Tropical Cyclone Case Study Hurricane Katrina (2005)

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1 Tropical Cyclone Case Study Hurricane Katrina (2005) Hurricane Katrina formed over the Bahamas in the Western area of the Atlantic Ocean. The Hurricane hit the city of New Orleans, the most populated city in the US state of Louisiana, on the 23rd August The Hurricane was initially a category 5 storm with winds speeds of up to 280km/h, but was downgraded to a category 3 storm by the time it hit New Orleans on the USA s South Coast. Why there was such a high impact SEVERITY As a category 3 storm the Hurricane had seriously strong wind speeds and storm surges which had high (social, economic and environmental) impacts. The storm was especially severe due to the impact of local global warming that had been exacerbated by up to 20% from deforestation in the Amazon Rainforest. ECONOMIC DEVELOPMENT New Orleans is an area of high economic development so the economic impact was high as the buildings and infrastructure was constructed from expensive, high quality materials. VULNERABILITY Hurricane Katrina s diversion meant it hit the poorer areas of New Orleans, where people weren t able to evacuate as easily (eg. few cars) and the build environment was of a low quality so could therefore be critically damaged more easily. DEFENSE FAILURES (Levees Failure + Marshland Removal) +Levee Defenses, initially designed to cope with a category 3 storm similar to Katrina, were broken by the 8m storm surges of the Hurricane, allowing 80% of the naturally below sea level city to flood. Evaluations state that the failure was due to faulty design, poor construction and incomplete sections, and that if they had not been broken, 1200 of the 1800 deaths could ve been prevented. +Removal of the natural protection from the wet marshlands from the Mississippi delta which increased vulnerability by not mitigating the severity of the Hurricane. The impacts of the event Economic $81 billion in economic damage the costliest natural disaster on record ever. Damage to infrastructure e.g. The Biloxi Bay Bridge on US Route 90 Highway was destroyed. 230,000 jobs lost as businesses suffered through stock damage/looting and lost trade. 24 million litres of crude oil spilled from damaged oil refineries. 9 refineries closed. Social 1800 fatal casualties (deaths). 300,000 homes destroyed. 3 million homes without electricity. Migration away over 1 million people migrated to other parts of the USA.

2 Environmental Storm surges caused substantial beach erosion. Nearby coastal habitats breeding grounds for sea turtles, marine mammals, migrating birds and fish were destroyed. Management strategies taken since the event Potential management strategies that could be used: Restore natural wetlands in Mississippi delta. Rebuild destroyed levees to a higher standard. Install water pumping system (to drain surface runoff in the event of a flood). Use NHC data more effectively to predict the events. Prepare for the potential impact by simulating the event and the prediction of it. Improve the warning system s ability to get information to everyone quickly and make it clear that evacuation was mandatory.

3 Depression/Flooding Case Study Boscastle Floods (2004) Boscastle is a village situated in the South West of England along the Northern coast of the county of Cornwall at the confluence of the River Jordan and the River Valency. It experienced a devastating flash flood on 16th August 2004 which has a high impact due to a combination of natural (severity) and human (vulnerability) factors. Natural factors: (that caused the flood) Unprecedented levels of rainfall of 130mm in 6 hours after a preceding period of heavy rainfall in the days leading up to the event which had saturated the ground. River Basin characteristics : narrow topography of basin valley, low basin drainage density, steep valley sides and low capacity channel. Human factors: (that caused the impacts of the flood to be greater) Impermeable building materials for infrastructure in the local area. Blocking channel flow with low footbridge and a 100m underground culvert. Deforestation in the Valency Valley (decreased interception, decreased lag time). Lack of adequate flood management system. The impacts of the event Economic: 500m damage to property. 80 buildings damaged and 3 houses destroyed. 25m lost in income to local businesses (mainly to the critical tourism industry) Very high insurance premiums / lack of economic security from lack of premiums. 60 cars swept into the river from the car park. Social: Residents homeless for 10 days after the flood during cleanup. Rebuilding jobs took 6 months. Due to sewage pipes bursting there is now a risk of contamination from tap water in the village. Electricity and water supply temporarily not available. Environmental: Local habitats destroyed for marine wildlife. Management strategies taken since the event A 4.5 million scheme has been implemented by the Environment Agency to prevent future flooding in Boscastle. The actions include: Riverbed widening and lowering (to increase capacity / bankfull discharge). Car park being raised to higher ground (to prevent channel blocking). Steel mesh installation (to protect the integrity of the channel width to hold capacity).

