Sediment Transportation

Question 1

Longshore drift

Answer 1

LD transports material along coastlines when waves approach the beach at an angle

Question 2

Swash direction

Answer 2

Wind approaches the coast at an angle because of a prevailing wind direction
Waves are controlled by the wind + so this angle will be the direction the swash moves up the beach

Question 3

Backwash direction

Answer 3

Gravity = only force that acts on the backwash so it falls back to the sea at right angles to the coastline

Question 4

Overall effect

Answer 4

Because of the difference b/ the angle of swash + angle of backwash sediment repeatedly moves in the shape of a rught angled triangle
Over time sediment is carried along a beach

Question 5

Depositional landforms

Answer 5

Coastal landforms caused by deposition include beaches, spits, bars, tombolos, cuspate forelands

Question 6

Spits

Answer 6

Coast changes direction at an estuary (river meets sea) longshore drift continues to move sediment across the inlet
River doesn’t let the spit completely join the coast on the other side because the river has the energy to move the sediment
Spits = long fingers of sand sticking out from 1 side in a coastline that have been curved by secondary winds. Often have salt marshes behind them.

Question 7

Bars

Answer 7

Bar is formed when a spit grows across a bay
Lagoons often form behind bars

Question 8

Beaches

Answer 8

Are made by constructive waves moving + depositing sand/shingle inland
Generally a more gently sloping beach tends 2 be formed from sand whereas a steeper sloping beach is formed from pebbles

Question 9

Tombolos

Answer 9

If a spit stretches across the mainland + joins an offshore island this causes the formation of a tombolo

Question 10

Cuspate forelands

Answer 10

Form when sediment is deposited across a bag caused by longshore drift transporting sediment in 2 directions
Leads to the formation of 2 spits which eventually meet + results in the trapping of sediment until eventually new land is formed

Question 11

Sediment cell concept

Answer 11

Describes a closed system operated by sources, transfer, sinks driven by erosion, transportation, deposition processes

Question 12

Sources

Answer 12

Sources are subaerial processes, erosional processes (breaking down cliffs) + sediment brought to the coastline by rivers

Question 13

Transfers

Answer 13

Transfers are longshore drift, onshore, offshore winds + tides

Question 14

Sinks

Answer 14

Sinks are depositional landforms (spits, bars, beaches, sand dunes)

Question 15

Uk

Answer 15

Has 11 key sediment cells + sub-cells each with its own shoreline management plan