coastal

Question 1

what type of system is a coast

Answer 1

it is an open system as it recieves inouts from outside systems and trasnfers outputs away from the coast into other systems. however you need to consider it as a closed system as the costal system inpacts and is impacted by the oceans.

Question 2

what are sediment cells

Answer 2

sections of a coats wich are often borderd by prominent headlands. within these sections the movement of sediment is almost contained and the flows of sediment act in dynamic equalibrium. within sediment cells there are smaller subcells

Question 3

what is dynamic equalibrium

Answer 3

the maintenence of a balance in a natural system, despite it being in a constant state of change. the system counteracts any changes imposedon the system in order to keep the balance

Question 4

what is dynamic equalibrium in sediment cells

Answer 4

where input and output of sediments are in a constant state of change but remian in balance.

Question 5

what can interupt the dynamic equalibrium

Answer 5

it can be upset in the long term by human interventions or in the short ter, by natural variations.

Question 6

inputs def and exapmles

Answer 6

material or energy inputs. they include: marine- waves, tides, salt spray atmosphere- sun, air pressure, wind speed and direction humans- pollution, recreation, settlements, defences

Question 7

outputs def and examples

Answer 7

material or energy outputs. e.g. ocean currents, rip tides, sediment transfer, evapouration

Question 8

stores/sinks def and examples

Answer 8

stores and sinks of sediment and materail. e.g. beaches, sand dunes, spits, bars and tombolos, headlands adn bays, nearshore sediment, cliffs, wave cut platforms, caves, arches, stacks, stumps, salt marshes, tidal flats, offshore bands and bars

Question 9

transfers/flows def and examples

Answer 9

the proccesses that link the inputs, outputs and stores in the coastal system. e.g windblowm sand, mass movement proccesses, long shore drift, weathering, erosion, transportation, deposition

Question 10

energy def and exapmles

Answer 10

the power and driving force behind the transfers and flows in the system. e.g. wind, gravitational, flowing water.

Question 11

what is the negative feedback loop

Answer 11

it lessens any change wich has occured within the system. when a system is taken out of dynamic eualibrium the negative feed back loop will balance it brining it back to dynakic equalibrium.

Question 12

example of a negative feedback loop

Answer 12

1. when the destructive waves from storm loose their energy excess sedimeny is deposited as an offshore bar.
2. the bar dissipates the waves energy wich protects the beach from further erosion
3. overtime the bar gets eroded instead of the beach
   4.once the bar has gone normal conditions ensue and the system goes back to dynamic equalibrium.

Question 13

what is a positive feedback loop

Answer 13

this exaggarates the change making the system more unstable and taking it away from dynamic eualibrium

Question 14

example of a positive feedback loop

Answer 14

1. people walking over sand dunes destroys vegetation growing there and causes erosion.
2. as the roots from the vegetation have been holding the sadn dunes together, damaging the vegetation makes the sand dunes more suspetible to erosion. this increases the rate of erosion. 3. eventually the sand dunes will be completely eroded leaving more of the beach open to erosion taking the beach further awau from its original state

Question 15

how is a river a sediment resource

Answer 15

most of the sediment in the coastal zone is a result of an input from rivers, especially in high-rainfall enviroments where signinfiant river erosion occurs. sediment may be deposited in estuaries wich are brackish (salty) areas where rivers flow into the sea. they are important wildlife habitats. the sediment is then transported throughout the coastal system by waves, tides and currents

Question 16

how is cliff erosion a sediment source

Answer 16

it is very important in areas with unconsolidated cliffs that are easily eroded. in some area, coastlines retreat by up to 10m per year, providing a significant sediment input. most erosion occurs during the winter months due to more frequent storms

Question 17

how is wind a sediment resource

Answer 17

it is an energy source and can cause sand to be blown along or up a beach. sediment transport by winds may occur where there are sand dunes or in glacial and desert enviroments wich provide sediment inputs.

Question 18

how are glaciers sediment sources

Answer 18

in some coastal systems glaciers flow directly into the ocean depostiting sediment that was stored in the ice. this occurs when glaciers calve(ice breaks off)

Question 19

how is offshore a sediment source

Answer 19

sediment is transfered to the coastal zone when waves, tides and currents erode off shore sediment sinks such as offshore bars. the sediment is transported onto the beach, helping build up the beach. storm surges or tsunami waves may also transfer sediment into the caostal zone.

