Coasts case studies


Sea level rise case study - maldives (1)

  • Economic
  • Tourism 28% GDP  and 60% foreign earnings would be greatly affected
  • The vast majority of government revenue (approximately 90 percent) comes from import duties and tourism-related taxes
  • Most tourist accommodation is on the low lying coasts / beaches. These are increasingly vulnerable to storms and will have to be moved if sea levels rise
  • Round the capital, a 3m high wall at cost of $63 million (borrowed from Japan) which has to be repaid
  • The Indian ocean tsunami inflicted $375 million in overall damages, $100 million of which included damages to resorts. As a result, the Maldives' GDP contracted by 3.6 percent in 2005. However, most losses to the resorts were covered by insurance and quickly rebuilt, which helped spur the significant rebound in the Maldives' tourism industry.
  • The IPCC estimates that global warming will result in warmer winters in the northern regions of Europe and North America. This could lead to a decline in tourism in the Maldives as residents of Europe and North America no longer travel to the Maldives to escape the harsh winters
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maldives (2)

  • Social
  • SL rise would mean homes and hotels then jobs would disappear
  • If SL rose by 1m, 365 000 would have to be evacuated and resettle in countries like Sri Lanka and India
  • People rely on fishing for income. With rising sea levels the marine ecosystems will change and so will the number of fish available
  • In 1987, unusually high tides swept over the country and inundated the capital city, Male' causing considerable disruption to people’s lives and homes
  • The Asian tsunami of December 26, 2004 killed 82 people, displaced an additional 12,000 and caused extensive damage to the country's important tourism industry.
  • If extreme events occur more frequently people will become reluctant to visit the area
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maldives (3)

  • Political
  • The airport is about 1m above sea level. It could be threatened by higher tides. If it could not be used regularly most economic activity from tourism to import of food would be severely affected
  • If the number of jobs in tourism goes down people will have less money to spend and the government will have less money to support them. This may lead to civil unrest.
  • Much of the population will have to be resettled. The government will have to negotiate with neighbouring countries to take the people
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maldives (4)

  • Environmental
  • The Maldives are comprised of nearly 1,200 islands and atolls in the Indian Ocean. The combined land mass of all the islands is 115 square miles-- which less than 2m above sea level at its highest point.
  • More natural disasters such cyclones will affect the islands
  • IPCC estimates that average global sea levels will rise by between 0.09m and 0.37m  Along with rising sea levels, increased beach erosion, more powerful storms, higher storm surges, and threats to biodiversity are among the major threatens to the Maldives due to climate change over the coming decades.
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coastal erosion to cliff collapse- holderness

  •  The Holderness Coast is on the east coast of England
  •   It is bounded at the North by Flamborough Head – a headland made of resistant chalk – and at the southern end by Spurn Head – a spit extending out into the Humber Estuary
  • Rates of erosion
  •   Highest rates of erosion in Europe
  •   Average of 1-2m per year
  •    But as high as 20m per year in places and 6-9m can be lost in individual storms
  • Since Roman Times, 4 km has been lost - 29 villages have fallen into the sea and lost forever
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holderness (2)

  • Why this area is susceptible to undercutting by the sea and collapse:
  •  20-30m high cliffs made out of really weak rock –  boulder clay (deposited by glaciers after the last Ice Age)
  •  When it rains on the cliffs, the rain saturates the boulder clay and makes the cliff top unstable
  • When strong winds blow from the North East, they bring with them destructive waves (strong backwash) which erode the bottom of the cliffs
  •  Most of the eroded material is washed out to sea rather than building up the beach or moving along by LSD
  •  This then can lead to mass movement – the cliffs slump into the sea
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holderness (3)

How people can worsen the situation:

· In 1991  the Council spent nearly £2 million building 2 large rock groynes and rock armour  to protect the village of Mappleton so they didn’t have to spend money rebuilding an important road B1242. Blocks of granite imported from Norway for the defences

· This trapped beach sediment and was therefore successful in protecting the road and village of Mappleton

· However, down the coast, there was no longer any beach, so the cliffs were exposed, and rates of erosion dramatically increased to up to 10m/year

· Similarly at Withernsea they have groynes, rock armour and a sea wall to protect the town but this has speeded up erosion downdrift

