Coasts specific content Flashcards
When talking about the relationship between climate and weathering what are key things to note with the three types of weathering (biological, chemical, mechanical)?
- Mechanical is associated with areas that gave low rainfall and low temperatures - COLD
- Both Biological and chemical weathering increases with higher temperatures and higher annual rainfall - HOT
Where is Holderness specifically located ?
- East Riding of Yorkshire
When talking about contemporary sea level change due to tectonic activity what key case study can we use?
- Turakirae Head near Wellington in New Zealand
What are some key local factors that increase flood risk on some low-lying estuarine coasts ( think about Bangladesh) ?
- Destruction of mangrove forests
- River straightening
- Groundwater abstraction causes subsidence and accelerates sinking
When talking about storm surges and low-pressure systems what is a key fact to use?
- Falling in air pressure of 1 millibar leads to a 1 cm rise in local sea level
For each of the main 3 storm surges in Bangladesh what was the year and the economic losses?
1970 = US$90million 1991 = US$1.7billion 2007 = US$1.7billion
What tells us that the process of corrosion has taken place at a given location?
- Visors
What is key to know with sea level change and the role of climate change?
- The Intergovernmental Panel on Climate Change (IPCC) estimated increases in sea level of 20-50cm by 2100
- The current rate of rise is 2mm per year
When are we most vulnerable to rotational slides?
- Where permeable strata (chalk) sits on top of impermeable strata (clay)
What plays a key role in slumping?
- Water
What are consequences for residents living near the Holderness coast?
-Eroding at 2m per year, so it will affect
- falling properties values, as the date of eventual loss approaces
- an inability to sell their property because the possibility of loss by erosion is to great
- the loss of their major asset, and the costs of getting a new home
What three areas are vulnerable to coastal flood risk?
- Coastal plains
- estuaries such as river Thames
- River deltas, such as the Nile and Mississippi
Why are areas of coastal flooding so densely populated?
- Coastlines are popular tourist attractions
- Deltas and estuaries are ideal locations for trade
- Deltas are especially fertile and ideal for farming
Inwhat part of the world hasthere been post-isostatic rebound fo 300m (this links into emergent coasts)?
- North America and Northern Europe
Why might over long periods of time a beach profile might change?
- Sediment supply from rivers are reduced for instance due to the contruction of a dam
- Inteference of sediment supply along the coast, often a result of coastal management in one place having effects on processes down the coast
- climate change - if globalwarming made UK climate stormier then destructive waves and ‘winter’ beaches would become more common
There is a number of factors that could affect sea level rise what are some of them?
- Thermal expansion of oceans due to climate change
- Melting of mountain glaciers (Alps)
- Melting of ice sheets (Greenland)
Give a key fact to know with environmental refugees?
- Around 22.5 million people have been displaced due to climate related events 2008-2016
What is the wave frequency for constructive and destructive waves?
Constructive = 6-8 waves per minute
Destructuce waves = 13-15 waves per minute
What is the pressure of when a wave hits into a cliff face(this links into the erosional process of hydraulic ation)?0
- 50kg/cm2
What are the three ways in which Mangroves can reduce coastal flooding?
- They reduce the height of the waves
- Their roots trap sediment, raising the height of the coast
- They reduce storm surge levels - by 0.5m for every 1 km of forest that sea water has to pass through
What are key things to remember when talking about consequences for communities?
- Loss from erosion is localised , costs are very specific to particular locations , Locations of high risk will have lower values. When talking about Land Values for England 2015 the £ per hectare of land for residential land for Great Yarmouth was £560,000 whereas for residential land for West Dorset it was £2.1million
- Rising sea levels is a factor, by 2050 it is estimated that 18 million people will be displaced in Bangladesh by rising sea levels
- It is estimated that an 20cm increase in sea level rise would cause US$ 1.4 million of economic damage in south-east Queensland alone
What is a stronger sedimentary rock and what is a weak sedimentary rock?
- Strong sedimentary rock - Limestone (coastal recession of 1-2cm per year)
- Weak sedimentary rock - Sandstone (coastal recession of 10-100cm per year)
What is a runnel and what does it link to?
Runnel = A small stream and is linked into winter type beaches and are located between two offshore ridges
Give named examples of ;
- Bayhead beach
- Barrier beach
- Spit
- Cuspate foreland
- Bayhead beach - Lulworth cove
- Barrier beach - Chessil beach
- Spit - Spurn head
- Cuspate foreland - Dungeness , Kent
What is the difference between a barrier beach and a bayhead beach ?
Bayhead beach is a beach between headlands and is low energy and mainly accretion because wave energy is refracted to headlands Waves also break 90* to the coastline
Barrier beach is a sand or shingle beach connecting two areas of land with shallow water lagoon behind
Where can we see vegetation playing a key role in stabilising depositional landforms ?
- Hurst Castle spit
The spit is stabilised by vegetation and salt marshes
What is a key fact to know with the monsoonal rainfall and how fast it occurs?
- In Asia about 70% of the average annual rainfall occurs during 100 days - July-September
