Farming union rhetoric and media headlines have repeatedly pointed the finger of blame at beavers for flood bank breaches, allegedly costing Scottish farmers millions of pounds. However, a deeper look reveals the true story, one where historical flood bank construction and our changing climate catastrophically collide.

The Influence of Climate Change

Recent meteorological data underscores a stark reality: our climate is undergoing significant change, manifesting in more extreme weather patterns and increased flooding. According to the Met Office, the single wettest day recorded in recent history in Eastern Scotland occurred on October 19, 2023, a testament to the intensifying rainfall events. Moreover, five of the ten wettest years for the UK since 1836 have occurred in the 21st century, illustrating a clear upward trend in precipitation extremes (State of the UK Climate 2022)

These changes are not just numerical figures but reflect a shift that has profound implications on hydrological cycles and flood management systems. Increased rainfall intensity leads to higher river flows, putting unprecedented pressure on flood defences that were simply not designed for such extremes. This surge in water volume can overwhelm riverbanks and flood defences, leading to floodbank breaches that are often  blamed on beavers. 

While scientific studies have shown that changes in storm patterns significantly influence river dynamics and flood risks (Brazier et al., 2020)​​ increased rainfall and more frequent flood events are only one part of the flood bank story.

Historical Alignment of Flood Banks

Originally built several centuries ago, many of these flood banks were constructed from locally available soils and gravels to transform wetland into farmland. Not generally built to high construction standards, these defences are ill-equipped to handle the hydrological pressures exerted by peak flow events. We therefore shouldn’t be surprised that flood defences are failing, as they were simply not constructed to cope with the current and future hydrological demands posed by a rapidly changing climate. It was inevitable that over time, agricultural flood defences would age and deteriorate. It is only now becoming evident that they are ineffective against the scale and frequency of flood events that we now face.  

We urgently need to re-evaluate flood management strategies to incorporate contemporary scientific understanding and climate projections.

An illustrative example of the impact of extreme weather events on flood bank integrity can be seen in the recent breaches in the river Spey Catchment. In October 2023 and November 2022 extensive flooding caused damage across the entirety of the UK. These events led to several flood bank breaches in the Spey Catchment— breaches that took place before the first beavers were released into the area in the Cairngorms National Park in late December 2023. These River Spey flood defence breaches could not possibly be due to beaver activity,  but instead were driven by storm severity and the existing vulnerabilities of the flood banks.

A Scapegoat for Broader Issues?

While beavers are ecosystem engineers that naturally alter their surroundings through dam building and burrowing, attributing flood bank breaches solely to their activities misleadingly oversimplifies the issue and merely serves to unfairly demonise a species which brings many environmental benefits. 

It would be wrong to suggest that wildlife burrowing plays no part in weakening floodbanks. However, the detailed observations from the 2022 NatureScot commissioned report reveal that, although beaver – and other animals, such as rabbits, moles, foxes and badgers – burrowing can locally weaken the structural integrity of flood banks, the scale of burrowing impact is minor compared to the impact of massive hydraulic forces unleashed during high-flow events caused by heavy rain and snowfall (NatureScot. Mitigation options for reducing beaver burrowing impacts on agricultural land in the River Isla Catchment, Scotland. 2022).

Beavers clearly do influence their environment, but this influence can also be positive.  Academic studies have shown that beaver dams in catchment headwaters can help moderate water flow, thereby reducing the velocity and eroding effect of floodwaters further downstream (Law et al., 2019). Recognizing the dual role of beavers—from potential challenges to ecological benefits—is crucial for holistic environmental management (Pollock et al., 2014; Rosell and Campbell-Palmer et al. 2022)​​.

Experience from Europe

In Europe, managing the impact of beaver burrowing on flood embankments has necessitated the adoption of various remedial measures to safeguard not only against beaver activities but also those of muskrats, coypu, red foxes, badgers, and rabbits. In Bavaria, for instance, authorities have effectively employed strategies such as facing flood banks with stones and mesh or installing sunken welded wire mesh to deter digging. These measures are crucial for reinforcing the banks and preventing burrowing that can undermine their structural integrity. Additionally, where new flood walls are being constructed, the incorporation of anti-burrowing features as a standard part of the design is becoming more common. However, when dealing with older flood walls, implementing effective mitigation techniques often proves to be both physically challenging and costly.

Wherever possible, the primary method for managing the impact of beaver burrowing is the realignment of flood banks and the creation of buffer strips of bankside vegetation. These have been adopted in Bavaria, the Netherlands and elsewhere across Europe to reduce potential conflicts between humans and beavers, while simultaneously enhancing flood mitigation and riparian habitats. These practices illustrate a proactive approach to integrating wildlife management with flood defence, addressing both ecological and agricultural concerns.

A Sustainable Solution is Required

Addressing the complex issues that lead to breaches in flood banks requires a strategic and evidence-based approach to management. This strategy should include repositioning flood defences to cope with both current and future threats, as well as generally improving the ecological resilience of river systems.

While NatureScot has recognised that the repeated investment in repairing flood banks at the same locations is not a sustainable solution, the Scottish Government has invested over £3.5 million in taxpayer funds in the last decade to repair these defences despite the likelihood of their recurrent failure. A shift in government funding and policy is imperative to prevent recurring instances of flood bank collapse, to support affected farmers, and to prepare for the impact of climate change that is already occurring.

Climate Adaptation not Castor Removal

The subjective narrative that seeks to blame beavers as the principal cause of flood bank breach is agenda-driven and lacks a sound scientific basis. To effectively address this issue, it is crucial for policymakers, conservationists, land managers and the public to embrace a wider perspective of river health that prioritises tackling climate change through mitigation and adaptation strategies. Recognising the substantive factors contributing to these environmental challenges—increased storm events and outdated flood defence systems—is a first step towards the development of holistic solutions. These solutions include natural flood management approaches, such as restoring natural river processes. In this way, we can not only mitigate flooding but also adapt our defences through measures such as setting back flood banks and creating natural river buffers. Emphasising these strategies is essential for developing policies that protect our agricultural lands and natural ecosystems from the growing threats of climate change, while promoting sustainable coexistence with our native wildlife.