Geography - Theme 2 case studies

New Orleans is located in South East America in the state of Louisiana, approximately 350 miles East of Houston

Hurricane Katrina formed over the Bahamas in the Atlantic ocean over warm water (over 27 degress celcius) and at latitudes between 8 and 20 degrees. It formed when wet air rose creating low pressure over the surface of the water, this low pressure sucks in air from warm surroundings which begins to spin anti clockwise due to coriolis effect, around the low pressure eye due to centripetal force. This gains energy from condensing water vapour. The system moved west pas It crossed Florida before gaining speed and energy over the Gulf of Mexico. It affected the Carribean, Florida and many Southern states of America. Louisiana, where New Orleans is, was hit the worst.  

The storm goes through some different stages. First it starts as a tropical wave then the pressure drops and there are sustained winds up to 38 miles per hour and this is called a tropical depression. When the cyclonic winds have sustained speeds from 39-73 miles per hour it is called a tropical storm. The storm then ends when it travels over cold water or land as the warm water which is its energy source is gone. It weakens and quickly dies.   

The economic effects of the storm were: Thirty oil platforms were destroyed or damaged and 9 refiners were shut down which reduced oil production by 25% and left thousands unemployed, fewer taxes were paid (trikle down). The social impacts were: 1 millions people evacuated/displaced/homeless with the less well off being the worst hit, overhead powerlines were brought down contaminating the water and food supplies and most of the major roads in and out of the cities were damaged as bridges collapsed. The enviromental effects were: the 6 metre storm surge destroyed sections of the barrier island and gulf beaches and 5300 kilometers of forest and woodland were destroyed

New Orleans was badly hit because it is below sea level and is surrounded by Levees which couldn't cope with the power of the storm and were breached. There was much criticism of the authorities for the way that they handled the disaster. Although many people were evacuated, it was a slow process and the poorest and most vulnerable were left behind. Areas of refugee were set up, one of which was the superdome stadium. However they were unhygenic and there was a shortage of food and water. $50billion was given in aid. The UK government sent food in the early stages. The National Guard was mobilised to restore and maintain law and order in what became a hostile and unsafe living enviroment.  

Carlise is located in Cumbria in the North of England, West of Newcastle upon Tyne. The area was hit by a flood that occurs once every two years.

The flood was caused by a few things. 2 months of rainfall fell in 24 hours, Carlise is at the confluence of three rivers (Eden, Petteril and the Caldrew), the urbanisation of Carlise over the flood plainof the River Eden increases overland flow, Low pressure system stopped moving when it got to Cumbria. Storm followed a period of heavy rainfall so the ground was saturated which reduced infiltration and increased surface runoff and Deforestation meant that there is less interception so an increased risk of flooding.

The impacts of the flooding were: 1,700 homes flodded and 120 people still hadn't returned home 1.5 years after the flood, it cost £400 million, local busnesses flooded which had a negative multiplier effect, schools were closed, police and fire stations were flood and so temporary ones had to be set up in Carlise Castle which reduced response times to flooding, 3 people died, transport in and out of the area was stopped and mould developed in some of the buildings when they dried out which if it wasnt cleared could have become a health risk.

The flood was managed in the following ways: sanbags were distributed to protect property, high volume pumping units were mobilised to remove water from the sewerage system which was preventing water from draining away, enviromental agency issued twenty flood warnings by text/phone and loud speaker, residents were airlifted or rescued by boats from flooded properties.

With climate change there is a higher chance that these events will occur again more often in the future so the following strategies will be used to manage events should they reoccur. 50% of people in the area hadn't signed up to flood warnings but this has now increased 80%, a £36 million flood defense scheme set up in 2010, embankments and flood walls built and drains installed behind defences to drain trapped water.   

