coasts case studies Flashcards
1
Q
Holderness Coast (coastal recession)
A
- Average annual erosion rate of 2m
- Fastest eroding coastline in Europe
- Most of the coast consists of boulder clay - unconsolidated material with little resistance to erosion.
- Exposed to winds and waves from the N.E with about a 500-800 km fetch across the North Sea.
- Distance isn’t that far compared to other oceans but exacerbated by deep sea floor so waves aren’t weakened, Atlantic currents with a fetch of 5000km add to North Sea waves causing powerful destructive waves
2
Q
Guinea (coastal recession)
A
- Shoreline has retreated by 700 m inland over the last 40 years
- Destruction of mangrove forests act as natural barriers
2
Q
Nile Delta (coastal recession)
A
- The construction of the Aswan High Dam on the River Nile in 1964 reduced sediment volume from 130 million tonnes to about 15 million tonnes per year.
- Erosion rates jumped from 20-25 m per year to over 200 metres per year as the delta was starved of sediment.
- Sediment trapped behind dam
- Agricultural land is lost
3
Q
California (coastal recession)
A
- Has a fluctuating eroding coastline
- Tectonically active fault lines
- Majority of coastlines relatively low relief
- Strong El Nino events result in higher winter rainfall, strong offshore winds, increased wave height and higher sea levels.
4
Q
Bangladesh (local factors increase flood risk)
A
- Most of the country is very low lying, most places are only 1-3 metres above sea level. In addition, there are many bays and rivers running far inland. These can allow storm surges to travel further inland, hence increasing the area affected.
- The coastline consists of mainly unconsolidated sediment which is easily eroded, therefore there are few cliffs and natural coastal defences against cyclones
- Deforestation of mangroves means there is little to dissipate wave energy when it initially hits land.
- Bay of Bengal is triangular/ funnelled which concentrates waves and increases their destructive power for the countries surrounding.
- Bangladesh is one of the world’s most densely populated country (population = 169m in 2015)
- Almost every year, huge areas of the country flood due to Himalayan snow melt adding to monsoon rains and high tides in the Bay of Bengal.
5
Q
Jakarta, Indonesia (local factors increase flood risk)
A
- The city is quickly sinking due to its rapid urbanisation.
- It is expected that by 2050 most of the city will be underwater.
- This has forced Indonesia to change their capital city to elsewhere since Jakarta cannot handle the weight of the megacity with over 10 million people.
- The sinking of Jakarta has the possibility of creating mass displacement of people creating climate refugees.
5
Q
Sri Lanka (local factors increase flood risk)
A
- In Indian Ocean Tsunami, a village with mangrove protection had a death toll of 2 whereas a settlement that removed this vegetation had up to 6000 deaths
- Partly as a result of this, Sri Lanka has become the first nation to protect all of its mangrove forests and replant mangroves that have been felled.
6
Q
North Sea storm surge
A
- In December 2013, there was a large depression which moved South East from the North Sea.
- Wind speeds over 140 mph were recorded in parts of Scotland
- Gale force northerly winds led to a storm surge reaching 5.8m in Lincolnshire
- There was significant flooding in North Eastern England and Eastern Scotland
- Scotland’s rail network had to be closed and 100,000 homes lost their electricity
- 15 fatalities across the UK, Holland, Germany and Belgium
- North Sea becomes shallower in Southern England, which leads to higher wave heights in the South
- The North Sea is open to the Atlantic and the coastline is funnel shaped, therefore low lying coastal settlements (such as Norfolk) are at a greater risk of flooding.
7
Q
Holderness coast (consequences for communities)
A
- On average, it loses 2 metres of coastline every year.
- Since Roman times, it has retreated 4km and at least 29 villages have been lost to the sea.
- Fastest eroding coastline in Europe.
- Predicted that 200 homes and several roads will fall into the sea between Flamborough head and Spurn Point by 2100.
- Although there are places for people to evacuate to, many will not be able to afford it due to the loss of businesses as a result of coastal erosion.
- Although the impacts are small in comparison to other areas, the UK is a small country where small amounts of coastal recession can have a big impact.
- Not as significant compared to Tuvalu where citizens have nowhere to evacuate to as the people on the Holderness coast can evacuate elsewhere
7
Q
Bangladesh (storm surges)
A
- Cyclone Sidr (2007)
- Winds up to 223 km/hr
- Category 4 storm with a huge storm surge reaching up to 6 metres in height
- Total cost of cyclone Sidr to Bangladesh was US$1.7 billion.
- 1,518,942 damaged houses, meaning many were left homeless after the event.
- Drinking water contaminated by debris and many freshwater sources were inundated with salt water.
- 6 million climate refugees.
8
Q
Typhoon Haiyan storm surge
A
- 315 kph winds (strongest tropical cyclone ever based on wind speeds)
- Category 5 storm
- Over 6000 people were killed
- San Pablo bay is funnel-shaped.
- 5-6 metre storm surge
- Was the strongest tropical typhoon on record at the time
- In total, 1.14 million structures were totally or partially damaged.
- Four million citizens were displaced. Economic losses were estimated at US$13 billion.
9
Q
Bangladesh (consequences for communities)
A
- World’s most densely populated country with an estimated population of 169 million in 2015.
- 685,528 hectares of damaged crops as a result of cyclone Sidr meaning Bangladesh may start to rely on imports for food which could damage the economy.
- Drinking water contaminated by debris and many freshwater sources were inundated with salt water.
- Poverty from the loss of agricultural land has caused girls to be forced to marry as young as the age of 9 for money.
- Impacts in Bangladesh are significant because of the amount of them. Bangladesh has many variables making it very vulnerable to flooding and coastal erosion that also amplify the impacts
- Bangladesh is also the most densely populated country making any impacts heightened as they will affect way more people compared to less densely populated countries.
10
Q
Tuvalu (consequences for communities)
A
- 11,000 people, fourth smallest nation in the world.
- Sea levels rising by 4mm every year
- Scientists say it could become inhabitable in the next 50 to 100 years.
- Fish levels are decreasing due to poisoning where reef fish have ingested microalgaes from bleached coral.
- Can’t plant on a lot of the land due to the water table rising up causing salt water encroachment, stopping plants from growing so they have to import food.
- Also underwater ground supplies so Tuvalu is now completely dependent on rainwater
- Increasing cost of living due to imported food which is raising the cost of groceries.
- If the infected reef fish are consumed by humans it causes an immediate and sometimes severe illness.
- The whole island is flat so people have nowhere to go
- Relatively small population so not as significant of an impact compared to other countries.
- Significant because although it is a small population that is affected, it is the entire population of the country.
11
Q
Jakarta, Indonesia (consequences for communities)
A
- By 2050 the majority of the city will be underwater.
- Sinking by around 2 inches every year on average.
- Streets 1 metre undersea.
- Megacity so has a population of over 10 million (10.5)
- Due to sinking many businesses have been abandoned.
- Indonesia has been forced to relocate its capital city to elsewhere in the country due to the severe flooding
- Jakarta sinking is making the city more at risk to coastal flooding
- In 2013 there were thousands of lost homes forcing people to relocate.
- The water that has risen has caused an outbreak of diseases like Typhoid causing death.
- Flooding is also causing the contamination of drinking water as it reaches wells posing a threat to life.
11
Q
Fairbourne coastal management
A
- Be decommissioned by 2054, no active intervention, hold the line and managed retreat until then
