Paper 2: Coastal Change and Conflict Flashcards
What is a concordant coastline?
Where bands of soft and hard rock run parallel to the coastline
What is a discordant coastline?
Where bands of soft and hard rock run perpendicular to the coastline
How do waves form?
Wind blowing over bodies of water
What does the size of the wave depend on?
How long the wind has been blowing, how strong the wind is, how far the wave has travelled (the fetch)
What is the fetch of a wave?
How far it has travelled
What is the swash?
The movement of water as it rushes up the beach from the sea at an angle
What is the backwash?
When water runs back down the beach
What is a constructive wave?
It causes deposition, common in summer, low frequency (8-10/m)
What is a destructive wave?
It erodes the coast, common in winter, high frequency (10-14/m)
What is erosion?
The wearing away or removal of material by water
What is transportation?
The movement of material by water
What is deposition?
The dropping of material by water
What is hydraulic action?
Water is forced into the cracks in rocks. This compresses the air. When the wave retreats, the air blasts out, forcing the rock apart.
What is coastal abrasion?
Sediment is thrown against the cliff by waves. This wears the cliff away and chips bits of rock off the cliff.
What is coastal attrition?
Loose sediment knocked off the cliff is swirled around by waves. It collided with other sediment and is worn down, becoming smaller and rounder.
How are headlands and bays formed?
The bands of rock run perpendicular to a discordant coastline. The soft rock erodes faster than the hard rock due to hydraulic action of destructive waves. Bays are formed from soft rock and headlands and formed from hard hard rock.
How are coves formed?
The bands of rock run parallel to a concordant coastline. An area of weakness is found in the hard rock. Erosion such as hydraulic action and abrasion occur at the weakness. Once the hard rock has eroded, the soft rock behind erodes much faster, therefore forming a big empty area, known as a cove.
How are wave cut platforms formed?
Destructive waves erode the cliff through processes such as abrasion. Waves erode the cliff between the high and low tide lines. Over time, this erosion creates a wave cut notch. This notch gradually gets larger and the wave cut notch is left unsupported. Mass movement occurs as a result of gravity and the cliff retreats. The process starts to repeat with a new notch forming. The cliff continues to repeat.
What kind of profile do sandy beaches have?
Gentle profiles
How are sandy beaches formed?
Deposition
What kind of profile do pebble beaches have?
Steep profiles
How are pebble beaches formed?
Cliffs being eroded
What is a spit?
An extended stretch of sand or shingle jutting out into the sea from the land
How is a spit formed?
By longshore drift
What is a bar?
When a spit has grown across a bay and traps a lagoon behind it
How is a bar formed?
By longshore drift
How are lagoons formed?
When an area of water is cut off by a bar. They can be covered up by sediment over time.
What is longshore drift?
The zigzag movement of sediment along the coastline
How is sediment transported by longshore drift?
The prevailing wind makes the waves move onto the beach at an angle. The swash follows this direction and transports and then deposits sediment onto the beach at a 90 degree angle. Gravity then causes the backwash to transport and deposit sediment into the ocean. This then repeats along the shoreline, creating a zigzag pattern. The sediment is transported and deposited further along the coastline.
When does deposition happen?
When waves enter an area of shallow water, waves enter a sheltered bay, creating beaches, there is little wind, a river flows into the sea reducing wave energy, there is a good supply of sediment energy
What is mass movement?
The downward movement of material under the force of gravity
What are the 3 types of mass movement?
Sliding, rockfall, slumping
What is sliding?
When large sections of rock shift downslope along a straight slip plane
What is rockfall?
When fragments of rock break away from the cliff face and fall, often due to freeze-thaw weathering
What is slumping?
When material shifts downwards rotating along a curved slip plane, usually as a result of becoming saturated
What are the 4 types of human activities that affect the coastal landscape?
Development, industry, agriculture, coastal management
What are the effects of development?
Housing: People often retire at the coast (e.g. Blackpool and Scarborough), people working in London can only afford houses at the coast as they are much cheaper but you can still easily commute to London
Office: London property prices are expensive so companies like JP Morgan are building offices in coastal areas (e.g. Bournemouth), a lot of universities are in the areas so there is a good work force
What are the effects of industry?
