1.2 Coastal Landscapes Flashcards
Define Hydraulic Action
Water is forced into cracks in the rock and air is forced out explosively, breaking off pieces of the cliff
Define Abrasion
This is when pebbles grind along a rock platform, much like sandpaper. Over time the rock becomes smooth.
Define Attrition
This is when rocks that the sea is carrying knock against each other. They break apart to become smaller and more rounded.
Define Corrosion
When acid rain causes chemical weathering
Define Chemical Weathering
Acids in seawater slowly dissolve rocks
Define Biological Weathering
Roots of growing plants and burrowing animals or nesting birds can cause rocks to weather
Define Mechanical Weathering
Caused by repeated freezing and thawing of water in a crack or hole in the rock.
How does Freezing and thawing weather a rock?
(Mechanical weathering) water freezes and expands, putting stress on the rock, ice melts and the water sinks deeper into the rock and the process repeats.
Describe Rock Falls
Bits of rock fall off the cliff face, usually due to freeze thaw weathering
Describe Slumping
Saturated soil slump down a curved face
Describe Sliding
Saturated soil (filled with water) flows down a slope
Describe Traction
Process by which large, heavy pebbles are rolled along the river bed, this is most common near the source
Describe Saltation
Pebbles are bounced along the sea bed, this is most common near the source
Describe Solution
Lighter sediment is dissolves within the water, most commonly near the mouth
What is deposition?
When sediment, usually carried by waves is laid down or deposited
When does deposition occur?
When their is not enough energy to carry sediment any further
What does LSD stand for?
Longshore Drift
What does Longshore Drift transport?
Sand and sediment
Describe the process of Longshore Drift
The swash brings in sediment at an angle, the backwash brings this back out to sea at 90 degrees
This transports material up the coastline
In which direction does swash come at the coast from?
Prevailing Wind
Describe Constructive Wave
Strong Swash
Weak Backwash
Long wave in proportion to height
What happens to sediment in constructive waves?
It tends to be deposited
Describe Destructive Waves
Weak Swash
Strong Backwash
High wave in proportion to length
Tall Breaker (breaks downwards with great force)
What happens to sediment in destructive waves?
It tends to be picked up from the coastline and taken out to sea
How does wind strength effect wave size?
Stronger winds cause bigger waves
How does fetch effect waves?
The further wind has travelled the more energy waves have
Describe a concordant coast
Has rock of one type
Describe a discordant coast
Has alternating bands of different rock
When do headbands and bays for?
When the sea attacks coast lines with alternating hard and soft rock
Describe the process by which a stump forms
1 - weak areas are attacked forming a cave
2 - the cave is eroded to form an arch
3 - the roof of the arch eventually collapses, leaving a stack
4 - the stack is eroded until only a stump remains
Define Spit
A strip of land stretching from the mainland into the sea
Define Bar
A strip of land that connects two headlands leaving a pool of water (lagoon) behind
Define Tombolo
A strip of land that connects and island to the mainland
How do spits form?
When longshore drift carries sediment in straight lines after the coastline has changed direction
How do rising sea levels effect erosion?
Increase rate of erosion
How do storms and storm surges effect erosion?
Dramatically increase rate of erosion
Define Beach Nourishment
Supplying extra sand to a beach/ shore
Is beach nourishment hard or soft engineering?
Soft
Define Offshore Reef
Artificial reefs made with sediment, tyres or cement
Is Offshore Reef hard or soft engineering?
Hard
Define Sea Wall
A cement wall which protects areas of the coast from flooding and erosion
Is a Sea Wall hard or soft engineering?
Hard
Define Groynes
Wooden headlands that stick into the sea to slow longshore drift
Are Groynes hard or soft engineering?
Hard
Define Rip Rap
Structures made of large cement rocks to take the impact of waves
Is Rip Rap hard or soft engineering?
Hard
Where is Holderness Coast located?
Within Hull
On the North sea
West Yorkshire coast
In The North
How much off Holderness Coast has been lost since Roman times?
5km
How much of Holderness Coast is lost yearly?
About 2m/ year
What type of coastline is Holderness Coast
Concordant
until Flamborough Head, north of here is discordant
What type of rock is Holderness Coast
Clay
What type of waves tend to hit Holderness Coast?
Destructive Waves
What often occurs after heavy rainfall at Holderness Coast?
Mass movement as clay frequently falls after rainfall
What type of coastal defences have been put up at Holderness Coast?
Hard engineering
rip rap, rock armour and groynes
What has been the negative side effect of groynes in Holderness Coast?
Preventing transport of sediment has meant that erosion has worsened in certain areas
What are the negative impacts of hard engineering?
- Not aesthetically pleasing
- Loss of habitats and organisms
- Starve areas further down the coast
Define Suspension
Small grains and particles bounce in the sea
Define Erosion
The wearing away of rocks
