Restore our meadows, a most cost-effective flood defence
For centuries, almost all lands lying in the floodplains of English rivers were meadows. Managing these meadows involved an annual hay cut followed by grazing, providing essential hay feed for livestock over winter. Nutrient-rich silts deposited on the meadows by regular flooding acted as natural fertilizer, leaving them reliably productive. But over the past 70 years, the vast majority of these meadows have been lost to housing development, gravel extraction and quarrying, water abstraction, changes in agricultural use, or just lack of management.
Flood meadows, the unsung hero
Natural floodplains, and in particular floodplain meadows, could play a vital role in reducing the sort of flooding that has repeatedly wreaked havoc in towns and villages across Britain over the past decade. Meadows have the capacity to store vast quantities of flood water and release it slowly over time, lowering the peak water level. In contrast, modern flood defences use embankments to constrain floodwater to a narrow channel. This simply pushes the problem downstream, until floodwaters reach levels that can overwhelm defences – with sometimes catastrophic results.
The reason why meadows are so effective at soaking up sudden influxes of water is because traditional meadow systems produce good, open-structured soil. This not only supports a wide range of plant species, but also increases their capacity to absorb and store water. By comparison, the tilling (ploughing) of fields common with modern agricultural methods leaves soils more compact, reducing their ability to absorb water. Meadows represent an agricultural system that actually works in harmony with a dynamic river system: as well as absorbing flood water, they collect and put to good use the sediment that would otherwise be deposited further downstream, causing blockages and smothering valuable riverbed habitats.
A contemporary example of how such a system is actively aiding flood protection is Clifton Ings in York, managed as an official washland by the Environment Agency. By storing floodwater during periods of high flow it can reduce peak levels in the centre of York by 15cm – enough to blunt the risk of significant flooding. The site is managed as a traditional meadow and is a valuable habitat for wildlife – so much so that it has just been designated as a Site of Special Scientific Interest.
So other than their role in alleviating floods, floodplain meadows are among the UK’s most biodiverse systems, commonly boasting more than 30 different plant species in a single square metre, such as great burnet and rare snakeshead fritillary. The soils and plantlife also sequester carbon, helping in its own way to mitigate global warming, improve water quality by trapping phosphates, and of course are by themselves a beautiful landscape to enjoy.
Restoring meadows’ place in the countryside
And yet despite all the environmental benefits they bring, the loss of floodplain meadows over the last 70 years has been so rapid that less than 1,500 hectares of species-rich habitat now remain in the UK – an area only slightly larger than Heathrow airport. This loss has undoubtedly contributed to the rise in catastrophic flood events we have seen. Is it possible to turn the clock back? Our research with the Floodplain Meadows Partnership suggests it is.
A key to these meadows’ survival is to maintain or revive their traditional management. Originally handled by farmers, they rely on a viable agricultural system to keep them productive, and so ensure they are not displaced for other agriculture or development. Understanding how traditional management systems work and disseminating that knowledge is one function of the partnership, created in 2007 to focus on this key, threatened habitat and explore means of conservation.
Once lost is not always lost. We have demonstrated that it is possible to re-create floodplain meadows, given the right sites and with the right techniques. There are a number of good examples where the process of restoring meadows has begun, with many new projects beginning around the country. Financial support for restoration is currently available through Natural England’s Higher Level Stewardship scheme, and the partnership website holds information on how to go about restoring meadows, and links to local organizations that can help.
Perhaps we can never return to the golden age of the British meadow, but a renewed focus on how we use floodplains is long overdue. Money spent to enhance the role of meadows as an environmentally beneficial, sustainable and effective system of flood defence would be a sound long-term investment.
Emma Rothero is Research Fellow, Outreach Coordinator at the Department of Environment, Earth & Ecosystems at The Open University
David Gowing is Professor of Botany at The Open University
David Gowing receives funding through the Floodplain Meadows Partnership from the Esmée Fairbairn Foundation, and is a member of the British Ecological Society and a Trustee of a Wildlife Trust.
Emma Rothero does not work for, consult to, own shares in or receive funding from any company or organization that would benefit from this article, and has no relevant affiliations.