The Sahel region is an area affected by desertification. The Sahel is located on the Southern edge of the Sahara desert and stretches between the Atlantic Ocean in the West and the Indian Ocean in the East

Desertification has occured for a range of reasons over time. In the 1950s people settled in the Sahel region in areas where ther was water. However they overgrazed the land and destroyed the perennial shirbs which left annuals which werre also destroyed to leave bare soil. The top soil was washed away leaving bare rock. The silt turned hard and roots couldn't penetrate the hard layer meaning that plants were unable to grow. Lack of vegitation meant that the soil eroded quickly and the area turned to desert. As rainfall has decreased sands have shifted about sixty miles south into the area. Slash and burn techniques made the problem worse by decreasing soil quality. Rainfall has decreased over this period making the problem worse.  

The short term impacts are that the soil isnt useful, vegetation is destroyed, erosion occurs and the land becomes salty so it is difficult to grow crops. The long term ipacts are that people and livestock die fo starvation and the soil becomes useless.

There are strategies to counter desertification. Harvesting branches rather than whole trees to prevent deforestation, soil erosion and desertification, controlling burning of grassland to avoid wildfires, crop rotation to keep a varied supply of nutrients in the soil and prevent soil erosion and desertification, stone lines along soil contours, known as bungs, which encourage rainwater to infiltrate soil, prevent soil erosion and increasing crop yield by 30% however it is labour intensive and diverts communities from other tasks. Afforestation however newly planted trees and plants will need lots of water which is a problem in the region. Decreasing livestock which solves problem of overgrazing but requires people to adapt if they rely on cattle or goats for their livelihoods.

In the region in 2004 subsistence farmers in Mali and Nigeria were hit by a double problem, of a severe drought and a plague of locusts destroying crops. By July 2005 3.3 million people were at risk of serious food shortages.  

The Amazon Rainforest is an ecosystem that is not being managed sustainably. The Amazon Rainforest is located in the North of South America, in the Amazon basin, North of Argentina.

The water cycle in the system: Roots take up water from the ground and water is intercepted as it falls. As the forest heats up evapotranspiration occurs to make the next day's rain. This is convectional rainfall. The high level of evapotranspiration makes the rainforest very humid. The nutrient cycle in the system: Hot damp conditions mean that decomposition happens quickly, which means that many nutrients enter the soil. However these nutrients are quickly used up by the fast growing plants. 

Deforestation is a huge problem in the rainforest and has profound impacts not just on the rainforest but the whole world. If vegetation is removed then the soil becomes infertile and vulnerable to erosion. The rainforest accounts for 50% of the world's global biodiversity and deforestation is killing of a number of plant and animal species. Rain forests also take in massive amounts of carbon dioxide and release oxygen, which is the reason that it is given the nickname 'the lungs of the planet'. They also store large amounts of carbon so cutting and burning their biomass is contributing to climate change. We also rely on the rainforest for food, crops and medicines.

There are many causes of deforestation. Population growth and poverty is encouraging poor farmers to clear new areas of the rainforest. The government allow peasants to own the land that they clear. The World Bank and other leading institutions provide money to the government which encourages large scale projects like mining, construction of dams, new roads and other infrastructure that directly reduce the forest. In addition to the projects new roads and facilities must be built to make the projects possible. The land is also being cleared for bananas, sugar cane ect.

Bangladesh is located in South East Asia, it is bordered by India in the North, East and West and has the Bay of Bengal to it's South. It is South of Bhutan. Flooding occurs annually in this region.  

80% of Bangladesh is less than 5 metres above sea level. The annual monsoons bring high levels of rainfall across the vast drainage basins of the rivers Ganges and Brahmaputra flooding up to a third of the country every year. The country is situated on deltas of rivers (land formed when a river approaching a body of still water slows and allows deposition to occur).       

Some advantages of living in Bangladesh are: the land is very fertile, new land can be claimed (important as it is one of the most densely populated countries on Earth), the area is great for fishing. Some disadvantages of living n Bangladesh are: it is difficult to build any roads or railways, there is no permanent settling (most families live on 'chars' which are changing islands and so have to move every year, investment is risky, up to a third of the country is flooded every year, industry has no raw materials as land is composed of alluvium.  

Predictions for the future of Bangladesh: The population will continue to grow, the floods will increase in size, millions of people will be made homeless and will migrate inland and global warming will cause rising sea levels submerging the delta.

Hurricane Katrina

Carlise

Sahel

Amazon RAINFOREST

Bangladesh