Coasts

Question 1

waves

Answer 1

Waves are essentially the movement of water molecules within the ocean, and are restricted to the surface layers of our oceans and seas.

Question 2

swash

Answer 2

When a wave reaches the shore, the water that rushes up the beach is known as the swash .

Question 3

backwash

Answer 3

The water that flows back towards the sea

Question 4

fetch

Answer 4

Area of ocean or lake surface over which the wind blows in an essentially constant direction, thus generating waves. The term also is used as a synonym for fetch length, which is the horizontal distance over which wave-generating winds blow.

Question 5

Destructive waves

Answer 5

Destructive waves are created in storm conditions. They are created from big, strong waves when the wind is powerful and has been blowing for a long time. They occur when wave energy is high and the wave has travelled over a long fetch. They tend to erode the coast. They have a stronger backwash than swash. Case study: Japan (2011).

Question 6

Constructive waves

Answer 6

They are created in calm weather and are less powerful than destructive waves. They break on the shore and deposit material, building up beaches. They have a swash that is stronger than the backwash. They have a long wavelength, and are low in height. case study: Holderness coast

Question 7

corrasion

Answer 7

Corrasion is when destructive waves pick up beach material (e.g. pebbles) and hurl them at the base of a cliff. Over time this can loosen cliff material forming a wave-cut notch.

Question 8

attrition

Answer 8

Attrition is when material such as rocks and stones carried by waves hit and knock against each other wearing them down. As these materials are worn down sand and rounded beach pebbles are formed. Sea cliffs are one of the clearest examples of sea erosion that we can see.

Question 9

corrosion/ solution

Answer 9

Is when certain types of cliff erode as a result of weak acids in the sea

Question 10

cave

Answer 10

Caves occur when waves force their way into cracks in the cliff face. The water contains sand and other materials that grind away at the rock until the cracks become a cave. Hydraulic action is the predominant process.

Question 11

wave-cut platform

Answer 11

Wave-cut platform, also called Abrasion Platform, gently sloping rock ledge that extends from the high-tide level at the steep-cliff base to below the low-tide level. It develops as a result of wave abrasion; beaches protect the shore from abrasion and therefore prevent the formation of platforms.

Question 12

longshore drift

Answer 12

Longshore drift is the movement of material along the shore by wave action. It happens when waves approach the beach at an angle. The swash carries material up and along the beach

Question 13

stack

Answer 13

A stack or sea stack is a geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast, formed by wave erosion. Stacks are formed over time by wind and water, processes of coastal geomorphology.

Question 14

how is a stack formed

Answer 14

Weathering and erosion can create caves, arches, stacks and stumps along a headland. When the arch collapses, it leaves the headland on one side and a stack (a tall column of rock) on the other. The stack will be attacked at the base in the same way that a wave-cut notch is formed.

Question 15

arch

Answer 15

A wave-eroded passage through a small headland. This begins as a cave formed in the headland, which is gradually widened and deepened until it cuts through.

Question 16

how is an arch formed

Answer 16

Cracks are widened in the headland through the erosional processes of hydraulic action and abrasion. As the waves continue to grind away at the crack, it begins to open up to form a cave. The cave becomes larger and eventually breaks through the headland to form an arch.

Question 17

beach

Answer 17

Beaches are a common feature of a coastline. Beaches are made up of eroded material that has been transported from elsewhere and deposited by the sea. … A cross-section of a beach is called a beach profile. The shingle ridges often found towards the back of a beach are called berms.

Question 18

Headland and bay

Answer 18

Headlands and bays are usually found together on the same stretch of coastline. Headlands and bays form on discordant coastlines, where bands of rock of alternating resistance run perpendicular to the coast. Bays form where weak (less resistant) rocks (such as sands and clays) are eroded, leaving bands of stronger (more resistant) rocks (such as chalk, limestone, granite) forming a headland. An area of Britain where it is possible to see headlands and bays is Dorset. One of the most famous bays is Weymouth bay.

