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Barton-on-Sea: Cliff Collapse 1

Location:

  • Hampshire
  • 7 miles east of Bournmouth
  • In Christchurch Bay facing out to Atlantic Ocean

Rate of erosion:

  • 1-2 metres per year

Physical causes of Erosion

  • Fetch/destructive waves- 3000miles across Atlantic-High wave energy to coastline
  • Rock types- weak sands/clays- easily eroded- hydraulic action/abrasion
  • Mass movemment provides material at the foot of the cliff for erosion
  • Arrangement of rocks-sands/gravel on top of clay- water 'ponds up'- results in rotational slip/slump
  • Local streams- local name 'bunny'- e.g. Chweton Bunny and Beckton Bunny adds further water into permeable sands, resluting in cliffs becoming saturated- slumping
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Barton-on-Sea: Cliff Collapse 2

People effect on situation:

  • Groynes at Hengistbury Head and Bournemouth- in particular the 'Long Groyne" which was bulit in 1938- 7km west of Barton- virtually stopped natural eastward drift of beach material from Poole Bay into Christchurch Bay
  • This starved beach from snad and shingle. 
  • Causes the destructive waves to have more of an effect on the cliff faces becasues there is less friction on beach to slow waves down
  • Buliding on top of cliffs- adds weight so more vunerable to collapse

Impacts on Environment

  • Negative- land lost is range of 1-2m per year and beach only 20m at widest point and Habitat loss
  • Positive- movement of eroded material from east by longshore drift, supplies Hurst castle Spit which helps protect Key Haven Salt Marsh- an SSSI.                                                    
  • Positive- protects  settlements along Western Solent from flooding- such as Lymington.
  • Positive- Exposure of Fossils from eroded cliffs 
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Barton-on-Sea: Cliff Collapse 3

Impacts on People's lives

  • Cliffs not safe- Reduce tourism numbers. e.g. Large landslide in March 2013 at Hoskins Gap, West Barton
  • Beach not very wide
  • unattractive cliffs
  • By tourist numbers reducing, negative impact on buisness and therefore local economy. e.g.  Becah cafe 'Beachcomber' could see a reduction in income if tourist numbers fall
  • Some buisnesses froced to close/ relocate- employment decrease. 
  • Barton on sea golf course forced to expand landwards to replace areas lost to the sea
  • House prices fall and rise in home insurance- anxiety for resident- some may have to move
  • Money has to spent on coastal defences which could be spent elsewhere
  • Cliff retreat averaging 1-2m per year, land and houses are lost- Barton court development is just 20m from edge of cliff. These houses will be lost in the next 20 years.
  • 15 properties in next 15 years to be lost
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Barton-on-Sea: Cliff Collapse 4

Responses:

  • 1960's New Forest Council built a system of cliff face drainage/ steel piling, now ineffective due to mass movement
  • 1990's rock armour and rock groynes using Portland stone from Dorset. 
  • 1991- 1,800m rock revetment was built costing £4.5 million
  • Current policy depends on area of Barton- just 3 coastal zones at Barton;
  • Central Barton- 'Hold the existive defence line' justified by a positive cost- benefit analysis- value of properties- but needing majort grant from Defra. Revolutionary inland drainage must have special soakaways to reduce groundwater build up.
  • West to Naish Farm- Managed retreat is preffered option. No major sea defences because of low value cliff top use (static caravan farm at Naish Farm, 90 beach huts and a golf course) also a need for fresh fossil exposure and some sediment to feed Barton and Hurst Castle Spit down drift. Also beach nourishment and cliff regarding (soft engineering)
  • East of Barton to Becton Bunny- still part of the SSSI- only looses to the golf course- policy is 'do nothing' 
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