Sea level Change
Changes result from either an increase in the volume of water in the oceans (eustatic) or subsidence at the coast (isostatic).
TASK
The current sea level rise is 4-5mm per year and future predictions vary at a rise of between 0.3 to 0.5m by 2090.
Make notes from the National Geographic link above, your text book pages 98 to 99 and other links here on the rise, causes and consequences.
Include the effects on:
- urban areas
- ground water resources
- agriculture
- coastal habitiats
- low lying islands
- sea defences
- insurance cost
Changing sea levels and the Dorset Coast
There is little doubt that the climate is becoming warmer and this may
cause sea levels to rise in some parts of the world. Authorities with a
responsibility for managing the coast have to take these changes into
consideration when they are developing their plans for coastal defence.
A future rise in sea levels will have a considerable effect on the
landforms of the Dorset Coast. The weak rocks at Lyme Regis and West
Bay will be more prone to erosion, Chesil Beach may be more prone to
breaching and Chiswell’s flood problems may increase again.
However Dorset’s coastal managers are more concerned about the
predicted increase in storminess. They believe that an increase in the
magnitude and frequency of storms will have a far greater effect on the
Dorset Coast than a slow rise in sea level.
Human and Physical causes of coastal flooding - see CPG revision guide p.28 and add detail to make a mind map of these causes:
Human
- Development at the coastline (destruction of natural barriers such as mangroves)
- River management - dams trap sediment and so deltas and estuaries are starved of supply.
- Coastal management - soft engineering
- Land reclamation - eg tha Polders in the Netherlands (these low lying areas reclaimed from the sea are more likely to flood)
Physical:
- High rainfall leading to high river discharge at the coast.
- Storm surges e,g 1953 North sea surge
- Hurricanes and low pressure areas creating storm conditions and raising ocean levels.
- Tsunami
- High tides
- Coastal erosion
A case study of Coastal Flooding, what the Spec says:
Case study of coastal flooding – specific physical and
human cause(s) and its physical and socio-economic
consequences. Use this to guide you.
Your chosen case study: The Boxing Day Tsunami 2004 (watch the clip).
Starting point: CPG revision Guide pages 28-29 and this Geo fact sheet. Use colour on the fact sheets to highlight the physical and human causes and the physical and socio-economic consequences.
Add details from this link and these slides detailing the effects
Exam Question:
With reference to an area that you have studied, evaluate the impact of coastal flooding. (15 marks)
Guidance - evaluate means to discuss and give a viewpoint, having considered all the evidence. Give an overall statement value.
Coastal flooding Christmas 2014 in pictures. Cliff collapse and before and after pictures.