By Laurence Kobrock

Coastal Management / Protection

What is Coastal Management?

Coastal management is defence against flooding and erosion and techniques that allow erosion to claim land.

Why do we do it?

In the case of humans, we use the coastline for agriculture, for fishing, for industry and power generation, for transport routes and for land upon which to live.  However, a lot of these land uses are incompatible with the fact that the coastline is constantly changing. Erosion processes remove land from some parts of the coastline, whereas deposition processes create new land in other places.  In addition, the fact that the sea level is rising locally and globally could add to these erosion and deposition problems whilst also removing land from use at the coastline.

What are Hard / Soft measures?

Hard

• Hard engineering involves the building of entirely artificial structures using various materials such as rock, concrete and steel to reduce or stop the impact of coastal processes

• Ex:– Groynes– Sea Walls

Soft

• Soft engineering options are often less expensive than hard engineering options. They are usually more long-term and sustainable, with less impact on the environment

• Ex: – Beach Nourishment– Due Regeneration

Recurved Sea Wall

• Massive, made of rocks or concrete, used to absorb waves. Some types can act as Baffles

Advantages

• Very effective• Reasonably long

lifespan• Traditional solution• Can prevent coastal

flooding in some areas

Disadvantages

• Very costly• Visual pollution• High maintenance

cost

Groynes

• Rock or wooden types, hold beach material threatened by LSD erosion

Advantages

• Low capital costs• Repaired pretty easily

Disadvantages

• Need regular maintenance

• Cause scour downdrift• Visual pollution

Rip Rap (rock armour)

• Very large rocks in front of sea walls to absorb waves

Advantages

• Very effective• Prevents large-scale

undermining

Disadvantages

• Expensive• May move in severe

weather

Off shore reefs

• Reduces power of waves offshore

Advantages

• Can be built of waste materials

• No visual pollution

Disadvantages

• Possible ecological impacts

• May not work at large scale

Toe armouring

Advantages

• Low maintenance costs• 30-50 years effectiveness

Disadvantages

• High construction costs• Disruption to ecology

Revetments

• Made of concrete or wood.

• Reflects waves rather than resist them

Advantages

• Cheaper than sea walls• Traditional solution to

protect valuable resources, densely populated areas an high-risk property

Disadvantages

• Costly• Do not cope well with

very strong waves• Visual pollution

Gabions

• Wire cages holding smaller rocks

• Bank/cliff stabilisation

Advantages

• Cheaper than revetments• The rocks absorb a

moderate amount of wave energy

Disadvantages

• Relative small scale solution

• Visual pollution

Cliff Stabilisation

• The drainage of excess rainwater by terracing, planting and wiring to keep the cliff in place

Advantages

• Cost effective

Disadvantages

• A moderate amount of visual pollution

• Effects the ecology of the cliff

Cliff drainage

• Removal of water in order to prevent landslides and slumping

Advantages

• Cost effective

Disadvantages

• Drained cliffs can dry out and lea to collapse

• Has effects on the ecology

• Visual pollution

Beach nourishment

• Sand pumped or transported to replace losses by LSD

Advantages

• Looks like a ‘natural looking’ process

Disadvantages

• Expensive• Will erode soon• Ecological effects

Natural (do nothing)

• Land no longer worth protecting. Lets the sea erode the land with no intervention

Advantages

• Saves expenditures on defence

• No impact on nature and ecology

Disadvantages

• May allow problems to get worse

• Loss of land