There is discussion about how the coast should be managed. There is debate about the costs and benefits of ‘hard’ and ‘soft’ engineering.
BBC Bitesize – coastal management video
There are two main ways in which you can manage coasts: hard and soft engineering. Hard engineering focuses on humans trying to control the environment and tends to be more expensive. Soft engineering aims to work with the environment and is more ecologically sensitive.
A wall made out of a hard material such as concrete that reflects the waves back into the sea.
Prevents erosion of the coast
Acts as a flood barrier
Creates a strong backwash which erodes under the wall
Very expensive to build and maintain
Wooden or stone fences that are built at right angles to the coasts which trap material transported by longshore drift.
Create bigger beaches which can absorb wave energy reducing erosion
Bigger beaches also give greater protection from flooding
Prevent areas further along the coast from receiving material which make those beaches narrower and allow increased erosion
Boulders of more resistant rock are placed in front of the cliff/coast
Boulders break up waves and absorb their energy thus reducing rates of erosion and flooding
Boulders can be moved by strong storm waves so may need replacing
Sand from elsewhere (e.g. the offshore seabed) is added to beaches to replace material lost
Creates bigger beaches which can absorb wave energy reducing erosion and flooding
Expensive as beach material has to be frequently topped up
Taking material from the seabed can kill organisms like sponges and corals
Creating or restoring sand dunes by either nourishment or planting vegetation to help stabilise sand
Dunes provide a barrier between the land and sea
Wave energy is absorbed reducing erosion and flooding
Stabilisation is relatively cheap
Protection is limited to area with dunes
Nourishment is expensive
Planting vegetation in mudflats along the coast to turn them into marshes
Vegetation stabilises the mudflats and reduces wave speeds which reduces erosion and flooding
Creates new habitats
Doesn’t work where erosion rates are high as the marsh won’t be able to establish itself
Removing an existing sea defence and allowing the land behind it to flood
Eventually the land will become marsh creating new habitats
Marshland slows waves down reducing erosion and flooding for the land behind the marsh
People may disagree about which land is allowed to flood e.g. flooding farmland would affect the livelihood of farmers
Case study – Holderness
Geo factsheet – Holderness coastal management
Homes under threat on the Holderness coastline – video
Place Strategy Bridlington 4.7km sea wall and wooden groynes Hornsea Sea wall, wooden groynes and rock armour Mappleton Two rock groynes – they were built in 1991 costing £2million and were built to protect the village and a coastal road from flooding Withernsea Groynes and a sea wall. Some rock armour was placed in front of the sea wall after it was damaged by severe storms in 1992 Spurn Head Groynes and rock armour
These strategies do help to protect the coastline but they do cause problems as well.
- The groynes do protect the area they are directly in front of but reduce the amount of material transported by the longshore drift along the coast. This increases the rate of erosion further along the coasty as beaches become narrower e.g. Cowden Farm, which is south of Mappleton, is now at risk of falling into the sea.
- The material created from the erosion of the Holderness coastline is normally transported south across the Humber Estuary and along the Lincolnshire coast. By reducing the amount of material that is eroded and transported the risk of flooding further south is increased.
- The rate of coastal erosion and retreat along the Lincolnshire coast is also increased due to a lack of material supplying the beaches there.
- Spurn Head (a spit) is at risk of being completely eroded away because less material is being added to it.
- Bays are forming between the areas protected by sea defences and the areas which are protected are becoming headlands. This makes the headland areas more prone to erosion and means that it becomes more difficult and expensive to maintain the sea defences there.