From drought to downpour: could nature help our towns and cities manage both?

Following weeks of exceptionally dry weather across much of the UK, rain will be a welcome sight.

But when significant rainfall follows prolonged dry conditions, it can bring a different challenge. Intense rain can arrive faster than the ground and drainage infrastructure can accommodate it, increasing surface water runoff and the potential for localised flooding.

Wildflower Co., the UK’s wildflower habitat specialist, believes this highlights a bigger question for the way we design our towns, cities and developments:

Can we make more of our spaces work with water, rather than simply moving it away? One opportunity is right above our heads.

Turning roofs into living infrastructure

Conventional impermeable roofs move rainfall relatively quickly towards gutters, drains and the wider drainage network.

Green roofs work differently.

Vegetation, growing media and the layers within a green roof can intercept and temporarily store rainfall, reducing and delaying the amount of water leaving the roof and entering drainage systems.

Green roofs aren’t a solution to flooding on their own. But as part of a wider Sustainable Drainage Systems (SuDS) approach, they can contribute to managing rainfall closer to where it lands.

And while doing so, they can perform another important job: creating habitat. A well-designed wildflower green roof can support pollinators and other wildlife, contribute to urban biodiversity and transform an otherwise largely impermeable surface into part of a development’s living green infrastructure.

James Hewetson-Brown, Managing Director of Wildflower Co. said:

“After such a prolonged period of hot and dry weather, it’s easy to think of rain simply as something we desperately need. But increasingly, we need to create places that are resilient to both sides of the equation – periods with too little water and periods when a lot of water arrives very quickly.

“Green roofs are particularly interesting because they allow a space that would otherwise be largely impermeable to perform several environmental functions at once.

“They can help intercept rainfall and slow runoff while simultaneously creating habitat and supporting biodiversity.

“A green roof won’t prevent flooding on its own. But alongside other sustainable drainage measures, it can be one piece of a much bigger solution.”

But the opportunity doesn’t stop at roof level

The same broad principle – using living landscapes to intercept and slow rainfall – can extend to the ground beneath our feet.

At ground level, vegetation and healthy, well-structured soils can help intercept rainfall and encourage water to infiltrate into the landscape. Diverse wildflower habitats also create varied root structures below ground as different species occupy and interact with the soil in different ways.

The hydrology of a ground-level habitat is different from that of an engineered green roof, and factors including soil type, compaction, slope and rainfall intensity all influence how water behaves.

But Wildflower Co. believes both illustrate a much bigger opportunity: to stop thinking about nature as simply an addition to our infrastructure and start recognising the role living landscapes can play within it.

James continued:

“We shouldn’t stop at roof level. From rooftops to roadsides, developments and public spaces, there are opportunities to create living landscapes that support biodiversity while contributing to how we manage water.

“For too long, biodiversity, drainage and landscape have often been treated as separate conversations. Increasingly, we need to look at how the same space can deliver multiple benefits.

“If it can create habitat, support pollinators, help manage rainfall and make a place more resilient, that’s a much better use of that space.

“From the ground beneath our feet to the roofs above our heads, nature has a role to play.”

For more than 20 years, Wildflower Co. has developed science-led solutions for creating long-lasting wildflower habitats, from seed and turf to growing media, green roofs, research and expert support.

Its mission is to create and enhance long-lasting, biodiverse wildflower habitats through expert advice, research and high-quality products – helping put nature back at the centre of our landscapes.

Click here to find out more about our Green Roof solutions.