Traditional Approaches to Management (AQA A Level Geography)
Revision Note
Written by: Alex Lippa
Reviewed by: Bridgette Barrett
Coastal Hard Engineering
Coastal management is essential to build resilience in coastal communities around the world
Climate change, increase tropical storm intensity, more frequent storm surges and sea level change are increasing the rates of coastal erosion and flooding
These hazards need to be adapted to, as they are already happening in many places
Preventing coastal erosion through hard engineering is generally effective but it is very expensive
Hard engineering can also often be unsightly
There are lots of different hard engineering strategies, to decide which is most appropriate in a particular area a cost benefit analysis must be carried out
Some areas are left with no protection because the costs are deemed to outweigh the benefits
Structure | How it works | Advantages | Disadvantages |
|---|---|---|---|
Groynes | Structures built perpendicular (at right angles) to the shore. Sediment is trapped as it is transported by longshore drift. The beach builds up which absorbs wave energy | Not as expensive as other hard engineering structures Builds up the beach which improves tourist potential | Causes sediment starvation further along the coast Can be unattractive Need lots of maintenance to ensure sediment isn’t getting through any holes or cracks |
Sea Walls | Walls with a curved or stepped surface that absorb and reflect wave energy | Highly effective Can have tourism benefits as walkways are created | Very expensive to build and maintain - £6000 per metre Are ugly and intrusive to the landscape |
Rip Rap/ Rock armour | Large concrete or granite boulders at the foot of a cliff. The spaces in between the boulders cause waves to bounce between many surfaces, reducing the energy of the wave | Cheaper than sea walls Used for recreation such as fishing | Dangerous when people are on them Rocks from elsewhere are intrusive to local geology |
Revetments | A sloped or ramp-like structure that breaks up wave energy | Cost-effective compared to other hard engineering strategies | Need lots of maintenance Unnatural looking Slopes are dangerous |
Offshore Breakwater | Rock barrier a little out to sea from the shoreline. This breaks the waves and dissipates their energy before they reach the coast. | Effective Away from the beach so does not disrupt tourist potential | Can create a navigation barrier in harbour areas |
Examiner Tips and Tricks
You need to be comfortable evaluating hard engineering strategies against each other and against other methods like soft engineering using examples.
Coastal Soft Engineering
Soft engineering is different from hard engineering as it works with natural processes and material
Soft engineering methods can be an integral part of the strategy to adapt to sea level change as well as coastal erosion, such as through the development of marshes
Method | How it works | Advantages | Disadvantages |
|---|---|---|---|
Beach nourishment/ replenishment | Adding sand or shingle to a beach to widen it - creates more surface area to absorb wave energy | Looks very natural Bigger beaches are good for tourism Relatively inexpensive | Material is constantly subject to erosion and longshore drift so lots of maintenance and monitoring are needed Dredging the seabed can have impacts on local ecosystems |
Cliff Regrading and Drainage | Reducing the angle of the cliff to stabilise the slope. Drainage of water also stabilises the cliff against mass movement | Cost-effective | Can look unnatural as the cliff is unnaturally flatter This effectively creates a cliff retreat Dried-out cliffs can collapse |
Dune stabilisation | Planting species like Marram grass so that the roots bind the dunes. The dunes absorb wave energy and protect the land behind them. | Cheap and sustainable Creates habitats for wildlife Maintains a natural environment | People walk on the dunes and damage them Planting is time-consuming and it takes time for plant species to become established |
Marsh Creation | This is a form of do-nothing or managed retreat. The land is allowed to be flooded by the sea and then left to become a salt marsh. This absorbs wave energy and also creates a buffer to rising sea levels and projects higher-value land. | A cheap option Creates important and unique wildlife habitats | Agricultural land is lost which creates a need for c |
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