Could Trees Provide Natural Flood Defences for London?

Trees provide natural flood defences

Over the last five years, news of catastrophic floods seems to have become a media staple. As Londoners, we’re used to seeing these events happen elsewhere – but we shouldn’t be complacent.

A 2002 study commissioned by the London Climate Change Partnership found that London is especially prone to flooding from three sources: river water, local flooding from overburdened drains and tidal surges in the Thames.

Given the damage floods can wreak, this sounds like pretty bleak news. Happily, a more recent study suggests that help may be at hand from an unlikely source: trees.

How do trees provide natural flood defences?

The study in question was part of a joint research project carried out by the Universities of Southampton and Birmingham.

Researchers from these institutions conclude that strategic tree planting has the potential to reduce the maximum height of flood water by 20%. This, as the study’s lead author Dr Simon Dixon points out, is a big contribution to reducing flood risk.

The original study area was a 100km section of river near Brockenhurst in the New Forest.

Researchers constructed a computer simulation of the land and used it to investigate the effect of different natural flood defences such as man-made dams, river restoration and, of course, tree planting.

All three methods, when used together over 25% of the river’s length and upstream of Brockenhurst, resulted in the aforementioned dramatic reduction in flood risk for the town.

Could planting trees save London from flooding?

Although the natural flood defences studied by the researchers produced good results, protecting a city the size of London presents a more complex challenge.

Turning a sufficiently large area into forest would impact upon the many landowners occupying the area. Flood risk managers for the Environment Agency say that the level of funding necessary to realise such a plan isn’t currently within reach.

But looking forward, if more areas of the country experience the kind of disruption to life and business seen in the Lake District in 2015, planting huge forests could start to look like a sensible, cost-effective option.

Although natural flood defences don’t perform in the same predictable way as their high-tech equivalent, they could come to be seen as a useful supplement to traditional engineering solutions.

We like the idea that decades from now London may be protected not only by tidal defences in the shape of the flood barrier at Woolwich, but also by an entirely new forest planted West of London, upstream of the tidal Thames.

Could I plant my own flood defences?

Of course, if you live in the most flood-prone areas of London, there’s nothing to stop you researching tree planting as a flood defence on a much smaller scale.

Not only do trees effectively reduce the height of floods, they also improve water quality. At best you could find yourself conducting an interesting experiment. At worst you’ll have your very own wooded area to enjoy.

Don’t forget our experienced tree surgeons are on hand to help you choose and plant new trees, and maintain the health of your existing trees. Get in touch with us today to find out more.

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