In Bacton in Norfolk North Sea gas is piped onto land at a terminal on the beach - some tourists don’t like this because they want just the beach, industries are set up by the coast due to flat land and good transport links
Some industries include: Oil and chemical refining locations with huge industrial installations (e.g. in Solent in Southampton), good shipping and power stations to supply places (e.g. the Thames in London)
What are the effects of agriculture?
The price of good farmland has risen sharply from £2400/hectare in 1995 to £30,000/hectare in 2015, the need for extra grazing puts pressure on the wildlife, climate change and rising sea levels are likely to lead to flooding by salt water during high winter tides which could threaten pastures
What are the effects of coastal management?
Hard and soft management alters the natural landscapes and processes, groynes trap sediment but cause faster erosion elsewhere, sea walls stop erosion but also means that features such as stacks won’t form
What does holistic mean?
Looking at the coastline as a whole instead of just one location. This may mean some places are protected and others are not.
What does a holistic approach take into account?
Needs of different groups of people (stakeholders/players), economic costs and benefits of different strategies today and in the future, environment both on land and in the sea
What are the 4 choices that people have to manage the coast?
Hold the line, advance the line, strategic realignment, do nothing
What does it mean to hold the line?
Use sea defences to stop erosion, and so the coast stays where it is today
What does it mean to advance the line?
Use sea defences to move the coast further into the sea. This is very expensive.
What does it mean to use strategic realignment?
Let the coast erode, move people/businesses away. May have to give financial compensation to those who lose their homes.
What does it mean to do nothing?
Take no action at all
What is hard engineering?
Building artificial structures to help reduce the rate of coastal erosion or river flooding
What is soft engineering?
Using the natural environment to help reduce the rate of coastal erosion or river flooding
What are the 4 types of hard engineering at the coast?
Sea wall, rock armour, gabions, groynes
What is a sea wall?
It acts like a barrier and it’s strong and protects against erosion by absorbing wave energy (£5000-£10,000 per meter)
What are some advantages of a sea wall?
Effective in slowing erosion, often has a promenade for tourists
What are some disadvantages of a sea wall?
Can look ugly, can be very expensive
What is rock armour?
Large boulders dumped at the base of the cliff or on a beach to absorb wave energy (£50,000 per meter)
What are some advantages of rock armour?
Effective against erosion, relatively cheap, easy to maintain
What is some disadvantages of rock armour?
Expensive to transport, might look ugly
What are gabions?
Wine cages filled with rocks built up to provide a buffer against the sea (£50,000 per meter)
What are some advantages of gabions?
Cheap and flexible to place, become vegetated
What are some disadvantages of gabions?
Only lasts 5-10 years before rusting, ugly to look at
What are groynes?
Wooden barriers built out into the sea to stop longshore drift (£150,000 each)
What are some advantages of groynes?
Creates a wider beach, cheap
What are some disadvantages of groynes?
Life expectancy of about 25 years
What are the 3 types of soft engineering at the coast?
Beach nourishment, reprofiling, dune regeneration
What is beach nourishment?
The addition of new material to a beach to make it wider - waves break earlier and are less destructive (up to £500,000 per 100m)
What are some advantages of beach nourishment?
Relatively cheap, increases tourism
What are some disadvantages of beach nourishment?
Needs replenishing regularly, groynes may be used to keep material in place (more expensive)
What is reprofiling?
Redistributing sediment from the lower section of the beach to the higher section - Increased gradient (the cost varies but cheaper than beach nourishment)
What are some advantages of reprofiling?
Cheap, reduces wave energy/erosion
What are some disadvantages of reprofiling?
Only works when wave energy is low, needs to be redone regularly
What is dune regeneration?
Action taken to build up dunes that increase vegetation on them - Includes planting marram grass and fencing (£200-£2000 per 100m)
What are some advantages of dune regeneration?
Cheap, maintains coastal habitat
What are some disadvantages of dune regeneration?
Takes a long time, can hinder tourism
What are some examples of stakeholders at the coast?
- Local residents
- Tourists
- Farmers
- Government
- Local councils
