With this winter’s flooding crisis still in full flow, I thought it would be useful to find out a bit more about the natural flood defences mentioned in my post last week. One of the areas where these kind of measures have been piloted is actually fairly local to me in the village of Belford in Northumberland.
Belford is a small village with a burn running through it that has had a history of flooding as far back as the 19th Century. After frequent flooding where some villagers and businesses were inundated up to five times during a two-year period and a further major flood in 2007, locals had had enough. Unfortunately, through the lens of cost benefit Belford was not deemed deserving of the funding required to construct “hard engineered” flood defences so the Environment Agency (“EA”) was forced to come up with an alternative.
In collaboration with Newcastle University the EA worked with local farmers to construct a number of “soft engineered” flood defences which went with the grain of nature rather than against it. Using a proportion of local farmland upstream of the village they created storage pools and wetlands using the natural contours of the land; as well as beaver dams and willow features along the Belford burn watercourse. These cost between just £200k and £300k (compared to an estimated £2.5 million for a hard engineered flood defence) and work to retain water upstream of Belford during flooding, as well as slowing the water’s pace so it is less damaging. Not only that but these measures help improve water quality, trap silt and create new areas of ecological benefit. The important question though is have they worked?
Well, Belford is now being held up as a prime example for other areas of the UK to follow and since these measures were introduced they have certainly helped alleviate the impacts of flooding in the village. Natural Flood Management techniques as these measures are termed, seem to be an environmentally sensitive and cost-effective way of flood mitigation. Other natural flood management techniques include;
- Land management and land use
The creation of grassland buffer zones and suitably placed strips of trees on farmland can help reduce surface water run-off and prevent separate flows of water merging into larger, more powerful bodies of water. This can also help prevent soil erosion and stop pesticides leaching into watercourses.
Planting river catchment areas and the sides of water courses with trees can help interrupt the flow of flood water and aid the absorption of flood water by the soil, as the tree roots channel water directly into the ground. Trees can also help by intercepting and evaporating off rainfall.
This includes measures such as tree planting along watercourses which help prevent soil erosion and the run-off of silt which can reduce the flow of rivers.
This involves the use of a small proportion of land as a reservoir to capture surface water run-off during floods. It can be expensive given the costs of land and any construction of built earth banks etc. but it is an effective technique.
Restoring river meanders so that river length is increased and slope decreased. This measure can help retain flood water upstream, away from low-lying areas vulnerable to flooding. It can also include the removal of in-stream structures such as culverts and weirs which can increase river capacity in times of flooding but also result in localised flooding and the creation of wetland areas with water storage potential.
Washlands are areas of land that are allowed to flood to prevent flooding further downstream. These can be natural flood plains or other specially created areas which can also have significant ecological benefits. However, the creation of washlands must balance other needs such as the requirement for sufficient land for food production.
If you have seen any of the media coverage of this winter’s flooding you might be forgiven for thinking that natural flood management techniques are something novel. In fact though you would be wrong. The planting of trees in river catchments and use of water storage pools and wetlands is something that British experts have long been helping developing countries do, in order to alleviate flooding and prevent soil erosion. You may remember learning this kind of thing in your geography lessons; I certainly do. It is somewhat ironic that we are only just recognising the need for such schemes in our own country.
There are numerous policies, strategies and legal requirements already in place to help prevent flooding, water run-off and soil erosion. Natural flood management techniques must surely play a key role in the execution of these strategies. However, their uptake remains limited for many reasons. Partly to blame is lack of funding (Labour have recently criticised the Government’s decision to withdraw funding for up to 300 “shovel ready” projects), although I suspect this may change in light of this winter’s events. Also to blame is the complexity of some of the projects and the fact they require communities and landowners to work together. Then there is the simple lack of political will to put something that goes with the grain of nature rather than against it at the centre of any policy decision.
In the aftermath of this winter’s flooding I wonder if this may change? Whether you believe in man-made climate change or not, or even if you do not believe in climate change at all, there is certainly a case for trying to ensure this kind of flooding doesn’t happen again. And however you look at it natural flood management techniques must surely form part of the solution.