It can only get worse – so we must be prepared

Wednesday, July 08, 2009

As the heatwave is followed by floods and a waterlogged Victoria Station is evacuated, Professor David Balmforth says it's time to shift the focus from defence to flood risk management

Like most natural disasters, people give little thought to flooding until it occurs. Reaction is strong at the time, but apart from those seriously or personally affected, memories quickly fade and anxiety decreases until the next time. This is how it has always been – except now major flooding incidents are becoming increasingly common.

This is no surprise. In 2004 the Office of Science and Technology Foresight report on climate change, floods and coastal defence showed that we could expect the number of properties at risk from flooding to rise from 80,000 at present to 350,000 by 2050, with associated damage costs rising by a factor of seven. The report also concluded that the cost of managing flood risk would increase by a similar amount if present approaches to flood defence and drainage were continued.

Put bluntly, this is unaffordable, and we must find a new way to tackle flood risk in the future.

Against this background, the floods of 2007 could be seen as an example of what we might expect on a regular basis in the future. So it is good that the subsequent Pitt Review has generated so much interest and activity. The forthcoming Floods and Water Bill will do much to implement its recommendations. It will shift our focus from flood defence to flood resilience, give the Environment Agency overall responsibility for flood management strategy in England and Wales, and put local authorities in the lead position for managing flood risk locally. All those bodies with responsibilities for drainage and flooding will in future have to work together.

A few simple themes can be distilled from the many recommendations of the Pitt Review. First, flood risk management must be put at the heart of urban design. In extreme flood events, large volumes of water have to be conveyed on the surface and our existing drainage and flood defence systems cannot be expected to cope with these. So we need to ask if can we create urban areas with adequate space between buildings to create flood pathways and identify dual use or "sacrificial" flood areas in low spots.

We also need to see if these sorts of measures could be applied immediately to all new development and urban regeneration projects – and if so shouldn't we also endeavour to retrofit such measures into existing urban areas?
Additionally we need to ask ourselves if we can make buildings more resistant to flooding. This does not simply mean raising buildings on stilts, since we need to create pleasant urban communities.

We also need our buildings to use more flood- resilient materials. Current practice leaves us with materials easily damaged by floodwater and homes that take months to dry out should flooding occur. Construction industry professionals must work together more closely to address this.

We must also protect our critical infrastructure from flooding. Losing basic services during a flood can turn an emergency into a disaster. But should this go beyond simply building defences around assets in the flood plain? Do we need to review the robustness of our infrastructure networks to assess how much of our infrastructure is actually critical?

And can we help our urban communities to become more resilient to flooding through better public engagement, improved forecasting and better emergency response?

A good start is placing local authorities at the forefront. This will give the public one point of contact and bring flood risk management together with emergency planning. However, it is not clear from the draft bill how all of this is to be funded. We cannot expect local authorities to take on new duties and responsibilities effectively if there is not an appropriate funding stream.

Over the past decade, most authorities have lost their drainage capability. This needs to be rebuilt, new staff employed and existing staff retrained. We need to see firm programmes of work emerging.

There is enormous enthusiasm to get to grips with flooding for the future. If we shift our focus away from defence and put flood risk management at the top of the urban agenda, we can create urban communities that are truly resilient to flooding.

Professor Balmforth is Technical Director with international consultants MWH and Editor in Chief of CIWEM's International Journal on Flood Risk Management