Coastal Opportunities, Hazards and Management

Coastal Opportunities, Hazards and Management

IGCSE Geography

Learning objectives

• Explain opportunities and hazards that coasts present

• Suggest ways to manage coastal erosion​

IGCSE Geography

Open Ended

How do hurricanes form? How does it affect human settlements?

a storm with a violent wind​

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One of the most dangerous natural hazards to people and the environment. (high windes, floods, storm surges)

Hurricanes

Hurricanes

• intense heavy rainfall, strong winds and high waves

• flooding and mudslides

• ​they bring enormous quantities of water due to their origin over moist tropical seas (500 mm in 24 hours)

• the path is erratic so it's not always possible to give more than 12 hours' notice​

How do Hurricanes develop?

1. intense low-pressure systems over oceans

2. wind spiral rapidly around a calm central area called (eye)

3. diameter of hurricanes is around 300-800 km

4. they move from low latitudes to higher latitudes​

Conditions:

• sea temperatures must be over 27^oc to a depth of 60 m

• lo​w-pressure area has to be far enough away from the equator for the Coriolis force to create rotation

• unstable conditions - some low-pressure develop into hurricanes while some don't​

saffir-Simpson scale

Assigns hurricanes to one of five categories of potential disaster

• based on wind intensity (must be over 118 km/hr)​

-developed by National Oceanic and Atmospheric Administration

Something to think about:

• The unpredictability of hurricane paths makes effective management of hurricanes difficult​

Something to think about:

• Strongest storms do not always cause the greater damage

Something to think about:

• Distribution of population throughout the Caribbean islands increases the risk associated with hurricanes

Something to think about:

• Hazard mitigation depends on the effectiveness of the human response to natural events

• urban planning laws

• emergency planning

• evacuation measures

• relief operations (rehousing and distribution of food)​

Something to think about:

• Developing countries continue to lose more lives to natural hazards a result of inadequate planning and preparation

*in contrast insurance costs continue to be greatest in American states such as Florida where multi-million dollar waterfront home proliferate​

COASTAL Management Strategies

Coastal defence protects against coastal erosion and flooding by the sea. Long-term or short-term, sustainable or non-sustainable.

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Defence options include:

• do nothing

• maintain existing levels of coastal defence

• improve coastal defences

• allow retreat of the coast in selected areas​

Hard engineering structures

Sea walls - effectivity depends on their cost and their performance​. Prevents erosion and flooding, but mostly dependent on:

• whether they are sloping or vertical

• whether they are permeable or impermeable

• ​whether they are rough or smooth

• what material they are made of (clay, steel or rock)​

In general: flatter, permeable, rougher walls perform better than vertical, impermeable, smooth walls.

​Cross-shore structures such as groynes, breakwaters, piers and strongpoints have been used for decades.

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Their main function is to stop the drifting of material. Traditionally, groynes were constructed from timber, brushwood and wattle. However, modern cross-shore structures are often made from rock. They may be part of a more complex form of management that includes beach nourishment and offshore structures.

SUMMER Holiday HOMEWORK

Check MS Teams Announcement

Read the two attached pdf documents about map skills and ​visit the attached website.​

EAL ACTIVITY c/o Ms. Jona