Coasts

Question 1

what instrument measures changes in sea level

Answer 1

tide gauge

Question 2

how many people are predicted to be living within 10m elevation of the coast by 2060

Answer 2

over 1 bil people

Question 3

how much faster is pop. growth in coastal zones in developing countries

Answer 3

3x world average

Question 4

what region of europe was especially affected by isostasy following the last glaciation

Answer 4

north west europe- land rose relative to the sea (therefore sea level rise has less of an impact now)

Question 5

4 scales of processes

Answer 5

instantaneous, event, engineering and geological

Question 6

name 4 ways that energy dissipates at the coast

Answer 6

friction, heat, longshore transport or percolation

Question 7

why are wide shallow bays dissipative coastlines

Answer 7

the wave breaking process is very drawn out and gradual so the energy is released more slowly

Question 8

what does v coarse material at the top of the beach indicate

Answer 8

there are events strong enough to carry material all the way inshore (eg, rocky storm beaches)

Question 9

how do we approach a study of changes at the coast?

Answer 9

segment the coast into chunks and see where the sediment is transported to

Question 10

3 main anthropogenic coastal sediment controls

Answer 10

climate change, land use change, coastal management and flood protection

Question 11

what occurs when there is a large amount of sediment in a delta

Answer 11

subsidence can occur, pulling the delta downwards relative to the sea level

Question 12

how is climate change likely to influence storm events

Answer 12

more intense but less frequent

Question 13

what percentage of the world’s beaches are eroding

Answer 13

over 30%

Question 14

difference between sensitivity and resilience

Answer 14

sensitivity is how easily an ecosystem responds to a stimulus and resilience is its ability to bounce back

Question 15

example of a low resilience low sensitivity ecosystem

Answer 15

hard rock cliff

Question 16

example of a high sensitivity high resilience coast

Answer 16

beach with dune systems

Question 17

example of a medium sensitivity high resilience coast

Answer 17

saltmarshes and mangroves

Question 18

what do the spatial boundaries of the coastal zone represent

Answer 18

the elevational range over which processes have operated during the Quaternary period

Question 19

examples of submerged coast

Answer 19

drowned river and glacial valleys

Question 20

example of emerged coast

Answer 20

coastal plain

Question 21

what is secondary coast

Answer 21

results from marine processes mostly: barrier coasts, coral reefs, mangroves

Question 22

what is primary coast

Answer 22

result mostly from non-marine processes: drowned river valleys, rocky coasts, deltaic coasts

Question 23

what are leading edge coasts

Answer 23

adjacent to subducting plate margins, eg. mountain belts with steep erosive rocky coastlines

Question 24

what are trailing edge coasts

Answer 24

away from subducting plates, older, lower elevation, sediment rich

Question 25

what major factor influences the global distribution of wave enviros

Answer 25

latitude according to wind patterns

Question 26

is the tidal range larger at the coast or in the middle of the ocean

Answer 26

coasts

Question 27

what factors influence tide amplification

Answer 27

gradient and width of continental shelf, location and shape of continents, presence of large embayments

Question 28

name 3 main environmental conditions driving coastal systems

Answer 28

geology, unconsolidated sediments, external forcing

Question 29

what source of sediment is most important at the coast

Answer 29

marine sources (rather than atmospheric or terrestrial)

Question 30

what equation can be used to determine morphological change due to sediment build up or removal

Answer 30

sediment continuity equation

Question 31

what is relaxation time

Answer 31

the time required to reach equilibrium after disturbance

Question 32

do big complex systems have longer or shorter relaxation times

Answer 32

longer

Question 33

what 3 factors impact relaxation time

Answer 33

energy level, sediment mobility and spatial scale

Question 34

do higher energy systems have long or short relaxation periods

Answer 34

shorter relaxation time due to large sediment transport rates

Question 35

under what conditions does coastal change take place most dramatically

Answer 35

higher energy conditions

Question 36

how does relaxation time respond to decreasing sediment mobility?

Answer 36

increases (eg. hard rock cliffs take longer to relax)

Question 37

what is self-organisation

Answer 37

feedback leads to internal changes in system dynamics that maintain the system in equilibrum

Question 38

what does it mean that coastal evolution is cumulative

Answer 38

the morphological outputs form the inputs for the next cycle of change (preservation of past inheritance)

Question 39

what is palimpsest

Answer 39

the sediments or landforms from one time period are preserved overprinted or destroyed by later conditions

Question 40

by how much is global sea level rising each year

Answer 40

3.2mm

Question 41

what can enhance resilience to sea level change

Answer 41

ecological buffers like coral reefs and salt marshes, morphological protection

Question 42

why might salt marshes and tidal flats be able to keep up with rising sea level

Answer 42

they have high deposition rates

Question 43

what do the gaps in a stratigraphic record indicate

Answer 43

erosion

Question 44

what is significant wave height

Answer 44

average of the top 1/3 of waves

Question 45

what is linear wave theory

Answer 45

estimating the behaviour of ocean waves- ratio of water depth to wavelength

Question 46

3 wave regions

Answer 46

deep water, intermediate water and shallow water

Question 47

what is the wave base

Answer 47

the point where wave motion ceases and cannot stir the bed sediment

Question 48

what kind of water motion takes place in shallow water

Answer 48

horizontal movements

Question 49

how does shoaling occur

Answer 49

waves start to feel the seabed and get steeper, becoming increasingly asymmetrical

