Discuss the costs and benefits of hard engineering strategies in protecting coastlines.
The command word in the questions is discuss. This means you need to present key points about the different strengths and weaknesses of hard engineering as a strategy for protecting coasts.
Groynes are wooden barriers constructed at right angles to the beach to retain the material. The beach material, including sand and pebbles, is trapped between groynes and cannot be transported away by longshore drift. Groynes encourage a wide beach which helps absorb energy from waves, reducing the rate of cliff erosion. A wide, sandy beach attracts tourists, bringing benefits to the local economy, and it is a relatively cheap option and easy to maintain.
However, groynes act as a barrier that impedes people from walking along a beach. The beach downdrift of the defences is starved of beach material due to their impact on longshore drift. This leads to increased erosion which has an economic impact further along the coast. Additionally, groynes can be ineffective during storm conditions and require regular maintenance.
Seawalls are usually built along the front of cliffs to protect settlements or other land of high economic importance. An economic benefit of sea walls is that they tend to have a long lifespan and provide excellent defence where wave energy is large. Also, sea walls do not impede sediment movement along the coast by longshore drift. Additionally, sea walls often have a promenade on top of them, which are popular with tourists.
However, an economic disadvantage of seawalls is they are very expensive to construct and maintain. Also, reflected waves scour the beach and can cause foundations to be undermined. The environmental impacts of sea walls include the destruction of natural habitats, which look unattractive. The main social issue of sea walls is they affect access to the beach.
Hard engineering coastal management involves building artificial structures that control natural processes. Hard engineering approaches to coastal management tend to be expensive, last only a short time and are visually unattractive and unsustainable. They often increase erosion in other places further down the coast.
AO2 – 3 marks
AO3 – 3 marks