Question 19

Wave-cut platform

Answer 19

is the narrow flat
area often seen at the base of a sea cliff caused by the action of the waves. It forms after destructive waves hit against the cliff face, causing undercutting between the high and low water marks, mainly as a result of corrasion and hydraulic power, creating a wave-cut notch. This notch then enlarges into a cave. The waves undermine this portion until the roof of the cave cannot hold due to the pressure and freeze- thaw weathering acting on it, and collapses, resulting in the cliff retreating landward. Wave cut platforms are most common at low tides when they become more visible as huge areas of flat rock. One of the most famous wave-cut platforms is at Southerndown, South Wales.

Question 20

Arches and stacks

Answer 20

This takes place is sedimentary rock where the waves begin to wear away at areas of weakness. These will get larger until caves are formed. This process will continue until the sea breaks through the headland until an arch is formed. The erosion will continue to take place until the roof of the arch will collapse and a stack is formed. The stack is then undercut leaving an arch

Question 21

How are stumps formed

Answer 21

Weathering and erosion can create caves, arches, stacks and stumps along a headland. Caves occur when waves force their way into cracks in the cliff face. … The stack will be attacked at the base in the same way that a wave-cut notch is formed. This weakens the structure and it will eventually collapse to form a stump.

Question 22

traction

Answer 22

Large boulders roll along the sea bed

Question 23

saltation

Answer 23

Smaller pebbles are bounced along the sea bed

Question 24

suspension

Answer 24

The finer sand and silt-sized particles are carried along in the flow of the waves

Question 25

solution

Answer 25

Minerals, like limestone and chalk are dissolved in the sea water and carried away

Question 26

longshore drift

Answer 26

Material is moved along the coast by a process called longshore drift. This is a zig zag movement. It is pushed along by the dominant wind. The waves rush up the beach at and angle and return to the sea at right angles to the coast line

Question 27

spits

Answer 27

A spit is a long beach made up of sand and shingle that extends out to sea. It is found in areas of shallow water and on a bend int he coast line

Question 28

Dorset coasts

Answer 28

In the south of England
Swanage Bay: made up of bands of hard and soft rock. The soft rock is made of clay and sands, and the hard rock is chalk and limestone. As erosion processes take place, the clay erodes away quicker than the limestone and chalk. This forms headlands and bays creating Swanage bay and two headlands - Ballard Point and Durlston Head.

Question 29

Old Harry rocks

Answer 29

Old Harry Rocks are located on the headland between Swanage and Studland Bay. The headland is made from chalk, a hard rock. The headland juts out into the sea, so it is more vulnerable to high-energy waves. This caused the formation of Old Harry, a stack. Over time Old Harry will collapse to form a stump.

Question 30

Chesil Beach

Answer 30

Chesil Beach is an example of a bar. Sediment has been deposited over time to form a spit. The spit has continued to join to the Isle of Portland. Behind the spit there is The Fleet, a lagoon.

Question 31

Beach nourishment (soft engineering)

Answer 31

This replaces beach or cliff material that has been removed by erosion or longshore drift. The main advantage is that beaches are a natural defence against erosion and coastal flooding.
Beaches also attract tourists. While it can be a relatively inexpensive option it requires constant maintenance to keep replacing
the beach material as it is washed away.

Question 32

Managed retreat (soft engineering)

Answer 32

This is where areas of the coast are allowed to erode and flood naturally. Usually this will be areas considered to be low value. The advantages are that it encourages the development of beaches (a natural defence) and salt marshes (important for the environment) and cost is low. While this is a cheap option, it will not be free as people will need to be compensated for loss of buildings and farmland.

Question 33

Soft engineering options

Answer 33

Soft engineering options are often less expensive than hard engineering options. They are usually also more long-term and sustainable, with less impact on the environment. There are two main types of soft engineering.

Question 34

Hard engineering options

Answer 34

Hard engineering options tend to be expensive and short-term options. They may also have a high impact on the landscape or environment. The table shows the most common hard engineering solutions.

