Coastal Management (AQA GCSE Geography)

Revision Note

Jacque Cartwright

Written by: Jacque Cartwright

Reviewed by: Bridgette Barrett

Hard Engineering

  • The aim of any coastal management is to protect the environment but mostly people from the impacts of erosion and flooding

  • Not all coastal areas can be protected or managed as there are economic constraints

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 to build

Hard Engineered Defences

Strategy

Description

Advantages

Disadvantages

Sea Wall

A wall, usually concrete, and curved outwards to reflect the power of the waves back out to sea

Most effective at preventing both erosion and flooding (if the wall is high enough)

Very expensive to build and maintain

It can be damaged if the material is not maintained in front of the wall

Restricts access to the beach

Unsightly to look at

Groynes

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

Slows down beach erosion

Creates wider beaches

Stops material moving down the coast where the material may have been building up and protecting the base of a cliff elsewhere

Starves other beaches of sand. Wood groynes need maintenance to prevent wood rot

Makes walking along the shoreline difficult  

Rip-rap

Large boulders are piled up to protect a stretch of coast

Cheaper method of construction

Works to absorb wave energy from the base of cliffs and sea walls

Boulders can be eroded or dislodged during heavy storms

Gabions

A wall of wire cages filled with stone, concrete, sand etc built at the foot of cliffs

Cheapest form of coastal defence

Cages absorb wave energy

Can be stacked at the base of a sea wall or cliffs

Wire cages can break, and they need to be securely tied down

Not as efficient as other coastal defences

Revetments

Sloping wooden or concrete fence with an open plank structure 

Work to break the force of the waves

Traps beach material behind them

Set at the base of cliffs or in front of the sea wall

Cheaper than sea walls but not as effective

Not effective in stormy conditions

Can make beach inaccessible for people

Regular maintenance is necessary

Visually unattractive

Off-shore barriers

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

Effective at breaking wave energy before reaching the shore

Beach material is built up

Low maintenance

Maintains natural beach appearance

Expensive to build

Can be removed in heavy storms

Can be unattractive

Prevents surfing and sailing

Soft Engineering

Soft engineering methods

  • Soft engineering works with natural processes rather than against them

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

  • Considered to be a more sustainable approach to coastal protection

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

Soft Engineered Defences

Strategy

Description

Advantages

Disadvantages

Beach replenishment

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

Beaches absorb wave energy 

Widens beach front

Has be repeated regularly which is expensive

Can impact sediment transportation down the coast

Removing material from the seabed damages fragile ecosystems such as corals and sponges

Dune regeneration

Planting vegetation helps to create or stabilise sand dunes and beaches 

Reduces wind erosion

Sand dunes act as a barrier between the sea and land.

The wave energy is absorbed, preventing erosion and flooding

Cheap method of stabilising dunes

Hard to protect larger areas of coastline cliffs with this method

Cliff re-grading

The angle of a cliff is reduced to reduce mass movement

Prevents sudden loss of large sections of cliff

Regrading can also slow down wave cut notching at base of cliffs as wave energy is slowed

Does not stop cliff erosion

Managed retreat

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

No expensive construction costs

Creates new habitats such as salt marshes

Disruptive to people where land and homes are lost

Saltwater damages existing ecosystems

Cost of relocation can be expensive

Compensation to people and businesses may not be paid

Managing Coastal Retreat

  • 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 best reflect all stakeholder's needs

Coastal strategies

  • Management of coastal regions is done through 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 allows resources to be allocated effectively to reduce the impacts of these risks

  • The 'cost to 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

    • 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 the line

    • Build new defences to extend the existing shoreline

    • Involves land reclamation

    • Hard and soft engineering is used

  • Managed realignment or retreat

    • Some or all coastal defences are removed, allowing the coastline to move naturally

    • Over time the land becomes flooded marshes, effectively protecting the land behind 

    • Most natural approach to coastal defence as it doesn't need maintenance and creates new habitats for animals and plants

    • However, the land is lost to the sea, which brings conflict, loss of livelihood and saltwater damages existing ecosystems

    • Mostly soft engineering with some hard engineering to support

  • Do nothing

    • Cheapest method, but 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

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

    • 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

Worked Example

Study Figure 10 and Figure 11, photographs showing soft engineering strategies. 

