Coastal Management (Edexcel IGCSE Geography)

Coastal Strategies

Spec point — 4GE1-S3.043

• Management of coastal regions is performed by identifying coastal cells

• This breaks a long coastline into manageable sections and helps identify two related risks:

  • The risk of erosion and land retreat
  • The risk of flooding

• Identification of the risks allows resources to be allocated effectively to reduce the impacts

• The 'cost-benefit' is easier to calculate using coastal cells

Shoreline Management Plans

Spec point — 4GE1-S3.043

• Shoreline Management Plans (SMP) set out an approach to managing a coastline from flooding and erosional risk

  • The plans aim to reduce the risk to people, settlements, agricultural land and natural environments (salt marshes etc.)

• There are four approaches available for coastal management, with differing costs and consequences:

  • Hold the line
  • Advance the line
  • Managed realignment
  • Do nothing

Hold the line

• Long-term approach and the most costly
• Build and maintain coastal defences so the current position of the shoreline remains the same
• Hard engineering is the most dominant method used, with soft engineering used to support

Advance

• Build new defences to extend the existing shoreline
• Involves land reclamation
• Hard and soft engineering is used

Managed realignment

• The coastline is allowed to move naturally
• Processes are monitored and directed when and where necessary
• The most natural approach to coastal defence
• Mostly soft engineering with some hard engineering to support

Do nothing

• The cheapest method, but the most controversial of the options
• The coast is allowed to erode and retreat landward
• No investment is made in protecting the coastline or defending against flooding, regardless of any previous intervention

Which approach to coastal management?

• Decisions about which approach to apply are complex and depend on:

  • the economic value of the resources that would be protected, e.g. land, homes, etc.
  • engineering solutions – it might not be possible to 'hold the line' for moving landforms such as spits, or unstable cliffs
  • cultural and ecological value of land – historic sites and areas of unusual diversity
  • community pressure – local campaigns to protect the region
  • social value of communities – long-standing, historic communities

Hard Engineering Methods

Spec point — 4GE1-S3.043

• Hard engineering involves building some form of sea defence, usually from concrete, wood or rock
• Structures are expensive to build and need to be maintained
• Defences work against the power of the waves
• Each type of defence has its strengths and weaknesses
• Protecting one area can impact regions further along the coast, which results in faster erosion and flooding
• Hard engineering is used when settlements and expensive installations (power stations, etc.) are at risk – the economic benefit is greater than the costs of building structures

Hard engineering strategies

Seawall

• A wall, usually concrete, and curved outwards to deflect the power of the waves

Groynes

• Wood, rock or steel piling built at right angles to the shore
• Groynes trap beach material being moved by longshore drift

Rip-rap

• Large boulders which are piled up to protect a stretch of coast

Gabions

• Wire cages filled with stone, concrete, sand, etc.

Revetments

• Sloping wooden or concrete fence with an open plank structure

Off-shore barriers

• Large concrete blocks, rocks and boulders are sunk offshore
• These alter wave direction and dissipate wave energy

Soft Engineering Methods

Spec point — 4GE1-S3.043

• Soft engineering works with natural processes rather than against them

• Usually cheaper and do not damage the appearance of the coast

• They are considered to be a more sustainable approach to coastal protection

  • However, they are often not as effective as hard engineering methods

Beach replenishment

• Pumping or dumping sand and shingle back onto a beach to replace eroded material

Fences, hedging and replacing vegetation

• These help to stabilise sand dunes or beaches
• Additional vegetation or fencing also reduces wind erosion

Cliff regrading

• The angle of a cliff is reduced to reduce mass movement

Managed retreat

• Existing coastal defences are abandoned, allowing the sea to flood inland until it reaches higher land or a new line of defences

• There are conflicting views about using a particular type of engineering for coastal defence
• Most coastal managers aim to use a range of methods depending on the value of what is being protected
• This method is known as Integrated Coastal Zone Management (ICZM)
• ICMZ aims to use a combination of methods to meet as many stakeholder needs as possible

Case Study - The Holderness Coast

Spec point — 4GE1-S3.043

Case Study – The Holderness Coast

• The Holderness Coastline is located on the East Coast of Yorkshire and runs for 61 km
• It stretches from Flamborough Head in the north down to Spurn Head, where it meets the Humber Estuary in the south
• It is the fastest-eroding coastline in Europe at 2 m per year

Map showing the Holderness Coast

• The cliffs are made of soft boulder clay and chalk deposited during the last ice age

  • This makes them easily eroded by hydraulic action and abrasion during storm events

• Longshore drift is the dominant process along the coast

  • This creates narrow beaches, which give less protection from erosion as wave power is not reduced

• The coastline directly faces the North Sea, which gives destructive waves a long fetch (travel long distances)

  • This increases wave energy and therefore high erosive energy when they reach the shore

Management of the Holderness Coast

• Bridlington is protected by a 4.7 km long sea wall

• Gabions have been built at Skipsea

• Hornsea's cliffs are formed from soft boulder clay

  • As a popular tourist destination, management is aimed at protecting hotels, and arcades and creating a sandy beach
  • Hornsea has spent money on repairing its wooden groynes at a cost of £5.2 million
  • It also has a concrete seawall
  • Recently, a stone and steel gabion along with a concrete revetment have been built south of Hornsea, helping to protect the caravan park

• Riprap, at a cost of £2 million, and groynes and beach nourishment at Mappleton have produced a sandy beach and protect the town

• Withernsea has a sea wall, groynes, riprap and beach nourishment to widen the beach and reduce wave energy

• Approximately, 2.25% of all UK gas comes through the gas terminal at Easington and £4.5 million was spent on riprap, but the scheme protects the terminal and not the village

• Spurn Head is protected with groynes and rock armour

Conflicts

• Careful management of coastal regions is necessary to ensure sustainability
• Conflict arises when coastal development is seen as being given a higher priority than overall coastal conservation
• Management along the Holderness Coast has been successful in part, with the village of Mappleton and the B1242 road no longer at risk from erosion
• Due to the use of groynes at Mappleton, sediment has been prevented from moving south, which has increased erosion at Great Cowden
• Erosion has destroyed farms, along with the loss of 100 chalets at the Golden Sands Holiday Park
• Locals have disagreed about where sea defences are located, especially if community land is not protected
• Some sea defences negatively impact tourism and reduce the amount of money coming into the area
• Spurn Head is at risk of losing habitats due to a lack of sediment to maintain the spit
• Overall, maintaining coastal defences is expensive and the cost may be too great to continue defending an area that is eroding quickly and will continue to erode