FLOODING: Are we Sleepwalking into a Disaster?

Groundwater flooding – the emergence of groundwater into buildings and infrastructure due to unusually high water levels – is not currently listed on the UK’s National Risk Register. This is despite its long-documented ability to drive extreme flooding events; with interactions that often trigger the worst river and flash flooding disasters, including, for example, last winter. The number of UK homes within areas at direct risk from groundwater flooding is 770,000 and damage from groundwater accounts for 13% of the UK’s average annual financial losses from flooding. What’s more, groundwater also contributes to losses from rivers, surface water and coastal flooding by prolonging the duration of flood events. The result is disproportionate, long-term damage to properties, infrastructure and the environment.

“Groundwater flooding is a serious risk because it often causes far more damage than other flooding and can be devastating for those who are flooded,” says GeoSmart director Mark Fermor. “It also leads to significant economic consequences for communities affected.”

Fermor adds that a “perfect storm” of factors – including the new government’s plans to build 1.5 million new homes – has made the current situation more acute.

“In the winter of 2019-2020, we narrowly avoided a full-scale disaster with groundwater flooding in the UK,” he says. “The impact of climate change, plus recently relaxed rules designed to speed up construction across the UK, means there’s worse to come.

“First off, we’re heading into autumn and winter, when the risk of groundwater flooding is higher, without enough focus on this. Secondly, the new Labour government has set out a target of 1.5 million new homes over the next parliament; while lacking a full baseline risk assessment for risk of flooding to property and infrastructure. And thirdly, climate change plays into both these risks, with increased temperatures and changing rainfall impacting the frequency and severity of groundwater driven flooding.”

The dangers posed by climate change mean 1.9 million people in the UK currently live in areas at significant risk of flooding; and this number could double by the 2050s. The Environment Agency also predicts that “bigger, more frequent floods are expected over the 21st century, particularly during winter.”

In the light of the increased risk, GeoSmart is urging the government to develop a robust management strategy that recognises groundwater flooding as one of the UK’s foremost natural dangers based on a more holistic flood risk assessment.

“Data from our national FloodSmart Analytics platform shows that groundwater leads to more annual losses than coastal flooding, and it’s also a central primer for other kinds of flooding events.” says Fermor. “Because groundwater flooding has been misread as a tiny part of the UK’s flood problem, we risk sleepwalking into disaster. It’s a bit like the Covid outbreak, where the government was found to have failed UK citizens through a lack of preparation.”

Fermor also cautions that obstacles to effective flood risk management created by the Flood and Water Management Act 2010 (FWMA) and consequential errors and omissions have resulted in the central role of groundwater being overlooked.

He adds: “That’s why we’re calling on Steve Reed, Secretary of State for Environment, Food and Rural Affairs, to hold an urgent review as the basis for a more comprehensive flood risk management strategy that includes listing groundwater flooding on the National Risk Register.”