coastal landscape and change Flashcards

Question

examples of transportation

Answer 1

- longshore drift - traction - saltation - suspension - solution

Answer 2

Sediment is predominantly transported along the coast through the process of longshore drift. It transports sediment along the beach and between sediment cells: ● Waves hit the beach at an angle determined by the direction of the prevailing wind. ● The waves push sediment in this direction and up the beach in the swash. ● Due to gravity, the wave then carries sediment back down the beach in the backwash. ● This moves sediment along the beach over time. ● It is one of the reasons why when swimming in the sea, you often move along the coast in a particular direction.

Answer 3

Large, heavy sediment rolls along the sea bed, being pushed by currents.

Answer 4

Smaller sediment bounces along the sea bed, being pushed by currents.

Answer 5

Small sediment is carried within the water column (a body of water)

Answer 6

Dissolved material is carried within the water

Answer 7

The impact of transportation depends on the severity of the angle that waves travel onto land. ▪ Swash-aligned – wave crests approach parallel to coast so there is limited longshore drift. Sediment doesn’t travel up the beach far. ▪ Drift-aligned – waves approach at a significant angle, so longshore drift causes the sediment to travel far up the beach.

Answer 8

Deposition occurs when a wave loses energy meaning the sediment becomes too heavy to carry. Deposition tends to be a gradual and continuous process - a wave won’t drop all of its sediment all at once. Gravity settling – the wave’s energy becomes very low and so heavy rocks and boulders are deposited followed by the next heaviest sediment. ▪ Flocculation – clay particles clump together due to chemical attraction and then sink due to their high density.

Answer 9

- spits - bars - tombolo - cuspate forelands - offshore bars - sand dunes

Answer 10

A spit is a long narrow strip of land which is formed due to deposition. Longshore drift occurs along the coast line but as the waves lose energy (normally due to going into a sheltered area such as behind a headland) they deposit their sediment. Over time this creates a spit. Periodically, the prevailing wind will change direction causing a hook to appear. Over time, the sheltered area behind a spit can turn into a salt marsh. The length of a spit is influenced by surrounding currents or rivers. For example, in the diagram the spit is forming in an estuary and the current from the river is preventing deposition to occur across the bay and is instead causing a recurved spit end.

Answer 11

A spit which, over time, crosses a bay and links up two sections of coast (the water within the bay is called a lagoon).

Answer 12

A spit which, over time, crosses a bay and links up two sections of coast (the water within the bay is called a lagoon).

Answer 13

Only occurs with triangular shaped headlands. Longshore drift along each side of the headland will create beaches, which where they meet, will form a cuspate foreland.

Answer 14

A region offshore where sand is deposited, as the waves don’t have enough energy to carry the sediment to shore. They can be formed as the wave breaks early, scouring the seabed and instantly depositing its sediment as a loose-sediment offshore bar

Answer 15

- Sand dunes occur when prevailing winds blow sediment to the back of the beach and therefore the formation of dunes requires large quantities of sand and a large tidal range. This allows the sand to dry, so that it is light enough to be picked up and carried by the wind to the back of the beach. Frequent and strong onshore winds are also necessary. The dunes develop as a process of a vegetation succession: ○ Embryo dunes – Upper beach area where sand starts to accumulate around a small obstacle (driftwood, wooden peg, ridge of shingle) ○ Yellow dunes – As more sand accumulates and the dune growns, vegetation may develop on the upper and back dune surfaces, which stabilises the dune. The tallest of the dune succession. ○ Grey dunes – Sand develops into soil with lots of moisture and nutrients, as vegetation dies, enabling more varied plant growth. ○ Dune slack – The water table rises closer to the surface, or water is trapped between hollows between dunes during storms, allowing the development of moisture-loving plants (e.g. willow grass) ○ Heath and woodland – Sandy soils develop as there is a greater nutrients content, allowing for less brackish plants to thrive. Trees will also grow (willow, birch, oak trees) with the coastal woodland becoming a natural windbreak to the mainland behind.

Answer 16

Depositional landforms consist of unconsolidated sediment and are therefore vulnerable to change. During major storms, large amounts of sediment can be eroded or transported elsewhere removing a landform from one region of the sediment cell. Depositional landforms depend on a continuous supply of sediment to balance erosion, which may see some landforms changed as their dynamic equilibrium shifts.

