The call from the Environment Agency came in the evening of 4th February, 2014. The incessant rain of the past few weeks, had created a tidal wave of water that was expected to reach the river Parrett in the Somerset Levels, within hours. The banks were likely to burst, and James Winslade would have to evacuate his farm. With the help of friends, neighbours and 14 tractors, they managed to get their 550-head cattle herd safely to higher ground – just in time. But when I visited the Winslades later that year, they were still living in a caravan next to the 170-year-old farmhouse: drying out and stabilising an old building takes time. The family hoped to move back in by Christmas.
Farmers in the Somerset Levels have learned to live with too much water. Canals criss-cross the low-lying marshland and help drain fields and grassland; sluice gates and pumps regulate the water flow. “We are used to winter floods and the grassland can withstand being under water for a few weeks,” says Heather Venn, who also farms on the Somerset Levels. But the 2014 mega-flood that followed the extreme flooding of 2012 was different. In some of Winslade’s fields, the water was 4 metres deep and most of the land remained flooded for months. When the water finally receded, the soil was a compacted, stinking mess with not an earthworm in sight, remembered James Winslade.
Why did the Somerset Levels see two major flood events in such quick succession? Farmers point to rivers which weren’t dredged properly, due to budget cuts, and couldn’t cope with the extraordinary amount of water coming downstream. For Venn an additional reason why flooding has become so much worse, can be found upstream: “In towns like Bridgewater and Taunton, thousands of new homes have been built, many of them on flood plains, and developers want to build more. The communities say they will build reservoirs for surface water, but downstream we see that there is more water in our rivers and it’s flowing much faster.”
A decisive factor in heavy rains leading – or not – to major flooding, is soil. Good soil contains a lot of organic matter and has a crumbly texture and good tilth. The space between the tiny lumps of soil-matter can absorb water like a sponge; rainwater can penetrate the soil and slowly percolate through it. Degraded soil, on the other hand, has little organic matter and is often compacted – rain is not absorbed and instead runs straight off into the nearest water course, taking topsoil with it.
It was only in the 1990s that scientists started to discover the complex microbiology of soil and how it functions – how microorganisms, fungi and plants depend on each other for food and nutrients, and earth worms drag organic matter to deeper soil levels, leaving aerating channels and fertilizing fecal matter in their wake. Particularly important for soil structure are mycorrhizal fungi which live in a symbiotic relationship with plant roots; these are the long, white threads that one often finds when digging up a plant. They produce glomalin, a sticky substance that helps clumping, making for good tilth. Using pesticides, herbicides and fungicides, however, harms the microbiology of the soil, as does ploughing which turns the microbial world upside down.
In permacultures, like forests, woodlands and well managed permanent pastures, soil microorganisms remain undisturbed. In February, the BBC’s Farming Today programme reported on a project in Cumbria where the Woodland Trust is planting nearly 250,000 trees across two sites. ‘Trees are extremely functional in terms of water,” Peter Leeson from the Woodland Trust told the programme, “they use a lot of water, they create more surface area so there is more evaporation, more transportation. There are also the roots that go down, [which] create porosity and break up soil panning.” All of this slows the flow of water and helps to prevent flooding in cities downstream. Nick Chappell, senior lecturer at the Lancaster Environment Centre, measures run-off and flow patterns. He told the BBC’s Farming Today that preliminary data are encouraging: water is being held back rather than “rushing over the land surface towards the water courses and into the stream”.
Another way to manage streams and water flow may be to bring back beavers. In the UK these ‘ecosystem engineers’ were hunted to extinction hundreds of years ago. Chris Jones farms in Cornwall, and he has seen the devastation flooding has brought to the area in the past and wondered whether a reintroduction of beavers might be beneficial. With a suitable stream and woodland area on his farm, he teamed up with the Cornwall Wildlife Trust and scientists from Exeter University and constructed an enclosure into which a male and a female beaver were released in summer of 2017. They immediately took to their new environment and started building a first dam after just two nights. ‘The water used to take 15 minutes to get from the top end of the enclosure to the exit at the lower end. Now it takes an hour,” says Cheryl Marriott, head of conservation at the Trust.
Along the River Otter in Devon, and in Scotland, beavers have just turned up, either through an unauthorised release or as escapees from captivity. The beaver project in Cornwall is special because the scientists from Exeter University spent two years gaining baseline data before the beavers were released. Richard Brazier at Exeter University has just published the initial findings from a beaver enclosure in Devon that was set up in 2011. The results are very encouraging. Beavers live in small streams with a water depth of about 70 cm – that’s their ‘comfort zone’, and if that doesn’t exist they create it by building dams and canals. The dams slow the water flow and create lakes and wetlands, and that increases the water storage capacity during wet periods, and in a drought, there is more water that can be released. Peak flows get ‘desynchronised’ when beaver dams delay the water flow, reducing the chance of a ‘wall of water’ coming downstream after a prolonged rainstorm. There’s a lot of evidence now that beavers can help to mitigate flood events.
Together with other members of the Cornwall Wildlife Trust, Cheryl Marriott recently went to Bavaria in Germany, where beavers were reintroduced several decades ago. Beavers need to be managed, she told me, but if people are prepared to do that there is lots they can do. To her, the perfect example was a small town that contemplated building a flood bank at a projected cost of €1 million, until conservationists suggested bringing back beavers to an area upstream. The beavers did a great job and saved the town a lot of money by making the construction of an expensive dam superfluous. But fencing is needed to prevent them from digging tunnels where they are not supposed to – like through flood banks along rivers. And not every farmer will be pleased to see them – beavers are herbivores with a healthy appetite and they regard any nearby field as a handy diner, with grains, rapeseed, sugar beets, the family favourites.
With the exception of the River Otter area, beavers in England and Wales are kept in enclosures. With projects getting bigger (like one planned – and licensed – in the Forest of Dean), it will be more “like a bit of countryside that gets fenced off,” says Cheryl Marriott. But once more beavers start living truly in the wild, as they already do in Scotland, the time will come when here, too, their numbers have to be controlled.
When farmers first settled in the US state of Iowa they took a different approach to dealing with too much water – with dire costs to the environment. When settlers arrived in this part of the Midwest, much of the region was ‘wet prairie’, a nicer description of ‘swamp’. Large- scale agriculture only became possible in the early 20th century, when farmers started to install ‘tiles’ for subsoil drainage: perforated pipes, dug three to four feet into the ground. Excess water goes from these ‘tiles’ into the nearest ditch, eventually running into the Mississippi and the Gulf of Mexico creating a huge dead zone caused by algae blooms from nitrate run-off.
Seth Watkins has a herd of 600 cows on pasture in south-western Iowa. He has created almost 60 ponds on his land to catch run-off from neighbouring farms. Thickets of reed help clean the water. By the time it’s slowly made its way into the troughs of his cattle, it is safe to drink. Watkins’ farm is situated in the hillier part of Iowa. To hold back water. he’s introduced 30-40 ft wide prairie strips into his arable land. Below the ground these long-rooted perennial grasses restore the soil; above they are a habitat for wildlife. “Mother Nature is a great partner in farming and she needs to have 51% of the shares,” says Seth Watkins. “She is a lot wiser than us and she wins in the end.”
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