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holderness (4)

  • Effects of cliff collapse on people’s live
  •  Along the whole of the coast, the value of house is going down and people are finding it difficult to insure them or sell them. This leads to uncertainty about their financial future so stress
  •  In late 1996 Sue Earle had to pay the £3 500 demolition costs of Cowden farm down drift from Mapleton when the erosion rates increased to 10m/yr so threatening her home.
  •  Tourism contributes hugely to the economy of the area and these incomes will be threatened
  • The local government has set out its Integrated Coastal Zone Management Plan ICZMP for this coastline
  • There are many caravan sites and holiday parks on the cliff tops that are threatened. The local government is pursuing a policy of ‘rollback’. Caravan park owners are encouraged to relocate further inland beyond  the 100 year safety distance. They will get preferential planning consent but will have to pay for the relocation themselves which will be very expensive. The caravan park owners feel they should be given financial assistance with this. In some cases, grants have been agreed to help with the costs of removing sea defences from in front of the sites and returning them to their natural state
  • More recently this policy of rollback is being extended to permanent dwellings. i.e. any dwelling likely to disappear in the next 50 years will get preferential planning permission to relocate beyond the 100 year zone.
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  • Effects on the environment
  • As the amount of beach is reduced so landslides, rotational slips and cliff collapse becomes more frequent.
  • This leads to changes in the environment and the ecology – some surface land will be lost but new minerals will be brought to the surface ( fossils at Walton-on the – Naze)
  • The caravan parks are now quite old with small pitches and little landscaping. If these are removed the land can be returned to its more natural state so improving the environment there.
  • The councils hope that the new sites under the roll back scheme will have larger pitches   and more emphasis on landscaping and creating a variety of ecosystems on the site.  As they will be further inland on lower ground it will be easier to landscape and screen them from view, again, improving the environment
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case study on management -minehead

Minehead, N.Somerset

         Premier tourist resort

         Home to a large Butlin’s resort

         1000s of visitors arrive each year

         Brings money and jobs to the local area 

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  • By the early 1990s it was clear present defences were inadequate. Storm damage was estimated to be £21mn if nothing was done.
  • The Environmental Agency developed a plan t defend the town and improve amenity value
  • Work started in 1997 and the sea defences opened in 2001, costing £12.3mn
  • A 0.6m high sea wall with a curved front to deflect the waves. It has a curved top to deter people from walking on it and its lowland side is faced with attractive local red sandstone
  • Rock armour at the base of the wall to dissipate some of the wave energy
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minehead (3)

  • Beach nourishment (sand) to build up the beach by 2m in height. This forces waves to break further out to sea and provides an excellent sandy beach to tourists
  • Four rock groynes to help retain the beach and stop longshore drift moving sand to the east.
  • A wide walkway with seating areas alongside the sea wall. This is popular with tourists and locals
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case study on salt marsh - keyhaven

  • Salt Marsh, Keyhaven, Hampshire
  • Found in the Lee of Hurst Castle spit, as more deposition takes place, the mud begins to break the surface to form mudflats. Salt tolerant (halophytes)plants such as Cordgrass colonise. 
  • These are pioneer plants and they can tolerate the salt and have long roots so it is not swept away by waves and tides. The roots also bind the mud and stabilise it. As the mud rises it is less frequently covered by water and it becomes less harsh as they rainwater washes out the salt and decomposing plant matter improves the fertility. Other plants then invade such as sea asters and vegetation succession occurs.
  • It supports grassland, shrub, salt marsh and reed beds
  • The variety of habitats accounts for a rich diversity of wildlife. 
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keyhaven (2)

  • The salt marsh is retreating by up to 6m a year. Although the causes of this are not yet fully understood, further sea level rise threatens a ‘squeeze’ of the salt marsh as it lies between a low sea wall built in the early 1990s and the encroaching sea.
  • The salt marsh has been under threat from the breaching of Hurst Castle Spit during severe storms. In December 1989 storms pushed part of the shingle ridge over the top of the salt marsh, exposing 50 to 80m to the full fury of the sea. It was eroded in less than three months.
  • Increasing demands for leisure and tourism have meant that increasing numbers of people wish to visit the marshes. Careful management is required to prevent damage by trampling, parking and pollution. The area is popular with mariners who use the many creeks to moor their boats.
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keyhaven (3)

