Transcript The factors that have led to the Holderness coast

The Holderness Coastline case study
We use this stretch of coastline to cover two case studies in
one.
1) A case study of an area of cliff collapse to include:
a) The reason for coastal erosion, including human causes
b) The effects of cliff collapse
2) A case study of coastal management to include the
benefits and costs of different strategies
This area of coastline
is found between
Flamborough head
and Bridlington on
the Yorkshire Coast,
North East England
5 Minute challenge: make a copy of the map on page in ….
Aim to include outline of coast and coastal settlements. Leave
room on your sketch map for more detail to be added later
An Overview of the Coastline
This area of coastline is found between
Flamborough head and Bridlington on the Yorkshire
Coast.
On average, over 2 metres of coastline is lost every year
and since roman times it has lost 4km of land, and 29
villages, with this number rising even now.
The Factors Affecting Erosion
On average, over 2 metres of coastline is lost
every year and since roman times it has lost
4km of land, and 29 villages, with this number
rising even now.
There are three main reasons for this erosion:
1. Geology (rock type)
2. The fetch
3. Longshore drift and beach material
Geology
The boulder clay has very
little resistance to erosion,
especially when wet, making
it very susceptible to erosion
The two main types of
rock on the Holderness
coast are Boulder clay
and chalk
Fetch
Holderness is exposed to winds and
waves from the north-east, which have a
small fetch of about 500-800km. This is
not far, but the coast at Holderness is
attacked by other factors, affecting the
ferocity of the waves.
Factors Affecting the Fetch
• Currents – or swell – which circulate around the UK from the Atlantic
and into the North sea. The Atlantic fetch is 5000km or more, and its
currents add energy to waves in the North sea. Therefore, there are
often powerful destructive waves along this coastline.
• Low pressure weather systems passing over the North sea are often
intense, and locally produce very strong winds and waves.
• Small, almost enclosed seas, like the North sea, often generate
huge waves during storms. Waves move within the sea but cannot
disperse their energy – rather like water slopping up against the side
of a washbasin
• The sea floor is deep along the Holderness coast. Therefore, the
waves reach the cliffs without first being weakened by friction with
shallow beaches.
Longshore Drift and Beach Material
The beaches at Holderness are its main problem.
Boulder clay erodes to produce mainly clay particles,
which are easily transported out to sea, rather than
accumulating close to the cliffs as beach sand. Although
there are beaches, there is never enough sand to stop
the waves reaching the cliff base at high tide.
What little sand is produced is taken southwards by
longshore drift, leaving the Holderness cliffs poorly
protected against wave attack. Eventually, a small
amount of beach material reaches a spit at Spurn Head,
where it accumulates.
Add the
Longshore
drift
details
onto your
sketch
map
Protect one
place erode
another (or
how people
can speed up
coastal
erosion
Some places along
the Holderness coast
are eroding even
quicker because
people have ….
Jess has just
bought a lovely
seaside house
built on the cliff
tops of
Holderness, East
Yorkshire.
Dear Jess
I am afraid you have bought your house in an area
with…(explain the rock type in detail)
In addition, the North sea is known to have a
long/short fetch which increases/decreases wave
energy. There are also some other factors that
affect the fetch ……
Also, people have recently made the situation worse
by protecting the beach with groynes just north of
your house. This means that …..
and therefore you will not be able to get insurance for
it.
In addition, you have the added factor (explain briefly
sea level rise and land sinking)
Sorry to bring the bad news!
I’m sorry I still don’t
understand, can you
just quickly sum up
your email in 5
VERY short points?
To locate areas of coastal
erosion (E-D)
To explain coastal erosion
(C-B)
To apply this knowledge
to a case study (A-A*)