Coastal Management Flashcards
(30 cards)
What is the Fetch
it is the distance over which wind blows over open water
What is the swash
What is the swash It is the movement of material up the beach
what is the backwash
It is the movement of material down the beach , due to gravity
what are constructive and destructive waves?Outline the differences
Constructive waves have a strong swash and a weak backwash.Deposition is greater.
Destructive waveshave a weak swash and a strong backwash.Erosion is greater than deposition.
What is the size and energy of a wave influenced by?
how long the wind has been blowing
the strength of the wind
how far the wave has travelled (the fetch)
What is hydraulic action
Hydraulic action. Air may become trapped in joints and cracks on a cliff face. When a wave breaks, the trapped air is compressed which weakens the cliff and causes erosion.
What is abrasion
Abrasion. Bits of rock and sand in waves grind down cliff surfaces like sandpaper.
What is attrition
Attrition. Waves smash rocks and pebbles on the shore into each other, and they break and become smoother.
What is solution
Solution. Acids contained in sea water will dissolve some types of rock such as chalk or limestone.
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 the process of cliff erosion
The process of cliff erosion
///Weather weakens the top of the cliff.
///The sea attacks the base of the cliff forming a wave-cut notch.
///The notch increases in size causing the cliff to collapse.
///The backwash carries the rubble towards the sea forming a wave-cut platform.
//The process repeats and the cliff continues to retreat.
==rockpools are left as a result behind
What is a headland
The bands of soft rock, such as sand and clay, erode more quickly than those of more resistant rock, such as chalk. This leaves a section of land jutting out into the sea called a headland.
What is a bay
The areas where the soft rock has eroded away, next to the headland
How is a cave formed
Caves occur when waves force their way into cracks in the cliff face. The water contains sand and other materials that grind away at the rock until the cracks become a cave. Hydraulic action is the predominant process.
How is an arch formed
If the cave is formed in a headland, it may eventually break through to the other side forming an arch.
How is a stack formed
he arch will gradually become bigger until it can no longer support the top of the arch. When the arch collapses, it leaves the headland on one side and a stack (a tall column of rock) on the other.
How is a stump formed
The stack will be attacked at the base in the same way that a wave-cut notch is formed. This weakens the structure and it will eventually collapse to form a stump.
What is a spit
==Spits are also created by deposition. A spit is an extended stretch of beach material that projects out to sea and is joined to the mainland at one end.
==Spits are formed where the prevailing wind blows at an angle to the coastline, resulting in longshore drift.
==An example of a spit is Spurn Head, found along the Holderness coast in Humberside.
==Over time, the spit grows and develops a hook if wind direction changes further out.
Waves cannot get past a spit, which creates a sheltered area where silt is deposited and mud flats or salt marshes form.
what is a tombola
A tombolo is a spit connecting an island to the mainland
What is Hard engineering
Hard engineering: Groynes,Rip Rap,Gabions,Sea wall
Give a named case study and how is it manaaged?
Happisburgh
What is slumping
it is the rotaional movement of land triggered by saturation
How is coastal Flooding prevented
Planning Monitoring sea levels Evacuation Defemnces Waterproof houses
