Coastal Management (AQA A-Level Geography): Revision Notes
Coastal management
Human intervention in coastal landscapes
Coastal areas face growing pressure from both natural processes and human activities. Many coastal landscapes are experiencing increased threats from erosion, flooding and sea level rise. To address these challenges, various protection and management strategies have been developed and implemented across coastal regions.
However, these management solutions are not always straightforward. In some cases, the strategies themselves can create additional problems. This makes careful planning and selection of appropriate management approaches essential.
Why coastal management is needed
Historical impacts
Coastal erosion and flooding have shaped Britain's coastline for centuries. Many low-lying coastal villages, particularly along the east coast, have disappeared over time. These losses have been documented since historical records like the Domesday Book were compiled.
Current risks from sea level rise
Several areas around the British coastline are particularly vulnerable to rising sea levels:
- Major cities and conurbations (such as London, Hull and Middlesbrough)
- High-grade agricultural land close to the coast
- Important transport infrastructure (major roads and rail links near coastal areas)
- Power stations situated on low-lying ground
Rising sea levels pose a significant threat not only to coastal infrastructure and communities but also to the economic assets and critical services located in vulnerable coastal zones. The combination of natural subsidence and climate-driven sea level rise means these risks are increasing over time.
Impact on water resources
Rising sea levels create challenges beyond direct coastal erosion and flooding. Higher sea levels can affect underground water supplies in several ways:
- Saltwater intrusion in rivers: Where seawater mixes with fresh water in rivers, rising sea levels can push this mixing zone further upstream
- Saline contamination of groundwater: Salt water can penetrate into rocks containing fresh water beneath the land, mixing with fresh water stored in underground sediments
- Threats to water abstraction: Points where water is extracted for domestic use and irrigation may become contaminated with salt water, requiring them to be relocated upstream or made intermittent
Aims of coastal management
Coastal management has two primary aims:
- To provide defence against flooding and reduce its impacts
- To provide protection from coastal erosion and reduce its impacts
Additional management objectives include:
- Keeping beaches stable where longshore drift causes sediment movement
- Maintaining sand dune systems
- Protecting fragile estuarine landscapes
These secondary aims support the primary goals by maintaining natural coastal features that provide protection and ecosystem services.
Management strategies
Coastal management strategies can be broadly categorised by whether they work with or against natural processes.
Two Fundamental Approaches:
Working with nature - Allows natural coastal processes to happen without major interference. This approach is increasingly being applied to large stretches of UK coastline where there are fewer buildings and developments.
Working against nature - Involves significant capital investment to protect buildings and communications infrastructure through physical barriers and defences.
Working with nature
This approach allows natural coastal processes to happen without major interference. It is increasingly being applied to large stretches of UK coastline where there are fewer buildings and developments.
Managed retreat
Managed retreat involves allowing the natural processes of erosion to continue rather than spending money defending the coastal area. This strategy is now used on extensive sections of the UK coastline where there are limited economic assets at risk.
Managed retreat is a cost-effective approach for areas with low development density. Rather than fighting natural processes, this strategy accepts that some land will be lost to the sea, focusing resources on protecting higher-value areas instead.
Soft engineering
Soft engineering uses natural coastal systems for defence purposes. These systems include beaches, sand dunes and salt marshes, which naturally absorb and adapt to wave and tide energy.
Examples of soft engineering techniques:
- Beach nourishment (adding sand to beaches)
- Dune restoration and management
- Salt marsh conservation
Soft engineering methods are described as working with nature because they utilise and enhance natural coastal features.
Soft Engineering in Action: Beach Nourishment
When a beach loses sand due to erosion, managers can add new sand to restore it. This:
- Maintains the beach as a natural buffer against wave energy
- Preserves recreational spaces for tourism
- Costs less than building sea walls
- Works with natural processes rather than fighting them
The added sand gradually redistributes along the coast through natural wave action and longshore drift.
Working against nature
This approach involves significant capital investment to protect buildings and communications infrastructure in coastal regions. It requires constructing physical barriers and defences.
The costs of such defences are justified by the high expense of replacing sea-damaged buildings and infrastructure if protection were not in place.
Traditional approaches to coastal erosion and flood risk
Hard engineering
Hard engineering involves making physical alterations to the coastal landscape using resistant, durable materials such as concrete, boulders, wood and metal.
Common hard engineering structures include:
- Sea walls
- Revetments
- Groynes
Characteristics of hard engineering:
- Large scale construction projects
- High costs
- Uses artificial, resistant materials
- Creates permanent physical barriers
These traditional engineering approaches have been widely used but are increasingly being supplemented or replaced by softer, more natural methods where appropriate. The choice between hard and soft engineering often depends on the economic value of the assets being protected.
When is Hard Engineering Justified?
Hard engineering solutions are typically used when:
- High-value infrastructure is at risk (power stations, major roads, urban areas)
- The cost of protection is less than the cost of potential damage
- Natural soft engineering options are insufficient for the level of threat
- Long-term permanent protection is needed
However, hard engineering can have negative impacts, including disrupting natural sediment transport and increasing erosion in adjacent areas.
Key Points to Remember:
- Coastal management aims to protect against both flooding and erosion
- Hard engineering uses resistant materials like concrete to physically alter the coastline, whilst soft engineering works with natural systems like beaches and dunes
- Managed retreat allows natural erosion processes to occur without expensive intervention
- Rising sea levels threaten not just coastal areas directly, but also underground water resources through saltwater intrusion
- Management strategies are selected based on the value of assets at risk - high-value areas typically receive hard engineering protection
- Working with nature is increasingly preferred where economically viable, as it is more sustainable and cost-effective