COASTAL MANAGEMENT Flashcards
how much of english coast is heavily developed
25%
how much has the coast retreated from 1872 - 1970
27m
What are the fundamental aims of coastal management
Defend against water inundation (flooding
Protect against coastal erosion
What are the two types of coastal defences
Soft coastal defense (natural structure)
Hard coastal defense (engineered solution)
What are the four defense options
Do nothing: let cliff erode/let area flood
Maintain existing defenses
Improve level of defense
Managed retreat: let some areas flood, but not all of it
Sea wall
Large curved, concrete surface, deflects wave.
Easy to make, good in high - density area
Expensive. Only 40 - 50 year lifespan.
Groyne
Long wooden fences perpendicular to beach.
Stops longshore drift, flooding, erosion. Lets beach build up.
Causes erosion on downdrift side. Can interrupt sediment flow. Expensive
Gabion
Rocks in metal mesh at base of cliff.
Reduces wave impact and inexpensive
Small scale solution. Not very attractive
Revetement
Slanted wooden planks on cliff/beach.
Prevents cliff erosion and absorbs energy form waves.
Expensive and can create strong wave backlash.
Coastal barrage
Partially submerged dam, controls tidal flow
more consistent water level and hydroelectricity
Impact on environment plus expensive
Rock Armour (rip rap)
Big rocks piled on beach in front of cliff/seas wall
Absorbs wave and builds beach
Inexpensive.
Cliff fixing
metal bars in cliff to reinforce
improves strength and prevents rock fall.
A big metal mess
Beach Nourishment
Pump sand from seabed to replace eroded sand.
Looks natural
Expensive, short term solution
Managed retreat
Let specific areas flood.
Encourages development of beaches and salt marshes
Compensate people losing land. Also unpopular
