The world's ageing dams are not built for ever more extreme weather

[Judi Lynn]

TECHNOLOGY | ANALYSIS 2 August 2019
By Michael Le Page



An RAF helicopter drops bags of aggregate to shore up the dam and divert water
A helicopter helps shore up the dam
ROLAND HARRISON/AFP/Getty Images

The town of Whaley Bridge in the UK has had to be evacuated after damage to a dam built in 1831. The Toddbrook Reservoir is just one of many ageing dams worldwide not designed for ever more extreme rainfall as the planet warms.

Dams are typically designed to cope with a so-called 1-in-100-year flood event. But as the world warms the odds of extreme rainfall are changing, meaning the risk of failure is far greater. Engineers have been warning for years that many old dams around the world are already unsafe and need upgrading or dismantling.

“The 1-in-100-year event is perhaps happening every five years,” says Roderick Smith at Imperial College London. “I’m absolutely convinced that it is due to climate change.”

What is happening at Toddbrook Reservoir, where 1500 people have had to evacuate, is very similar to what happened at the Oroville Dam in California in February 2017. Both are earthen dams where excess water flows over the top of the dam and down a concrete-lined spillway.nffj

Read more: https://www.newscientist.com/article/2212427-the-worlds-ageing-dams-are-not-built-for-ever-more-extreme-weather/#ixzz5wLGL8yYJ

[eppur_se_muova]

1. Brilliant sunlight, fast shutter, and slow-moving rotors make that Chinook look eerily frozen.

Even the shadows of the rotors are crisp and clean.

OT, I know.