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Water flooding the road

Why is London flooding so much?

Almost one month’s worth of rain fell in a 24-hour period

Written by
Chiara Wilkinson

If you weren’t stuck in the thick of it yourself, you’ll have probably seen pictures and videos of the torrential rainfall and flooding that caused havoc in London last night. Lots of streets, hospitals and stations were affected, with several roads still shut and many flood warnings continuing into today. 

The most notable rainfall that hit the Met Office’s system yesterday was the 41.8mm recorded at St James’s Park tube. ‘The average rainfall for [the whole of] July in London is 45mm,’ said a Met Office spokesperson, ‘So it was almost a month’s worth of rain in one 24-hour period.’ That made it the station’s second wettest July since records began in 1912. 

There could be further disruption over the next four days, with the Met Office issuing yellow weather warnings for thunderstorms and rain in parts of England and Scotland. But the question all of us want the answer to is why has there been so much flooding in London? 

Long story short, it’s down to climate change (shock). According to Herta Gatter, an expert at urban planning practice BDP, London’s increased flood risk is due to a mix of ‘climate breakdown and urbanisation’. It’s not surprising then that the floods came immediately after an extreme heatwave in the UK.

‘As global cities like London face increasingly extreme weather conditions, while also developing more land with roads and buildings, water needs a place to go,’ said Gatter. Thanks to the paving over of gardens and green spaces to create more patios and parking in the city, drains can quickly become overloaded from heavy rain. ‘To prevent future flooding, new urban developments must have sustainable drainage systems integrated into streets and playgrounds to manage water in the built environment,’ she explained. That means that the city is going to have to invest in improvements to flood management, such as the Thames Barrier, to stay on top of future extreme weather. 

Be prepared: this website will tell you if you’re at risk to future London flooding.

These roads are still closed after the flooding in London last night.

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