Answer 17

Weathering is the breakdown of rocks (mechanical, biological or chemical) over time, leading to the transfer of material into the littoral zone, where it becomes an input to sediment cells. Mechanical (Physical) Weathering: the breakdown of rocks due to exertion of physical forces without any chemical changes taking place Chemical weathering - the breakdown of rocks through chemical reactions. There are different Biological Weathering - the breakdown of rocks due to the actions of plants, bacteria and animal types of chemical weathering:

Answer 18

Freeze-thaw (Frost-Shattering): Water enters cracks in rocks and then the water freezes overnight during the winter. As it freezes, water expands by around 10% in volume which increases the pressure acting on a rock, causing cracks to develop. Over time these cracks grow, weakening the cliff making is more vulnerable to other processes of erosion ● Salt Crystallisation: As seawater evaporates, salt is left behind. Salt crystals will grow over time, exerting pressure on the rock, which forces the cracks to widen. Salt can also corrode ferrous (materials that contains iron) rock due to chemical reactions ● Wetting and Drying: Rocks such as clay expand when wet and then contract again when they are drying. The frequent cycles of wetting and drying at the coast can cause these rocks and cliffs to break up

Answer 19

Carbonation: Rainwater absorbs CO2 from the air to create a weak carbonic acid which then reacts with calcium carbonate in rocks to form calcium bicarbonate which can then be easily dissolved. Acid rain reacts with limestone to form calcium bicarbonate, which is then easily dissolved allowing erosion. ● Oxidation: When minerals become exposed to the air through cracks and fissures , the mineral will become oxidised which will increase its volume (contributing to mechanical weathering), causing the rock to crumble. The most common oxidation within rocks is iron minerals becoming iron oxide, turning the rock rusty orange after being exposed to the air. ● Solution: When rock minerals such as rock salt are dissolved.

Answer 20

● Plant Roots - Roots of plants growing into the cracks of rocks, which exerts pressure, eventually splitting the rocks. Research Angkor Wat for more information on this, even though it is not coastal! ● Birds - Some birds such as Puffins dig burrows into cliffs weakening them and making erosion more likely. ● Rock Boring - Many species of clams secrete chemicals that dissolve rocks and piddocks may burrow into the rock face ● Seaweed Acids - Some seaweeds contain pockets of sulphuric acid, which if hit against a rock or cliff face, the acid will dissolve some of the rock’s minerals. (e.g. Kelp) ● Decaying Vegetation - Water that flows through decaying vegetation and then over coastal areas, will be acidic, thus causing chemical weathering

Answer 21

which tend to be determined by the weight of the sediment and its ability to flow downhill. as well as - the angle of the slope/cliff - the rock’s lithology and geology - the vegetation cover on the cliff face - the saturation of the ground/ previous weather patterns

Answer 22

a slide and a flow. For a slide, sediment keeps its same place within the whole material, simply moves downhill. However, for a flow, all the material flows downs and mixes.

Answer 23

● Soil creep - The slowest but continuous form of mass movement involving the movement of soil particles downhill. ● Solifluction - Occurs mainly in tundra areas where the land is frozen. As the top layers thaws during summer (but the lower layers still stay frozen due to permafrost) the surface layers flows over the frozen layers. ● Mudflows - An increase in the water content of soil can reduce friction, leading to earth and mud to flow over underlying bedrock.

Answer 24

● Rock falls - Occur on sloped cliffs (over 40o ) when exposed to mechanical weathering. ● Rock slides - Water between joints and bedding planes (which are parallel to the cliff face) can reduce friction and lead to more sliding. ● Slumps - Occur when the soil is saturated with water, causing a rotation movement of soft materials (such as clay and sand) forming rotational scars and terraced cliff profiles.

Answer 25

land-based processes and occur above the waterline. They include weathering and mass movement, which happen on the cliff rocks. These processes operate on the cliff lithology to weaken them and provide material for erosion.

Answer 26

Temperature and climate can influence the prominent process of weathering. In colder climates, mechanical weathering is more common whereas in warmer climates, chemical weathering is more common.

Answer 27

- The resistance of the rock to erosion - The dip in rock strata in relation to the sea

Answer 28

Concordant coastlines are where the rock strata run parallel to the coast. The rock type varies between different concordant coasts and normally consist of bands of more resistant and less resistant rock. For example, limestone may run in parallel bands with clays and sands. These different rock types create different landforms due to erosion. Concordant coastlines can lead to the formation of Dalmatian coastlines Haff coasts

Answer 29

where a rise in sea levels led to the flooded widen river valleys between tall headlands. The headlands become islands, running perpendicular to the mainland.

