The race to save the Underground from flooding
By Chris Stokel Walker
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An earlier report, published in 2009 by the Greater London Authority (GLA), found that 72 London Underground and Docklands Light Railway stations are located on floodplains – the majority of which are on the tidal Thames floodplain. A 2018 version of the same GLA report found that 20 stations were susceptible a flood so severe it is expected to happen only once every 100 years, while one-tenth of the entire Underground and DLR network would also be affected by a one in 100 flood event. “Flood water getting into underground stations presents a particular hazard and a major engineering problem if the flood waters were to enter tube tunnels,” the report says.
“London has been fortunate to escape the worst of recent storm events in the UK, but it is only a matter of time before heavy rainfall seriously affects London and the underground network,” TfL’s unpublished 2016 report adds. “The risk is generally expected to increase [as] climate change predictions are that storms will become more intense. There is some evidence to show that these have already increased in frequency.”
According to the report, five times a year ruptured water mains cause flooding on the Tube network, while even holding the water at bay is a full-time task. A 2014 freedom of information (FOI) request to Transport for London revealed 1.4 million cubic metres of water are discharged from the Underground network into London’s sewer system by pumping stations installed across the system. At least 170 pump controller units are installed across the London Underground, gathering data and being remotely operated when needed to alleviate the impact of flooding. And most of the stations situated on the flood plain have had flood doors installed.
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