Holderness Coast - Landforms Flashcards
What sediment cell is it
Sub-cell of sediment cell 2
Where is there erosion
Of weak and unconsolidated till cliffs
Where does the sediment go
Some is deposited to form spurn head while a significant amount goes towards the Wash and East Anglia
What are the three distinct coastal units
Flamborough Head in the north
Bridlington Bay to Spurn Head
Spurn Head
What is Flamborough Head
A chalk promontory that exhibits many typical landforms associated with coastal erosion
What is Bridlington Bay to Spurn Head
An extensive zone of erosion and sediment transfer characterised by a very rapid rate of cliff retreat
What is Spurn Head
A classic spit formed at the estuary of the river Humber
What is the main input
Erosion of the weak and unconsolidated till cliffs.
Where is some of the finer cliff sediment deposited
Offshore to form an output from the system while the coarser material is moved southwards as a transfer involving longshore drift
What is the Holderness Coastal system
NE Wind (long fetch) Most of the eroded material is carried out to sea. Rest of the material is carried south by longshore drift.
What is an important factor in affecting the processes and landforms
Geology
Wind
Engineering
What is the Geology of the Holderness Coast
Chalk, a relatively resistant rock, forms a broad arc in the region. The eastern edge of the hall outcrop formed the preglacial coastline.
What is the great sweep of the coastal zone a result of
Sediment carries and dumped by ice sheets originating from Scandinavia
What formed the present-day cliffs
As sea levels rose at the end of the last glacial period, the North Sea took shape and started to erode the thick till deposits to help form the cliffs
What drives powerful waves towards the coast
The wind blowing from the north-east (the direction of greatest fetch)
What can create storm surges several metres high
Occassionally, areas of extremely low pressure move down the North Sea, funnelling water and creating storm surges. These low-frequency, high-magnitude events can lead to significant erosion and flooding
Example of a storm surge
In 1953 more than 300 people lost their lives along the east coast of England during one
Why does longshore drift operate from north to south
As a result of the north east waves
What was the response to the rapid rate of erosion and the threat to settlement and infrastructure
Parts of the coastline have been protected with hard-engineering structure such as sea walls, rock armour and groynes
Where have the engineering strategies helped
Hornsea and Mappleton but they have deprived areas further down of sediment, thereby increasing coastal erosion
What does the lack of a beach render cliffs more vulnerable to
Undercutting and collapse
Where do the hard engineering strategies disadvantage
Skipsea, where rates of erosion are 2 metres a year
Where is Flamborough Head
Hurting into the North Sea from the east coast of England
What is the geology of Flamborough head
Chalk, a resistant, sedimentary rock
What are the characteristics of the chalk that forms Flamborough head
White.
Layers of chalk are horizontal with vertical cracks (joints).
In some places while sections of chalk have been displaced along faults.
Joints and faults are weaknesses in the chalk.
How are joints and faults weaknesses in chalk
They are readily exploited by the processes of weathering and erosion to form narrow clefts in the coastline
What formed Selwick Bay (on Flamborough head)
A faultline was exploited
What leads to frequent rock fall on Flamborough Head
Sea is actively eroding and undercutting the base of the cliffs
What is the high tide line shown by
Dark staining at the foot of the cliffs
What landforms are on Flamborough Head
Selwicks Bay
Wave-cut platforms and stacks
What happens when waves approach Flamborough head
They are bent or refracted by the shape of the coast
What results in a deposited beach
Refracted waves that curve and have low energy in the Bay
Why are headlands often characterised by steep cliffs and other feature of coastal erosion
The more exposed headlands bear the full force of the incoming waves
What factors account for the rapid rate of erosion of the Holderness Coast
Long fetch and powerful waves from the North-East.
Weak and unconsolidated till cliffs.
Extensive mass movement, especially slumping, caused by undercutting and saturation of clay within the cliffs.
Narrow beach making the cliffs vulnerable to wave attack and undercutting.
Lack of coastal defences.
What had the stretch of coast from Bridlington Bay to Spurn head retreated by since Roman times
Up to 5km
What does the erosion of the stretch of coast from Bridlington Bay to Spurn head account for the loss of
Several settlements and ports of erosion
What are the rates of erosion in the Holderness Coast
Excess of 1m per year (and up to 10m per year in places). The most rapid rates of erosion in Europe
What does erosion generate
A vast amaount of sediment that feeds the sediment cell
What is a negative feedback system in the the stretch of coast from Bridlington Bay to Spurn head
Erosion. A great deal of sediment is transferred by longshore drift to the south, building up beaches and reducing erosion
What does Spurn Head protect
The towns and land bordering the River Humber from the effects of storm waves and flooding
What is the Wash
Fuether south than Bridlington Bay it is an important sediment sink
What does the Wash protect
Towns such as Kings Lynn
Where does some sediment from the Holderness end up
On the coast of the Netherlands, this helps protect it from flooding
What is the massive planning conundrum because of Bridlington Bay to Spurn Head
Should erosion be halted to protect a few houses and agricultural land or should it be allowed to continue because it is a vital source of sediment (the Netherlands)
What does Spurn Head represent
A temporary sediment store or sink
How is spurn head created
Sediment transferred south by longshore drift.
Once it reaches the River Humber estuary, the deposited sediment grows out to form a narrow finger of new land. It’s curved tip results form the direct wave action.
Characteristics of spurn head
Extremely narrow for much of its length.
First formed 8000 years ago at the end of the last glacial period.
It goes through a number of cycles of growth and decline, lasting on average about 250 years.
Why is Spurn Head classified as a temporary store
It has frequently been breached and destroyed by major storms
What happened to Spurn Head in 1849
Following a massive beach, groynes and recentmenrs were placed to stabilise the spit
What happened to Spurn Head after 1849
Military forces established so royal engineers took over the task of maintaining coastal defences
What happened to Spurn Head in 1950
The military left
What happened to Spurn Head in 1960
Spit was bought by the Yorkshire Naturalists Trust. They couldn’t afford all the maintenance so some were left to fall into disrepair
What happened to Spurn Head in 2013
Largest tidal surge hit it in 60 years. Defences couldn’t cope - buildings and access to roads were swept away