Excavators and bulldozer moving sand on a beach for nourishment purposes, with the ocean in the background and a clear blue sky overhead.
Map showing coastal geography with areas like Bridlington, Hornsea, and Easington. It features longshore drift, prevailing wind, and a small inset of the UK.

Discuss the costs and benefits of soft engineering strategies in protecting coastlines. Use Figure 10 and Figure 11 and your own understanding.

[6 marks]

Answer: 

  • Do not get distracted and discuss hard engineering, keep your focus on the two soft engineering strategies shown in the figures, and include other soft engineering methods that you have studied

  • Figures 10 and 11 show beach nourishment and dune regeneration

  • This is a levelled question and to gain Level 3 you will make sure you discuss the costs and benefits of named soft engineering strategies

  • Use geographical terminology throughout

  • Advantages:

    • Soft engineering works with nature rather than against it, blends in with the environment and can improve it e.g. adding sand to beaches, doesn’t interfere with processes elsewhere and affect other areas; is more sustainable

  • Disadvantages:

    • Areas can just be left at the mercy of the sea, more gentle intervention may not be effective, people can lose their homes and livelihoods

  • Beach nourishment -

    • 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. It usually looks natural and can improve the attractiveness of a stretch of coast. It creates a useful amenity for tourism, it is a relatively cheap option and easy to maintain

    • However, it does require constant maintenance to replace the beach material as it is washed away. This is particularly the case after winter storms. People may be prevented from using the beach for several weeks during maintenance 

  • Beach reprofiling is the artificial re-shaping of a beach using existing beach material. For example, after winter storms, bulldozers may move shingle back up the beach. The costs and benefits are similar to those for beach nourishment. The disruption caused by reprofiling may have negative impacts on beach habitats

  • Dune regeneration -

    • The artificial creation of new sand dunes or the restoration of existing dunes using strategies such as marram grass planting or fencing them off from human impact. Sand dunes act as a physical barrier between the sea and the land. They absorb wave energy and water and in doing so protect the land from the sea. This strategy is considered natural by most people and can produce an attractive amenity for tourists. They may also increase biodiversity, providing a greater range of natural habitats for plants, animals and birds.

    • However, they can be easily damaged by storms, and it can be time-consuming to plant the grass and maintain the area/it can also deter tourists at this time 

Case Study: The Holderness Coast

  • The Holderness Coastline is located on the East Coast of Yorkshire and runs for 61 km 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 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

Map showing the Yorkshire coast with locations Bridlington, Skipsea, Hornsea, Mappleton, Great Cowden, Withernsea, Easington, and Spurn Head. Arrows indicate prevailing wind and longshore drift.
  • The biggest issue of the Holderness coastline is that it is retreating too quickly

Management

  • 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 and as a popular tourist destination, management is aimed at protecting hotels, arcades and creating a sandy beach. Hornsea has spent money on repairing its wooden groynes at a cost of £5.2 m, it also has a concrete sea wall. 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 m, groynes and beach nourishment at Mappleton have produced a sandy beach and protects the town 

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

  • 2.25% of all UK gas comes through the gas terminal at Easington and £4.5 m 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 to be given a higher priority than overall coastal conservation

  • The 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 

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Jacque Cartwright

Author: Jacque Cartwright

Expertise: Geography Content Creator

Jacque graduated from the Open University with a BSc in Environmental Science and Geography before doing her PGCE with the University of St David’s, Swansea. Teaching is her passion and has taught across a wide range of specifications – GCSE/IGCSE and IB but particularly loves teaching the A-level Geography. For the past 5 years Jacque has been teaching online for international schools, and she knows what is needed to get the top scores on those pesky geography exams.

Bridgette Barrett

Author: Bridgette Barrett

Expertise: Geography Lead

After graduating with a degree in Geography, Bridgette completed a PGCE over 25 years ago. She later gained an MA Learning, Technology and Education from the University of Nottingham focussing on online learning. At a time when the study of geography has never been more important, Bridgette is passionate about creating content which supports students in achieving their potential in geography and builds their confidence.