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A2 CAMBRIDGE GEOGRAPHY: COASTAL ENVIRONMENTS - SUSTAINABLE MANAGEMENT OF THE COASTS

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A2 CAMBRIDGE GEOGRAPHY: COASTAL ENVIRONMENTS - SUSTAINABLE MANAGEMENT OF THE COASTS, It contains: definition of coastal management, shoreline management plans SMP, long term objectives, conflicts of interests, reasons for concerns, management strategies, hard engineering, soft engineering, sea walls, curved walls, groynes, rock armours, beach management, managed retreat, beach nourishment, dune regeneration, coastal management Holderness, case studies, tourism in UK, sea sand mining Mangawhai Pakiri New Zealand.

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A2 CAMBRIDGE GEOGRAPHY: COASTAL ENVIRONMENTS - SUSTAINABLE MANAGEMENT OF THE COASTS

  1. 1. A2 GEOGRAPHY - COASTAL ENVIRONMENTS 8.4 SUSTAINABLE MANAGEMENT OF COASTS
  2. 2. WHAT IS COASTAL MANAGEMENT? Coastal management is about resolving the conflicts between human benefits and the well- being of coastal ecosystem and protecting the coast e.g. long stretches of beaches.
  3. 3. SHORELINE MANAGEMENT PLANS (SMP) Every stretch of coast has a Shoreline Management Plan. SMP’s provide: ‘an objective large-scale assessment of the risks to people and the developed, historic and natural environment, resulting from the evolution of the coast. It goes on to present a policy framework that does not tie future generations to costly and unsustainable activities. In the setting of policy it attempts to balance all of the sometimes conflicting interests at the coast in a sustainable manner.’ (Defra, 2004)
  4. 4. LONG TERM OBJECTIVES OF SMP’s The subsections of coast are defined by sources and sinks of material and cells of sediment movement. SMPs set out long-term objectives that are: • technically sustainable • environmentally acceptable • economically viable
  5. 5. HOUSING DEVELOPMENT, POLITICAL AND SOCIAL ATTITUDES SMPs are used to help coastal managers plan into the 22nd century, but because many changes will inevitably occur in this time span, the plans have to be used flexibly and all participants need to agree that SMPs may have to be altered in the light of new circumstances, such as housing development or political or social attitudes.
  6. 6. COASTAL MANAGEMENT Successful management of coastal areas depends on understanding the different uses of coastal land and the physical processes impacting on the coast, such as erosion and longshore drift. Techniques for managing these physical processes can be divided into hard engineering options (such as building sea walls) and soft engineering options (such as beach nourishment and managed retreat).
  7. 7. CONFLICTS OF INTEREST Land uses in coastal areas include tourism, industry, fishing, trade and transport. There are many different groups of people who have an interest in how coastal areas are managed. These include: • local residents • environmental groups • developers • local councils • national governments • tourist boards • National Park Authorities
  8. 8. REASONS FOR CONCERNS Each interest group may have a different view about what should be done to protect and manage coastal areas. A difference of opinion can cause conflict between interest groups. Reasons why groups of people might be concerned about the coast are: • Erosion may be threatening beaches or coastal settlements. • People may want to develop tourism in the area or existing tourism could be declining. • There is a danger of flooding if sea levels rise. • There could be a problem with sewage and/or pollution.
  9. 9. MANAGEMENT STRATEGIES: HARD ENGINEERING Physical management of the coast attempts to control natural processes such as erosion and longshore drift. Hard engineering options tend to be expensive, short-term options. They may also have a high impact on the landscape or environment and be unsustainable.
  10. 10. SEA WALLS AND CURVED WALLS IN UK Sea walls are walls of concrete, supported by Iron pilings dug into the underlying rock, that are designed to prevent coastal erosion. They are generally placed at the foot of vulnerable cliffs or at the top of a beach. They can be up to 5m high and can be flat faced or curved. The curved walls are more expensive but dissipate the energy from incoming waves better. These defences can be up to £6 million per kilometre to construct. Their good points are that they are very effective, have a reasonably long lifespan and often have walkways along the top for people to walk along. However, they are very expensive and are accused of being ugly (not aesthetically pleasing!). Also, sea walls have been known to cause down current scarring, where waves cause more damage to unprotected areas.
  11. 11. SEA WALLS
  12. 12. GROYNES IN UK Groynes are basically wooded fences that run at right angles to the beach. These fences run out into the sea, and are designed to interrupt longshore drift and catch sediment as it moves along the coastline, thus widening a beach. This larger beach can then act as a buffer against waves, as there is more beach to absorb wave energy. these features can cost as much as £10,000 each, and need to be spaced at 200m intervals. They are good because they result in a larger beach, which not only protects the coastline but can also be good for tourism. In addition, they are not that expensive. However, they starve down current (or drift) beaches, which makes them more vulnerable to erosion, and again they are not that attractive.
