Re-meandering and Rewilding River Systems: An Effective Flood Management Strategy in the UK?

   Storm Desmond was an extratropical cyclone; so far has the fourth named storm of the 2015-16 UK and Ireland windstorm season. Desmond was notable for directing a plume of moist air, known as an atmospheric river, which brought record amounts of orographic rainfall to uplands areas of northern Atlantic Europe and subsequent major floods. The worst affected areas in the UK were centered on Cumbria, Lancashire and the Scottish borders, with severe rain and flooding also reported in Northumberland, north Wales and Yorkshire. The storm broke the UK's 24-hour rainfall record, with 341.4 mm of rain falling in Honister Pass, Cumbria on the 5th of December (Met Office, 2015). As a consequence, 43,000 homes across the north of England were left without power, 3 people died and the damage cost £400-500 million. The damage was not solely confined to human impacts, however - ecology was also greatly harmed. For example, this somewhat flippant article from The Metro about a ‘sad otter’ does actually demonstrate that flooding can be a very hazardous time for young otters; they can easily be washed out of their holts by high rivers, and at that age are not accomplished swimmers.

River Eden burst its banks in Appleby due to Storm Desmond. Source

   On Tuesday 8th December, on the Today Programme on Radio 4, George Monbiot - an environmentalist - and Meurig Raymond - the President of the National Farmers Union - engaged in a debate over the impacts and possible causes of Storm Desmond flooding in the North of England. I thought this debate very fitting to my blog, it distinctly fits in well with my previous blogpost on Storm Abigail. With extreme weather events set to increase with climate change, it is vital that we look at ways to mitigate flooding effectively, particularly with the devastating impacts flooding has on urban areas. You can get the podcast of this debate here, at 2:48:00 into the episode.

   George Monbiot is an accomplished writer, known for his environmental and political activism, and weekly column in The Guardian. In this debate, he first began by outlining the issue with current flood mitigation strategies: instead of preventing the flood from happening, we wait and act after it has hit. We should, he argued, use soft engineering approaches as a flood prevention strategy, such as reforesting bare hills and rewilding river systems. This is for a number of reasons - by reforesting hills, the percolation rate into the soil will increase and therefore water is released more slowly. Additionally, by rewilding rivers and allowing them to meander, to form islands and banks of gravel and shingle, the river system will become more dynamic, and the flow of water will be held back.

   The processes of channelisation and river dredging were described by Monbiot as turning rivers into ‘straight drains’, whereby water bypasses farmland, but subsequently then rushes into the nearest settlement. Furthermore, bare hilltops produced from pastoral grazing has meant that too much water cascades down hillslopes that rivers are unable to contain; either water is allowed to spread over agricultural land, or it is sped past farmland through dredging and channel clearing, whereupon it comes down to the nearest ‘urban pinchpoint’ - such as a bridge. The resulting impact is the flooding of homes and the threatening of lives. To illustrate his point, Monbiot drew upon the example of the River Liza in the Lake District, where rewilding strategies meant that even after the last massive rainfall in 2009, the river was still running clear as all other rivers in the surrounding areas were bursting their banks.

Meandering River Liza in Ennerdale. Source

   In contrast, Meurig Raymond stance on flood management differed greatly, advocating hard engineering techniques. He argued that the flooding impacts from Storm Desmond resulted from too little investment in river dredging, channel clearing and flood defences - and that there should be more money set aside for maintenance of rivers to keep channels clear. One of his main defences of hilltop farming was that it attracted tourists into north, due to farming practices shaping the tapestry of land in an aesthetically pleasing manner. Sheep farming, food production, and agriculture, he argued, are vital to maintain wealth created by the tourism industry. Interestingly, and rather unexpectedly, Raymond stated that livestock numbers are now falling, and vegetation is increasing overall, with undergrazing now causing a larger problem than overgrazing. Therefore, water is being held back by the current fabric of the countryside. He rounded off the debate by stressing the importance of agriculture - as both a creator of top quality beef and lamb, but also as a generator of wealth.

Bare hills in Cumbria due to hilltop farming. Source

  The majority of the public listening to the debate seemed to concur with Monbiot’s opinion - that rewilding river systems can prevent flooding (shown through the handle @BBCr4today on Twitter). However, farmers have expressed anger at Monbiot’s seemingly ‘anti-farming’ rhetoric, expressed in his various articles and interviews, and argue that he has little knowledge of hilltop farming practices. Personally, I agree with Monbiot; I think rewilding river systems would be an incredibly beneficial mitigation strategy to control flooding. What do you think - is rewilding a viable solution, or has land-use changed so much that it is near impossible to go back to such an environment?