Coasts Flashcards

Question

What happens behind the spit?

Answer 1

In the low-energy environment behind the spit, deposition of fine silt and mud will occur and salt marsh forms.

Answer 2

Over time, spits may move inland and many are regularly broken by storms and reform in subsequent years. If longshore drift carries material across a bay, it may form a bay barrier or bar. Such bars rarely form across estuaries as the power of the river erodes material from the ends of the spit if the gap becomes very narrow. If longshore drift transports material across to a nearby island, then it forms a tombolo linking the island to the mainland.

Answer 3

The river current will prevent the spit from reaching across the bay and forming a bar.

Answer 4

Beaches are made higher and wider by importing sand and shingle to an area affected by longshore drift to increase its height and width to provide protection from erosion or flooding by absorbing wave energy. Advantages: The approach is cheap and retains the natural appearance of the beach. Beaches are a natural defence against erosion. Additionally, the beach is a valuable amenity for tourism, bringing economic benefits to the area. Disadvantages: Offshore dredging of sand and shingle increases erosion in other areas and affects the marine ecosystem. Large storms will require further beach replenishment, increasing costs.

Answer 5

This is when areas of the coast are allowed to erode. This is usually in areas where the land is of low value. Advantages: Managed retreat retains the natural balance of the coastal system. Eroded material encourages the development of beaches and salt marshes. Creates new habitats and it is cheap. Disadvantages: People lose their livelihood, e.g. farmers. These people will need to be compensated. It is difficult to predict the sea's movements

Answer 6

Dune regeneration involves taking action to build up dunes and increase vegetation. This helps to strengthen the dunes and prevent coastal retreat. New sand dunes can be created to protect from coastal flooding. Often, marram grass is planted to hold the dunes together. Advantages: Dune regeneration provides a barrier between land and sea, absorbs wave energy, and provides cheap stabilisation. It also maintains a natural-looking coastline. Dune regeneration can increase biodiversity by providing a greater range of natural habitats for plants, animals and birds. Disadvantages: During dune regeneration, the land must be carefully managed so that any new vegetation planted is appropriately protected from trampling by humans. This could involve temporarily fencing off the dunes or providing wooden walkways. Storm waves can also damage dunes.

Answer 7

Groynes are wooden barriers constructed at right angles to the beach to retain the material. The beach material, including sand and pebbles, are trapped between groynes and cannot be transported away by longshore drift. Groynes encourage a wide beach which helps absorb energy from waves, reducing the rate of cliff erosion. Advantages: -keeps the beach in place for tourist industry -effective for a long time Disadvantages: -disrupt natural processes continues erosion below where the groynes are place -unattractive and makes it difficult to walk on the beach.

Answer 8

Rock armour(rip rap) is a barrier of large boulders placed in front of a cliff or sea wall to absorb wave energy and reduce backwash by encouraging percolation. Advantages: -dissipates wave energy and is effective for many years -can be cheap depending on rock type Disadvantages: -makes beach inaccessible -unattractive -doesn't work in storm conditions.

Answer 9

Seawalls are usually built along the front of cliffs to protect settlements or another land of high economic importance. They are often recurved which means waves are reflected back on themselves. This can cause the erosion of material at the base of the seawall Advantages: -visible making residents feel safe - very effective for many years Disadvantages: -ugly and very expensive -wave scouring

Answer 10

A man made structure of rocks or concrete built from the coastline Advantages: -allow build up of sand -break the waves further removes their erosive power Disadvantages: -difficult to install -may be removed by heavy storms

Answer 11

Coastal flooding does not only impact people directly, as in injured or dead, but it can also damage or destroy houses, businesses, infrastructure, and agriculture (including the death of livestock).

Answer 12

Coastal erosion is the process by which rising sea levels, storms, and other phenomena wear down or carry away the rocks, land, and sand making up a coastline. This process causes the loss of tens of thousands of acres of land in the UK. each year, as well as millions of pounds in property damage. Coastal erosion also has an impact on industries dependent upon coastlines.

Answer 13

In the winter storms are more powerful which means that waves have more energy The prevailing wind direction may change leading to more waves approaching the coastline from the direction of the fetch . Climate change/ changing weather patterns lead to waves having more energy

Answer 14

Constructive waves deposit material onto the beach because they have a strong swash

Answer 15

Cliffs made from harder rocks will erode less rapidly because they are more resistant to erosion . Where cliffs have lots of faults they will erode more rapidly because they have more lines of weakness

Answer 16

Shingle or pebble beaches are typically steep because as the waves flow through the porous surface of the beach, the effect of backwash erosion is reduced. Porous means the sea water passes through easily.

Answer 17

Soft engineering does not involve building artificial structures, but takes a more sustainable and natural approach to managing the coast.

Coasts Flashcards

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