coasts

Question 1

hydraulic action coasts

Answer 1

water forced into cracks compressing the air inside by forcing rock apart

Question 2

corrasion coasts

Answer 2

loose rocks thrown against the cliff by waves

Question 3

attrition coasts

Answer 3

loose sediment in water constantly collides with other sediment becoming smaller and rounder

Question 4

corrosion coasts

Answer 4

acids in seawater dissolve material of cliff rocks

Question 5

traction coasts

Answer 5

larger pebbles and cobbles rolled around seabed

Question 6

saltation coasts

Answer 6

small pebbles bounced along seabed in “leapfrog motion”

Question 7

suspension coasts

Answer 7

fine sediment carried as suspension in water

Question 8

solution coasts

Answer 8

dissolved material carried along in solution

Question 9

formation of headlands and bays

Answer 9

-hydraulic action
-corrasion
-corrosion
-hard and soft rocks present alternately
-joints (bedding planes)
-differential erosion: soft rocks erodes more rapidly forming bays and hard rock erodes less rapidly forming headland
(also can be crack to stack)

Question 10

what is wave swash

Answer 10

wave that approaches beach

Question 11

what is backwash

Answer 11

wave that leaves the beach into the sea

Question 12

constructive waves property

Answer 12

• lower energy
• stronger swash
• less than 8 waves per min
• lower height
• deposit material on the beach
• longer wavelength
• further distance between wave crests
• spill forward gently

Question 13

destructive waves properties

Answer 13

• higher energy
• stronger backwash
• 13-15 waves per min
• greater height
• erode beach material
• shorter wavelength
• smaller distance between
• wave crests
• plunge forward

Question 14

what is longshore drift

Answer 14

• prevailing winds cause waves to approach at an angle to the shore
• swash carries loose material up the beach at an angle (in the same direction as prevailing wind)
• backwash takes material back out at 90 deg
• zigzag motion moves material along the beach

Question 15

(coast) spit properties

Answer 15

• long and thing
• curved hooked end
• stretches partly across estuary
• made of sand shingle
• low in height (just above sea level)
• salt marsh develops behind spit

Question 16

formation of sand dunes

Answer 16

• wind blows from the sea
• wind picks up sand particles
• wind drops them around an obstacle
• dunes increase in size due to more build up of sand (deposition)
• colonization by vegetation anchors sand forming sand dune

Question 17

conditions required for coral reefs

Answer 17

• warm water (18-27 C)
• shallow water (less than 60m)
• water free from sediment
• plentiful supply of oxygen in water
• plentiful supply of plankton
• calm water (no strong currents)
• pH 8 or above
• high salinity

Question 18

what are mangrove swamps

Answer 18

areas of vegetation found along sheltered tropical coastlines and estuaries

Question 19

conditions of mangrove swamp

Answer 19

• temp above 20C
• large area between high and low watermark
• salty water
• no strong waves or tidal currents

Question 20

mangrove adaptations

Answer 20

• specially adapted roots to filter salt

- roots prop tree up and take in oxygen in low tide

Question 21

coastal hazards

Answer 21

• coastal erosion
• coastal flooding
• tropical storms
• tsunamis
• cliff collapse

Question 22

what is a sea wall

Answer 22

large walls constructed from concrete, steel or stone located along the shoreline of a beach

Question 23

advantages of sea wall

Answer 23

-protects cliffs from upland erosion and is a barrier to flooding

Question 24

disadvantages of sea wall

Answer 24

eaves can erode the wall defeating its purpose, and is expensive to implement and maintain

Question 25

what is a groyne

Answer 25

wooden fence-like barriers built at right angles at the beach

Question 26

groyne advantages

Answer 26

prevents longshore drift, flooding and erosion, allows beach to build up

Question 27

groyne disadvantages

Answer 27

can create erosion further down the coast

is unattractive and expensive

Question 28

what is a gabion

Answer 28

bundles or rocks in metal mesh located at cliff bases

Question 29

gabion advantages

Answer 29

reduces impact of waves

Question 30

gabion disadvantages

Answer 30

inexpensive hard engineering structure, but not very effective or attractive

Question 31

what is a revetment

Answer 31

slanted structures made from concrete, wood or rocks along a cliff

Question 32

revetment advantages

Answer 32

prevents cliff erosion as it absorbs the waves energy

Question 33

revetment disadvantages

Answer 33

expensive to implement

can create a strong backwash

Question 34

what is a coastal barrage

Answer 34

partly submerged dam-like structures that can control tidal flow

Question 35

coastal barrage advantages

Answer 35

create a more consistent water level, can be used to create hydroelectricity

Question 36

coastal barrage disadvantages

Answer 36

has a strong impact on the enivronment and expensive to maintain and implement

Question 37

what is rock armor/rip rap

Answer 37

large boulders or rocks piled up on a beach infront of a cliff or seawall

Question 38

rock armor/rip rap advantages

Answer 38

absorbs energy of waves and helps build up beaches

Question 39

rock armor/rip rap disadvantages

Answer 39

expensive to implement and maintain

Question 40

what is beach nourishment

Answer 40

beach made wider using sand and shingle

Question 41

advantages of beach nourishment

Answer 41

increases distance a wave has to travel, slowing it down and preventing erosion

Question 42

disadvantages of beach nourishment

Answer 42

sand and shingle need to be sourced from somewhere else, usually by dredging
requires a lot of maintenance and can be costly

Question 43

coastal opportunities

Answer 43

• water supply and irrigation
• farming
• tourism
• settlement
• transport
• ports and trade
• fishing
• industry