Depositional landforms

Question 1

what does deposition form?

Answer 1

beaches

Question 2

where are depositional landforms most common?

Answer 2

lowland coasts, beaches are the most common depositional landform

Question 3

what are beaches?

Answer 3

beaches are accumulations of sand and shingle deposited by waves and currents

Question 4

where does the sediment on a beach come from?

Answer 4

cliff erosion but most is brought down to the coast by rivers

Question 5

what are the two different types of beaches?

Answer 5

-swash aligned
-drift aligned

Question 6

swash aligned

Answer 6

beaches where waves approach parallel to the shore and break with swash moving directly up the beach and the backwash returning directly back, these form wide beaches with an even shoreline

Question 7

how do you identify a swash aligned beach on a photograph?

Answer 7

the lines are parallel to the coastline (berms)

Question 8

what’s an example of a swash aligned beach?

Answer 8

chesil beach

Question 9

drift aligned

Answer 9

form when waves approach the beach at an angle resulting n swash moving diagonally up the beach and the backwash returning though gravity, these beaches have an uneven profile especially when groynes have been used to slow the long short drift

Question 10

how do you identify a drift aligned beach on a photograph?

Answer 10

most likely a straight coastline

Question 11

what is an example of a drift aligned beach?

Answer 11

west wittering

Question 12

why are pebble beaches steep?

Answer 12

A strong swash and a weak backwash causes deposition, on a pebble beach the water goes through the gaps in the rocks and goes back to the sea under/through the rocks. This means lots of material is put into the beach but very little is pulled back into the sea which causes it to be very steep.

Question 13

nearshore

Answer 13

the breaker zone where waves break

Question 14

backshore

Answer 14

an area that is not usually affected by waves, so the sand is usually dry

Question 15

foreshore

Answer 15

the inter-tidal zone repeatedly covered, then uncovered by changing tides

Question 16

offshore

Answer 16

fairly far out to sea where the waves do not break

Question 17

beach profile`

Answer 17

shows the gradient from the back of the beach to the sea

Question 18

what kind of bay is a sandy beach formed in?

Answer 18

a sheltered bay as low-energy constructive waves transport material onto the shore

Question 19

what is the main type of transportation used to form sand dunes?

Answer 19

saltation

Question 20

how are sand dunes formed?

Answer 20

1. wind pushes sand grains along by saltation
2. sand grains start piling up as something has trapped the sand at the back of the beach (e.g. seaweed or driftwood)
3. more sand piles up
   4.the dune stops growing at the high water mark, this is where the highest tide reaches
4. the dune becomes stabilised by grasses such as Marram or Lyme growing on the new dune
5. as the dune is growing another embryo dune is forming in front of it (closer to the sea) over time the new dunes get closer and closer to the sea

Question 21

what conditions are needed for a sand dune to form?

Answer 21

-large flat beach
-good supply of sand from the seabed that gets deposited on the beach
-a large tidal range
-a regular onshore wind
-an obstacle

Question 22

why is a large flat beach important for sand dunes to form?

Answer 22

have enough room for the dunes to form without being swept away by waves/tides

Question 23

why is a good supply of sand from the seabed important for sand dunes to form?

Answer 23

to create dunes at the back of the beach

Question 24

why is a large tidal range important for sand dunes to form?

Answer 24

to expose large amounts of sand at low tide

Question 25

why is a regular onshore wind important for sand dunes to form?

Answer 25

to move the sand to the back of the beach

Question 26

why is an obstacle important for sand dunes to form?

Answer 26

to trap the sand

Question 27

embryo dune

Answer 27

a newly formed sand dune closest to the sea

Question 28

marram grass

Answer 28

a plant found in sand dunes that has long, binding roots

Question 29

crest

Answer 29

top of a sand dune

Question 30

windward slope

Answer 30

slope that faces the wind

Question 31

leeward slope

Answer 31

the slope that faces away from the wind

Question 32

dune slack

Answer 32

where there is a trough or low point in a line of dunes

Question 33

water table

Answer 33

the upper horizontal limit of wet sand

Question 34

describe a spit

Answer 34

-beaches joined to the coast at one end -at their seaward end, shingle ridges form a series of recurves or hooks

Question 35

where do spits often develop?

Answer 35

across river mouths or where the direction of the coastline changes abruptly

Question 36

what process causes spits to form?

Answer 36

longshore drift

Question 37

what's tucked away behind spits?

Answer 37

quiet backwaters that waves cannot reach, where tidal currents deposit fine silt and build up mudflats and salt marshes

Question 38

name some depositional landforms

Answer 38

-spits -bars -beach -sand dunes

Question 39

describe bars

Answer 39

-bars are extended spits that join up to another headland

Question 40

how do bars form?

Answer 40

due to the lack of a strong river current that would wash the sediment away like in the tidal race of a spit

Question 41

give an example of a bar

Answer 41

Slapton Sands in Devon

Question 42

what is a tombolo?

Answer 42

when a spit extends and joins with an island

Question 43

what's the difference between a barrier bar and a submerged bar?

Answer 43

a barrier bar touches the land and has a salt lagoon behind it whereas the submerged bar doesn't

Question 44

what are the different types of coastal management?

Answer 44

-hard engineering -soft engineering

Question 45

what are the different types of hard engineering?

Answer 45

-sea walls -groynes -rock armour -gabions

Question 46

describe sea walls

Answer 46

a wall made out of a hard material like concrete that reflects waves back to the sea, placed at the top of the beach or the foot of the cliffs

Question 47

describe groynes

Answer 47

timber or rock structures built out to sea from the coast (at right angles), they trap sediment being moved along by longshore drift

Question 48

describe rock armour

Answer 48

pieces of large boulders dumped at the foot of the cliff, rocks force waves to break, absorbing their energy and protecting the cliffs

Question 49

describe gabions

Answer 49

wire cages filled with rocks that can be built up to support a cliff or provide a buffer against the sea

Question 50

what are the benefits of sea walls?

Answer 50

-effective against erosion -gives a sense of security against flooding -often has walkway or promenade for people to walk along

Question 51

what are the benefits of groynes?

Answer 51

-creates a wider beach which slows the waves, giving more protection which is beneficial for the tourists -not too expensive -useful structures for fishing