Rising waters | Rooted solutions
Where NFM works best - and why context matters
Explore how Ousewem uses evidence and modelling to identify where natural flood management can best support flood resilience.
Natural flood management (NFM) is often discussed as if it can be applied in the same way everywhere. In practice, the opposite is true. What works in one location may not be appropriate, feasible or effective in another. That is why context matters.
Ousewem’s work across the Swale, Ure, Nidd and Upper Ouse (SUNO) catchments is helping build a clearer evidence base for where NFM may contribute most usefully to flood resilience, what scale of action may be needed, and where its limits need to be understood.
Why place matters in NFM decisions
NFM is shaped by the characteristics of a place. Factors such as topography, soil type, land use, hydrology, catchment position, existing infrastructure and the scale of the flood event all influence what type of intervention is realistic and what role it may play as part of a wider flood resilience approach.
This is one reason Ousewem uses modelling at different scales: not to produce a single answer, but to support better questions and better decisions. Strategic modelling helps us understand the scale of change that may be needed across a catchment, while local modelling and site-based evidence help test how individual measures perform in specific places.
What modelling helps us understand
Modelling does not predict the future or guarantee outcomes. It helps build an evidence-based picture of where water may go, how risk may change, and where interventions could make a meaningful contribution.
Ousewem’s emerging whole-system modelling reinforces an important point: small, isolated interventions are unlikely to significantly influence peak flows at York on their own. To affect flood risk at this scale, NFM needs to be considered across a much wider scale in the catchment, in the right places, and alongside other flood resilience approaches.
That does not reduce the value of local NFM. It helps clarify the role it can play. Strategic modelling helps set realistic expectations about scale, while local evidence helps show how specific interventions can slow, store or filter water in particular settings.
Where NFM may contribute most usefully
There is no single landscape, catchment or community where NFM can be said to work best. Instead, suitability depends on local conditions.
In some locations, interventions such as woodland creation may help slow runoff and intercept rainfall before it reaches watercourses. In others, floodplain reconnection, wetlands or offline storage may provide more benefit by temporarily holding water within the landscape. Equally, there are places where certain forms of NFM may not be appropriate because of local geology, geohazards, land use, infrastructure constraints or other site-specific considerations.
This is why NFM cannot be copied wholesale from one location to another. Geography, local land management decisions and catchment conditions all influence what is realistic, effective and appropriate.
Why realistic expectations matter
NFM is an important flood resilience measure, but it should not be presented as a universal solution. In most situations, it works best as part of a wider flood resilience approach alongside existing flood defences, engineered solutions and other measures.
NFM can help slow, store and filter water, reducing pressure on rivers and drainage systems and contributing to long-term resilience. Many interventions can also deliver additional benefits, such as improved water quality, habitat creation, biodiversity recovery and more resilient land management. However, the benefits achieved will vary depending on local conditions, the type of intervention used and the scale of the flood event.
Not all forms of NFM are suitable everywhere. For example, steeper catchments may be better suited to interventions such as woodland creation and tree planting that help intercept and slow runoff, whereas flatter landscapes may benefit more from wetlands, floodplain reconnection or offline storage that temporarily hold water within the landscape.
That does not reduce the value of NFM. It sharpens the case for using evidence, local knowledge and partnership working to decide where NFM can play the most credible and proportionate role.
Looking ahead
For local authorities, practitioners and policy audiences, the key message is simple: place-based decisions matter. Understanding where NFM works best means understanding context, scale and limits, and using evidence to guide action responsibly.
As Ousewem’s modelling and site evidence continue to develop, this learning will help strengthen the evidence base for future catchment-scale planning and support for measuring what matters for NFM success. We will share more about Ousewem’s whole-system modelling in a future update.
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