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What are groynes and their purpose in coastal protection?
They are fences placed at right angles to the beach to trap sand moved by longshore drift to create wider beaches that absorb wave energy.
What is the lifespan and cost per metre of groynes?
They have a lifespan of 25 years and cost £1200 per metre.
What does a sea wall do?
It is a concrete wall that protects towns by absorbing wave energy and reflects waves back out to sea.
What is the lifespan and cost for sea walls?
They have a 100 year lifespan and cost £5000 per metre plus any repair work.
What is rock armour, and what is its function?
They consist of large boulders piled on the beach to absorb wave energy and prevent erosion.
What is the lifespan and cost per metre of rock armour?
They last 100-500 years and costs £1000 per metre.
What does managed retreat involve in coastal protection?
They allow some coastal areas to erode and flood naturally without preventing erosion.
What is the lifespan and cost for managed retreat?
They have an unlimited lifespan and a varied cost.
Why is managed retreat often unpopular?
It is unpopular because it can lead to flooding of tourist sites which are rural lands.
What are gabions used for?
They are steel mesh cages filled with boulders used to absorb wave energy near the coast.
What is the lifespan and cost per metre of gabions?
They have a lifespan of 10 years and cost £400 per metre.
What are revetments and their function?
They are ramps that absorb wave energy and filter sediment through holes.
What is the lifespan and cost for revetments?
Revetments last 25-30 years for wooden ones and 40 years for concrete, costing £2000 per metre.
What is beach replenishment?
It involves replacing sand that has been washed away to restore the beach.
What is the cost of beach replenishment per metre?
It costs £3 - £10 per metre.
What is dune stabilising and its purpose?
It involves using plant roots to bind sand to prevent erosion and protect against waves.
What is the cost of dune stabilising per metre?
It costs £200 per metre.
What is an offshore breakwater?
It consists of large piles of concrete and cement parallel to the beach to reduce wave force.
What is the cost and lifespan of offshore breakwaters?
They cost £300 per metre and can last between 50 to 100 years.
What is a common disadvantage of hard engineering techniques like sea walls and groynes?
They can create strong backwash that erodes sediment under the structures.
Why are giant boulders in rock armour considered good for the environment?
It looks good and can be moved, making it less intrusive in coastal areas.
What is a potential drawback of using gabions near the beach?
They can be sharp and may hurt tourists, which is negative for tourism.
What advantage does managed retreat have over other techniques?
It is very friendly to the environment and preserves natural coastal processes.
What maintenance is required for dune stabilising to last indefinitely?
It needs to be maintained, specifically by ensuring plant roots remain intact.
What is a trade-off of using revetments in coastal areas?
While they provide easy beach access for tourists, they can create strong backwash that leads to erosion.
How do groynes affect sediment distribution along the coastline?
They trap sand, reducing sediment deposits further down the coastline and potentially causing erosion there.
How does beach replenishment compare environmentally to other techniques?
It is environmentally friendly but needs to be conducted continuously.
What benefits do sea walls provide for tourism?
They allow for easy access to the beach, benefiting tourism.
What is a potential environmental issue with hard engineering methods like sea walls?
They can lead to erosion of sediments under the wall due to strong backwash.
How do offshore breakwaters function in coastal protection?
They reduce the speed of wave erosion, but they do not completely stop it.
What is one reason beach replenishment may be less preferable than other methods?
It requires constant replacement of sand, making it less sustainable in the long term.
Why is the cost of managing retreat variable?
The cost can vary greatly depending on the specific area and its value.