Answer 30

are also dependant on a concordant coastline, where large bays are crossed by spits, creating a extensive lagoons.

Answer 31

This is where the rock strata run perpendicular to the sea, which can create successions of headlands and bays; less resistant rocks are eroded faster than the more resistant rocks, which leads to the formation of bays. Headlands and bays

Answer 32

Rocks and sediment play a very important role in influencing the shape of the coastal landscape. However, vegetation is essential in stabilising any landforms from further change. Vegetation helps to stabilise coastal sediment in many ways: ▪ Roots of plants bind soil together which helps to reduce erosion. ▪ When completely submerged, plants provide a protective layer for the ground and so the ground is less easily eroded. ▪ Plants reduce the wind speed at the surface and so less wind erosion occurs. Plants grow in different coastal environments and are either halophytes or xerophytes ▪ Xerophytes – plants that are tolerant of dry conditions. ▪ Halophytes (or brackish) – plants that are tolerant of salty conditions.

Answer 33

have an effect on income waves and cause wave refraction. Wave refraction is the process by which waves turn and lose energy around a headland on uneven coastlines. The wave energy is focussed 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 environments such as beaches

Answer 34

Plant succession is a long-term change in a plant community in an area. On coasts where there is a supply of sediment and deposition occurs, pioneer plants begin to grow in bare mud and sand. Due to the salty soil conditions only certain plants can grow there. As more deposition occurs and the vegetation dies and releases nutrients into the sand this reduces the saltiness of the soil which means different plants can start growing there. These processes continue over time allowing new species of plants to colonise. Marram grass is a very good example of a pioneer plant: - it is tough and flexible, so can cope when being blasted with sand. - it has adapted to reduce water loss through transpiration. - Their roots grow up to 3 metres deep and can tolerate temperatures of up to 60oC

Answer 35

Algal Stage - Gut weed & Blue green algae establish as they can grow on bare mud, which their roots help to bind together. ▪ Pioneer Stage - Cord grass & Glasswort grow, their roots begin to stabilise the mud allowing the estuarine to grow. ▪ Establishment Stage - Salt marsh grass & Sea asters grow, creating a carpet of vegetation and so the height of the salt marsh increases. ▪ Stabilisation - Sea thrift, Scurvy grass & Sea lavender grow, and so salt rarely ever gets submerged beneath the marsh. ▪ Climax vegetation - Rush, Sedge & Red fescue grass grow since the salt marsh is only submerged one or twice a year.

Answer 36

are associated with more powerful waves, so occur in areas where there is a large fetch. They typically have rocky headlands and landforms and fairly frequent destructive waves. As a result these coastlines are often eroding as the rate of erosion exceeds the rate of deposition.

Answer 37

have less powerful waves and occur in sheltered areas where constructive waves prevail and as a result these are often fairly sandy areas . There are landforms of deposition as the rates of deposition exceed the rates of erosion.

Answer 38

- The strength of the wind - How long the wind has been blowing for - Water depth - Distance of fetch

Answer 39

Strong swash, weak backwash ▪ Low wave height, long wavelength ▪ Low frequency ▪ Depositional

Answer 40

▪ Strong backwash, weak swash ▪ High wave height, short wavelength ▪ High frequency ▪ Erosional

Answer 41

● In summer, constructive waves dominate but destructive waves dominate in winter. ● Constructive waves may turn into destructive waves as a storm begins. ● Climate change could mean that the UK may become more stormier meaning an increase in destructive waves. ● Dams prevent sediment being transported from rivers and entering into the coastal area which means erosion could increase. ● Interference with natural processes along the coast (e.g. through human activity) could affect sediment supply across a coastal area.

Answer 42

- High tide and low tide - a daily phenomena due to the gravitational pull of the Moon. - Wind strength and direction - these can change causing a change in sea level for a couple of minutes or longer - Atmospheric pressure - the lower the pressure, the higher the sea levels.

Answer 43

Isostatic sea level change could be due to post-glacial adjustment (glaciers weigh down the land beneath, and so the land subsides until it melts). For example, post-glacial adjustment for the UK after the Ice Age has caused Southern England to subside around 1mm per year and Scotland to rebound and increase around 1.55mm per year. Tectonic activity (such as earthquakes and volcanic eruptions) may cause land subsidence, therefore causing isostatic sea level increase.

