Coasts and Holderness Flashcards
What is the average rate of erosion at Holderness?
1.8 m per year
How long is the Holderness coastline?
61 km
4 Main reasons for rapid erosion?
- Easily eroded rock type - boulder clay
- Naturally narrow beaches
- Human impacts - groynes
- Powerful waves - prevailing wind from the north east - waves increase in power over a long distance - from the Arctic Ocean
4 Economic Impacts of coastal erosion?
- Property prices of houses near the sea have fallen
- B1242 at risk of falling into the sea ->less tourism
- Businesses are at risk from erosion - people will lose their jobs
- Farmland is lost
Why is Easington important?
- 25m from the cliff edge
- Accounts for 25% of Britain’s gas supply
Social impacts of coastal erosion
- Houses are lost forcing people to move
How much farmland is lost each year?
80km^2
How much of Holderness’ coast line has been protected by hard engineering?
11.4km
Intro to holderness
The Holderness Coast is located on the east coast of England. It extends 61km from Flamborough in the north to Spurn Point in the south. The Holderness Coastline is one of Europe’s fastest eroding at an average annual rate of around 2 metres per year.
Why should Holderness be protected
As caravan parks such as Long Beach leisure park in Hornsea attract tourism for the holderness boosting the local economy
Why should Holderness be protected?
As caravan parks such as Long Beach leisure park in Hornsea attract tourism for the holderness boosting the local economy
What defences are at Hornsea?
- 4.7km Sea wall at Bridlington
- Wooden groynes
- Rock armour
Explain what they would do for managed realignment at the holdernees coast
They would relocate caravan parks (sandy caravan parks) further inland and allowing the land they are on to erode.
this is beneficial as it would allow the coast to erode as normal without endangering buissinesses or messing up the dynamic equilibrium.
what is the problem with managed realignment
issues surrounding how much compensation buissinesses will get for relocating. Also relocation isnt always possible e,g there maybe no land for sale
What does the SMP suggest to do with Easington gas terminal
1) Its currently protected by rock revetments, and the SMP recomends that these defences are maintained for as long as the gas terminal is opertaing.
explain mass movement
Mass movement is the downhill movement of sediment that moves because of gravity.
Water makes the clay heavier and acts as a lubricant between particles, which makes it unstable.
The Boulder clay the slumps and rotates
explain deposition
when the wave loses energy and deposits the material it is carrying
where do spits form on the Holderness
Erosion and longshore drift have created a spit with a recurved end across the mouth of the Humber Estuary - this is called Spurn Head. It’s 5.5km long
are the defences sustainable
no.
The groynes trap sediment, increasing the width of the beaches. Mappleton scheme has caused increased erosion to the holderness cliffs south of mappleton
what is managed realignment
allowing certain parts of the areas of the coast to flood to save the other
formation of a spit
process of longshore drift
- some eroded material carried by the waves in cells called littoral cells
- material is carried along the shore in a zig zag manner and builds out into the sea
- the spit often curves inwards to the land as a result of the prevailing wind pushing the sediment to the shore
how is a bar formed
when a spit extends from headland to headland
formation of salt marsh
- salt marshes usually form behind spits. the spit provides shelter for material to build up behind it
- halophytes such as glass worts trap more sediment
- causing the salt marsh to grow and develop more
example of a negative feedback loop on the coasts
(taking a system back to equilibrium
- storms erodes a coastline
- when destructive waves from the storm lose energy they deposit their material as an offshore bar
- beach is protected from erosion and beach replenishes
- the offshore bar is eroded and the beach returns to normal conditions.
example of a positive feedback loop on the coasts
taking a system away from the equilibrium
- people walking on the beach destroys vegetation and causes erosion
- as the roots hold the sand dunes together without them the coast becomes more vulnerable to erosion
- Eventually the sand dunes will be completely eroded leaving more of the beach open to erosion taking the beach further away from its original state
describe the process of longshore drift
- prevailing winds alter the direction of the waves
- the swash approaches the beach at an angle transferring sediment along the beach
- backwash pulls sediment directly down from the beach
- swash moves the sediment along again
factors affecting wave energy
- strength of the wind
- duration of the wind
- fetch (distance the wind has travelled)
Characteristics of a destructive wave
wave length- short frequency- 11-16 per minuite swash - weak backwash -strong effect on coastline- steep coastline
characteristics of a constructive wave
wave length -long frequency- 6-9 per minuite swash- strong backwash- weak effect on coastline- shallow depositional coastline.
when does a spring tide occur
- when the sun and the moon are in alignment.
- The gravitational forces combine and pull the ocean towards them.
- the highest tides are created closest to the moon
- the lowest tides are created on the other side of the planet
- largest possible tidal range
when does a neap tide occur
- when the moon and the sun are perpendicular to each other
- gravitational forces act against each other
- pull is minimised at high tide and low tide is higher
- smallest possible tidal range
hydraulic action
- when waves crash into a cliff face causing air to fill cracks
- as the air expands the cracks widen
- rock breaks and erosion occurs
erosional processes
- hydraulic action
- abrasion- rocks grind along the sea bed causing them to become smooth
- attrition- rocks bash against each other
- corrosion- the sea water dissolves some rock such as chalk or limestone
how is coastal erosion caused by humans in the holderness
- destroyed vegetation on paths ect
- the implantation of Rock groins in Mappleton causes further erosion down the coast as they are starved of material which protect the coast from erosion (terminal groyne syndrome)
natural factors affecting coastal erosion
- rock type
2. wave energy
eustatic sea level change
the change in sea levels relative to the land
isostatic sea level change
Isostatic adjustments may result from tectonic uplift or changes caused by the enormous weight of ice depressing the crust during an Ice Age, only for the land subsequently to uplift (rebound) on melting.
Size of the economy in Bridlington
£34 million per year
Why may it be particularly important to protect bridlington currently
As the local economy will be in a recession from COVID-19
Evaluation of a sea wall
may be unsustainable in the long term as they have a life span of 30-50 years
Evaluation of the coastal erosion caused by the rock groins in Mappleton
the erosion affects areas such as Crowden farm and as the population is so little the effects may be minor
soft engineering in the holderness
- beach nourishments- sand is pumped onto shore to replace the loss from longshore drift
- Cliff stabilisation- lowing the angle of the cliff to allow waves to run up them
- managed retreat- to create marshland which stabilises sediment and slows waves down
evaluation of cliff stabilisation
erosion still occurs. It is a short term fix as once eroded the cliffs need to be re dug and stabilised
sea level rise at the holderness
30cm per year
cusp formation
- occurs at a junction between sand and shingle
- once the curve is created the swash is concentrated in the centre of the curve
]3. creating a strong backwash pulling more material down the beach
what are the inputs within a coastal setting
Energy is inputted in the form of waves, wind currents and tides.
what is the ICZM
refers to a large scale management of costs by multiple stakeholders
how many SMPS were implemented
22 in 1995
