coasts case studies Flashcards
what is happening in the Kiribati islands
sea levels are rising 1.2cm a year and most of the island is only 2m above sea level
it is the most vulnerable place due to global warming and is creating the first climate refugees
what is happening in the River Nile Delta
it is the longest river in the world and river discharge has fallen from 35 to 10billion m3, casued by the trapping of sediment in a dam (Aswan dam). The erosion rates at Rosetta (the main branch that meets the sea) has gone from 25 to 200m, meaning it is being starved of sediment
what happened in bangladesh regarding Cyclone Sidr
- 2007
- storm surge of 6m
- drinking water contaminated
- electricty and communication was cut off
- extensive flooding in low-lying areas
- US$1.7bn
most of the losses where due to lack of/failure embankments and subsequent flooding
the death toll was lower than expected due to improved forecasting and weather warnings
coastal flooding in developed areas
2013 december storm surge that affected the UK
- storm surge was triggered by a powerful low-pressure system moving across the North Sea. This resulted in extremely strong winds and a drop in atmospheric pressure, which caused the sea level to rise significantly.
The surge coincided with the highest spring tides of the year, which exacerbated the flooding risk.
- £100 million in damage
- the Thames barrier was closed which protected most of London
- hundreds of thousands of properties where protected by flood defences
what happened with hurricane sandy
a hurricane caused by a tropical wave which led to a tropical depression
- $18bn for NYC
- 100mph gusts of wind
- heavy rainfall which led to flooding
- around 300,000 homes in NYC destroyed/damaged
- climate change exacerbated the hurricanes impacts
what is happening in Jakarta
the mega-city is the capital of Indonesia and homes 32million people. it is slowly sinking due to illegal over-abstraction of the underground aquifers due to a lack of public access to water. this is leading to the ground sinking 25cm a year and is expected to have most of the city underwater by 2050
why is Bangladesh vulnerable to flooding
169million people live in Bangladesh and 46% live less than 10m above sea level and are at extreme risk of coastal and river flooding.
physical = height of the land makes bangladesh more vulnerable
Seasonal Flooding: Bangladesh experiences a tropical monsoon climate, with heavy rainfall from June to October. The monsoon rains can be intense, and the sheer volume of rainfall causes rivers to swell and flood the surrounding lowlands.
Low-Lying Delta: Bangladesh is situated on one of the largest river deltas in the world. The country is very low-lying, with much of its land being only a few meters above sea level. This makes it highly susceptible to flooding from both riverine and coastal sources.
Multiple Rivers: The country is crisscrossed by several major rivers, including the Ganges. These rivers carry large volumes of water, and during the monsoon season, they frequently overflow, leading to river flooding.
human = subsidence for agriculture and water abstraction and removal of vegetation
Insufficient Flood Control Infrastructure: infrastructures are often inadequate, poorly maintained, or overwhelmed during extreme events.
Urbanization and Drainage: Rapid urbanization has led to the filling of natural floodplains and wetlands, reducing the land’s capacity to absorb floodwaters. In addition, inadequate drainage systems in cities like Dhaka cause urban flooding during heavy rains.
High Population Density: Bangladesh is one of the most densely populated countries in the world. Many people live in flood-prone areas, particularly in rural regions and along riverbanks. During floods, this dense population faces higher risks of displacement, loss of livelihoods, and increased vulnerability to disease outbreaks.
Poverty and Limited Resources: Many people in flood-prone areas live in poverty and have limited resources to protect themselves or recover after floods. This lack of resources makes it harder for communities to build resilience against flood risks.
Loss of Natural Buffers: Deforestation and the loss of wetlands and mangrove forests along the coast also diminishes the land’s natural flood defenses, leaving coastal areas more vulnerable to storm surges and rising sea levels.
holderness coastline
one of the fastest eroding coastlines in Europe
- The coastline is composed largely of soft, easily erodible rocks, particularly boulder clay, which, during storms, is significantly more likely to be eroded ad washed away by winds/waves than harder rocks
- The Holderness Coast faces the full force of the North Sea, which is known for having powerful waves, especially during winter storms.
- rising sea levels
- natural supply of sediment is often insufficient to counterbalance the rate of erosion due to longshore drift
- mass movement of the cliffs (retreat) as the soft rock is easily eroded
borth, wales
hard and soft engineering
created a large offshore rock reef, 2 large groynes and beach nourishment
costed £12million
+ increased tourism and surfing
- groynes have created tensions with fairbourne as they starve beaches further down
fairbourne, wales
- had coastal management schemes that have now been scrapped
- all residents (around 1000) will have to relocated sometime around 2050 as protecting the area from coastal erosion has been too difficult and expensive
- will become the first decomissioned town due to climate change in the UK
- tensions with borth as they are having £12million invested
bridgewater, somerset
soft engineering
- creation of wetlands and nature reserves
- creation if one of the largest salt marshes in the UK
- costs £21million
+ no eye-sore
+ good for nature and biodiversity
- compulsory purchase of land from farmers
rossall, blackpool
hard engineering
- creation of a new sea wall, promenade and reventments
- 327000 tonnes of rock armour to protect 7500 properties from flooding
- costs £64 million
+ employment
+ used local materials and expertize which supported the local economy
- visual pollution as some residents said it was ugly
- sea levels are rising so significantly some say that they have wasted money on the defences so they’re only seen as semi-permanent by some
bacton, north norfolk
soft engineering
- 1.8 million cubic meters of sand pumped into the coastline for beach replenishment
- cost £20million for a 6km strech of coastline
+ protects a gas terminal that is very important for the uk
- only has a 20-25 year lifespan and will have to be regularly replenished
aswan dam, sudan
two large dams located on the Nile River in Egypt
- The primary purpose of the Low Dam was to control annual flooding of the Nile, store water for irrigation, and provide a small amount of hydroelectric power
- the high dam was built a few decades after the low dam was built, one of the main objectives of the High Dam was to control the periodic flooding of the Nile, water storage and hydroelectric power
+ Agriculture: allowed for year-round irrigation, significantly boosting Egypt’s agricultural output. With more stable water flow, farmers could irrigate crops more reliably, improving food security.
+ Electricity: The hydroelectric power generated by the dam provided a reliable and inexpensive source of electricity, supporting the country’s industrialization and economic growth.
+ Flood Control: floods are now predictable and manageable.
- Sediment Trapping: sediment is now trapped in the reservoir, leading to the depletion of soil nutrients in downstream regions.
- Environmental Changes: The dam has affected aquatic ecosystems, as well as fishing communities, which rely on the natural flow of the river for their livelihood. The reduced flow of nutrient-rich silt has also impacted wetland habitats.