Question 20

how is longshore drift a sediment source

Answer 20

sediment is moved along the beach due to prevaling winds which alter the direction of the waves. this allows sediment to be transported form one section of the coast to another stretch of caostline. the swash approaches the coast at an angle due to the prevaling winds, transferring sediment along the beach. the backwash pulls the sediment direvtly back down the beach. the swsh then transfers the sediment along the coastline and the proccess repeats

Question 21

what are sediment budgets

Answer 21

they use data of inputs,outputs, stores and trasfers to sases the gains an losses of sediment within a sediment cell. in principle a system will operate in a state of dynamic equalibrium where input and outputs of sediment are equal.

Question 22

what is the littoral zone

Answer 22

the area of land beteen the clifs or dunes on the coast and the offshore area that is beyond the influence of waves. it is therefore covered by the sea at different points in time.

Question 23

what are the long term adn short term factors that affect the littoral zone

Answer 23

short-term: tides and storm surges
long-term: changes in sea level and human intervention

Question 24

shore/shoreline def

Answer 24

the boundary betweeen the sea and the land

Question 25

offshore def

Answer 25

the area beyond the influence of waves

Question 26

onshore def

Answer 26

the area of lanf not covered by the sea but is very close to it

Question 27

what is the main source of energy at the coast

Answer 27

the main source of energy is form waves wich are formed pffshore, wich are most commnoly generated by wind or less frequently tectonic activity or underwater landslides causing tsunami waves

Question 28

how do waves form

Answer 28

wind moves across the surface of the water, causing frictional drag wich creates small ripples and waves. this leads to a circular orbital motion of water particles in the ocean. as the seadbed becomes shallower towards the coastline, the orbit of the water particles become more elliptical, leading to more horizontal movement of the waves. the wace height increases, but the wave length and ave velocity bith decrease. this causes water to back up from behind the wave until the wave breaks and surges up the beach

Question 29

how does wind strength affect wave energy

Answer 29

wind is air that moves from an area of high pressure to an area of low pressure. the different pressures are cuased by variation in surface heating by the sun. the larger the difference in pressure between the toe areas the stonger the winds. as winds casue waves, stronger winds also mean stronger waves.

Question 30

how does wind duration affect wave energy

Answer 30

if the wind is active for longrt periods of time, then the energy of the waves will build up and increase.

Question 31

how does the size of the fetch affect wave energy

Answer 31

the fetch is the distance over wich the wind blows and the larger it is, the more powerful the waves will be. it could also be thought of as distance to the nearest land mass in a particular direction

Question 32

what is the formation of a constructive

Answer 32

it is formed by weather sytems that operate in the open ocean

Question 33

what is the wavelength on a constructive wave

Answer 33

long wavelength

Question 34

what is the frequency of cinstructive waves

Answer 34

6-9 per minute

Question 35

what are the characteristics of constructive waves

Answer 35

low waves, wich surge up the beach

Question 36

what are the swash characteristics of constuctive waves

Answer 36

strong swash, weak back wash

Question 37

what effect do constructive waves have on the beach

Answer 37

occurs on gently sloped beaches

Question 38

how are destrcutive waves formed

Answer 38

localised storm events with stronger winds operating closer to the coast

Question 39

what is the wave lenth of a destructive wave

Answer 39

short wavelength

Question 40

what is the frequency of destructive waves

Answer 40

11-16 per minute

Question 41

what are the characteristics of a destructive wave

Answer 41

high waves, wich plunge onto the beach

Question 42

what are destructive wave swash characteristics

Answer 42

weak swash, strong backwash

Question 43

what are destructive waves effect on the beach

Answer 43

occurs n steeply sloped beaches

Question 44

what is the negative feedback proccess of beaches and waves

Answer 44

constructive waves cause depositionn, wich leads to the beach profile becoming steeper. steep beaches favour the formation of destructive waves. the destructive waves erode the beach reducing the profile and leading to the formation of construtive waves.

Question 45

how does the beach profile change throughout the year

Answer 45

constructive waves occur more in sumer when there are fewer storms meaning the beach profileis genteler and steeper during the winter months when destructive waves are more common. this leads to the state of dynamic.