Question 35

Building a sea wall (hard engineering)

Answer 35

Protects the base of cliffs against erosion, can prevent coastal flooding
But is expensive to build and thew waves remain powerful

Question 36

Building groynes (hard engineering)

Answer 36

A wooden barrier built at right angles to the beach
Prevents the movement of beach material along the coast through the process of longshore drift, allows the build up of a beach
However it is ugly and expensive

Question 37

Boulder barriers (hard engineering)

Answer 37

Large boulders are piled up on the beach and used to absorb the energy of waves and encourage the build up of beach material
They absorb energy fo waves and allow the build up of a beach
But are expensive

Question 38

Holderness coast

Answer 38

Located in the north east of England. This is one of the most vulnerable coastlines in the world, retreating at a rate of one to two metres a year. There are two causes of the problem. The Holderness coast is a 61km stretch of coast running from Flamborough Head in the north to Spurn Head (a spit) in the South.
Mainc causes of retreating: strong prevailing winds create longshore drift that moves material southwards along the coast. The cliffs are made of soft clay, so the they erode quickly

Question 39

Management on Holderness

Answer 39

A coastal management scheme costing 2 million was introduces to protect the settlement of Mappleton. It involved two types of hard engineering (placing rock armour along the base of the cliff and building two rock groynes

Question 40

Hornsea

Answer 40

The main settlement on the Holderness coasts. Has a population of around 8,500 and is an important holiday destination. Because it generates a large income through tourism, it was decided to protect Hornsea. On the sea front a 3 metre high recurved sea wall was built to absorb and reflect wave energy. Groynes were also places along the beach to try and prevent longshore drift

Question 41

Possible conflict on the Holderness Coast

Answer 41

Because coastlines are in demand, conflicts can often take place. For example, the Holderness coast is used as a holiday destination, it’s also used for walking, bird watching, farming, golf, transport, refining oil and gas, etc

Question 42

Coral reefs

Answer 42

A coral reef is a line of coral polyp found in warm shallow seas. Polyp are tiny carnivorous (meat eating)
animals.
Polyps live in groups called colonies. A polyp has a mouth at one end. The mouth is surrounded by a
number of tentacles. These tentacles resemble feet, which is how they get their name (‘polyp’ is a Greek word
meaning ‘many feet’)Polyps cannot move from their limestone homes. They mostly feed at night. A polyp reproduces by dividing its own body to form two polyps,
builds a case of limestone around itself, using calcium from the water. It is like a house, with a floor and walls. This
by producing sperm and eggs. Each polyp
remains after it has died and forms a foundation for another polyp to build a house on, putting a floor on the roof
of the old one. When these limestone formations increase, they are called a coral reefs.

Question 43

Coral reefs are very delicate and need what conditions to form

Answer 43

tropical sea conditions (between the two tropics), warm waters (over 18 degrees), clear water, no pollution, sunlight, water less that 60 metres deep.

Question 44

Fringing Reef

Answer 44

Fringing reefs circle or fringe the coastline or islands. They are often protected by barrier reefs further out to sea, so the plants and animals that live in fringing reefs are suited to low wave energy environments.

Question 45

Barrier Reef

Answer 45

These occur further from the sea and are commonly separated from the mainland or island by a deep lagoon. Barrier reefs are normally older and wider than fringing reefs. The Great Barrier reef in Eastern Australia is a barrier reef and stretches for 1600km.

Question 46

Atoll

Answer 46

They rise from submerged volcanoes. They are similar to barrier reefs in terms of biodiversity and
form. However, they are confined to submerged oceanic islands, unlike barrier islands which can follow continental coastlines e.g. Great Barrier Reef.

Question 47

Benefits of coral reefs

Answer 47

support 25% of marine species, protect coastlines from erosion, forma s a natural barrier against tropical storms and even tsunamis, act as a natural recycling agent for carbon dioxide from the sea and atmosphere, they contribute material for formations of beaches, raw material (used for jewellery and ornaments), benefit the tourism industry (snorkelling and fishing)

Question 48

How coral reefs are being damaged

Answer 48

Rising sea levels mean that the water above coral reefs is increasing, therefore the coral reefs do not get enough sunlight to grow, global warming and climate change mean that carols are being bleaches, hurricanes destroy coral reefs, deforestation means more surface run off and an increase in sediment, overfishing damaged coral reefs, tourism (boats) damage reefs and marine trade

Question 49

Coral reef management

Answer 49

dynamiting can be banned, conservation zones where tourists aren’t allowed can be created, areas where coral reef cannot be farmed can be created, sewage outlets can be moved downstream of coral reefs, banning. the use of fertilisers near coral reefs, educating people about why coral reefs are important and how to protect them

