Dam Good Idea: The London Beavers Offering Respite from Drought

Forget sex in the city. In Greenford, a leafy but distinctly urban part of Ealing, they've introduced beavers to the city. Just 10 minutes from Greenford station and 50 yards from McDonald's, you'll find the Ealing Beaver Project, a mosaic of ponds, channels and woodland. After a summer of heatwaves, it is conspicuously lush and seemingly a few degrees cooler than the congested roads it sits under.

A different answer to flooding

Beavers were introduced to this part of Ealing in 2023, partially to prevent flooding. After frequent floods affected Greenford station, local authorities considered creating an artificial reservoir using concrete and heavy machinery. A group of conservationists, led by Sean McCormack, suggested a different idea: beavers.

By creating dams, digging channels and felling small trees, the semi-aquatic rodents slow water flow during floods. McCormack says what makes them so brilliant is that their dams create complex wetlands. Sometimes referred to as ecosystem engineers or keystone species, beavers build dams that trap water and woody debris, soak nearby soil, and create conditions for wetland species to establish.

When flood protection meets drought

Following a public consultation in the area, which McCormack says was met with overwhelming public support, beavers were introduced in October 2023. This marked Britain's first and only beaver enclosure fully accessible 24 hours a day, 365 days a year. Since 2024, across the beavers' second and third winters onsite, the station has not flooded for the first time in over a decade.

However, with August confirmed by the EU's Copernicus Climate Change Service as the joint hottest month on record, flooding is not top of mind. Tied with July 2023 and driven by a combination of climate change and El Niño, August 2026 saw average temperatures over the month hit 1.65°C above pre-industrial levels. The Met Office found the summer's temperature increase was approximately 130 times more likely because of human-caused climate change.

The impacts of August's record-breaking heat are severe. Drought struck two-thirds of England, triggering hosepipe bans for almost 30 million households. Meanwhile, farmers are expecting the lowest harvests since records began in 1984 after crops were stunted by heat. Fire and rescue services also responded to 1,132 wildfires this year, up from 848 the previous year.

Beavers, the flat-tailed rodents hunted to extinction in the UK about 400 years ago, offer some respite from drought. In McCormack's words, while beavers "don't care about urban flooding or mitigating droughts" when building dams for their own protection, "they turn the entire landscape into a giant sponge that can absorb a flood event and release it slowly."

In a very arid, fire-prone landscape, this creates "oases of green, lush, damp, marshy land, and if a wildfire is ripping through the landscape, beaver wetlands act as a break." Beaver wetlands do not burn, he says: "You can't burn wet soil."

Across the canal, a control site

Across the canal from the project is a control site. It has a similar geographic location and habitat type, but no beavers. McCormack took me there, and the contrast was striking. "It's just bone dry," he said. "There's no aquatic or invertebrate life compared to here because there's no moisture in the system."

We should be explicit: this is not a perfect scientific experiment. There is ample data to capture, but as a volunteer-run organisation, the project does not have the resources to conduct extensive scientific research. The ecosystems at the sites are very similar, though the beaver site has a brook with running water while the control site's ponds, now dried up after the summer drought, would typically be static. Even with those limits, the comparison gives us a strong idea of the beavers' impact on their local environment.

Moreover, research from Devon found that a beaver enclosure on intensively managed grassland stored an additional one million litres of water across 13 dams. Onsite in Greenford, even with the beavers, water levels dropped to their lowest point yet after this summer's temperatures. Still, the beavers have kept virtually all the water coming onto the site there.

One tool, not a climate cure

Let's be clear, says McCormack: "Beavers are not this panacea for climate change. That's stupid, that's for sure over-egging it. But they're certainly one of our solutions." What beavers do very well, he thinks, is teach us that sometimes nature-based solutions are best.

According to the Met Office, in our current climate we can expect a summer like the one just experienced every nine years. Previously, a summer like this would have been exceptionally unlikely, occurring approximately every 1,000 years. Against this bleak backdrop, the nature-based solutions beavers bring by helping put water back into our landscapes are increasingly worthwhile.