4.5 Challanges For The Coastline Flashcards
Why is the sea level rising?
- Global warming is causing sea level to rise by raising the global global temperature which causes:
- The sea to warm up meaning that all the particles of water have more energy and therefore, a single particle of water will occupy more volume than before causing sea level to rise.
- Ice sheets and glaciers melting, because of higher temperatures, on land and flowing into the sea via rivers causes sea level to rise as all the ice on land has a lot of volume.
How bad will sea level get and how will it affect different places around the world?
The sea level is estimated to rise another 15cm by 2030 and by 2100, it could have risen by 30cm to 1metre.
•The worst it could possibly get was if the whole Antarctic ice sheet melted as it would raise the sea level by 61.1 metres.
• If the sea was to rise by 2 metres, in the UK, over 480,000 properties would be at significant risks of being flooded and lost - this would mean about 1,454,000 people would be at risk.
• In Bangladesh, due to its very low and flat lands, if the sea was to rise by 1.5 metres, around 17,000,000 (15% of the population) would be affected in a space of land of 22,000km^2.
How will climate change affect erosion/deposition?
Climate change will cause:
• Sea level to rise meaning that normal waves will start to hit cliffs higher than usual meaning that the wave cut notch is raised and widened so erosion of cliffs is sped up.
- Also deposited landforms such as beaches or spits will get submerged or carried away. Also the waves reach further meaning they collect and deposit more sediment.
• A warmer atmosphere would cause it to have more energy and create bigger storms and therefore bigger waves more frequently. This means that waves have more power and erode more.
• More wind will also cause bigger waves created in the Pacific/Atlantic oceans.
How will climate change affect storm frequency, intensity, and storm surges?
- Storms will be created more often as the atmosphere would have been warmed up meaning it has more energy and creates more and bigger storms. Since they have more energy, they will have more power.
- Storm surges will be made more powerful as the winds will be made stronger by the bigger storms meaning that more water would get bunched up on (eg) the east side of the UK causing the water to rise higher than usual meaning more dangerous floods.
How will storms and storm surges affect people and the environment?
Storm surges will cause storms to become more powerful meaning they affect the people and environment more.
• The impact on people would be:
-possible deaths
-properties flooded/destroyed
-residents evacuated
-cost for the insurance and rebuilding all the buildings and things destroyed
• The impact on the environment would be:
-fresh water habitats flooded
-reserves flooded
-parks and grasslands/farmland flooded
-coastal landforms submerged/destroyed/moved by water
-ecosystems ruined
Explain how groynes and sea walls work.
• Groynes
- LSD brings sediment across the coastline picking it up and depositing it further down the coast. Groynes stop LSD from bringing the sediment too far down the coast so the beach where the groynes were placed remains where it is.
• Sea wall
- Waves come in to the coastline and bash ashore,slowly eroding it. Sea walls stop this as it causes the incoming wave’s power to be curved back away from the shore as it is formed as a curve so that the waves hit the bottom and get propelled back with their own force.
Explain how beach replenishment and slope stabalisation work.
• Beach replenishment
- Once a year, lots of sand is collected and, using bulldozers, is placed into a beach making it bigger and replacing all the sand that was washed away. It increases the beaches height making it harder for waves to break at the base of the cliff.
• Slope stabilisation
- Vegetation is planted by laying geo-meshes and planting grasses and shrubs as their roots stabilise the soil. Drainage pipes are also installed sometimes as it helps with reducing water pressure in mounds preventing saturation. This also stops mass-movement.
What are the advantages and disadvantages for each management type?
• Groynes
-Advantages: builds up beaches, absorbs wave energy, good for tourists as they make wide beaches.
-Disadvantages: erosion is worse downdrift, high maintenance costs, £100,000 per kilometre.
•Sea wall
-Advantages: stops the undercutting of cliffs.
-Disadvantages: makes beach assess difficult for tourists, ugly, very expensive-£5 million per kilometre.
•Beach nourishment
-Advantages: looks natural and attracts tourists, relatively cheap, absorbs wave energy and prevents wave breaking at the base of the cliff.
-Disadvantages: winter storms transport material away, replacement of sediment is needed often, £500,000 to £1,000,000 per kilometre.
•Slope stabilisation
-Advantages: Vegetation planted cause the roots to stabilise the soil, keeps cliff in place and is safer for beach users, reduces mass movement, drainage pipes reduce water pressure and prevent saturation.
-Disadvantages: difficult to install and beach may be closed for a long time, £1 million for full slope stabilisation.
What is the difference between hard and soft engineering? Which is best?
•Soft engineering
-Uses mainly natural materials like sand. They try to go along with nature – improve drainage and deposition. Simple engineering is needed but very little anyway.
•Hard engineering
-Uses large amounts of man-made materials such as concrete. They aim to stop natural processes – LSD, erosion. Typically involves large-scale construction.
There is no real best as they are both useful and their situations.
What is strategic realignment and which areas might be left to erode?
•Strategic retreat/realignment
- Gradually let low value areas of the shoreline to erode backwards to help protect high value areas – compensation is given.
- Areas that might be let to erode could be farmlands that do not earn lots of money and who don’t pay lots of taxes so the government or owners of that area let them get eroded away as they do not earn money from that, however places that have hotels and shops and cafes are protected as they give lots of tax money to the owners and they can earn from it.
Explain why ITCM schemes are a sustainable form of coastal management.
•ITCM
-They are sustainable because it means that you can decide whether to change your act upon something straightaway rather than having to do it later or when he has been badly affected. Also, you can see where you can leave something to get eroded and where to protect, at once so you don’t spend useless money on places with no use. Also, it takes into account the whole coast rather than placing defences in one single spot and leaving the rest to the mercy of erosion and LSD.