Answer 44

Eustatic rise is due to thermal expansion. Water expands when it gets warmer, and so the volume of water increases which as a result, sea levels increase. This is due to Global Warming. However, predicting sea level change is very difficult because various factors could affect changes, and the cause isn’t still fully understood

Answer 45

movement of people towards the coast. Despite having a high flood risk, may people move to the coast due to tourism, high-yield agricultural lands, or housing pressure. Coastalisation can increase the environmental vulnerability of these locals to flooding due to storm surges

Answer 46

A storm surge occurs when there is a short-term change in sea level, which may be due to low pressure during a depression or tropical cyclone.

Answer 47

Subsidence of the land - through tectonic activity or post-glacial adjustment. ● Removing natural vegetation - Mangrove forests are the most productive and complex ecosystem in the world. Mangroves also provide protection against extreme weather events like cyclones which are very common in the Bay of Bengal. However, due to pressure for land space, much mangrove forests are destroyed for tourism, local industry, or housing plains. ● Global Warming - As the surface of oceans get warmer, it is estimated that the frequency and intensity of storms will increase, and so the severity of storm surges and flooding is also expected to increase.

Answer 48

Some areas of the coast may have significantly reduced house and land prices (as the area becomes known to be at significant risk). This can lead to economic loss for homeowners and local coastal economies. In the UK, many insurers don’t provide home insurance to people living along coastlines that are at extreme risk of erosion or storm surges. Storm surges also damage the environment by destroying plant successions and damaging many coastal landforms. Depositional landforms, due to their unconsolidated nature, are most likely to be destroyed. Also, erosion may take place at accelerated rates or higher up along the cliff face, which can increase the risk of collapse.

Answer 49

Globally, more than 1 billion people live on coasts that are at risk from coastal flooding and 50% of the world’s population currently live within 200km of the coast. As storm surges and erosion along some coastlines are predicted to increase, so too is the volume of environmental refugees displaced internally or internationally. People may lose their homes, way of life and culture as they are forced to migrate to avoid the rising eustatic sea level and the rising risk of coastal flooding.

Answer 50

Approaches to coastal management have changed greatly due to new knowledge and research about the positive and negative impacts that management can have on a coastline. New approaches have been created, though the specific strategies used can mostly be classified into two types - hard and soft engineering. Hard and soft engineering both relate to traditional approaches to coastal management. 'There is erosion occurring in this area, so lets build a beach or sea wall to reduce the erosion’. These approaches are a direct solution to the problem that is occuring.

Answer 51

Hold the line – Defences are built to try and keep the shore where it is. ● Managed realignment – Coastline moves inland naturally but managed. ● Advance the line – Defence are built to try and move the shore seawards. ● Do nothing – No defences are put in place and the coast is allowed to erode.

Answer 52

▪ Economic value of assets that could be protected is looked at, for example the important natural gas terminal at Easington would be protected however farmland and caravan parks wouldn’t ▪ The technical feasibility of engineering solutions, for example a sea wall may not be possible for a certain location. ▪ The ecological and cultural value of land. For example, it may be desirable to protect historic sites or SSSI.

Answer 53

Cost-benefit analysis (CBA) ICZM – Integrated Coastal Zone Management Shoreline management plans (SMPs)

Answer 54

This is an analysis that is carried out before any form of coastal management takes place. The cost involved include construction, demolition, maintenance etc. is then compared to the expected benefits like the value of land saved, homes and businesses protected. Costs and benefits include both tangible and intangible things. For a project to be given the go ahead, the expected benefits have to outweigh the costs (according to DEFRAs 1:1 analysis)

Answer 55

▪ A coastal area (sediment cell) is managed as a whole. This often involves management between different political boundaries e.g in the UK different councils will have to work and manage coasts together. ▪ The ICZM recognises the importance of the coast for people’s livelihoods. ▪ The ICZM recognises that coastal management must be sustainable whereby economic development is important but this should come at a cost for the environment. The ICZM must involve all stakeholders, plan for the long term and try to work with natural process and not against them.

