![]() London already knows how flash floods can cause chaos. ![]() But even this engineering marvel won’t be able to prevent floods in the city’s many different neighbourhoods when their older, smaller sewers are temporarily overwhelmed by rain. The Thames Tideway Tunnel, a 16-mile super sewer, should stop sewage flowing into the capital’s river during storms. This means gulleys in roads and pipes underground need to be bigger to capture water quicker.” What we are seeing now is more short, sharp, intense rainfall, typical of summer. Mr Laister explains the UK has long designed its drainage systems “for long-duration, low-intensity rainfall, typical of winter. Heavy rain hit towns across the UK this week including Seaford in East Sussex (Photo: Dan Kitwood/Getty Images) Fundamentally, our ageing town and city sewer networks were not built to cope with monsoon-like conditions and they need to improve. ![]() Traditional flood defences like levees and sea walls are less relevant in these instances. Tackling this threat doesn’t involve debates about building on floodplains or how much should be spent on dredging rivers. More attention will be assigned to this as we increase the intensity of development and sewage infrastructure investment doesn’t catch up.” “But there is an increased risk in urban areas of ‘pluvial flooding’ – caused by surface water from heavy rainfall – which needs greater attention. Rightly so: it can lead to substantial loss of loss of life,” he says. “Historically, river flooding – ‘fluvial flooding’ – was the main concern. Usually they’re just a nuisance but we shouldn’t downplay them, they can result in loss of life.” Indeed, flash floods last July killed 196 people in Germany and 43 in Belgium. “It’s just a question of how big a deal those are. “Almost certainly we will see more localised flooding events,” warns Guy Laister, director of the engineering consultancy Water Environment. Liz Truss's new economic advisor is a fan of tax cuts, but prefers life on Mars 07 September, 2022 Boris Johnson’s ‘green legacy’ has major flaws – it’s up to Liz Truss to rescue net zero 05 September, 2022 Jane Fonda reveals cancer diagnosis but vows to continue climate change campaigning 03 September, 2022 This nightmare could happen.” More on Climate Change But in parts of the city it pours into basements, where it’s several feet deep, and people start to drown. It’s dark, and water starts coming into thousands of homes. The underpasses start to fill up and the roads become impassable,” he said. Within minutes, water is overwhelming the drainage system. “The clouds burst with astonishing intensity. In 2018, its chief executive Sir James Bevan gave a speech in which he outlined just how disastrous flash floods could be in a major British city. The Environment Agency has been warning of the dangers for some time. This will create a ‘perfect storm’, with more rainfall and less capacity to manage it.” ![]() This is because hotter air can hold more water – making extreme bursts of rain more typical – and that same severe heat will more often bake land rock hard, so when the rain does come more of it flows faster into inadequate drains which fill up and flood unsuspecting towns.Īlejandro Dussaillant, a senior hydrologist at the UK Centre for Ecology & Hydrology, says: “The rainfall totals for extreme storms lasting up to three hours could increase by 25 per cent in the 2050s compared to now.”Ī council worker in London attempts to clear a drain with his broom after torrential rain this week (Photo: Leon Neal/Getty Images) The risks to our urban areasĪs Burton Bradstock shows, it’s not just a problem for towns and cities, but Mr Dussaillant explains this is where risks are being “exacerbated by increased urbanisation such as development and paving over gardens for parking, making surfaces impermeable. The type of rainfall that causes flash floods will also become more common with global warming, explains Met Office climate spokesman Grahame Madge. In fact, surface water presents the most widespread form of flooding in England, with around 3.2 million properties at risk, according to the Department for Environment, Food & Rural Affairs (Defra). “It can happen anywhere, especially in urban areas.” “This makes surface water flooding very unpredictable,” says Dermot Kehoe, a director at Flood Re, a scheme which which aims to make flood cover more widely available and affordable. Highly localised downpours like we saw this week can suddenly overwhelm places within minutes when the rain is so intense.
0 Comments
Leave a Reply. |