UNITED KINGDOM: Heavy rains in July wrought havoc in parts of London and the south of England. Flash floods across Europe and Asia submerged many cities and towns – a common phenomenon seen this year, owing to climate change.
A BBC report says why flash floods are occurring frequently, impacting cities and towns particularly.
Flash floods are a result of intense rainfall – when the amount of water exhausts drains and sewers. Apart from devastating roads, vehicles, homes and shops, floods can affect key public infrastructure including transport networks and hospitals.
In London, some hospitals had to ask patients to stay away after they lost power.
Infrastructure of cities and towns
Urban areas are more vulnerable to experience “surface water” flooding because of their hard surfaces. When rain hits these hard surfaces it can’t soak into the ground as it would do in the countryside.
An example was seen when New York City was hit by Storm Elsa in July, flooding the subway system. The city’s transit authority president, Sarah Feinberg, said “if the drains at the street level can’t handle the water, it goes over the curb and then makes things even worse”. Water had come through subway vents and down the stairs, she said.
In many places, including much of the U.K., old sewer systems were built based on historic rainfall projections.
Dr Veronica Edmonds-Brown of the University of Hertfordshire said London’s Victorian-era drainage system “cannot cope with the huge increase in population”.
Also Read: Monsoon Flash Floods In Bhutan, Nepal
Flash floods “no more unusual” – climate change, man’s production
Many factors contribute to flooding, but climate change plays a dominant cause, making extreme rainfall more likely. Besides that, a warmer atmosphere means more moisture in the air and so these storms become more intense.
According to Prof Hayley Fowler, of the UK Climate Resilience Programme, flash flooding used to be “relatively unusual”. But she said warming means “these heavy short-duration bursts from thunderstorms which cause flash flooding are becoming more common”.
Fowler’s research suggests if climate change continues on its current track flash floods – measured as 30mm of rain per hour – “will increase five fold by the 2080s.”
Preventive but temporary measures
Dr Linda Speight, a flood expert at Reading University, says urban areas could benefit from changes like “permeable pavements and green roofs that can help rainwater to soak away rather than causing floods”. She added, “weather and flood forecasting science has improved rapidly and it is now often possible to forecast surface water flooding events in advance”.
To protect houses, the Met Office recommends creating a flood plan, for example moving valuables out of the basement and to a safe place, choosing tiled flooring and moving plug sockets further up the wall.
It is also possible to take preventative measures – check if your area is at risk of flooding, and sign up for flood warnings on the Met Office website.