Introduction to Coastal Environments

Question 1

What are the sediment cells inputs?

Answer 1

River sediment, sediment from cliffs that have been eroded or suffered landslides, and sediment that has been transported from offshore.

Question 2

what are sediment cells processes?

Answer 2

Wave action, tidal movement, erosion, erosion, weathering, transportation, deposition.

Question 3

What are sediment cells outputs?

Answer 3

Sediment washed out to sea, or deposited further along the coast.

Question 4

What are sediment cells?

Answer 4

They are lengths of coastline that are self-sufficient and self contained . There re 11 around the UK.

Question 5

How are waves created?

Answer 5

Waves are created by wind blowing over the surface of the sea. The friction between the wind and surface of the sea give the wave a circular motion.

Question 6

What are constructive waves?

Answer 6

They are low frequency waves. (6-8 per minute) They are low and long which gibes them an elliptical cross profile. The powerful swash deposits sediment on the beach.

Question 7

What are destructive waves?

Answer 7

They are high and steep. They have a circular cross profile. They are high frequency (10-14 per minute). There strong backwash removes sediment from the beach.

Question 8

What causes tides?

Answer 8

Tides are the periodic rise and fall in the oceans surface. This is caused by the gravitational pull of the moon and the sun.

Question 9

Whats sub-aerial weathering?

Answer 9

It is a term used to describe coastal processes no linked to the action of the sea.

Question 10

What causes throughflow and runoff?

Answer 10

They are caused by heavy rain which makes the cliffs unstable increasing the risk of mass movement.

Question 11

What is mass movement?

Answer 11

Mass movement is the movement of material downhill due to gravity.

Question 12

What are the 5 ways the coastline can be eroded?

Answer 12

Abrasion,Hydraulic action, Quarrying, Solution, Attrition

Question 13

What is quarrying?

Answer 13

It is the energy of the wave as it breaks against a cliff and it has enough energy to detach bits of rock.

Question 14

What is the width of the beach?

Answer 14

It is the distance between the high and low tidemarks.

Question 15

What factors effect the rate a coastline is eroded at?

Answer 15

The width of the beach, he breaking point of waves, the aspect (the wind direction), The fetch of the waves , the rock type.

Question 16

What is the fetch?

Answer 16

The maximum distance of sea the wind has blown over when creating the wave.

Question 17

What is a current?

Answer 17

It is the general flow of water in one direction

Question 18

What is longshore drift?

Answer 18

It is when the swash carries sediment up the beach, parallel to the prevailing wind. The backwash then carries sediment back up the beach at a right angle to the shoreline.

Question 19

How is a wave-cut platform created?

Answer 19

Weathering and erosion cause a notch to form at the high water mark. This develops into an cave. Above the cave the rock becomes unstable and collapses. Wave cut platform is then left behind when the cliff is eroded. This is a wave cut platform.

Question 20

How are headlands and bays formed?

Answer 20

Headland and bays form where there are bands of alternating hard rock and soft rock at right angles to the shorelines. The soft rock is eroded quickly, forming a bay. The harder rock is eroded less and sticks out as a headland.

Question 21

How are caves, blow holes, arches and stacks formed?

Answer 21

Weak areas in the rock are eroded to form caves. Occasionally, the roof of a cave is weakened along a major joint by hydraulic pressured and the roof collapses to form a blowhole. Caves on the opposite sides of the narrow headland may eventually may eventually join up forming an arch. When the arch collapses it forms a stack.

Question 22

How are beaches formed?

Answer 22

Beaches are formed when constructive waves deposit sediment on the shore. Shingle beaches are steep and narrow. They’re made up of larger particles, which pile up at steep angles. Sand beaches, formed by smaller particle are wide and flat.

Question 23

What features are often found on beaches?

Answer 23

Berms and ridges, runnels and grooves, cusps and crescent-shaped indentations.

Question 24

What are berms and ridges?

Answer 24

They are made up of sand and ridges, they are found at high tide marks. They’re formed by deposition of coarse material at the limit of the swash.

Question 25

What are ridges and runnels?

Answer 25

They are grooves in the sand running parallel to the sea. They are formed by backwash draining into the sea.

Question 26

What are cusps?

Answer 26

They are recreant shaped indentations that form on beaches of mixed sand and shingle. They are found in the foreshore.

Question 27

How are spits formed?

Answer 27

Longshore drift continues to deposit material across the river mouth, leaving a bank of sand and shingle sticking out to sea. Occasionally changes in the dominant wind and wave direction may lead to the spit having a re-curved end. Over time several re-curved ends may be abandoned as the waves return to there original direction. The area behind the spit is sheltered from the waves and often develops into mudflats and salt marshes.

Question 28

How are bars formed?

Answer 28

Bars are formed when a spit joins two headlands together. This can occur across a bay or across a river mouth. A lagoon forms behind the bar.

Question 29

How are land dunes formed?

Answer 29

Sand dunes are formed when sand deposited by longshore drift is moved up the beach by the wind. Sand trapped by driftwood or berms is colonised by plants and grasses e.g marram grass. The vegetation stabilizes the sand and encourages more sand to accumulate, forming embryo dunes. Over time the older dunes migrate inland as newer embryo dunes are formed.

Question 30

How are salt marshes formed?

Answer 30

Salt Marshes form in an area of sheltered water. As a silt and mud are deposited by the river or at tide, mud flats develop. The mud flats are colonised by vegetation that can survive high salt levels and long times in water. The plants trap more mud and silt, and gradually create an area of marshland.