Sand Coast

Once upon a time, the Welsh mined coal.

These days it's sand they're after.

And lots of it.

85% of the sand that we use is taken from the sea bed.

I'm going to find out what effect that's having.

I'm in the Bristol channel and we're heading out

to Nash Bank, which is about five miles off the coast of south Wales

and I'm gonna get on that, which is a dredger.

I've watched these ships going up and down since I was kid,

but I've never been on one so I'm excited.

'The Arco Dart spends 360 days a year

'dredging up sand and pebbles from the sea bed.'

-Hello, Alice.

-Hello.

Mick Forster, master of the Arco Dart. Welcome aboard.

-Thank you.

-Would you like to come over?

It's Mick Forster's job to position his ship precisely

over a sand bank.

Can you dredge anywhere in the Bristol Channel?

No. We're restricted to what we call dredging areas.

We're only allowed to load on a licensed area.

-So does this blue streak here represent a bank of sand?

-Yes.

This is where we're heading for, called the Nash dredging grounds.

The sea bed is owned by the crown

and every tonne of aggregate taken has to be paid for.

The Nash Bank is eight miles long

and a mile wide.

That's a lot of sand.

The dredge is, basically, an enormous vacuum cleaner.

1,300 tonnes of aggregate are sucked up this tube every two hours.

As it's pumped aboard it gets graded.

Sand for cement, gravel for gardens.

The dredging companies are required to do detailed surveys

to try to measure the effects

of their operations on the local environment.

This is a chart of the sea bed. It shows the bank very clearly.

Erm, the Nash Bank itself, is this area here.

After you take sand out from this area, is it being replenished?

You must remember, there are no renewable sources of sand.

-Just like oil.

-No.

-There's no renewable sources of oil.

Erm, you just must use those resources carefully.

The sand in Nash Bank was made in the last ice age.

If the visibility of the water was better,

we'd be able to see that the sand lies on the sea bed

in remarkable 20 meter high waves,

gradually being eaten away by dredging.

Since the 1920s, one fifth of the Nash Bank has already been consumed

and it will never be replaced.

We may not be taking precious sand directly from our beaches

but some worry that dredging sand banks

unleashes the power of the sea to erode beaches away.

Can you be absolutely sure that if you remove the sand down here

it's not going to have an effect on the coast line?

These beaches have been changing for thousands of years.

They've been coming, going. Yet we see a change in our...

perhaps on a decade and we think it's important, but actually it isn't.

That change has been occurring over many, many hundreds of years.

Whatever the effect of dredging, one thing is for sure -

sand is a finite resource.

Once it's gone, it's gone for good.

But if we want to use sand for our buildings

and gravel for our gardens,

we've got to get them from somewhere.