Question 50

Case study for coral reefs (The Great Barrier Reef)

Answer 50

Largest coral reef system composed of over 2,900 individual reefs and 900 Islands stretching for over 2,300 kilometres. The reef is located in the Coral Sea, off the coast of Queensland, Australia. A large part of the reef is protected by the Great Barrier Reef Marine Park. other environmental pressures on the reef and its ecosystem include runoff, climate change accompanied by mass coral bleaching and cyclic population outbreaks of the crown of thorns starfish. It has long been known to and used by the Aboriginal Australian and Torres Strait Islander peoples, and is an important part of local groups’ cultures and spirituality. It is very popular for tourists generating $3 billion per year

Question 51

Mangroves

Answer 51

They are a tree of shrub which grows in tidal, chiefly tropical, coastal swamps, having numerous tangled roots that grow above ground and form dense thickets. It is thought that they originate from South- east Asia and then spread across the globe. Because they grow in the intertidal zone, they live in a constantly changing environment.

Question 52

Distribution of mangroves is controlled by

Answer 52

1. temperatures (most mangroves grows only 30 degrees latitude of the equator), 2. salinity (the water around mangroves has to be of a certain salt content if not the mangrove will suffer so if fresh water is added to salty water this would be harmful, 3. exposure to air (air is too rich in oxygen will harm to mangrove if the mangrove is exposed for too long)

Question 53

Value of mangroves

Answer 53

• they contain natural resources like charcoal, firewood, fish, medicines
• foraging and living place fo wildlife (habitat)
• reducing water pollution (root system of mangroves species absorb inorganic substances and reduce water pollution
• protecting the coastline (because the roots of a mangroves act can stabilise the coastlines of the river shores and mouths

Question 54

Threats to mangroves

Answer 54

• Clearing (mangrove forests have often been seen as unproductive and smelly, and so cleared to make room for agricultural land, human settlements and infrastructure and industrial areas
• Overharvesting – While harvesting has taken place for centuries, harvesting of mangroves become unsustainable and threaten their future.
• River Changes – Dams and irrigation reduce the amount of water reaching mangrove forests, changing the salinity of water in the forest.
• Overfishing – The global overfishing crisis facing the world’s oceans has effects far beyond the directly overfished population. The ecological balance of food chains and mangrove fish communities can also be affected.
• Destruction of Coral Reefs – Coral reefs provide the first barrier against currents and strong waves. When they are destroyed, the stronger-than-normal waves and currents reaching the coast can undermine the fine sediment in which the mangroves grow. This can prevent seedlings from taking root and wash away nutrients essential.
• Pollution – Fertilizers, pesticides, and other toxic man-made chemicals carried by river systems from sources upstream can kill animals living in mangrove forests.
• Climate Change – Mangrove forests require stable sea levels for long-term survival.

Question 55

Mangrove case study (Bangladesh, Sunderbans)

Answer 55

The Sundarban forest lies in the vast delta on the Bay of Bengal
formed by the super confluence of the Ganges, Padma, Brahmaputra and Meghna rivers across southern Bangladesh. The seasonally flooded Sundarbans freshwater swamp forests lie inland from the mangrove forests on the coastal fringe. The forest covers 10,000 square kilometres (3,900 sq mi) of which about 6,000 square kilometres (2,300 sq mi) are in Bangladesh. It became inscribed as a UNESCO world heritage site in 1997. The Indian part of Sundarbans is estimated to be about 4,110 square kilometres (1,590 sq mi), of which about 1,700 square kilometres (660 sq mi) is occupied by waterbodies in the forms of river, canals and creeks of width varying from a few meters to several kilometres.
The Sundarbans is intersected by a complex network of tidal waterways, mudflats and small islands of salt-tolerant mangrove forests. The interconnected network of waterways makes almost every corner of the forest accessible by boat. The area is known for the eponymous Royal Bengal tiger (Panthera tigris tigris), as well as numerous fauna including species of birds, spotted deer, crocodiles and snakes. The fertile soils of the delta have been subject to intensive human use for centuries, and the Eco-region has been mostly converted to intensive agriculture, with few enclaves of forest remaining. The remaining forests, taken together with the Sundarbans mangroves, are important habitat for the endangered tiger. Additionally, the Sundarbans serves a crucial function as a protective barrier for the millions of inhabitants in and around Khulna and Mongla against the floods that result from the cyclones. The Sundarbans has also been enlisted among the finalists in the New 7 Wonders of Nature.

