Coasts EQ4 Flashcards
What’s the location description of Bangladesh (Meghna Estuary)?
What are the human influences on Bangladesh?
What are the physical influences on Bangladesh?
What were the short/long-term impacts of flooding?
Located at the mouth of the river Meghna to the east of the bay of Bengal in Bangladesh.
Population pressure of over 1000 people per square km. Mangroves have had to be deforested in order to keep up with population pressures. Increased surface runoff.
Tropical cyclones are seeded by warm tropical oceans of the Indian ocean. Low pressure draws heat from oceans.
- 138,000 died
- 10 million homeless
- Soil erosion
- Food scarcity
- Land/ water pollution
What is the flooding taking place in the North Sea in 1953 and 2013?
January 1953, a nighttime storm surge caused the death of 307 people in England and over 2100 people in the Netherlands.
- The sea level rose by 5.6 m as the storm coincided with extreme tides.
- Flooding occurred on the east coast of England, with almost 65,000 ha of farmland and 20,000 homes flooded.
- There were no flood warning systems, weather forecast for basic and communications limited.
- In December 2013 the largest storm since 1953 took place. The surge reached 6.3m in places, for example, Blakeney, North Norfolk. 18,000 people evacuated, but only 14,000 properties are flooded with no deaths.
- The major impact of avoided due to the Thames barrier, better sea defences and better forecasting.
What are the consequences of flooding in Australia?
What are the consequences of flooding in the Philippines?
- Low-lying bays tripled in the last century.
- Bondi may lose 20-40m.
- $226bn coastal assets at risk.
- 80% of coastline at risk.
- Fisheries affected.
- Relocation of homes.
Loss of: - 116,000 homes causing property damage of US $72 billion;
- $87 billion worth of commercial property threatened
- $67 billion road and rail infrastructure.
- 5 power stations,
- 258 emergency service stations,
- 75 hospitals and
- 44 water and sewage plants.
- Social costs would include the break up of communities, loss of livelihood, e.g. fishing, tourism, and amenity loss (?)
- Coral reefs forming the Great Barrier Reef will die if they are unable to grow fast enough to keep up with sea level rise, leading to a loss in tourism income.
- 2000 live on Manila bay.
- IPCC estimates a rise of 60 cm - 1 m by 2100 in the Philippines
- Losses of $6.5bn a year.
- 130 fishermen earn about $12 a week.
- Natural mangroves, coral damaged.
- Welfare loss of $168,000 a year.
- Much of the threatened area is poor shanty towns, e.g. Cavite City and Las Piñas in Manila, with low property value.
- A 1 m rise would affect 2.3 million people, and 62% of Manila in the south of Luzon Island.
- Loss of livelihood - fishing, tourism
What is happening in Kiribati?
What are the effects on Kiribati?
What is next for Kiribati?
Situated in the middle of the Pacific Ocean and is composed of 33 islands. These islands are low-lying sand and mangrove atolls that are only 1m or less above sea level. Many of the islands can disappear under the sea in the next 50 years. Sea levels are rising by 1.2 cm taller.
Rising sea levels are contaminating its groundwater sources. Climate changes cause bleaching of the coral reefs. Homes and businesses are particularly damaged during the King tides. There has been an increase in beach erosion and flooding. Food sources are becoming increasingly insecure.
The Kiribati government has purchased the land in Fiji for farming agriculture and fish farming. Its people could become environmental refugees. Under a scheme supported by the government, known as the migration with dignity policy, people have decided to relocate for better job opportunities in New Zealand and Fiji.
What are hard engineering techniques?
Man made structures to prevent coastal flooding.
What are sea walls as well as pros and cons?
Stone or concrete walls at the foot of the cliff or at the top of the beach. They’re usually curved to reflect the waves back.
+ Very effective.
+ Creates a promenade to walk along
- Unattractive and expensive.
- If theres a gap erosion can occur.
What are rip rap as well as pros and cons?
Large rocks at the foot of the cliff, or at the top of the beach. Breaks up wave energy, allowing water to pass through.
+ Relatively cheap.
+ Energy is taken out.
- Unaesthetic to look at.
- Dangerous if people climb on them.
What are groynes as well as pros and cons?
Set at right angles to the coast to slow down longshore drift. They make the beach wider and higher.
+ Maintains the size of the beach.
+ Enhances the beach.
- Unattractive.
- Expensive, £1000 per metre
What are revetments as well as pros and cons?
Sloped walls placed parallel and in front of the backshore. They take the force of breaking waves.
+ Absorbs wave energy.
+ Longshore drift can still occur.
- Costs £1500 per linear metre.
- Consistent maintenance.
What is offshore breakwater as well as pros and cons?
Boulders dropped in shallow nearshore waters and aligned parallel to the shore waters. They absorb wave energy and dissipate waves.
+ Creates sheltered areas.
+ Protects vulnerable areas.
- Costs £1/2 million.
- Other defences are needed.
What are soft engineering techniques?
The natural environment is used to help reduce coastal erosion and river flooding.
What is beach nourishment as well as pros and cons?
Replaces beach sediments eroded or transported by long shore drift.
+ Uses natural sediments.
+ Supports the tourist industry.
- Costs £10 per m^3.
- May have to be replaced.
What is cliff regrading as well as pros and cons?
Part of the cliff has been taken away in order for the angle of the cliff to be reduced.
+ Creates a natural slope.
+ Should remain stable.
- Land/ property lost.
- Costs about £1 million.
What is dune stabilisation as well as pros and cons?
Dunes provide a natural barrier to sea level and storm waves.
+ Looks natural and effective.
+ Provides a natural ecosystem.
- Short term.
- May need to be fenced off.
What is managed retreat as well as pros and cons?
Areas set out to be flooded and kept protected.
+ Allows for natural processes.
+ Extends current ecosystems.
- No compensation.
- Doesn’t prevent land being lost.
What are three adaptation strategies in managing future coastal threats?
- Restoring mangroves: These are effective against storm surges, boost fish numbers, and benefit local communities.
- Zoning areas of the coast: Threatened by sea level rise to protect further development there. This avoids increasing risk.
- Elevating critical infrastructure: For example power stations to protect them from flooding.
