Unit 2 - Natural Environment: Coastal landscapes Flashcards
What are the four types of mass movement?
Slumping- rock weaken and simply falls down the hill
Rockfall- rock fall of cliff due to freeze thaw and weathering
Mud flow- saturated soil and weak rock falls down and produces lobe.
Soil creep- this is the only slow process and it is when soil moves down the hill do to gravity and its weakness
What are the 2 types of transportation?
Solution- when molecules are dissolved in water and are then moved to another location
Suspension- this is when bits of rock and sand hang in the water and are then moved to another location by waves
What is a constructive wave?
This builds coast, they have a strong swash and they are found on gently sloping beaches.
What are destructive waves?
- takes away the coast
- they have a strong backwash
- they are found on steep beaches
Waves -> landforms
The waves create landforms
What is a salt marsh?
Forms behind a spit, when cut off from sea. This is where salt loving plants are found.
Define DEPOSITION and all examples.
When sediment is deposited in a new place (when the coast moves) to form new land such as spit, salt marsh or bar.
Define Spit
Deposition, when coast changes direction. Deposition continues to form new land in a straight line, this is called a spit.
Define BAR
Another form of deposition, when a spit extends all the way across the mouth of a river. This is where salt marshes are formed.
The processes of cliff erosion (say what they are what they look like and how and when they are formed.)
- bay, cove
- headland
- crack
- cave
- arch
- stack
- stump
- wave cut notch
- cliff recession
- wave cut platform
Processes ways of erosion (attrition, hydraulic action, abrasion, solution.)
Attrition- rocks being thrown against rock in the sea. Rock on rock.
Hydraulic action- water forced into crack weakening rock.
Abrasion- bits of rock thrown at cliff wearing it down.
Solution- acids and salt dissolved in the sea water react with the minerals in the cliff dissolving then therefore weaking the rock
Types of hard protection(what are they what do they do and what do they look like)
Groynes Sea wall Gabions Rip-rap (tetripods) Revetments Breakwaters Off shore reaf
Compare hard protection to soft protection
Hard COSTS MORE Hard NEEDS MORE ENGINEERING Hard NEEDS MORE MAINTENANCE Hard NORMALLY NOT LOCAL Soft NOT AS EFFECTIVE
Protection - Soft protection
Cliff reprofileing
Beach replenishment
Protection - HOLD THE LINE
This is when no more land is lost. At all cost they can t lose the land
Protection - Managed retreat
This is when land is lost but at a steady rate
Protection - DO NOTHING
This is when nothing is done.
Waves -> management
Management needed to protect from waves.
Protection -> processes
Protection is trying to manage the processes.
Management -> protection
Management decides which type of protection.
Define Slumping?
Rock weaken and simply falls down the hill.
Define Rockfall?
Rock fall of cliff due to freeze thaw and weathering.
Define Mud flow?
Saturated soil and weak rock falls down and produces lobe.
Define Soil creep?
This is the only slow process and it is when soil moves down the hill do to gravity and its weakness.
Transportation - Solution?
When molecules are dissolved in water and are then moved to another location.
Transportation - Suspension?
This is when bits of rock and sand hang in the water and are then moved to another location by waves.
Erosion - Attrition
Rocks being thrown against rock in the sea. Rock on rock.
Erosion - Hydraulic action
Water forced into crack weakening rock.
Erosion - Abrasion
Bits of rock thrown at cliff wearing it down.
Erosion - Solution
Acids and salt dissolved in the sea water react with the minerals in the cliff dissolving then therefore weaking the rock.
Protection - Hard Protection
cost more, more engineers, more maintenance
Examples of Hard Protection?
groynes, sea walls and gabions
Case study?
Happisburgh
How has the coast originally been protected in Happisbutgh?
The coast was protected by wooden revetments, however they are now in disrepair. Also groynes.
Arguments - In favor of protection (managed retreat)
Historians think that there are many historical buildings that need to be protected
Arguments - In favor of protection (hold the line)
Spending money on sea defenses is a waste of resources - the sea will always win. You should go all the way or do nothing to stop the sea.
Cost and life span of - Sea Wall
100 years, £5000 per m
Cost and life span of - Gabions
5-10 years, £50 m cubed
Cost and life span of - Revetments
10 years, £800 per m
location of Happisburgh?
North east of Norwich. on the coast between Cromer and Sea Palling. on the coast Norfolk broads, below the Wash
Opinions of stakeholders - Local councilor
Happisbough is a thriving community - a school, a shop, a Post Office, a pub and places where people work. it is sustainable community so it should be protected.
