Over the past few weeks it has been impossible to avoid reports of the devastation caused by flooding in the north of England and Scotland. As is often the case much of the flooding appears to be from rivers over-topping their banks causing inundation of nearby houses and businesses. The rhetoric that these are unprecedented events caused by a series of severe storms falling on saturated ground may be true, but these conditions no longer appear to be as rare as we once believed.

Sir James Bevan, the Chief Executive of the Environment Agency, commented earlier this week that we must now begin to take a new approach to flooding. What this approach is has not yet been stated, but surely it will involve a thorough reassessment the Source – Pathway – Receptor model.

The key question is which of these should we begin to tackle first and which will have the most impact in preventing or reducing the impact of flood events?

When considering the ‘source’ we clearly cannot prevent the rain from falling, and without extreme intervention we cannot dictate where the primary watercourses will form. However, several studies have shown how poor management of our upstream catchments does increase the volume and rate of water flow into our rivers, which subsequently raises the risk of the channel capacity being exceeded. We are beginning to understand how our urban environments contribute to this and policies and guidance regarding SuDS have been put in place accordingly (albeit there is further work to do). However, very little is being done, or is fully understood, about how mismanagement of our ‘green’ space through the removal of trees and vegetation can also have a detrimental impact on flooding. Current farming policy often undermines that of good flood prevention practice, but balancing these two complex and competing land demands is extremely challenging. Should we now be stating that flood protection takes priority and force farmers to manage land accordingly through the implementation of new policy?

For many years the main focus of flood prevention has been by controlling or preventing the pathway through the construction of flood defences. This has been carried out on a risk based approach and to date has been relatively successful. However, as we have seen recently with our severe weather, even the highest of defences can be overtopped or breached in certain circumstances and this will only get worse due to the effects of climate change. The question is therefore; what level of flood risk are we prepared to tolerate? Increased protection costs huge amounts of money, not only in capital cost but also in maintenance. Who should pay for this? Only those that live and operate in flood risk areas, or all of us as a society? The new ‘Flood Re’ insurance scheme would suggest all of us, but is this fair? What about farmland? this would seem an obvious choice to use for additional storage in times of flood, but the issues raised in respect of the Somerset levels last year shows that even this is extremely controversial and would surely require vast compensation payments to made.

This leaves the receptor, our developments. Within the UK, as in many other countries around the world, our cities have developed around rivers due to their potential to provide energy, transport links, sanitation etc. The Environment Agency do a good job of restricting new development in high-risk flood plain areas (although some may argue more could be done), however should we now be thinking more of a slow and managed retreat away from our rivers, as has been carried out to areas of our coastline? Clearly we cannot move our cities wholesale and instantly to areas of higher land and there are many physical, economic and social difficulties in doing so; however, it is something which may prove the best long-term option for some particularly vulnerable areas?

Despite the best endeavours of us as engineers, we will never truly be able to fully control the forces of nature and there will always be occurrences of flooding. The hard questions are therefore how often are we prepared to be affected by severe flood events, where (and to whom) do we allow this flooding to occur, and how much money (and from where) are we prepared to throw at the problem. From a purely financial perspective a decision could be established relatively quickly, the more difficult and incalculable consideration is the emotional price on the victims.