Formation of landforms - Deposition

Question 1

What are flood plains

Answer 1

flat areas of land that flood

Question 2

How do flood plains form

Answer 2

when a river floods onto the flood plain, the water slows down and deposits the eroded material that it’s carrying which build up the flood plain, meander migrate across the flood plain making it wider, disposition that happens on the slip-off slopes of meanders also build up the flood plain

Question 3

What are levees

Answer 3

natural embankments - raised bits along the edges of a river
channel

Question 4

How do levees form

Answer 4

during a flood, eroded material is deposited over the whole flood plain, the heaviest material is deposited closest to the channel slower, over time the material builds up

Question 5

What are estuaries

Answer 5

tidal areas where the river meets the sea (mouth), the land is so close to sea level the river valley is at it’s widest

Question 6

How are mudflats formed on estuaries

Answer 6

water here is tidal (level falls and rises), the water floods over the banks of the river carrying the silt and sand ono the valley floor, as tide reaches highest point the water moves very slowly so sediment is deposited, more and more mud builds up, at low tide the muddy banks are exposed

Question 7

What is formed due to deposition

Answer 7

beaches, spits, bars and sand dunes

Question 8

What is the difference between sandy and shingle beaches

Answer 8

sand - flat and wide, sand particles are small and the weak backwash can move them back down the beach making a long gentle slope, shingle - steep and narrow, shingle particles are large and the weak backwash can not move them back down the beach so they build up

Question 9

How are spits formed

Answer 9

they form at sharp bends in the coastline, longshore drift transports sand and shingle past the bend and deposits it in the sea, strong winds and waves can curve the end of the spit, the sheltered area behind the spit is protected from waves and lots of material accumulates in this area which means plants can grow, over time the sheltered area can become a mud flat or salt marsh

Question 10

How are bars formed

Answer 10

when a spit joins 2 headlands together, the bar cuts off the bay between the headland from the sea, this means a lagoon can form behind the bar

Question 11

How are sand dunes formed

Answer 11

when sand deposited by longshore drift is moved up the beach by the wind, obstacles cause wind speed to decrease so sand is deposited, this sand is colonised by plants and grasses which stabilises the sand and encourages more sand to accumulate forming small sand dunes, over time the oldest dunes migrate inland as newer dunes are formed