Coastal Management (Edexcel IGCSE Geography)

Coastal strategies

• 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

• 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

• 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

• 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

Sea wall

• 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

• 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

• 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

• It is made of soft boulder clay and chalk

• The coastline has naturally narrow beaches, which give less protection from erosion as wave power is not reduced

• Longshore drift is the dominant process due to North Sea waves

• Waves along the coastline have a long fetch (travel long distances), which increases wave energy

• The biggest issue of the Holderness coastline is that it is retreating too quickly

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