2B.5 Sediment Transport and Deposition

Question 1

how is sediment transported alone a coastline

Answer 1

long shore drift

Question 2

name 4 processes of sediment transportq

Answer 2

saltation
solution
suspension
traction

Question 3

traction

Answer 3

sediment rolls along, pushed by waves and currents

Question 4

saltation

Answer 4

sediment bounces along, due to the force of water or wind

Question 5

suspension

Answer 5

sediment is carried in the water column

Question 6

solution

Answer 6

dissolved material is carried in the water as a solution

Question 7

on what type of coast are depositional landforms most common?

Answer 7

drift-aligned
-wave crests break at an angle to the coast
-longshore drift occurs and features develop

Question 8

swash aligned coasts

Answer 8

wave crests approach parallel to the coast, there is limited longshore movement of sediment

Question 9

gravity settling

Answer 9

the energy of water transportation is too weak to move sediment so it is deposited

Question 10

flocculation

Answer 10

depositional process for small particles, they remain suspended in water, clump together and sink due to a chemical attraction

Question 11

longshore current

Answer 11

zigzag movement of water in the surf zone

Question 12

longshore drift

Answer 12

movement of sediment caused by longshore current

Question 13

bayhead beach

Answer 13

a swash aligned feature
-waves break at 90 degrees to the shoreline and move sediment into a bay where beach forms
-erosion occurs at headlands
-deposition occurs at the bay

Question 14

example of a bayhead beach

Answer 14

Lulworth Cove in Dorset

Question 15

spit

Answer 15

a sand or shingle beach ridge that extends beyond a tun in the coastline
-longshore drift currents spread out and lose energy leading to deposition
-length is determined by whether secondary currents cause erosion

Question 16

example of a spit

Answer 16

Spurn Head, Holderness Coast

Question 17

tombolo

Answer 17

a sand or shingle bar that attaches a coastline to an offshore island
-forms due to wave refraction around offshore islands, creating an area of calmness and deposition

Question 18

example of a tombolo

Answer 18

St Ninian’s tombolo in Shetland

Question 19

bar/ barrier beach

Answer 19

a sand or shingle connecting two areas of land, a shallow water lagoon forms behind

Question 20

example of a bar/ barrier beach

Answer 20

Chesil Beach in Dorset

Question 21

recurved/ hooked spit

Answer 21

a curved landward spit into a bay or inlet
-seaward end of the spit curves landward in to shallow water
-hook can be more pronouced by waves fro another direction to the prevailing wind

Question 22

example of a recurved or hooked spit

Answer 22

Hurst Castle Spit in Hampshire

Question 23

cupsate foreland

Answer 23

rough triangular shape feature that extends from a shoreline
-longshore drift from opposing directions converge at the boundary of two sediment cells
-sediment is deposited by both currents

Question 24

example of cupsate foreland

Answer 24

Dungeness, Kent

Question 25

why can depositional landforms often be unstable?

Answer 25

they are made up of unconsolidated material, dynamic environments -loose material is transported by the waves tides, currents and wind -can be stabilised by plant succession (binding sediment, encouraging more deposition)

Question 26

what are salt marshes?

Answer 26

areas of flat, silty sediment that accumulates up, around estuaries or lagoons -they develop in sheltered areas, fresh and saltwater meet, no strong tides or currents

Question 27

sediment cell model

Answer 27

consists of sources, transfers and sinks, it shows how sediment moves along the coast in sediment cells

Question 28

sediment cell

Answer 28

a linked system of sources, transfers and sinks along a section of coastline each cell operates between physical barriers that prevent the sediment form moving any further along the coastline

Question 29

sediment budget

Answer 29

the amount of sediment available within a sediment cell

Question 30

what happens if the sediment budget falls?

Answer 30

the waves transport sediment (positive feedback) -increasing the original change

Question 31

what happens if the sediment budget increases?

Answer 31

more deposition occurs (negative feedback) works against original change

Question 32

dynamic equilibrium

Answer 32

the way in which systems attempt to balance inputs and outputs

Question 33

how many sediment cells are in the UK

Answer 33

11 e.g. the east coast of england source region: Flamborough Head transfer zone: Holderness Coast sink region: Spurn Head

Question 34

how does a sediment cell operate?

Answer 34

as a CLOSED SYSTEM

Question 35

examples of sources and inputs

Answer 35

sediment is generated -cliff erosion -onshore currents -river transport -wind blown sediment from land -sub-aerial processes -marina organisms

Question 36

examples of transfers

Answer 36

places where sediment is moving along the shore -longshore drift -swash or backwash -tidal/ sea currents -wind

Question 37

examples of sinks or outputs

Answer 37

deposition dominates and landforms form backshore depositional landforms e.g. sand dunes -foreshore depositional landforms e.g. beaches- berms, runnels and ridges -nearshore depositional landforms e.g. bars -offshore depositional landforms e.g. barrier islands