Recovering from Hurricane Katrina

9 September 2005

The ferocious Hurricane Katrina has gone, leaving the streets of New Orleans wrecked and flooded. Clearing up is a dangerous task and it could be months before the citizens can return.

Antenna investigates the recovery of New Orleans.

The streets of New Orleans are flooded with water.

Image: FEMA

On 29 August 2005, 100 mph winds raced through New Orleans. The hurricane was category 4 but the flood defences were only designed to cope with a category 3, so engineers weren't surprised when the walls of the canals leading from the Mississippi River and Lake Pontchartrain were breached and water flooded the city.

Hurricane Katrina over the Gulf of Mexico.

Image: NOAA

The hurricane has now subsided and engineers are repairing the flood defences, but it's only the first step to recovery. Next they'll have to pump the water out of the city.

Find out how the US Army Corps of Engineers are getting on with their hurricane response efforts by visiting their Website:

The areas of New Orleans under sea-level are flooded.

Image: DigiGlobe

'Engineers will drive steel-sheet piles along the line of the breaches and once they've repaired the breaches they'll bring in external pumps to pump water back into the lake.
'Once the water gets below a certain level they can activate the permanent pumps in the city. New Orleans has these pumps because it is in a basin. Every time there is heavy rain the water needs to be pumped out.'
Gordon Masterton, civil-engineering expert, Institution of Civil Engineers

Images: BBC
Next is the mammoth task of cleaning up the silt left behind - some of it contaminated with chemical and biological nasties...
'There will be contamination of sediment and water from infrastructure that has failed including the sewage infrastructure, from the fires that have been happening there and any physical damage will release chemicals. It is going to be a horrible place to be.'
Simon Hughes, flooding expert, Environment Agency

Flooded streets and houses in New Orleans.

Image: FEMA

It could take months for the buildings to dry and the houses still won't be fit to live in.
'There is a difference between properly engineered buildings and poor local housing. The large buildings are built to withstand strong wind. The tall buildings will have suffered superficial damage to cladding, roofing, etc. but the buildings won't be unsafe.
'However non-engineered houses built to local standards are often timber framed and they will have suffered from water and wind damage. Some of the buildings have moved off their foundations and been lost. For many houses it will be cheaper for them to be demolished and rebuilt.'
Peter Waldron, structural engineer, University of Sheffield

Both flooding and strong winds have damaged this property.

Image: FEMA

'The ground will have absorbed water like a sponge and there could be upheavals and subsidence as it drains. This will damage underground pipes and cables.'
Gordon Masterton
Residents may want to rebuild their city, but isn't there a chance major floods could happen here again?

'Yes. New Orleans is in one of the highest-risk locations for a city in the world. It is in a hurricane zone, near the coast and 5 or 6 metres below sea level.'
Gordon Masterton

Gordon Masterton, civil-engineering expert, Institution of Civil Engineers

Image: Institution of Civil Engineers

Could the chaos caused by Katrina ever happen in the UK?
'There is nowhere in the UK with the same risk profile, but it is a wake up-call. Engineering on the coast in low-lying areas has to be carefully assessed and defences put in place.'
Gordon Masterton
'The kinds of flooding risks we face are different from New Orleans. But we encourage people to be aware and be prepared. Find out if you live or work in a flood risk area. If you do, there are simple steps you can take, like checking how you can receive a flood warning, and making a simple plan for what to do if you get one.'
Simon Hughes

Find out if you live in a flood risk area.

Image: Environment Agency

Is your home or business at risk of flooding? What should you do if you get a flood warning? Check the Environment Agency Website...
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