The Pantiles district of Tunbridge Wells in Kent is an attractive tiled street of shops and tea rooms that has been a popular tourist destination since Tudor times. Almost a year to the day, the same area has been hit by flash surface flooding, causing substantial damage to the town’s vital heritage infrastructure.
The long and intense heat wave has been a joy for many this year. However, recent events in Tunbridge Wells prove that even on what seem like gin clear skies in the morning, raging torrents can follow in the afternoon on a very local scale.
In just one hour on 5th July, a sudden thunderstorm in the town led to traffic gridlock and delays for rail passengers as torrential rain fell. The dry, dusty ground, steep High Street gradient and paved surfaces ensured the surface water was funnelled rapidly into the historic shopping area.
Residents and shopkeepers described a “torrent of rain descending” and “drains erupting” as they could not cope with the sudden deluge.
The Pantiles were left covered in mud, sewage and rubbish from upturned wheelie bins after the water cleared. Some businesses in the town have only just reopened following surface flooding there a year ago. Many that who had concerns about a repeat event were proved right.
Surface Flooding: Managing the Unknown?
Tunbridge Wells Borough Council has stated that detailed plans have been made for a scheme to discharge floodwater into the nearby River Grom, instead of the sewer. Kent County Council has said that they aim to complete this work by the end of summer to reduce the risk of flooding.
While this may mitigate the surface flow in part, it is impossible to design on the basis of today’s magnitude. They are sure to get ever more severe as more moisture builds in the atmosphere through climate change.
In this episode, Light winds and high temperatures meant a sea breeze developed along the coast. This caused a temperature difference between land and sea which in turn set up a pressure difference. This instability was enough to create a highly localised, very potent storm cell.
But it could appear anywhere in the UK at any time – and we are never far from the coast in this country. The scenes in Tunbridge Wells also serve to remind us that our sewers are ill equipped to deal with these intense downpours.
These can easily back up into properties or cascade overflow down to the lowest point in the land and therefore the most vulnerable infrastructure. In this case, it affected vital transport links to the south coast, and historic tourist industry assets. Sewers can also be overwhelmed by groundwater during longer duration rain systems.
Flood Modelling for Community Resilience
GeoSmart works with local authorities, infrastructure providers and community groups to plan for better flood resilience. Our detailed flood models cover flooding from all sources including surface flooding incidents. They enable asset managers, business owners and community leaders to effectively plan ahead to combat future threats.