RainScape: How can we reduce flooding in our towns and cities?

A major project to tackle flooding in Llanelli is underway.

Welsh Water's RainScape scheme involves a large tunnel being dug under the town to take rainwater away from the sewer network.

Watch my report below:

Stebonheath Primary School became involved in the scheme at the start.

The school's grounds were excavated to allow water to be stored underground, while water butts and vegetation were installed on the surface to capture more surface water.

Headteacher Julian Littler explains how the school plays its part in the scheme

Since the school is situated on top of a hill, the modifications mean less water is now allowed to flow into the town of Llanelli itself.

Historically there's been a lot of flooding, with drains overflowing. And the system hasn't been able to cope with the actual runoff of the rainwater.

In fact, for 270 degrees around the site of this school, it's just urban land. And the water's got to go somewhere.

– Julian Littler, Stebonheath Primary School

A giant machine is at work underneath the Llanelli, driving a tunnel 1km long to send surface water to the Delta Lakes.

A swale of greenery helps capture rainwater and release it slowly

This tunnel, along with additional greenery and swales in the town, helps stop the sewer system from being overwhelmed during heavy rain.

With climate change looking like we'll have another 20% more intensity in rainfall, with growth, with people paving over lawns, and adding to their houses, all those things were adding to the amount of water that would run off into the sewerage system that we already have.

Even with our newer sewers, there's only a limited capacity for them to cope with that.

– Fergus O'Brien, Welsh Water

In Cardiff, the Greener Grangetown scheme is nearing completion.

The project also aims to reduce the surface water running into the sewer network, diverting to the River Taff instead.

The newly planted greenery in Grangetown

The disruption caused by the work has frustrated some residents, but the people behind the scheme say the environmental benefits will make it worthwhile.

The big worry for everybody in the area is the parking. We have had our ups and downs.

But saying that, I think you can see yourself now that it's starting to take shape and think we're going to be very pleased when it's finished!

– Robert and Heather Rowland, residents