  13. 13. ROCK ARMOURS IN UK Rock armours are simple strategies that involve the dumping of huge boulders of rock at the base of a cliff. These rocks help the wave to break and they absorb the wave energy. They cost between £1,000 and £4,000 per metre, depending upon the material used, and are relatively cheap and easy to maintain. They are however unnatural and do not fit with the geology of the cliff line, and can be expensive to transport. Another type of rock armour are Gabions - which are cages of smaller rocks that work in much the same way.
  14. 14. EFFECTIVE BUT EXPENSIVE Hard engineering schemes are effective but expensive, and recent attempts to manage coastal processes have focussed on softer engineering techniques. These techniques seek to mimic natures own ways of managing coastal processes and to use natural materials and strategies to prevent erosion. In effect, these measures can be better for the environment, cost less money to implement and maintain, but not totally control the erosion problem. They are a more sustainable way of managing the coastline.
  15. 15. MANAGEMENT STRATEGIES: SOFT ENGINEERING Soft engineering options are often less expensive than hard engineering options. They are usually more long-term and sustainable, with less impact on the environment. There are two main types of soft engineering.
  16. 16. BEACH MANAGEMENT This replaces beach or cliff material that has been removed by erosion or longshore drift. The main advantage is that beaches are a natural defence against erosion and coastal flooding. Beaches also attract tourists. It is a relatively inexpensive option but requires constant maintenance to replace the beach material as it is washed away.
  17. 17. MANAGED RETREAT Areas of the coast are allowed to erode and flood naturally. Usually this will be areas considered to be of low value – eg. places not being used for housing or farmland. The advantages are that it encourages the development of beaches (a natural defence) and salt marshes (important for the environment) and cost is low. Managed retreat is a cheap option, but people will need to be compensated for loss of buildings and farmland.
  18. 18. BEACH NOURISHMENT Beach nourishment is a measure whereby additional sand and shingle is added to a beach to make it higher and wider. This material is brought onshore by barge, and moved about by large trucks and diggers. It costs around £3000 per km and is a cheap method. It will blend in with the beach if the sediment is locally sourced and will have benefits for tourists. However, this method needs constant maintenance or else this new sediment will also eventually be eroded by the sea.
  19. 19. DUNE REGENERATION Dune regeneration basically involves artificially creating new sand dunes along the coastline to act as a buffer between the land and the sea. Sand dunes occur naturally but are under threat because they are fragile and people walk all over them, ride horses and motorbikes on them and destroy the dune ecosystem. Using fencing to help trap sand, planting Marram grass into coconut matting and encouraging dune formation helps to protect these systems which protect our coastline and absorb storm and wave energy. This can cost £2,000 per 100m and helps to maintain the ecosystem of the area whilst offering protection. However, it is time consuming to plant the Marram grass and fence off areas, and is less effective than hard engineering schemes.
  20. 20. MANAGED RETREAT Managed retreat is a method whereby we humans concede defeat to the power of the sea and allow it to erode and create salt marshes for example. We can also allow cliff erosion to occur in areas of low value farmland and just compensate farmers for their losses, rather than construct more expensive coastal defences. This can only work where the coasts of compensation are significantly less than the coasts of building coastal defences, and can be a cheap option. It can also be beneficial to plants and animals by providing new habitat. This method is highly controversial however, as land is lost and the human cost can be greater than just financial. Imagine a farmer told to quit land and a family home that could have been in the family for generations because the council do not want to build a sea defence - the trauma of this is huge.
  21. 21. COASTAL MANAGEMENT IN HOLDERNESS The Holderness coast is in the north east of England. This is one of the most vulnerable coastlines in the world and it retreats at a rate of one to two metres every year. The problem is caused by: • Strong prevailing winds creating longshore drift that moves material south along the coastline. • The cliffs are made of a soft boulder clay. It will therefore erode quickly, especially when saturated.
  22. 22. COASTAL MANAGEMENT IN HOLDERNESS cont. The village of Mappleton, perched on a cliff top on the Holderness coast, has approximately 50 properties. Due to the erosion of the cliffs, the village is under threat. In 1991, the decision was taken to protect Mappleton. A coastal management scheme costing £2 million was introduced involving two types of hard engineering - placing rock armour along the base of the cliff and building two rock groynes. Mappleton and the cliffs are no longer at great risk from erosion. The rock groynes have stopped beach material being moved south from Mappleton along the coast. This has increased erosion south of Mappleton. Benefits in one area might have a negative effect on another.
  23. 23. VIDEO Holderness Coast GCSE Geography Case Study
  24. 24. COASTAL MANAGEMENT IN HOLDERNESS cont. The increased threat of sea level rise due to climate change, means that other places will need to consider the sustainability of coastal defence strategies for the future.
