FLOOD HAZARDS

Storm fears - will London's flood defences cope in a crisis?

A one in a thousand year storm hits the South East. Everyone knew it could happen, but didn't act quickly enough. The roads are rivers. Thousands are dead. Everyone's blaming everyone else.

Of course this is fiction. But global warming does make this more likely as Inside Out London investigates.

Professor Colin Green of the Flood Hazard Research Centre says, "We’ve got sea level flooding coming up the Thames as far as the barrier. We have the Thames and its tributaries that flood. All of these things will get worse with climate change".

So the danger is clear but we are protected - to a degree. Along the Thames, there's 180 kilometres of river wall for a start. This all requires the efforts of the flood defence team.

Dave Williams from the Environment Agency heads the team that are responsible for carrying out the repairs:

"It’s a bit like building an old jigsaw. We have to get a variation of sizes of stones so that we can match it in. If the hole here wasn’t repaired it will keep eating into the back and the footpath could collapse."

The walls are key to protecting the South East - but so is the Thames Barrier - which has the job of protecting Central London. There is also nature's own engineering.

In the vast areas of marshland at Gravesend, Essex, when the water comes in its force is soaked up. And by spreading here - the risk of flooding further down the river where people live is reduced.

Protection from the storm

At the moment London enjoys the same sort of protection - thanks to the Thames Gateway. There's 80 miles of coastline acting as a storm water sponge. It helps protect over a million people living in Central London.

But the land here now has the developers circling. They see room for a new City.

Time for a rethink on London's flood defences?

By 2015 the Government plans to build 120,000 new affordable homes here for key workers. This is because it's one of the few untouched areas close to London where developers aren't constrained by Green Belt laws.

But all these homes will be sitting on a flood plain, and history has shown living so close to the river is not without its dangers.

Fifty years ago a freak storm lashed the South East. Three hundred people died as they lived in the flood's path. The storm breached defences as far as Canvey Island.

At City Hall there is real concern that building on the Gateway is racing ahead unchallenged.

Darren Johnson from the Green Party thinks the flood risk is being overlooked:

"I was fairly appalled by the Mayor’s redevelopment framework for East London which simply doesn’t take the flood risk seriously enough. The need for new development, and new houses is so high up the agenda that flood risk issues aren’t getting a proper look in”.

The Environment Agency is the prime body responsible for making sure new housing plans are safe - they are advising caution but say they are not the key decision makers.

"We don’t really decide where development takes place, so if it’s on a flood plain that’s not our choice. We have to ensure if that is where the building is going to take place there is proper planning," says David Wardle from the Environment Agency.

That means allowing some space for flood.

This has been thought about. The plan's called the Green Grid where swathes of parkland would be built in between the housing blocks - providing leisure space - and grassland to soak up storm water.

Sound thinking - but we don't know whether it'll happen. Darren Johnson thinks things are moving too slowly.

But by creating these natural flood plains, we have to be careful about what we build.

One vision called Mast Quay is already sitting on the river bank in Woolwich. It's a housing complex build on stilts. And you could push the thinking even further.

A builder in Camden has come up with the idea of a house that floats on a polystyrene platform. It sounds unlikely but even expert engineers agree that it is a sound plan.

"The building would have to be a reasonable compact shape; a two or three story house made of timber would be reasonably straight forward," says engineer Sam Price.

The building rises on guide rails, and it all sits in a concrete box - so you're not moving address every time it floods. The design has been patented and the inventor is looking for a developer to build a full-size version.

Inventor Tom Meere thought of the idea while watching victims of previous floods sweeping water out of their houses. So whether it's homes that float - or apartment blocks on stilts - what is clear is that any building on the Thames Gateway must be flood proof because of the risk.

Fears for the future

If developers ignore this they could be building homes no-one can get a mortgage for because they're uninsurable says Jane Milne from the Association of British Insurers:

"We’ve always made it clear that ability to insure depends on flood risk and in very high areas that frankly isn’t going to be possible. Insurers are working hard to stay with existing customers but won’t take on new properties if there’s a flooding risk. Just because it’s the right place for factories that might need access to ships doesn’t mean it’s the right for houses."

With so much of the Thames Gateway being at a high risk some people are beginning to question the logic of building so extensively.

And even environmentalists are now suggesting sacrificing countryside to take some of the housing growth instead.

Flood fears - could London be another New Orleans?

"Obviously I’ve always fought to protect the green belt and green fields but occasionally there might be a strong case for actually doing a land swap in parts of the Thames Gateway where a field that is of little ecological value maybe developed in exchange,"says Darren Johnson.

But even if the Government leaves the Thames Gateway alone, London is still threatened by rising sea-levels.

And that means our defences will need raising anyway. This comes with a huge price tag of £4 billion.

It’s yet to be decided where the money comes from. "I think that’s still to be decided and clearly a lot will come out of the national purse and developers but there’s still a lot of work to do. There will be a cost to Londoners," says David Wardle from the Environment Agency

Keeping London safe has a huge financial cost - but most agree it's one bill that's must be paid on time.

"New Orleans showed us that while people are squabbling over who pays for what you can pay a terrible price if you don’t actually get the money," warns Darren Johnson.

Read this week's other London stories:

Illiteracy in London
Traffic wardens

Links relating to this story:

• BBC News - Thames flood barrier
  Environment Agency
  Association of British Insurers
  Thames Gateway

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