Question 50

wave divergence

Answer 50

waves propagate over a localised area of quite deep water, reduction in wave energy and height, and the spreading out of rays

Question 51

water convergence

Answer 51

focusing of the wave rays together

Question 52

3 main types of breakers

Answer 52

spilling, plunging and surging

Question 53

what parameters can be used to predict breaker type

Answer 53

Iribarren number or surf similarity parameter

Question 54

wave set-up

Answer 54

rise in mean level of water above the still water elevation of the sea

Question 55

where do nearshore currents derive their energy

Answer 55

wave breaking

Question 56

name 3 nearshore currents

Answer 56

longshore currents, bed return flow, rip currents

Question 57

what intensifies longshore currents

Answer 57

alongshore winds

Question 58

when are rip currents strongest

Answer 58

low tide

Question 59

what 3 factors determine the extent of a storm surge

Answer 59

low pressure, onshore wind and coastal topography

Question 60

what are amphidromes

Answer 60

tidal systems constrained by coastal topography- tide travels around centre as a wave

Question 61

at what point of the amphidrome is the tidal range 0

Answer 61

the centre

Question 62

what direction do the tides travel in a Northern hemisphere amphidrome

Answer 62

anticlockwise

Question 63

where are the largest tidal ranges seen

Answer 63

complex coastal configurations like the irish sea

Question 64

how does tidal range influence tidal current strength

Answer 64

strength increases with range

Question 65

3 causes of tsunamis

Answer 65

submarine earthquake, large landslide into ocean, meteorite impact

Question 66

where do tsunamis shoal

Answer 66

at the edge of the continental shelf

Question 67

what is the shoreface

Answer 67

an underwater slope seaward of the beach, much larger than the beach area

Question 68

what features can be found in wave dominated coastal enviros

Answer 68

barriers, beaches, coastal dunes

Question 69

what feature is found in tide dominated coastal environments

Answer 69

estuaries

Question 70

what main feature is found in fluvial dominated coastal enviros

Answer 70

deltas

Question 71

4 types of barriers

Answer 71

swash-aligned, drift-aligned, transgressive and regressive

Question 72

berms

Answer 72

accumulations of sediment at the top of the beach away from swash influence

Question 73

beach cusps

Answer 73

rhythmic shoreline features from swash action

Question 74

what occurs to the beach profile in calm conditions

Answer 74

onshore sediment transport in the nearshore zone to steepen the beach profile, bars can migrate on shore

Question 75

what occurs to the beach profile during energetic conditions

Answer 75

offshore transport with prolonged high wave conditions- destruction of berm and formation of a flat beach

Question 76

intermediate beaches

Answer 76

nearshore bar mophology = lots of dissipation due to wave breaking while upper part is quite steep and reflective

Question 77

what is needed to form dunes

Answer 77

enough sand, energetic wind

Question 78

what allows sand dunes to begin forming

Answer 78

tidal litter above spring high tide blocks wind and allows accumulation

Question 79

foredune ridge

Answer 79

where shadow dunes coalesce

Question 80

blow-outs

Answer 80

damage to veg causes saucer shaped depressions in dunes

Question 81

when did estuaries begin to develop

Answer 81

when coastal and river valleys flooded at the end of the last ice age, then infilled after stabilisation of sea levels

Question 82

3 zones in an estuary

Answer 82

inner zone- river dominated, central zone- mixed, outer zone- tidal domination

Question 83

what accumulates in the centre of wave dominated estuaries

Answer 83

deep central mud basin

Question 84

what shape ae tide-dominated estuaries

Answer 84

funnel shaped

Question 85

what can be found in the centre of tidal estuaries

Answer 85

tidal flats and salt marshes

Question 86

3 types of estuary based on mixing

Answer 86

stratified, partially mixed and well-mixed

Question 87

tidal prism

Answer 87

the total volume of water entering an estuary on the flooding tide

Question 88

delta plain

Answer 88

sedimentary platform that covers recent seaward advance

Question 89

delta front

Answer 89

seaward front of delta in relatively shallow water

Question 90

pro-delta

Answer 90

toe of delta in quite deep water

Question 91

when might freshwater flow below seawater

Answer 91

high load makes it denser

Question 92

delta switching

Answer 92

active region of coastal accumulation switches from 1 location on the delta to another

Question 93

what factors impact rock breakdown processes

Answer 93

wave energy level climate and rock type

Question 94

what percentage of the world's coastlinea re cliffs

Answer 94

80%

Question 95

angle of repose

Answer 95

the angle of the cliff profile

Question 96

ICZM

Answer 96

integrated coastal zone management

Question 97

4 principal management options

Answer 97

no active intervention, managed realignment, accommodation, hold the line