Holderness case study


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Holderness case study

  2. 2. The Holderness Coast is a 61 km long stretch of low glacialdrift cliffs ranging from 3m to 35m in height, which stretchesfrom Flamborough Head in the north to Spurn Head in thesouth.The coastline sweeps in a smooth S-shape which is onlybroken where sea defences have reduced erosion at theprotected point and increased it southwards.The Holderness coastline suffers the highest rate of coastalerosion in Europe and mainly consists of soft glacial drift cliffswhich have been cut back up to 200m in the last century.
  3. 3. GEOLOGY: About a million years ago the Yorkshire coastline was a line of chalk cliffs almost 32km west of where it now is. During the Ice Age (18,000 years ago) deposits of glacial till (soft boulderclay) were built up against these cliffs to form the new coastline. The boulder clay consists of about72% mud, 27% sand and 1% boulders and large pebbles.CAUSES OF EROSION:The whole coast in graduallytrying to reshape its self into ashape that lies at a right angleto the predominant wave direction-The coast faces the dominant wind and wave direction and the long the long fetch from the Arctic Oceancreate powerful waves. Waves during normally occurring storm events can reach up to 4 m and are ofgreat importance as erosion mainly occurs during storms and tidal surges.-The chalk headland of Flamborough prevents transport of materials from the north, therefore little beachmaterial is transported southward to the beaches, as a result of this, beaches are narrow and unable tostop wave erosion- The rock type is easily eroded through corrasion and is prone to slumping when wet.
  4. 4. FLAMBOROUGHHEAD:Flamborough head is characterised by high steep chalkcliffs containing numerous caves, arches, stacks and slumpsSPURN 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
  5. 5. SOCIAL IMPACTS OF EROSION: ECONOMIC IMPACTS OF EROSION:- Around 30 villages have been lost since Roman - Numbers of visitors to areas along of this coastlinetimes, meaning homes and businesses have been has dropped.lost. - Some settlements unable to maintain a viable- Many of the settlements rely heavily on tourism, as population to warrant shops.facilities close down the settlements are unable tomaintain a good population. - Money has to be spent on coastal management and protection- Properties under threat of erosion lose their valueleaving owners with negative equity. - The Gas Terminal in Easington, which supplies 25% of Britains 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
  6. 6. Today the coastline is approximately 4km inland from where it was during theRoman times and there are many lost villages that have been lost to the sea sincethen.There is a debate about whether humans should intervene and attempt to defendthe coastline as its geology, the north sea waves and the shape of the coast linemakes erosion almost inevitable.
  7. 7. 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 zonemanagement programmes for the whole Holderness coastline and the Humber estuary.
  8. 8. BRIDLINGTON:Bridlington is predominantly an urban development offering tourism relatedestablishments and recreational water sports. It is an operational fishingcommunity and nationally important for sea birds.To prevent erosion here, there are coastal defences such as, a 4.7km longsea wall to protect the sea front and a wide beach, which is encouraged bywooden groynes.
  9. 9. SKIP SEASkipsea is located on approximately 10miles(16km) South ofBridlington.Coastal Management here is limited to a small concrete wallto protect the residential area.
  10. 10. HORNSEA:Hornsea has 2.9km stretch of shoreline fronting the town. This high-densityurban development is dependent on tourism and recreation as well as a smallfishing industry. Due to the towns infrastructure, it was one of the placeschosen for protection against erosion.There are original, 100 year old defences which have held up well, howevermore recently, new defences were installed. Presently there is a wave returnwall, they also have groynes and riprap. They also use beach nourishment toprotect the coastlineJust south of Hornsea, gabions help protect the caravan park
  11. 11. MAPPLETON:Mappleton, a small village that consists of approximately 50 properties, it has the B1242 road runningthrough 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 thatthe 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 anda 500m long revetment was built.
  12. 12. WITHERNSEA:Withernsea is a thriving holiday resort comprising 2.3km ofdeveloped frontage. It is recognized as a popular tourist andrecreational site. Caravan parks, a golf course, residential andcommercial developments add to the local economy. Surroundingland is put over to agriculture or open land. There are groynes on Withernsea beach to ensure wide andrelatively steep beaches. The beach material is made up of sand andshingle. The majority of the Withernsea frontage is provided coastalprotection in the form of concrete seawalls and riprap.
  13. 13. PROBLEMS WITH HARD ENGINEERINGMANAGEMENT STRATAGIES HERE:- They can be costly- Have to be maintained (e.g. sea walls + create strong backwash which erodes under the defenceand other types of defences can be damaged in storms)- Encourage erosion further down the coast as they starve down drift beaches of sand- thinnerbeaches don’t protect the coast as effectively. E.g. Coastal protection at Mappleton has causedincreased 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 theybays develop wave pressure on the headlands will increase, and the cost and difficulty ofmaintaining 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.