Question 46

how are tides formed

Answer 46

gravity pulls the sun or moon and changes the water levels of the seas and oceans.

Question 47

what is tidal range

Answer 47

the difference in height between tides and it tends to be largest in channels such as river esturies.

Question 48

what is a spring tide

Answer 48

its when the highest and lowest tide occur. this happens when the sun and the moon are in aligment. both of their gravitational forces combine to effectivly pull teh oceans towards them to cause the highest tides. on the other side of the planet this creates the lowest possible low tide.

Question 49

what is a neap tide

Answer 49

its when the lowest high tide and highest low tide occur. this happens when the sun and moon are perpendicular to eachother.both their gravitational forces act against eachother, so the overall pull is minimised at high tide, but therefore creates a higher low tide.

Question 50

what are rip currents

Answer 50

powerful underwater currents occuring in areas close to the shoreline on beaches when plunging waves cause a buildup of water at the top of the beach.

Question 51

how are rip currents formed

Answer 51

the backwash is forced under the surface due to resistsnve frombreaking waves, forming an underwater curent. this flows away from the shore more quickly due to resistance from breaking waves, forming an underwater current. this flows away from the shoremore quickly due to beach features, suchas a gip in a sandbar.

Question 52

what are riptides

Answer 52

they are an energy source in coastal enviroments and can lead to outputs of of sediment from the beach area. they occur when the tide pulls warer througha small area such as a bay or lagoon.

Question 53

where do high energy coastlines occur and their factors

Answer 53

they occur is areas where there is a large fetch as there are more powerful waves. they typically have rocky headlands and landforms and fairly frequent destructive waves. as a result the coastlinesare often eroding as the the rate of erosion exeeds the rate of deposition.

Question 54

where do lowenergy coastlines occur and their factors

Answer 54

they occur is sheltered areas where less powerful constructive waves prevail and as a result these areoften fairlt sandy areas. there are landforms of deposition as the rate of deposition exeeds the rate of erosion.

Question 55

what is waves refraction

Answer 55

the process hwere waves turn and lose energy around a headland on uneven coastlines. the wave energy is focused on the headlands, creating erosive features in these areas. the energy is dissipated in bays leading to the formation of features associated with lower energy enviroments such as beaches.

Question 56

negative feedback process of headlands and bays

Answer 56

different rock strengths lead to the formation of headlands where resitant rocks and bays where unconsolidated rocks and clays are dominant. this then increases theforces of erosionon the headlands and reduced erosion on the bays as wave refraction dissipates wave energy and a beach protects the coastline behind. eventually the headland is worn away wich then increases erosion withinthe bays. this wouldlead to dynamic equlibrium if conditions stayed constan.

Question 57

erosion as a marine proccess def

Answer 57

a collaborative proccess wich invloves the removal of sediment from a coastling by difefrent types of erosion not one type acting by itslef.

Question 58

corrasion def

Answer 58

sandand pebbles are picked uo by the sea from an offshore sediment sock or temporal store and hurled agaisnt thecliffs at high tide, causing the cliffs to be eroded

Question 59

abrasion def

Answer 59

the proccess where sediment is moved along the shoreline, causing it to be worn down overtime.

Question 60

attrition def

Answer 60

wave action cause rocks and pebbles to hit against eachother, wearing eachother dowm and so becoming round and eventually smaller. its an erosive proccess within the coastal enviroment but has little to no effect of the erosion of the coastline.

Question 61

hydraulic action def

Answer 61

as waves crash onto a cliff face, air is forced into cracks, joints and faults within the rock. the high presure causes the cracks to force apart and widen when the wave retreats and the air expands. overtime this causes the rock to fracture.

Question 62

cavitation def

Answer 62

bubbles found within the warer may implode under the high pressure creating tiny jets of water that overtime erode the rock.

Question 63

corrosion (solution) def

Answer 63

the midily acidic seawater can cause alkaline rock such as linestone to be eroded and is very similar to the process of carbonation weathering.

Question 64

wave quarrying def

Answer 64

when breaking waves that hit the cliff face exert a pressure upto 30 tonnes per meter squared. it is very similat to hydraulic action but acts with significantly more pressure to directly pull away from a cliff face or remove smaller weathered fragments. the force of the breaking wave hammers the rock surface, shaking and weekening it and leaving it open to hydraluc action and abrasion.