Coastal flooding 3.3

Local factors increasing flooding in low lying areas

• height, vegetation, subsidence

Height increasing coastal flooding- Tuvalu

• low lying coastlines are only 1-2m above sea level

• Tuvalu is less than 5m above, population of 10,000

• Small island so most live along coast- suffer from sea water encroachment

Subsidence increasing coastal flooding- Tuvalu

• low lying coastlines vulnerable to subsidence

• Human activity also causes subsidence- drainage of soil for agriculture, weight of buildings compressing sediment

Vegetation increasing coastal flooding- Tuvalu

• Vegetation traps sediment to increase land height, also reduces wave impact

• Tuvalu used to have lots of vegetation removed- 50% for tourism, housing

• Recently, afforestation taken place to reduce flooding

How do storm surges increase coastal flooding

• They’re a short term rise in sea level due to high winds pushing towards coast due to low pressure from depressions and tropical cyclones

• Threat to low lying areas

How do depressions increase coastal flooding

• It’s an area of low pressure, causing lots of rain

• Causes storms brining strong winds and heavy rain

How do tropical cyclones increase coastal flooding

• area of low pressure like depressions formed due to warm air rising form oceans

• Brings heavy rain and strong winds

Climate change

• won’t increase number of tropical cyclones but increases it’s impact

• Increased temp cause storm to be larger- more flooding, stronger winds producing more waves

• These waves erode costs more, wash away embankments protecting low lying areas