Question 63

What is eustatic change?

Answer 63

A rise or fall in sea level because of the amount of sea water across the whole planet is called Eustatic change.

Eustatic change may be due to thermal expansion/contraction or changes in glacial processes.
Thermal expansion is the process of water expanding when it gets warmer, and so the volume of water increases leading to rising sea levels.
In the last ice age, sea levels were over 100m lower than they are currently due as the water was stored in large ice caps as the majority of precipitation fell as snow. When the ice caps melted, this lead to rising sea levels.

As a result of global warming, both processes are acting to increase sea levels

Question 64

What are emergent coastal landforms?

Answer 64

Where the land has been raised in relation to the coastline, landforms such as arches, stacks and
stumps may be preserved

Question 65

What are submergent coastal landforms and what are the examples?

Answer 65

Landforms of submergence occur when the sea level rises or the coastline sinks in relation to
the sea. Rising sea levels leads to the following landforms:

• Rias
• Fjords
• Dalmation Coastlines

Question 66

What are Dalmation Coasts and how are they formed?

Answer 66

Composed of long, narrow islands running parallel to the caostline separated by narrow sea channels. They are produced by sea-level rise flooding the shoreline where geology creates valleys aligned parallel to the caost.
The best example of a dalmation coast is the Dalmation Coast in Croatia

Question 67

What are rias and how are they formed?

Answer 67

A ria is a drowned (flooded) river valley (V-shaped). Rias are formed when rising sea levels flood narrow winding inlets and river valleys .
They are deeper at the mouth of the inlet, with the water depth decreasing further inland.

Question 68

What are fjords and how are they formed?

Answer 68

Fjords are drowned glacial valleys rather than drowned river valleys. Deep water + predominently salt water. They are dangerous due to mass movement causing tsunamis (large rocks breaking off and falling into water)

Fjords are formed when rising sea levels flood deep glacial valleys to create natural
inlets and harbours

Question 69

What is a CBA?

Answer 69

Cost-benefit analysis.

This is carried out before a coastal-management project is given the go ahead. Coasts are forecast e.g. a sea-wall along with its design, maintenance, cost and then compared with the expected benefits e.g. the value of land saved, housing protected, savings.

Costs and benefits are either:

• Tangible - where costs and benefits are known and can be given monetary value
• Intangible - where costs may be difficult to assess but are important

Question 70

What are the two strategies for managing a coastline?

Answer 70

• Hard engineering - man made structures that aim to prevent erosion . They are often very effective
  at preventing erosion in the desired area, but are high cost and have a significant environmental impact due to the use of concrete and other man-made materials.
• Soft engineering - aims to work with and complement the physical environment by using natural methods of coastal defence. They are useful for protecting against sea-level change as well as coastal erosion.

Question 71

Examples of soft engineering

Answer 71

• Beach nourishment
• Cliff regrading (make cliff less steep)
• Dune stabilisation
• Marsh creation

Question 72

Examples of hard engineering

Answer 72

• Groynes
• Sea walls
• Concrete tetrapod (tetrahedral shape to dissipate the force of incoming waves by allowing water to flow around rather than against them)
• Revetments (wooden/concrete ramps)
• Offshore breakwater (rock barrier forcing waves to break)
• Rock armour/riprap

Question 73

CASE STUDY
Holderness Coast

Answer 73

Stretch of coast begins at Flamborough Head and ends at Spurn.