4 Heatwave Case Study European Heatwave (2003) A Heatwave, a period of prolonged unusually hot weather, hit continental Europe in August France was the worst affected country with temperature highs of 40 degrees celsius. Why the impact was so high There was high economic and social impacts due to the severity of the event and the vulnerability of the European population subjected to it. SEVERITY The Heatwave was of significant magnitude, producing temperature as high as 40 degrees celsius in France. The Heatwave was also persistent so the effects were ongoing. VULNERABILITY Continental Europe, especially France, has an aging population that was more vulnerable to the social impacts of illness and death as elderly people are more vulnerable to the organ failure caused by dehydration because they have worn organs. Children were also highly vulnerable as their organs haven t fully developed yet so have a lower physical capacity to cope with dehydration effects on the body. Impacts of the event Economic: Decreased economic output from both decreased labour force productivity and the absence of energy sources as Nuclear Power Stations closed in France and Hydroelectric / Tidal / Wind Power sources declined in output (due to the high pressure). Crop shortfalls from the drought cost European farmers 10.4 billion. UK Domestic Tourism industry boosted in the short term. Social: 50,000 related deaths from organ failure, 15,000 of them being in France alone. Many vulnerable elderly and young people experiencing heat related illnesses e.g. sickness. Rail Transport services delayed due to fears of derailing. Environmental: Forest fires broke out in Portugal. Mitigation operation by the Portuguese emergency services cost 800 million. These destroyed 215,000ha of habitats for local wildlife. Landslides occurred in the Alps mountain range due to the melting of holding snow/ice. Management strategies Generic solutions to mitigating the severity of Heatwaves and their impacts: Install air conditioning systems (esp. In homes of the elderly / nursery schools) Use artificial snow in ski resorts to prevent the landslides from snow/ice melt. Reduce global warming through combination of mitigation and adaptation strategies. Use of green architecture which reduces need for polluting air conditioning systems.

5 Drought Case Study Australian Murray Darling Basin Drought (since 2002) The Murray Darling drainage basin in South East Australia is currently suffering from a severe, long term drought which has occurred since As the Murray Darling basin is the most important agricultural region in the country, and lies in proximity to Australia s densely populated south coast, the drought has had profound economic, social and environmental impacts. Why the impact was so high SEVERITY The drought in the Murray Darling Basin is the worst Australian drought on record. Rainfall levels in June 2008 were the worst recorded for 117 years. ECONOMIC DEVELOPMENT Australia is an MEDC so experiences high levels of economic damage but does have a high combating capacity to cope. However, the area is dependant on primary industry, contributing over 30% of Australia s Agricultural GDP output in VULNERABILITY Poorer people in the region are badly affected by the drought because they are unable to afford the increasing price of food exported from abroad. The prominent local farming community is vulnerable to the impacts because water security is vital to their lifestyle and medium of income. The impacts of the event Economic Increased food prices as local agricultural production of cereals, fruit, vegetables, dairy and livestock has decreased and production of irrigation reliant/thirty crops has partially ceased. Closure of farms and small businesses and reduction of outputs in others. Resulting unemployment is now 7% above the Australian average. 23,000 rural families and 1500 small businesses now dependent on financial support from the Australian Government. Social Enforcement of water use restrictions for 3 million people in the Murray Darling basin. 10,000 farming families forced to leave in last 10 years as farming has become unsustainable. Structural damage to properties in the basin due to increasing groundwater salinity. FInancial hardship is engendering mental health problems in the area. Environmental Vegetation loss and soil erosion. Wildfires and dust storms. Depleted rivers and lakes are suffering from toxic algae outbreaks, which is threatening the local endangered biodiversity.

6 Management strategies taken since the event AUSTRALIAN NATIONAL PLAN FOR WATER SECURITY The plan aims to reduce the negative implications of the decline in Australia s nationally available water resources by specifically increasing the sustainability of rural water consumption in the Murray Darling Basin. Actions of the NPWS: Piping/Lining Water Channels, adopting more efficient irrigation techniques and identifying and subsequently closing unsustainable irrigation projects in Salty areas of the basin. Farmers of more thirsty crops given financial help to leave the industry. Saved water used to restore wetlands and tributaries of the Murray Darling Basin. Set up the Murray Darling Basin Commission as an enforcement agency. New water meters installed to monitor and punish over usage of waters. NEW FARMING SYSTEMS Australia needs to develop farming systems which are better suited to Australia s natural environment: Genetically modified drought resistant crops (which require less water). Sustainable crop and pasture management (fallow periods and soil nutrient rotations). Precision farming using new technologies e.g. GPS, GIS. +OTHER METHODS Afforestation in the Murray Darling Basin. Construction of desalination plants (to solve short term shortages by increasing quantity).