Topic 1: Coasts
Key Question 1: How and why are coastal environments different and dynamic?
How are coastal environments different?
Why are coastal environments dynamic?
· Definition of coast – the area where the land meets the sea
· Coastal environments are dynamic and changing due to
– Waves
– Currents
– Tides
– Geology
– Human activities
– Ecosystem type: mangrove and coral
What are waves and how are they generated?
· Waves are generated when there is a transfer of energy from wind to water surface
How do waves affect coastal areas?
· Wave energy depends on the following factors
– Fetch
– Wind speed
– Wind duration
· Wave refraction and associated concentration and dissipation of wave energy
· Processes which occur when waves break
– Swash
– Backwash
· Types of waves and wave environments
– Constructive waves occur in an environment with low gradient and low energy
– Destructive waves occur in an environment with steep gradient and high energy
Why and in what ways do coastal landforms and features vary from place to place?
· Coastal processes
– Erosion by waves
o Abrasion
o Hydraulic action
o Attrition
o Solution
– Transportation through longshore drift
– Deposition
· Formation of coastal landforms
– Erosional landforms
o Cliffs and shore platforms
o Headlands and bays
o Caves, arches and stacks
– Depositional landforms
o Beaches
o Spits and tombolos
How do people use coastal areas?
· Human activities in coastal areas with reference to an example for each of the following:
– Fisheries and aquaculture (e.g. Kung Krabaen Bay in eastern Thailand)
– Housing and transportation (e.g. houses built on stilts and ferry services to Kukup in southern Johor in Malaysia)
– Tourism and recreation (e.g. marinas and integrated resort on Sentosa in Singapore)
Why are coral reef ecosystems distinctive and valuable?
· Coral reefs:
– Environmental conditions for growth
o Sea surface temperature
o Amount of sunlight received, dependent on turbidity and water depth
o Level of salinity and oxygen content
– Distribution in the Tropics (e.g. Great Barrier Reef in Australia, reefs around Philippines and Indonesia)
– Value
o Coastal protection
o Habitat for marine creatures
What pressures are coral reefs facing?
– Pressures
o Over-collection of corals
o Fishing methods
o Recreational use of the coast
o Coastal development
o Climate change causing coral bleaching
Why are mangrove ecosystems distinctive and valuable?
· Mangroves
– Environmental conditions for growth
o Sediment supply
o Sheltered coastline resulting in low energy wave environment
– Distribution in the Tropics (e.g. the Sundarbans in India and Bangladesh)
– Adaptations
– Value
o Habitat for marine creatures
o Stabilise shorelines by trapping sediments
o Protect coastal areas by absorbing force of storms
What are the pressures on mangroves?
– Pressures
o Clearing of mangroves for fuel wood and charcoal
o Conversion to other land uses (e.g. paddy fields, shrimp farms)
o Coastal development
o Rising sea level
How can coastal areas be managed?
What are the coastal protection measures?
· Sustainable management of coastal areas
– Laws and regulations (e.g. Limit damaging activities, protect coastal resources, restrict development in areas prone to natural hazards)
– Measures to protect the coast from erosion
o Soft engineering
Ø Beach nourishment
Ø Planting of vegetation
Ø Stabilising dunes
Ø Encouraging the growth of coral reefs
o Hard engineering
Ø Seawalls
Ø Tetrapods
Ø Gabions
Ø Groynes
Ø Breakwaters
With reference to a case study of Singapore, consider the following guiding questions:
1) What are the uses of coastal areas?
2) What measures have been adopted to protect the coast?
3) How effective are the coastal protection measures?
4) Should the coastal environment matter?