Whilst flooding is usually portrayed in the media as impacting upon residents in their homes, the effects are much more far reaching
Flooding can create devastating consequences for infrastructure and transport systems.
Travel is affected, impacting on both businesses and individuals and unfortunately the impact is not necessarily limited to the length of the flood, but can cause damage which takes months to repair.
Historically, railway lines were often constructed on low lying land which makes them particularly susceptible to flooding. This is further exacerbated by building on land near railways, reducing available drainage, resulting in water running off hardstanding and on to the lines. Careful review of planning applications is necessary to assess impact of such building. Floodwater can damage trains, cause electrical faults and destabilize the lines due to ballast washing away.
Repair works bear on recovery time of rail networks, affecting the economy and hindering both businesses and the public. In the floods of 2014, the only rail line connecting the Southwest was severed at Dawlish, casing suspension of rail transport to the west of Exeter for more than two months.
This not only caused more traffic on the roads, testing its capacity, but also caused concern for the West Country which could have been cut off should road flooding also have occurred.
Flash flooding is the main cause of weather related problems affecting transport. This is particularly evident in built up areas where greater numbers of impermeable surfaces reduce drainage capability.
Drains are unable to cope with surface water and often become blocked with debris, exacerbating the problem. On June 28 2012, 50mm of rain (equivalent to the average for the month) fell on Newcastle-upon-Tyne in a two-hour period, late afternoon when roads were busy with commuters and school collection.
Some roads became unpassable, others experienced hours of slow moving traffic and the majority of public transport was cancelled. Drivers were forced to abandon their cars either due to road closures or running out of fuel after severe hold ups. Not only were many homes flooded but £8 million of damage was caused to roads and pavements. A 2005 Department for Transport report estimated the road network was worth £62 billion, making it the country’s most expensive asset.
A 2014 report estimated that at peak times, flooding costs the economy around £100,000 per hour per major road affected. Not only is the economy affected directly by flooding of infrastructure, but indirectly too as disrupted traffic flow causes problems to businesses and increases emissions into the environment.
A 2016 report on the London Underground states that 57 tube stations are at high risk of flooding, including some of the busiest such as Kings Cross and Waterloo. The London tube network facilitates more than 3.5 million passenger journeys daily across 270 stations, making it one of the busiest in the world. Flooding caused by heavy rain or burst water mains, poses safety risks for passengers and employees not to mention the significant financial implications both to the tube and the wider economy.
Tubes are often delayed by rainwater flooding and 2015 saw rainwater flooding cause line closures. Burst water mains reportedly cause problems an average of five times a year. A particularly expensive example occurred in 2012 when the Central line was closed between Mile End and Stratford, for 26 hours, costing £4 million when three million litres of water was sent down a ventilation shaft.
Flooding effects are not restricted to the road and rail network. Airports may also fall victim to flooding. Gatwick Airport experienced disruption due to flooding of one of the terminal buildings affecting critical power and IT systems. Forced closure of the Port of Immingham occurred in December 2013 due to an east coast tidal surge overtopping the main dock gates, causing flooding to the port area.
This too caused damage to essential electrical and IT installations disrupting operations for several days whilst repairs were carried out. According to The Environment Agency, the disruption caused by the 2012 floods to utility, transport and communication links, cost the UK economy £82 million. They estimate the total cost of the 2012 floods to the UK economy to be nearly £600 million, £200 million of which came from the impact on UK businesses.
Future flood risks
The UK’s threat from flooding is likely to increase, with factors such as climate change, population growth, future development, and the way in which we manage our lands, all accelerating the issue.
Transport networks are essential to both a national and global economy dependent on the movement of people, information and goods so measures need to be taken to minimise disruption and economic and social distress which flooding causes.
Flash flooding inevitably puts extra demands on the emergency services who are required to deal with rescue and recovery operations, health and welfare, traffic disruption and may be restricted in their ability to reach emergency situations and expedite those in need to medical care.
Whilst these extreme weather events appear ever more likely, it is important to ensure resilience measures are put in place to lessen the disruption. Being prepared is essential. Identifying potential flooding areas and having easily accessible and deployable resilience equipment, can reduce the damage flooding causes and improve flood resilience.
Well trained responders need access to weather and flood alerts in the appropriate vicinities to ensure swift action. The importance of safeguarding electrical and IT installations is critical, either raising them to higher ground or protecting them with flood barriers, or defence schemes.
Rapidly deployable flood barriers, such as the Water-Gate barrier can be used to help protect assets. Drains require regular monitoring and clearing, particularly in the autumn to ensure free drainage of water. Pumps or pumping stations may be necessary to remove or redirect water.
As flooding has become more of a widespread issue, future construction projects should be carefully thought out to ensure they do not negatively impact upon the transport network, and where possible, future road and rail networks and electricity substations should be on higher ground.
Flooding is the biggest threat the U.K faces as a result of climate change, but despite this, it is regularly overlooked or ignored. There hasn’t been a large-scale flood in the U.K for a few years now, resulting in funding being cut. This may mean awareness of flood risk will reduce even further. It is important that flooding remains high on the agenda, it can have huge social, economic and environmental impacts for all of us. Going forwards, we must work hard to raise awareness of flood risk, and better protect our transport networks from the disruption flooding causes.
About the Water-Gate
The Water-Gate flood barrier is a temporary system which is unique in the way that once rolled out, it self deploys. It uses the weight of the water to hold the water back. The water lifts the top of the barrier whilst at the same time weighing the base down, forming a seal. By utilising this unique self-opening method, it reduces the time, effort and number of people required to install it, making this a truly rapid flood or water diversion barrier.
Simon Crowther is the founder and MD of Flood Protection Solutions, the UK’s sole distributor of the Water-Gate flood barrier.