Opinions of Stakeholders - Beach road resident
When i bought our house on beach road in Happisburgh, the government policy was to ‘hold the line’. Now the policy has changed and my property is worthless. I can’t afford to move, and no council accommodation is available. I’ve paid taxes all my life and i feel we should be protected here at Happisburgh.
Opinions of Stakeholders - Local historian
There are historic buildings in Happisburgh. they should be protected so that generations in the future can see them.
Opinions of Stakeholders - Local farmer
It’s not fair to spend £60 million on defending other places just along the coast like Sea Palling whilst the land around happisburgh is left to erode.
Opinions of Stakeholders - Sea palling resident
It’s not worth paying for the cost of the sea defenses in Happisurgh. It’s a different story at sea Palling which is a vibrant economic community with more shops, businesses and so on.
Opinions of stakeholders - local holiday park owner
Money should be spent by the government on the sea defenses to protect coastal industries, such as my holiday park. This will help to maintain jobs and livelihoods. our coastline should be protected - we don’t want to lose it.
Opinions of Stakeholders - Stalham resident
Spending money on sea defenses is a waste of resources - sea will always win. the money would be better spent on hospitals and schools especially with the country’s fiances in the state they are in.
Opinions of Stakeholders - Environmental officer
The Norfolk broads are a unique fresh water environment. They are protected from the sea by the local beaches which are made of sediment bought from further north along the coast. This may possibly cause our beaches to become eroded and the broads to become flooded with seawater. This will obviously kill fresh water plants and animals.
The problem at Happisburgh?
The wooden sea defenses built in the late 1950s at Happisburgh, North Norfolk have been failing over the last few years, and large chunks of the sandy cliffs are regularly collapsing into the sea. Changes in government policy now limit funding for coastal protection, but there is no compensation for any losses suffered.
Plans put forward for Happisburgh?
North Norfolk district council has been awarded £3 million to help deal with the problem. Also a plan is under way for the council to buy the most at risk houses so that people have enough money to move away.
what is long shore drift?
LSD occurs when waves approach the beach at an angle (direction of the prevailing wind) Swash carries material in at an angle then the backwash pulls it backwards under gravity (90 degree angle to the beach) This process repeats so that material is moved down the beach. the process can be slowed using groynes (describe groynes).
Why do salt marches form behind the spit?
They start to form because of the fact that the river supplies the area with mud. the spit protects the mud, after this, slat loving plants will begin to grow with continued protection from the spit.
How are bars formed?
Bars are formed when a spit builds across two headlands. this is only possible if there is a gently sloping beach and no river entering the sea. bars can straighten coastline. behind the bar is a lagoon or marsh were salt water plants grow. the approximate point of the bar is towards the main land.
The size and energy of a wave is influenced by?
how long the wind has been blowing, the strength of the wind, how far the wave has traveled (the fetch)
Characteristics of Destructive waves?
storm conditions, big, strong, powerful, wind has been blowing for along time, energy is high and wave has traveled over a long fetch. Backwash is stronger then swash
Characteristics of Constructive waves?
calm weather, less powerful, deposit material building up beaches. swash stronger then backwash, long wavelength and low in height.
What is solution?
Minerals are dissolved in sea water and carried in solution. The load is not visible. Load can come from cliffs made from chalk or limestone, and calcium carbonate is carried along in solution.
What is suspension?
Small particles are carried in water, eg silts and clays, which can make the water look cloudy. Currents pick up large amounts of sediment in suspension during a storm, when strong winds generate high energy waves.
What is saltation?
Load is bounced along the sea bed, eg small pieces of shingle or large sand grains. Currents cannot keep the larger and heavier sediment afloat for long periods.
What is traction?
Pebbles and larger sediment are rolled along the sea bed.
What are the four ways that waves transport sediment?
solution, suspension, saltation and traction
When is deposition likely to occur?
When waves enter an area of shallow water, when waves enter a sheltered area, e.g. cove, bay. there is little wind and there is good supply of material.
five problems with coastal rescission in Dawlish?
- When the sea is rough trains have to be cancelled because of the fact that it is dangerous.
- The sea wall has no refracting curve so they get the full force of the waves.
- The sea wall was built in the 1800s and is constantly being repaired. Annual cost of £400,000
- If the line is washed away the connection to the south west of England is lost.
- Global warming is causing rising sea levels, so the issue is only going to get worse.
Case studies for Coastal landscapes?
Happisbough - coast rescission
Dawlich - coast rescission
