How we can reduce the risk of flood damage to UK roads

As Storm Frank’s wrath in late 2015 demonstrates, UK infrastructure must recognise the very real and increasing risk of floods.

Not only has this winter’s flooding bought devastation to people across the country, with some 5,000 homes and businesses affected by the rising waters, but the destruction is spreading to implicate the road network too, the fallout of which will see transportation suffer and industries such as tourism hindered. So what can those in important highway jobs do to reduce the risk of flood damage to UK roads?

How far does flood damage spread?

Where areas in the UK fall victim to flooding, road access is likely to be limited. Naturally, going about our normal day becomes a challenge as commuting to work or getting from A to B is no longer an option. For businesses operating in these affected regions, the fallout from floods can be disastrous with the highways that would usually support the delivery of goods cut off.

Nationally, many more will experience major road and rail network disruption as the country’s transportation infrastructure takes a hit.

In the UK, the majority of travel happens on the road. Despite this, maintenance has declined while the number of routes requiring attention has only grown. The Government has previously committed £6 billion towards tackling these issues by 2021, but with the recent floods bringing a new wave of costs with it, will this investment trickle down far enough to build an infrastructure for the roads that can respond better to future natural disasters?

Well, maybe. Speaking to The Telegraph , chief European and UK economist at IHS Economics, Howard Archer, believes that gains could be achieved as Britain responds to the damage, rebuilding affected areas and creating repair work. The financial contribution made here may be felt further down the line, helping to balance out the impact of flooding on economic growth in the UK.

He said: “The floods could well shave 0.1pc - 0.2pc off GDP growth overall in the quarter that it occurs, in terms of businesses not being able to open, loss of agricultural output, people not being able to get to the shops and travel.

“There will be some boost to growth through the construction work that will be generated by major repair work to buildings and infrastructure, replacement buildings, purchases of furnishings and household goods lost or damaged during the flooding.”

As it stands at present, the cost of flooding far outweighs a potential spike in GDP. For instance, the Association of British Insurers has suggested that Cumbria could be looking at a loss of £520 million worth of damage caused by Storm Desmond, which hit the region in the first week of December last year.

What can we do to minimise the impact of flooding on the roads?

That’s the big question.

When floods occur, funding is desperately needed to repair roads, fords, drainage systems and public rights of way. Currently, £2.3 billion capital investment has been put aside to reduce the risk of flooding and coastal erosion. Of this, £235 million is being poured into managing the floods in the UK and 55% of this amount specifically for inland flood risk where roads are likely to be affected. The idea is that this contribution will go some way towards initiating long-term benefits for the country’s transport, commerce, infrastructure and industry. Just how to spend this pot, however, is still up for debate.

Speaking at a briefing held in London by the Royal Academy of Engineering and the Science Media Centre following the flooding of the Somerset Levels, Roger Falconer, Professor of Water Management and director of the hydro-environmental research centre at Cardiff University, suggested that ministers should allocate some funding to raising the roads around the site so that communities inhabiting the area aren’t cut off as the water rises.

He said: "I think it would be a better investment to raise the roads so at least people can communicate with the outside world. I personally think that would be a better investment of the money."

Civil engineering projects such as this would consequently support jobs in the industry and in this way could well have a positive impact on the UK’s economy.

Prevention is the best cure?

Over time, rural landscapes have been developed into urban areas with hard surfaces, which has only acted to speed up water runoff and allowed it to gather in larger quantities. As natural features in the landscape, which once would have acted as a calming measure to slow down water passage, have made way for built up areas, a higher flow has caused major flooding in towns and cities.

Avoiding this outcome, or at least managing it more effectively, is a key priority in planning for new developments and infrastructure including roads.

While flooding, being a natural disaster, is impossible to prevent, UK planning policy obligates built environment professionals across the engineering and construction sectors to factor flood mitigation into applications. Furthermore, every local authority must demonstrate how flood risk can be minimised when proposing new developments. If permission is granted, a Strategic Flood Risk Assessment must be conducted to evaluate the probability of floods to the intended site now and in the future.

Transportation also factors into planning, with a Strategic Environmental Assessment also required to ensure that the local transport plan does not negatively affect the environment. This must also include measures to reduce flood risk to any new or existing transport infrastructure in the area.

James Harris, Policy and Networks Manager at the Royal Town Planning Institute (RTPI), explains: “When creating new plans or policies, all authorities are required to take into account the flood risks identified by the Environment Agency for river catchment and coastal areas, along with their recommendations for sustainable flood risk management over a 50 to 100 year period.

“These strong planning controls are needed to ensure that our road infrastructure is both protected from flooding and does not contribute to flooding elsewhere.”

The RTPI is the UK’s leading planning body, its expertise spreads to spatial, sustainable and inclusive planning. Its approach to flood risk management differentiates from the norm to accommodate a shift from reliance on traditional flood defences to a more holistic approach to risk management.

RTPI’s sustainable approach to planning for flood risk incorporates a number of measures:

• The inclusion of Sustainable Urban Drainage Systems (SUDS), which are now generally required as part of the design of new roads. SUDS are natural drainage solutions that mimic nature and are more environmentally-friendly and resilient than the traditional approach of directly channelling surface water through pipes and sewers to nearby watercourses or wastewater treatment plants. SUDS measures include permeable surfaces, planting and swales (areas planted with reeds and lined with gravel that help stop pollutants from reaching the water table), along with wetland and water rendition ponds. 

• Other passive measures – for example including multifunctional green spaces (e.g. playing fields) near roads, which can act as water storage areas during times of flooding, or the planting of grass and trees to stabilise soil and increase water infiltration underground, or the reinstatement of natural flood plains where possible 

• More traditional physical defences such  as flood levees, drains, sewers and dredging of channels in special cases

• Emergency management measures for when flooding does occur, including flood warnings, emergency management plans and  recovery plans.

Where are we now?

At the same briefing in London attended by Professor Roger Falconer, Jim Hall, Professor of Climate and Environment Risks and director of the Environmental Change Institute at Oxford University, stated that "In some senses we're still in a mode of 'discovery by disaster'.

"With the exception of rail infrastructure, critical national infrastructure has come through this latest set of floods pretty well, but adapting to changing climate risk is still very much a work in progress."

The Government has recently launched an open consultation to collect supporting evidence about previous floods. The National Flood Resilience Review calls for people to submit their evidence of damage resulting from extreme rainfall, which the Department for Environment, Food & Rural Affairs will collate in this report.

As floods occur, the focus is placed on managing disruption. Currently we learn by exposure but in order to reduce the risk of damage to our roads, new approaches must be explored, whether this be through planning that aims to curb the potential for destruction on transport infrastructure or through civil engineering projects.

We need experts in the highways sector to work together, contributing their experience of flood mitigation, to form a solid grounding on which we can suggest alternative solutions to managing flood risk on Britain’s roads.

Image Credit: Heart of the Lakes, Nick (flickr.com)

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