Hard And Soft Engineering Coastal Methods Flashcards
What is a description of a sea wall and how much do they cost
5000/metre
Concrete walls placed at foot of cliff to prevent erosion
Curved to reflect energy back into the sea
What are the advantages of sea walls
1.Often have promenades on top- popular with tourists
2.Long lifespan - cope well with high energy waves
3.doesn’t impede natural movement of sediment
What are some disadvantages of sea walls
1.can affect access to beach
2.costly to construct and maintain
3.recurved sea walls can increase erosion of beach material
4.they look ugly and destroy habits
What is the description of groynes and how much do they cost
Wooden barriers constructed at right angles to prevent long shore drift
5000 each
What are some advantages of groynes
1.Cheaper than other hard engineering methods
2.last up to 40 years
3.cheap to repair
4.wide sandy beach attracts tourists
What are some disadvantages of groynes
1The look ugly
2.beaches down drift don’t get any material - increases erosion elsewhere
3.ineffctive during storms
What is the description of gabions and how much do they cost
110/metre
Wire mesh cages filled with pebbles and rock
As water enters the cages , wave energy is absorbed and dissipated
Ehat are some advantages of gabions
1.Cheap and easy to build
2.Wuick and easy to maintain
3.Last between 20-25 years
4.Overtime vegetation covers it and blends in with environment
What are some disadvantages of gabions
1.When damaged gabions can be dangerous-rocks falling
2.Limited use- only used at sandy beaches as pebbles would wreck them
3.Damaged gabions can cause sea birds to get stuck
What is the description of revetments and how much do they cost
Revetments are wooden slanted barriers near the back of beaches to protect the base of cliffs
2000/metre
What are some advantages of revetments
1.Cheaper and less intrusive to nature than sea walls
2.Less beach material is eroded than a sea wall
What are some disadvantages of revetments
1.Short lifespan- not suitable for high wave energy
2.Destroys habitats when constructed
3.Reduces input of sediment - affecting coastal system
What is the description of barrages and how much do they cost
Dams built across a bay or estuary to control the flow of water
Around a billion
What are some advantages of barrages
1.Can create hydroelectric power
2.Reduces flooding as it controls tidal flow
What are some disadvantages of barrages
Very expensive to construct and maintain
High environmental impacts because of impact on tides
What is the description of offshore reefs and how much do they cost
Old tyres and sediment placed in the intertidal zone to create an offshore reef
Waves break offshore reducing their energy
What are some advantages of offshore reefs
Natural marine ecosystem is barely affected
Rocks create new intertidal habitat
Dunes are able to stabilise onshore- natural barrier to erosion
What are some disadvantages of offshore reefs
May cause navigation hazard for boats
Can look like an eyesore at low tide-intangible cost
Con disrupt recreational use of beach-jet skis
What is a description of beach nourishment and how much does it cost
Beach nourishment is making beaches higher and wider by importing sand or shingle
Protection against flooding or erosion by absorbing wave energy
20/metre cubed
What are some advantages of beach nourishment
Cheap and retains natural appearance
Tourists like wide , big beach
What are some district beach nourishment
Offshore dredging of material increases erosion in other areas
After Larger storms will require further beach nourishment
What is the description of dune regeneration
Taking action to build up dunes and increase regeneration
Marram grass is planted to hold dunes together
What are some advantages of dune regeneration
1.Makes barrier between land and sea - absorbs wave energy before it gets to land
2.Increases biodiversity and creates natural habitats
What are some disadvantages of dune regeneration
During regeneration the land is closely monitored to ensure marram grass isn’t trampled on- costing time and resources
This means fencing off dunes
What is the description of managed retreat and how much does it cost
When areas of the coast are allowed to naturally erode
Usually in low value areas
Have to compensate land owners
What are some advantages of managed retreat
Retains natural balance of coastal system
Encourages development of beaches and salt marshes- important habitat
What are some disadvantages of managed retreat
People lose their livelihood if there’s industry there or farmland
Donna Nook Casestudy
What is the description of do nothing
Nothing is done and natural processes are allowed to continue
Done with very low value land
What are some advantages of doing nothing
Doesn’t interfere with coastal system and allows natural processes to take place
What are some disadvantages of doing nothing
The coastline is eroded and any land in the way is destroyed, potentially destroying cultural or historical land