  25. 25. VIDEO The Village That’s Falling into the Sea
  26. 26. CASE STUDY: TOURISM IN STUDLAND BAY NATURE RESERVE Studland Bay is located in the Isle of Purbeck in Dorset and is popular with tourists. It can be accessed by ferry from the desirable area of Sandbanks in Poole during the summer. It is only a few minutes drive from the resort of Swanage and most visitors arrive by car. Studland Bay is a good example of a place where conflict can occur between interest groups.
  27. 27. HOW IS THE AREA MANAGED? Vulnerable areas and areas recently planted with marram grass (which is used to stabilise the dunes) are fenced off to limit access and damage. Boardwalks have been laid through the dunes to focus tourists onto specific paths. Car parks have been provided and people are not permitted to drive onto the beach. Fire beaters are positioned within the dune area in case of a fire. Facilities including a shop, café, toilets and litter bins are provided near the car parks to focus tourists into one area. Information boards educate visitors about the environment and how they can help to protect it.
  28. 28. VIDEO Bournemouth Coast A bird’s eye view
  29. 29. SEA SAND MINING AT MANGAWHAI, PAKIRI, NEW ZEALAND The purpose of New Zealand's Resource Management Act (1991) is to promote the sustainable management of natural and physical resources. Coastal sand mining may be consistent with this purpose where: (1) extractions occur from sediment systems open to inputs of sediment, and the volumes extracted do not limit the natural development, physical characteristics, and ecological diversity of the coastal environments affected; or (2) extractions from palimpsest or relict sedimentary deposits occur at a rate where the rate of extraction is insignificant compared with the volume of the resource.
  30. 30. VIDEO MANGAWHAI HEADS DRONE OVERFLIGHT 1
  31. 31. SEA SAND MINING AT PAKIRI Sand mining at Pakiri Beach has been extended for a further 14 years by the Environment Court. In a reserved decision, the court has dismissed objections to continued mining from the Auckland Regional Council and Friends of Pakiri made on the grounds of serious environmental effects. McCallum Bros and Sea Tow appealed to the court after the council turned down their application to take 76,000cu m of sand a year for 20 years near the shore at Pakiri.
  32. 32. EROSION OR NOT? The companies sought to renew consents to take the sand from where the water was 5m to 10m deep in the Mangawhai-Pakiri bay area. In court, the firms disputed the claim of the council and experts that the bays formed a closed system and no new sand was coming in. The ARC said continued extraction would eventually lead to beach and dune erosion and would spoil the significant natural character of the coastline. But the companies said that despite huge volumes of sand having been extracted from the Pakiri inshore area over the past 85 years, no significant erosion or change to the coastline could be blamed on the extraction.
  33. 33. SAND FOR CONSTRUCTION PROJECTS The firms sought 20-year terms because of the quality and value of the Pakiri sand, which is needed for Auckland construction projects. It has also been used to replenish the beaches at Mission Bay, Kohimarama and St Heliers. Judge David Sheppard said no link between sand extraction and environmental damage had been shown. He authorised coastal permits for the mining for 14 years. ARC environment chairman Dianne Glenn said last night she was disappointed by the decision. In December, the council paid $20 million to create a regional park at Pakiri and the dunes there have two threatened bird species - the NZ fairy tern and the NZ dotterel.
  34. 34. VIDEO MANGAWHAI HEADS DRONE OVERFLIGHT 2
  35. 35. OPPOSING MINING The ARC hearing drew 678 submissions about the proposal - 658 were against and 20 for. Friends of Pakiri chairman Nick Williams said the group would consider its option of appealing against the decision to the High Court on points of law. "We opposed mining because Pakiri is a great place for lots of people to go to and enjoy its unspoiled white sand." The decision created an absurd situation, he said, because mining was banned in the Mangawhai part of the bay system, which was under the Northland Regional Council. The Mangawhai Harbour Restoration Society chairman, Graham Mackenzie, said near-shore mining was disgraceful and posed a serious risk to the rebuilding of the town's sandspit.
  36. 36. SEA SAND MINING IN THE WORLD The world’s beaches are being mined for sand for a variety of uses (aggregate in concrete, fill, beach nourishment). The practice is often very destructive and poorly managed (or unmanaged). This is a global phenomenon (Morocco, Caribbean Islands, India, South Africa, NZ). This theft of beach and dune sand is a direct cause of erosion along many shorelines. It is very damaging to the beach fauna and flora, ruinous to beach aesthetics, and frequently causes environmental damage to other coastal ecosystems such as wetlands.
  37. 37. HISTORIC ACCOUNTS Another major impact of beach sand mining is the loss of protection from storms surges associated with tropical cyclones and tsunamis. Some communities affected by the 2004 tsunami in the Indian Ocean had higher storm surges probably due to beach sand mining resulting in fatalities. Sometimes it is difficult to tell that a beach has been mined. Sand extraction becomes difficult to recognize as the beach readjusts to a new profile after a few storms. But historic accounts of beaches in the Caribbean often reveal that beaches have been narrowed considerably. Mining is particularly senseless in a time of rising sea level when sand is sorely needed as a storm energy buffer.

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