What is “natural flood management”?

For several years I’ve been interested in “natural flood management” (NFM) and how to implement it.  When I started working on this topic, I thought I had a good understanding of what NFM was. If people asked me, I would have said that NFM includes a number of different features such as ponds that store water in the landscape or measures such as willow dams that slow the flow.

Recently, I have been working on a research project, in which we’ve been conducting interviews with people in diverse organisations, including statutory bodies, Local Authorities, and consultants, to try to get a sense of the ‘institutional barriers’ to implementing NFM. One of the first questions we ask people in the interviews is ‘how do you define NFM’ to try to get a sense of how they understand it. I never thought that this simple question would cause such a stir.

I’m finding that each person I speak to understands NFM in a slightly different way. Everyone is using the term differently, and they would not necessarily agree with each other about what qualifies as NFM.  For example, some say that SUDS (sustainable urban drainage systems) can be an example of NFM, whereas others argue that they have no associated flood management benefit and are implemented for water quality purposes only.

Understandings about what specific measures qualify as NFM are linked to underlying meanings or interpretations of the concept. When I first started researching NFM the emphasis was (perhaps unsurprisingly!) that it was very natural and about intervening to restore systems in line with natural processes.  Some still understand NFM very much along these lines, however, others place more emphasis on engineering. For example, when I speak to people with engineering backgrounds they often see NFM as something that is grounded in engineering and usually has to be accompanied by hard engineering flood defences. For others, any engineered features would not count as NFM, for them, NFM is by definition something that does not include engineering. The line is blurred where NFM ends and where engineering begins and also it depends who you speak to.

Another complication is that some actions or measures to manage the environment might affect flood risk, but are not actually carried out explicitly for flood management purposes. Afforestation can be an example of NFM, but the motivation for planting trees may actually be for biodiversity gains or other reasons, even though one of the other side effects or ‘multiple benefits’ of this action is supporting NFM. But is it really NFM at all, if it was not purposively designed to help manage flood risk?  If so, might a tree planting project be badged as NFM even if there is not a flood risk in the area?  One interviewee told us that they thought housing developers tried to legitimise building on flood plains by planting trees elsewhere and claiming that the flood management benefits of the tree planting would offset the flood risk that houses would be exposed to.

Is the term NFM being thrown around too much?  My concern is that when we talk about NFM, we are sometimes talking about different things and using the term in an arbitrary way. Debate around NFM is healthy but when we are all talking about different things, it can get unhelpfully confusing. What’s more, it leaves room for the term to be used, represented and politicised in ways that ultimately might not really help us manage flood risk. These problems could potentially lead to disenchantment with the term altogether.

I think this challenge is not unique to NFM (we also found something similar in looking at examples of applying the Ecosystem Approach), and is perhaps is shared with any effort to try something new in natural resource management and explore the unknown. Perhaps this problem will reduce as more examples of NFM implementation become available, as has been requested in many of our interviews.  It is important however that we learn lessons as we go along, but I think the first lesson is that we need to explicitly discuss ‘what counts’ as NFM, and why. Checking whether we are all on the same page with NFM would be helpful.

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.