August's 'In Perspective' blog is written by Professor Colin Thorne of Nottingham University.
Farming floodplains is a good idea and we should continue doing it sustainably. Why? Because history tells us that from Mesopotamia to the Yellow River, all of the world’s great civilisations were founded on farming of floodplains, and illustrates that civilisations that fail to conserve their topsoil or adapt to climate change seldom long survive. The fact is that we all like to breath, eat and drink – which means that any civilisation, and the wealth of nations, depends ultimately on access to clean air, safe drinking water and quality top soil. But a resilient society also needs protection from environmental disasters, and of these flooding presents the greatest risk to life and property.
Floodplains play a key role in both respects. Not only do they help provision our larders, they also detain and diffuse floods that might otherwise overwhelm the defences protecting our many flood-vulnerable towns and cities. It follows that the sweet spot in managing floodplains for maximum overall benefit to society lies in harmonising their use for farming and flood risk management. The good news is that if we are smart, we can have both.
Sustainable farming requires economically successful farmers, who are a rare breed these days due to a variety of intractable socio-economic problems in rural areas. The current fragility of rural economies, coupled with the precarious finances of many farmers, means that crop losses associated with severe flooding can be the final straw for a farm business. Farmers and country land owners make a fair point when they call attention to their current plight. But while society is sympathetic to their pleas for dredging and better defences to reduce or eliminate floodplain inundation, the nation needs to carefully consider its priorities before setting aside environmental laws and writing cheques. For their part, farmer’s surely need to maximise production from the soil and water resources provided to them by nature, but the way they farm the land must also protect the natural capacity of the floodplains and rivers to sustain those water and soil resources. Providing a degree of natural flood management, while simultaneously renewing floodplain soil and water resources through managed flooding, is clearly the best way forward.
At school, everybody learns about the ‘rich silt of the Nile’ and, though over simplified, the fact is that floodplains do need to be flooded. The floodplain was built, and can continue to be built, by the river and thus is within the river’s domain, regardless of who owns it in a fiduciary sense. Nature doesn’t grant property rights or recognise the decisions made by land agents. But neither does the river occupy the floodplain continuously and it’s a fine place to farm – most of the time.
As a natural landlord, rivers are usually pretty relaxed, encouraging plants and animals to flourish and people to use their floodplains as they wish. But the river’s mood changes when it is in spate and let’s be clear-- when the river swells and overtops its banks, it is simply reclaiming land that it has created and nurtured with water, sediment and debris since the end of the last ice age. We now understand that this is not only inevitable, but also vital: hydrological, morphological and ecological connectivity with the channel is crucial to maintaining richness and diversity in both wild and human floodplain communities.
As a country, we cannot afford to sacrifice any of the multiple functions and benefits provided by healthy floodplains. But how do we avoid doing just that? There is no simple answer – it depends on the geography (human as well as physical) of the catchment and its drainage system. But we’re a creative and resourceful island nation and I’m confident that, given the chance and necessary funding, floodplain communities will work out local solutions to local problems. Nevertheless, the process could be accelerated by learning from countries whose flood risks dwarf our own and who have, of necessity, become very smart about managing their floodplains.
Much of the Netherlands is below sea level and the Dutch have become masters of land drainage as they have worked out how to protect their towns and cities from river, coastal and surface water floods. The Dutch recognised years ago that dykes alone could not prevent flooding and adopted a policy to ‘Make Room for the River’. This involves moving agricultural flood embankments back and reconnecting rivers to more of their floodplains. The Netherlands is a tiny country and every hectare of farmland is precious, even more so than in the UK. Understandably, Dutch farmers were unwilling to give up their land, but that was OK because they weren’t asked to – you see it isn’t necessary. Farm houses and key infrastructure have been relocated to higher ground and arrangements made for evacuating stock to places of safety as soon as flood alert is issued, but other than that farming continues much as before . Farming hasn’t been sacrificed to flooding, but the floodplain has been recognised as a condominium – an uneven ‘time share’ within which farmers use the land 90 to 99% of the time, but allow the river to access and replenish it when necessary!
This type of accommodation is of course nothing new. Farmers in Bangladesh are experts at co-habitating with some of the most powerful rivers on Earth -- rivers that demand respect and which are truly beyond our control. A Bangla proverb captures this very eloquently, “farming in the floodplain is like camping in a rich man’s garden: it’s a great place to live but when asked to leave temporarily, you must do so quickly and without argument”.
Accordingly, while farming does not need to be sacrificed to flooding, it is unwise to sacrifice floodplains to farming. The sensible way forward is to recognise and value the multiple benefits floodplains provide to society and then take the steps necessary to conserve and sustain our floodplains and their functions, which requires that we nurture both our rivers and the rural communities that farm their floodplains. In practice, farmers need to equitably share the floodplain with the river and society needs to support them by buying the food they produce and compensating them for the flood risk reductions they facilitate. It’s really not that complicated.
Colin Thorne is a fluvial geomorphologist with an educational background in environmental sciences, civil engineering and physical geography. He has published 9 books and over 120 journal papers and book chapters. During a career spanning four decades, has held academic posts at UEA, Colorado State University, the USDA National Sedimentation Laboratory, USACE Waterways Experiment Station, NOAA Fisheries, and the University of Nottingham. Colin is the PI on the Blue-Green Cities Project and is a member of the FCERM.net Steering Group.