THE HOLDERNESS COASTLINE.

COASTAL EROSION AND COASTAL MANAGEMENT CASE STUDY

BY SIOBHAN & KAYA

The Holderness Coast is a 61 km long stretch of low glacial drift cliffs ranging from 3m to 35m in height, which stretches from Flamborough Head in the north to Spurn Head in the south.

The coastline sweeps in a smooth S-shape which is only broken where sea defences have reduced erosion at the protected point and increased it southwards.

The Holderness coastline suffers the highest rate of coastal erosion in Europe and mainly consists of soft glacial drift cliffs which have been cut back up to 200m in the last century.

GEOLOGY: About a million years ago the Yorkshire coastline was a line of chalk cliffs almost 32 km west of where it now is. During the Ice Age (18,000 years ago) deposits of glacial till (soft boulder clay) were built up against these cliffs to form the new coastline. The boulder clay consists of about 72% mud, 27% sand and 1% boulders and large pebbles.

CAUSES OF EROSION:

The whole coast in gradually

trying to reshape its self into a

shape that lies at a right angle

to the predominant wave direction

-The coast faces the dominant wind and wave direction and the long the long fetch from the Arctic Ocean create powerful waves. Waves during normally occurring storm events can reach up to 4 m and are of great importance as erosion mainly occurs during storms and tidal surges.

-The chalk headland of Flamborough prevents transport of materials from the north, therefore little beach material is transported southward to the beaches, as a result of this, beaches are narrow and unable to stop wave erosion

- The rock type is easily eroded through corrasion and is prone to slumping when wet.

SPURN HEAD:

Clear evidence of the long shore drift is found in the development of the spit at the southern end of the Holderness coast. The spit is built up of sand and shingle and is extending in the Humber estuary at a rate of 10cm per year

FLAMBOROUGH HEAD:Flamborough head is characterised by high steep chalk

cliffs containing numerous caves, arches, stacks and slumps

SOCIAL IMPACTS OF EROSION:- Around 30 villages have been lost since Roman times, meaning homes and businesses have been lost.

- Many of the settlements rely heavily on tourism, as facilities close down the settlements are unable to maintain a good population.

- Properties under threat of erosion lose their value leaving owners with negative equity.

ECONOMIC IMPACTS OF EROSION:- Numbers of visitors to areas along of this coastline has dropped.

- Some settlements unable to maintain a viable population to warrant shops.

- Money has to be spent on coastal management and protection

- The Gas Terminal in Easington, which supplies 25% of Britain's gas, is at risk.

- 80000m2 of farmland is lost each year, this has a huge effect on farmers livelihoods

ENVIRONMENTAL IMPACTS OF EROSION:- Wildlife behind Spurn Point is losing diversity as

the environment cannot support many species due to the lack of sediment

- Some SSSIs (Sites Of Special Scientific Interest) are threatened by erosion

 

Today the coastline is approximately 4km inland from where it was during the Roman times and there are many lost villages that have been lost to the sea since then.

There is a debate about whether humans should intervene and attempt to defend the coastline as its geology, the north sea waves and the shape of the coast line makes erosion almost inevitable.

SO WHAT IS BEING DONE TO COMBAT COSTAL EROSION ?

-Since the late 19th century coastal protection has been used to enforce a ‘hold the line’policy at the coastal towns of the Holderness coast.

-In between the coastal towns large areas are eroding while no measures are taken.

-Nowadays the local and regional authorities are trying to set up integrated coastal zone management programmes for the whole Holderness coastline and the Humber estuary.

BRIDLINGTON:

Bridlington is predominantly an urban development offering tourism related

establishments and recreational water sports. It is an operational fishing community and nationally important for sea birds.

To prevent erosion here, there are coastal defences such as, a 4.7km long sea wall to protect the sea front and a wide beach, which is encouraged by wooden groynes.

SKIP SEA

Skipsea is located on approximately 10miles(16km) South of

Bridlington.

Coastal Management here is limited to a small concrete wall

to protect the residential area.

HORNSEA:Hornsea has 2.9km stretch of shoreline fronting the town. This high-density urban development is dependent on tourism and recreation as well as a small fishing industry. Due to the towns infrastructure, it was one of the places chosen for protection against erosion.

There are original, 100 year old defences which have held up well, however more recently, new defences were installed. Presently there is a wave return wall, they also have groynes and riprap. They also use beach nourishment to protect the coastline

Just south of Hornsea, gabions help protect the caravan park

MAPPLETON:

Mappleton, a small village that consists of approximately 50 properties, it has the B1242 road running through it that links the towns along the Holderness coastline.

This road would have been lost to erosion had no protection been put in place but it was decided that the total cost for coastal protection in the small village was less that the cost of building a new road.

As a result of this, rock armour was placed along the base of the cliff, two rock groynes were built and a 500m long revetment was built.

WITHERNSEA:

Withernsea is a thriving holiday resort comprising 2.3km of developed frontage. It is recognized as a popular tourist and recreational site. Caravan parks, a golf course, residential and commercial developments add to the local economy. Surrounding land is put over to agriculture or open land.

There are groynes on Withernsea beach to ensure wide and relatively steep beaches. The beach material is made up of sand and shingle. The majority of the Withernsea frontage is provided coastal protection in the form of concrete seawalls and riprap.

PROBLEMS WITH HARD ENGINEERING MANAGEMENT STRATAGIES HERE:

- They can be costly

- Have to be maintained (e.g. sea walls + create strong backwash which erodes under the defence and other types of defences can be damaged in storms)

- Encourage erosion further down the coast as they starve down drift beaches of sand- thinner beaches don’t protect the coast as effectively. E.g. Coastal protection at Mappleton has caused increased erosion of the cliffs south of Mappleton.

- Sea walls make it more difficult to access the beach so may discourage tourism

- In areas where nothing has been done to protect the coast, ad hoc, private sea defences have been put in place- private defences are not of the same engineering standard so can pose health and safety issues, they can undermine defences elsewhere.

-The protection of local areas is leading to the formation of bays between areas, however as they bays develop wave pressure on the headlands will increase, and the cost and difficulty of maintaining these may become impossible to sustain. This pressure will be due partly to theconcentration of wave energy on any projecting headland but also because the sea bed willcontinue to erode offshore and the resulting deeper water will allow more wave attack at theshore.