Three measures that could prevent flooding

Lawrence McGinty

Former Science and Medical Editor

Permeable pavements. Credit: ITV News

Could more have been done to prevent two months of record-breaking rainfall - almost 20 inches of it - causing devastating floods?

A group of expert institutions say yes it could, in a letter to the Daily Telegraph today.

ITV News decided to find out how.

1. Head for the hills

We started at the beginning - at the source of the much flooded River Severn in mid-Wales.

In the hills lowering over Machynlleth, farmers have been encouraged for years to drain the land to make it suitable for sheep grazing.

They've done a good job, but unfortunately draining the land has also eroded and destroyed the peat layers on the hilltops. I saw whole cliffs of peat, 20 feet high, where drainage ditches have cut into the landscape.

Machynlleth in mid Wales. Credit: ITV News

Peat, which is basically rotting vegetation in layers where oxygen can't get at it, is a fantastic natural sponge.

When it rains on these hills, the peat used to soak up the rainfall and release it slowly -preventing it rushing down the hillside into the Severn and adding to floodwater.

Machynlleth in mid Wales. Credit: ITV News

Erosion of the peat is destroying the natural sponge. So the Montgomeryshire Wildlife Trust has started a project to regenerate the peat layers. For the past three years, they've been blocking drains over an area of 1,000 hectares.

Blocking the drains creates a chain of small pools, water which soaks into the peat. Eventually they hope to cover 40,000 hectares - an area as big as Birmingham.

Will it make any difference? Clive Faulkner of the trust told me perhaps 10-20 cm. Doesn't sound a lot, but as Clive says, it could be the difference between your house being flooded or dry.

Permeable pavements. Credit: ITV News

2. The word on the street

But what can you do in your home or in your street? There are lots of ideas at the Building Research Establishment near Watford.

Like permeable pavements. They look like ordinary pavements but they're made with a special resin that holds constituent particles apart - a bit like a Crunchie bar, it's full of holes.

I poured a bucket of water over the pavement and, as if by magic, it seeps through instantly into the ground below, not into the drains, and then the river and then via floodwater into your house.

Flood proof doors. Credit: ITV News

3. The wolf at the door

And if the floodwater does reach your door what can you do? Sandbags probably - but they're heavy cumbersome and water eventually soaks through. So how about a flood-proof door?

They're here now. I saw one on a full-scale test rig at a company called Aquobox which has a lab on the BRE site. On one side, water a foot deep and over the threshold. On the other side dry as a bone. Simple - just fit waterproof seals.

Bone dry on the inside. Credit: ITV News

Ok that's just three ideas, there are lots of others.

In their letter the group of experts say: “In the long-term, the way in which we manage, store and distribute our water, and how we rethink and plan both the natural environment, and the built environment of our towns and cities to make them more resilient, requires a clear strategy.”

Hear hear.