Flamborough Head

Cliffs made of chalk -> resistant rock, distinctive white colour
The sea is actively undercutting and eroding the base of the cliffs leading to fequent rockfalls. Wave refraction concentrates wave energy on the headland and lack of beach renders cliffs more vulnerable.
One of the most recognisable features on the map in the UK (tourist attraction). Natural environment is economically beneficial.
SMP: Do Nothing. This is because of the slow erosion rate withing this area meaning no settlements or properties are at threat

Hornsea & Mappleton

Land made of boulder clay deposited by glaciers -> retreats at 10x the rate of chalk cliffs
Management is aimed at protecting hotels, arcades and creating a sandy beach as they are economically valuable and there is settlement.
Spent money on wooden groynes, gabions and a concrete sea wall alongside riprap, groynes and beach nourishment at Mappleton to produce a sandy beach.
Hornsea cliffs are a popular tourist destination but have a rapid rate of cliff retreat
SMP: Hold the line

Easington

2.25% of all UK gas comes through gas terminal at Easington. £4.45 million spent on riprap to protect the terminal/village. The terminal is one of the six main gas terminals in the UK
Locals disagreed about where sea defences are located as they mainly protect the terminal and not the village
SMP: Hold the line

Spurn

Spit made of sand and shingle. 6km long. Salt marsh developed behind it due to the saline conditions.
Groynes in the north on Hornsea disrupt LSD, spit recieves less sediment opening it up to erosion.
Protected with groynes and rock armour but is at risk of losing habitats due to the lack of sediment to maintain the spit.
Extremely narrow for much of its length and has been frequently breached and destroyed by major storms. Plays an important role in protecting the town and land bordering River Humber from effects of flooding and storm waves
SMP: No active intervention/managed realignment

Question 74

CASE STUDY
The Sundarbans, Bangladesh

Answer 74

The Sundarbans is a coastal zone occupying the world’s largest delta, that extends over 10,000km2 of southern Bangladesh and India on the Bay of Benga. The delta is formed from the sediment deposited by the Ganges, Brahmaputra and Meghna rivers. The natural climax ecosystems of the Sundarbans are mangrove forests and swamps where Bengal tigers use as their habitat.

Challenges

• Tiger attacks
• Coastal flooding
• Salinisation of soil
• Remoteness/ lack of accessibility due to few roads
• Cyclones
• Lack of knowledge of coastal issues by those in charge
• Deforestation of mangroves due to population growth inceasing flood risk and conflict with bengal tigers
• Located on big flood plain
• Destructive shrimp farming
• Poor communications
• High poverty
• General lack of employment

Resilience

• Solar energy project set up so people spend less time in forests meaning less exposure to tigers
• The light deters the tigers and means shops can stay open at night
• Trackers on tigers
• Better roads and bridges being built
• Public Health Engineering department is improving access to clean water and sanitation

Mitigation

• Investment in physical infrastructure
• Government plan to move 1.8mil people to cyclone shelters
• Planting of 16 million mangroves to strengthen existing manmade structure as mangroves decease windspeed by 20km
• Mangrove restoration stores 700,000 tonnes of CO2

Adaptation

• Salt-resistant rice planted by countless farmers to help feed the Sundarbans population as rice usually requires an abundance of water, this is disrupted when storm surges cause salt-water flooding
• US-Aid provides better info on climate change and biodiversity. Promotes green energy and solar panels and has helped 100,000 people from 15,000 hectares of land with better tools

Question 75

What are ICZMs?

Answer 75

Integrated Coastal Zone Management

Brings together those involved in department, management and use of the coast because human actions in one place affect other places down coast. Management occurs between different political boundaries , which is both beneficial and problematic as decision making is likely to be a longer process. Aim is to establish sustainable levels of economic and social activity, resolve environmental, social, economic challeneges and protect coastal environment.
ICZMs provide a more holostic overview of the coast

Question 76

What are SMPs?

Answer 76

Shoreline Management Plans

For each sediment cell in the UK, an SMP has been created to help with coastline management.
Each SMP identifies all of the activities, both natural and human which occur within the coastline area of each sediment cell.

Four options are considered for each stretch of the coastline:

● Hold the Line: Defences are used to maintain the current position of the shoreline
● Managed Retreat: Defences and engineering techniques are used to allow
the coastline to advance inland and create its own natural defences such as salt marshes
● Advance the Line : Defence are built to try and move the shoreline seawards, potentially to
protect an important population centre or tourist amenity
● No Active Intervention: The coastline is exposed to natural processes