The Holderness Coastline

Question 1

Describe 4 coastal processes at the Holderness

Answer 1

EROSION- soft boulder cal (till) is eroded by wave action e.g. In Great Cowden the rate of erosion has reached over 10m a year in the last 10 years

DEPOSITION- ocean current meets outflow of Humber river which causes turbulence and deposition of sediment

TRANSPORTATION- prevailing winds from the North East transport material Southwards and create an ocean current which transports sediment via LSD. High rates of erosion mean that sedimenting constantly being transported.

MASS MOVEMENT- boulder clay is prone to slumping when it becomes saturated with water which makes it heavier and more unstable. This combined with high rates of erosion at the base of cliffs increases instability so the soil slumps as the cliff is worn away.

Question 2

Landforms of each process?

Answer 2

HEADLANDS AND WCPs- In the North, the discordant coastlines geology is made up of bands of chalk and coulder clay perpendicular to the sea. Chalk is harder so is eroded less easily, forming headlands e.g. flamborough head (contains caves, arched and stacks) and wave cut platforms e.g. at New Sewerby.

BEACHES- the area south of flamborough head is sheltered from wind and waves so forms a wide sand and pebble beach near Bridlington

SPITS- erosion and LSD have created a spit with a recurved end off the mouth of the Humber estuary called spurn point
Estuarine mudflats and saltmarshes have formed behind

SAND DUNES- sediment is deposited by aeolian deposition around spurn head, forming sand dunes which are colonised by vegetation as a part of succession

SLUMPING CLIFFS- rotational slip of boulder clay has caused a distinct stepped cliff shape in Atwick Sands

Question 3

Why is management needed?

Answer 3

• Holderness is 61km long from flamborough head to spurn point
• the coastline has retreated 4km over the past 2000 years, destroying 30 villages in the process
• 80,000m2 of farmland is lost annually and the village of skipsea is at risk which threatens livelihoods
• loss of infrastructure such as the gas terminal at easington (25m from the edge)
• loss of SSSIs such as the lagoons near easington which provide bird habitats

Question 4

Hard engineering at the Holderness?

Answer 4

• 11.4km of the 61km coastline is currently protected by hard engineering
• Bridlington is protected by a 4.7km sea wall and timber groynes
• Hornsea is protected by a concrete sea wall, groynes and riprap
• Mappleton has 2 rock groynes and a 500m long revetment which were installed in 1991 and cost £2million in order to protect the village and the B1242 coastal road
• A caravan park in skipsea is protected by gabions that the landowner installed
• Withernsea is protected by groynes, sea wall and riprap which was installed after severe storms in 1992
• Easingtin gas station is protected by a revetment
• Eastern side of spurn head is protected by groynes and riprap which

Question 5

Sustainability of defences?

Answer 5

• groynes trap sediment which protects the local area but increases erosion down the coast as less sediment to absorb wave energy e.g. defences at Mappleton has put Cowden Farm at a risk of falling into the sea
• sediment produced from erosion is usually washed into the Humber estuary where it helps form tidal mudflats so a reduction in sediment inputs increases the risk of flooding of the estuary
• protection of coastal areas forms bays between them which puts additional pressure on headlands meaning the cost of maintaining sea defences may become too high so the current schemes are currently unsustainable

Question 6

Challenges of management?

Answer 6

• the SMP at the Holderness currently recommends holding the line at some settlements and doing nothing along less populated stretches (land owners are unhappy)
• managed realignment has been suggested meaning caravan parks to be moved inland, however this sims always possible as compensation often doesn’t cover the cost of moving
• in 1995, Holderness Borough council changed their method to do nothing at spurn head in order to save money and allow the spit to function naturally. However, this damages marshlands and risks the coastguard station.
• Easington gas terminal is protected by rock revetments which the SMP advises be maintained as long as the terminal is operating. The revetments only span 1km in front of the terminal which doesn’t protect the village of easington which is home to 700 people. Sea defences here endanger SSIs in the south