Question 56

Sand dunes

Answer 56

They are large heaps of sand that form on the dry back shore of a sand beach

Question 57

For a sand dune to form, it needs…

Answer 57

• a large flat beach
• a large supply of sand
• a large tidal range, so there is time for the sand to dry
• an onshore wind to move sand to the back of the beach
• an obstacle such as drift wood for the due to form against

Question 58

Formation of sand dunes

Answer 58

1. embryo dunes form around deposited obstacles such as pieces of wood or rocks
2. these develop and become stabilised by vegetation to form fore dunes and tall yellow dunes. Marram grass has adapted to the windy, exposed conditions and has long roots to find water. These roots help bind the sand together and stabilise the dunes
3. in time, rotting vegetation adds organic matter to the sand making it more fertile. A much greater range of plants colonise these ‘back’ dunes
4. wind can form depressions in the sand called dune slack, in which ponds may form

Question 59

benefits of living near the coast (Galveston)

Answer 59

• tourism (in Galvestion 6.4 million tourist per year, particular attractions are holidays such as a cruise where visitors can sail to the Caribbean and Mexico
• fishing
• resources (such as oil, Gulf of Mexico one of the major sources of oil in the US and so many rigs and refineries are located in the area
• Home to unique ecosystems (Galveston bay home to the largest and most biologically productive ecosystem in Texas- home to migratory birds and turtles etc other coastal parts of the world are home to coral reefs and mangroves (can be used for tourism)
• transportation hubs
• unique geological landforms

Question 60

threats of living near the coast

Answer 60

• coastal erosion
• coastal flooding
• climate change
  need for expensive management
  -tropical storms and hurricanes
• coastal erosion

Question 61

Hurricane case study (Hurricane Harvey, 2017)

Answer 61

• When this warm and wet air rises, it condenses to form towering clouds, heavy rainfall. It also creates a low pressure zone near the surface of the water.
• Rising warm air causes the pressure to decrease at higher altitudes. Warm air is under a higher pressure than cold air, so moves towards the ‘space’ occupied by the colder, lower pressure, air. So the low pressure ‘sucks in’ air from the warm surroundings, which then also rises. A continuous upflow of warm and wet air continues to create clouds and rain.
• Air that surrounds the low pressure zone at the centre flows in a spiral at very high speeds - anti-clockwise in the northern hemisphere - at speeds of around 120 km/h (75 mph).
• Air is ejected at the top of the storm – which can be 15km high – and falls to the outside of the storm, out and over the top, away from the eye of the storm. As this happens, it reduces the mass of air over the ‘eye of the storm’ - causing the wind speed to increase further. Some
36
ejected air also cools and dries, and sinks through the eye of the storm, adding to the low
pressure at the centre.
• The faster the winds blow, the lower the air pressure in the centre, and so the cycle continues.
The hurricane grows stronger and stronger.
• Seen from above, hurricanes are huge circular bodies of thick cloud around 450 km (300 miles)
wide. The cloud brings heavy rain, thunder and lightning.
• In the centre is the eye of the hurricane, about 45 km across (30 miles) across. Often there will
be no clouds in the eye. Seen from below it will seem calmer, with a circle of blue sky above.
The eye is formed because this is the only part of the hurricane where cold air is descending.
• In the northern hemisphere, the prevailing easterly tropical winds tend to steer hurricanes
toward land - although their course is unpredictable. As hurricanes move inshore, their power gradually reduces because their energy comes from sucking up moist sea air.

Question 62

Effects of Hurricane Harvey

Answer 62

• The most expensive in U.S. history at over $190 billion, surpassing Hurricane Katrina.
• Harvey has also swamped one-third of oil refining capacity of the US. It could be weeks
before refineries return to full operation. This has caused huge concerns about fuel
supplies. Prices for refined products like gasoline have jumped.
• Death toll more than 60
• 1 million cars lost
• 50,000 homes destroyed
• 150,000 homes damaged
• Schools and other services closed for approx. 2 weeks