Paving the way for pumps

21 August 2023

Any mention of climate change can quickly polarise opinions but there can be no denying that the number of extreme weather events such as flash flooding is rising. 

And looking overseas, southern California is currently being battered by Tropical Storm Hilary, with 26 million people under flood warnings and in some places record daily rainfall levels have been reached.

Whatever the reasons behind the sudden and intense downpours, one aggravating factor is the ongoing replacement of porous surfaces and green spaces with impermeable paving and concrete. 

A recent article in the Times reported that while the National Infrastructure Commission, a government advisory body, has been urging local authorities to include more measures like green roofs and ponds in developments, impermeable surfaces in UK towns and cities have risen from 37 per cent of their area in 2001 to 46 per cent in 2022. 

Warmer air holds more moisture, raising the risk of extreme downpours and if rainwater cannot be absorbed or drained away quickly, flooding is inevitable. 

Pete McMutrie, Sales Director at Obart Pumps, suggests there are two types of seasonal rainfall. “In winter you often have a sustained period of rain when the water table is already high and not much rainfall is required to cause surface flooding. And in serious floods, because there is nowhere else for the water to drain to it takes longer to clear. 

“In summer the water table might be lower but if the ground is dry and hard, a really intense downpour won’t soak in quickly and will cause flash flooding as the drains can’t handle it. Because it subsides more quickly, it’s easier to use hired-in pumps to move the water to unaffected areas.” 

Until planning ideas change – and trends like building on flood plains diminish – the risk of floods will remain and people will need to hire pumps, dehumidifiers and other equipment to deal with the impact. 

Photo: Chris Gallagher