Answer 56

For each sediment cell in the UK, an SMP has been created to help with coastline management. Each SMP identifies all of the activities, both natural and human which occur within the coastline area of each sediment cell. The sediment cells are considered to be closed for the purposes of management, although in reality there will be some exchanges between the different sediment cells. SMP’s are recommended for all sections of English and Welsh coastlines by DEFRA (governing body responsible for majority of environmental protection in the UK). Four options are considered for each stretch of the coastline:

Answer 57

Hard engineering is a very traditional and in many ways outdated approach to coastal management and it involves man made structures that aim to prevent erosion . They are often very effective at preventing erosion in the desired area, but are high cost and have a significant environmental impact due to the use of concrete and other man-made materials. By reducing erosion in one area of the coastline, they may act to exacerbate erosion elsewhere. Therefore their only impact is to change where erosion is occuring. - offshore breaker - groynes - seawalls - rip rap (rock armour) - revetments

Answer 58

Description: Rock barrier which forces waves to break before reaching the shore 👍 Effective at reducing waves’ energy 👎 Visually unappealling 👎 Navigation hazard for boats 👎 Can interfere with LSD

Answer 59

Description: Timber or rock protrusions that trap sediment from LSD 👍 Builds up beach, protecting cliff and increasing tourist potential 👍 Cost effective 👎 Visually unappealling 👎 Deprives areas downwind of sediment increasing erosion elsewhere

Answer 60

Description: Concrete structures that absorb and reflect wave energy, with curved surface 👍 Effective erosion prevention 👍 Promenade has tourism benefits 👎 Visually unappealling 👎 Expensive to construct and maintain 👎 Wave energy reflected elsewhere, with impacts on erosion rates

Answer 61

Description: Large rocks that reduce wave energy, but allow water to flow through 👍 Cost effective 👎 Rocks are sourced from elsewhere, so do not fit with local geology 👎 Pose a hazard if climbed upon

Answer 62

Description: Wooden or concrete ramps that help absorb wave energy 👍 Cost effective 👎 Visually unappealling 👎 Can need constant maintenance, which creates an additional cost

Answer 63

Unlike hard engineering, soft engineering aims to work with and complement the physical environment by using natural methods of coastal defence. They are useful for protecting against sea-level change as well as coastal erosion. -beach nourishment -cliff regrading and drainage - dune stabilisation - marsh creation

Answer 64

👍 Builds up beach, protecting cliff and increasing tourist potential 👍 Cost effective and looks natural 👎 Needs constant maintenance 👎 Dredging may have consequences on local coastal habitats

Answer 65

Description: Reduces the angle of the cliff to help stabilise it. A steeper cliff would be more likely to collapse 👍 Cost effective 👎 Cliff may collapse suddenly as the cliff is drier leading to rock falls which pose a hazard 👎 May look unnatural

Answer 66

Description: Marram grass planted. The roots help bind the dunes, protecting land behind 👍 Cost effective and creates an important wildlife habitat 👎 Planting is time consuming

Answer 67

Description: Type of managed retreat allowing low-lying areas to flood 👍 Creates an important wildlife habitat 👎 Farmers lose land and may need compensation as a result

Answer 68

▪ Managing natural resources like fish, water, farmland to ensure long-term productivity. ▪ Creating alternative livelihoods before people lose their existing jobs. ▪ Educating communities about the need and how to adapt. ▪ Monitoring coastal changes and then adapting or mitigating. ▪ Managing flood risk or relocating if needed.

Answer 69

When considering coastal management their may be winners and losers . Winners can be classified as those who benefit economically (e.g. their homes and businesses are protected), environmentally (e.g. habitats are protected) and socially (community ties still remain in place, people still have jobs so less stress and worrying). Losers can be classified as those who lose their property, lose a job, or have to relocate elsewhere. Communities and homeowners have a strong attachment to a place so losing their properties and their social networks is a great loss. This will make them financially worse off and many people may feel lonely if forced to move and may be angered if areas are not chosen to be protected. Business owners may be angered if nothing is done to protect the area in which they have their business, which could cause them to lose profitability and regular clients. DEFRA funding has been reduced by the central government since 2010 so they cannot invest in coastal management in all areas and now have to prioritise their funding in the most important locations. Some people may feel aggrieved by this. However there may be arguments which supports the decision for no active intervention: ● Coastal managers produce SMP for an entire area so they have to see what kind of impacts other may have if the coast is managed in one specific area ● Local authorities and DEFRA have had their budgets reduced as central government funding since 2010 has dropped and so they cannot invest in coastal management in all areas, they have to prioritise their funding to the most important places

Answer 70

Coastal management has a variety of impacts on sediment cells and any form of intervention will cause some kind of impact. Installing a sea wall would reflect wave energy downdrift increasing wave energy and erosion elsewhere on the coastline. Less erosion occurs in these areas with the sea wall , so there is also less sediment in the areas with increased wave energy . Less sediment reduces the beach size , so the cliff is more exposed to erosion from the higher energy waves. Building groynes has the same effect on downdrift areas as longshore drift can no longer transport sediment away from one stretch of coastline.