Coasts 5 - Coastal managment Flashcards
What is the aim of coastal management?
To protect homes, business and the environment from erosion and flooding
Why is coastal management appropriate
As flooding and erosion have severe social, economic and environmental impacts
How are places that need to be protected chosen?
Cost-benefit analysis (CBA)
What are the 4 options for coastal erosion
- Hold the line
- Advance the line
- Do nothing
- Managed realignment
What is the money give to coastal settlements used for?
To protect large settlements and important industrial sites rather than the small isolated settlements
What is hold the line?
Maintain the existing coastal defences
What is advance the line?
Build new coastal defences further out to sea than the existing line of defence
What is doing nothing
Build no coastal defences at all and deal with the erosion and flooding as it happens
What is managed realignment
Allow the shoreline to move but manage retreat so it causes the least amount of damage
What Are 9 examples of hard engineering?
1) Sea wall
2) Revetment
3) Gabions
4) Riprap
5) Groynes
6) Breakwaters
7) Earth bank
8) Tidal barrier
9) Tidal Barrage
What does a sea wall do?
Reflects waves back out to sea, preventing erosion of the coast. It acts as a barrier to prevent flooding
What are 2 issues with sea walls
- Expensive to build and maintain
- Creates a strong backwash that erodes under the wall
What is revetment
Slanted structures built at the foot of cliffs. They’re made of concrete wood or rocks. Waves break against the revetments which absorb the wave energy and prevent cliff erosion
What are 2 issues with revetment
- Expensive to b build, but cheap to maintain
- Create a strong backwash
What are gabbion’s?
Rock filled cages. A wall of gaboon’s is built at the foot of the cliff. They absorb wave energy and reduce erosion
Whats an issue with gabion’s
Cheap but ugly
What are rip rap
Boulders piled along the coast, they absorb wave energy and reduce erosion
Give a - of rip rap
They’re cheap but can shift in storms
What are groynes?
Fences built at right angles to coast. They trap beach material that’s transferred by longshore drift. Creates wider beaches which slow the waves (reducing their energy) and gives greater protection from flooding and erosion
What are the issues with groynes
They’re cheap but they starve down-drift beaches of sand. Thinner beaches don’t protect the coast as well, leading to greater erosion and flooding