  • In 1996 rock armour and beach nourishment were used to increase the height and width of the spit in an attempt to stop breaching. Since the completion of the £5mn sea defences, the spit has not been breached and Keyhaven Marshes seems safe…at least for a the time being.
  • Keyhaven Marshes has been nationally recognised as an important site for wildfowl and wading birds. The area is officially a Site of Special Scientific Interest (SSSI) and part of the salt marsh is also a National Nature Reserve. This means that the area is carefully monitored and managed to maintain its rich biodiversity. Access is limited and development restricted.
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case study on sand dune management- camber sands

  • Sand Dune Management Plan – Camber Sands East Sussex
  • Camber Sands is situated towards the eastern end of the East Sussex coast and is the only sand dune system in East Sussex.
  • A large section of the western end of the dunes lie within the Camber Sands and Rye Saltings Site of Special Scientific Interest (SSSI), while the rest is designated a Site of Nature Conservation Importance (SNCI). Camber village lies behind the dunes towards the eastern end.
  • Dune systems are formed by a complex interaction between geology, tide, sun, wind and vegetation.
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camber sands (2)

  • Sand, produced by the grinding action of the waves or from material brought down by river systems, is deposited along the coast. When the tide goes out (almost 1km at Camber) the sand is dried by the sun and wind, and blown inland by the prevailing south-westerly wind. This process is called saltation.
  • When the sand meets an obstruction, eg vegetation and the wind speed drops, the sand is deposited and forms dunes.
  • Camber is an accreting dune system, which means the dunes are gradually getting bigger. 7,500 cubic metres of sand are deposited here every year
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camber sands (3)

  • Management:
  • Flood defence and sand stabilisation
  • The dunes form an essential part of shore protection. This is particularly important for Camber Village and parts of Romney Marsh, which lie below the high tide level and would quickly be flooded.
  • Sand dunes are a dynamic system, with wind-blown sand moving inland with strong winds. To prevent Camber village flooding and reduce the amount of sand being blown by the wind, the sand must be stabilised. Maintaining the sea defence is carried out by the Environment Agency in partnership with East Sussex County Council and Rother District Council.
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camber sands (4)

  • The main sea defence strategy is to remove wind-blown sand from the front of the dunes and public paths going over the dunes. Chestnut fencing is used to trap the sand and stop it blowing over the dunes onto the village. It is also used to encourage people to keep to the marked paths, protecting fragile vegetation which stabilises the sand. This vegetation is mainly Marram Grass (Ammophila arenaria)
  • The rangers operate a Christmas tree recycling scheme every January to collect old trees from the local community. The trees are ‘planted’ on their sides in shallow trenches where gaps (caused by trampling from visitors) have been created in the dunes. The trees help trap wind-blown sand, allowing vegetation to grow and stabilise the sand.
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camber sands(5)

  • The county council is working to an agreed five-year management plan with English Nature. The plan includes the removal of Sea Buckthorn (Hippophae rhamnoides) from the back areas of the dunes located in the SSSI. This shrub is very invasive and quickly spreads, shading out other plants. It also fixes nitrogen in the soil, which encourages other invasive species like Nettle (Urtica dioica) and Elder (Sambucus nigra). An area of Sea Buckthorn is cut and burnt each year between October and February and the regrowth sprayed the following spring. Other invasive species are also cleared in each area. Ragwort (Senecio jacobaea) in particular is controlled by spraying and hand pulling during the spring.
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camber sands (6)

  • Surveys are carried out to monitor the effects of Sea Buckthorn clearance. Fixed-point photography and quadrate surveys establish what species of flora are re-colonising the opened up areas.
  • Post and rail fences encourage visitors to keep to the paths over the dunes. Many plants on the dunes are very fragile and are damaged by visitors trampling them. Vegetation along the paths is cleared during the summer to keep paths open. Interpretation panels have been erected along the paths informing visitors about the wildlife they might see.
  • The rangers regularly clear broken chestnut fencing and rubbish from the dunes. This is particularly important during the summer when the site is very busy with visitors
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