Venturing into the unknown– Natural flood management and uncertainty

Natural Flood Management (NFM) means working with or restoring natural processes in order to reduce flood risk. It can include many actions such as woodland creation to slow water flow and/or store water in the landscape to help reduce the risk of flooding downstream. NFM can deliver other benefits such as biodiversity improvements and water quality.

 Although this may sound like a good idea, I see that current views on NFM are mixed; there are lots of people saying ‘yes please, NFM is great. It’s good for biodiversity and diffuse source pollution as well as flooding’ but there are also lots of others saying ‘it sounds good in theory but we don’t really know much about it. Does it work and where’s the evidence?’  I’ve been working with colleagues on a project exploring the challenges to implementing NFM, and we are finding that many people are apprehensive about NFM, because they do not know if it will work. In a formal cost-benefit analysis, NFM doesn’t stack up because there are so many unknowns and it’s difficult to quantify the type of associated benefits (i.e. improvements to water quality or recreation). With current knowledge and expertise, it’s still easier to make a case for dams and flood walls.

I’m interested in this topic of uncertainty and evidence needs. In response to the uncertainty surrounding NFM, several research projects are underway to provide evidence. For example some colleagues are testing the effectiveness of NFM in Bowmont to see how NFM measures there may impact flow.  In the meantime, uncertainty remains and we still don’t have a very clear understanding of under which conditions NFM works. 

How can we move forward in light of this uncertainty? NFM is a good example to use as a basis for discussion but it could be applied to any domain of natural resource management including ecosystem management.  We know climate change is happening but don’t have a clear idea of what the impacts will be and where they will happen, only that weather patterns will change, be more extreme and sea levels will rise (http://www.ipcc.ch/). We have entered a period of environmental change that we have never seen before. It may be impossible to control or reduce uncertainty to a level that we would prefer or are used to.

So, what do we do in light of this uncertainty? In the case of flooding, if we expect complete protection from flooding but want to try new sustainable flood measures, then we probably need to change the way we see flooding and the way that we organise our towns and cities.  Competing objectives between building houses and flooding exist. If we can’t eliminate flooding risks, it seems common sense not to build in a flood plain, or at least to change the design of what we do build there.

We are taught to demand evidence for everything but in some cases things are difficult to measure and it can take many years and a lot of money and time to build up and evidence base for something (such as NFM). I am not suggesting that we move ahead without evidence, or that we forget engineering in flood risk management (that would be naïve and dangerous), my suggestion is more about posing a question about how we can progress as a society towards sustainable management of natural resources while dealing with uncertainty. 

Maybe, one step in the right direction is to connect different sectors better (e.g. flood management and planning) but, more generally, maybe we need to be more honest that we can’t perfectly control risk and start discussions about it?

Disclaimer: The views expressed in this blog post are the views of the author(s), and not an official position of the institute or funder.