Is it getting wetter? Is the intensity of rainfall greater than it used to be? Whether the answer to the above questions is yes or no (and evidence suggests it is yes), in practical terms is there anything we can do about it? The COP21 agreement, hailed as a success by leaders around the world, is targeted at maintaining global temperatures below 2 degrees. Which viewed another way is that the current climate situation – and all the adverse impacts – will get worse, but hopefully (fingers crossed) not to exceed a tipping point.
What is evident, both empirically and as experienced by thousands of homes and businesses across the UK, is that flood events are becoming more frequent and widespread. So if there is nothing we can do about the level and intensity of rainfall, does that mean there’s nothing we can do about flooding?
Currently, spending and works to address flooding are overwhelmingly aimed at the symptoms rather than the cause, based on protecting those at risk, and then when that doesn’t work on helping those affected. Of course this needs to happen to help the people and communities whose lives are turned upside down by flooding. It also makes sense financially, because flood defences return £8 for each £1 invested. The floods in December caused £5 billion of damage. Wouldn’t it be nice to have that money to spend on other things?
But what about prevention? Just because we can’t stop the rain, that doesn’t mean we can’t stop homes and businesses from flooding. The real problem is not the rain, but where the water goes after it comes out of the sky.
Right now, land cover and land management often means that water comes off hills and farmland as fast as possible. This leads to soil erosion and increases the volume of water in watercourses. To allow for this, watercourses are dredged and channels straightened, which in turn speeds up the flow of water. What this means is that by the time it reaches the homes, villages, towns and cities downstream, the water is fast flowing and full of sediment. Flood defenses, planned for 1 in 100 year events, are breached. Property level protection may or may not hold – but as private measures these won’t help everyone and simply highlight the division between the haves and have-nots. And if the flood defenses do hold, then it can just make the situation worse for the next community down-stream.
There is an alternative. It works better than building hard-engineered defenses, and it is cheaper. Up to 20 times cheaper. It means increased biodiversity and carbon sequestration. It helps to recharge aquifers, preventing a cycle of flood and drought. But it is less visible, needs a strategic approach and the co-operation of those who aren’t currently affected by flooding. So by and large it is not happening. But it needs to take place as a priority – and IN ADDITION – to protection and remediation measures.
Natural systems – restoration of woodland and peatland; riparian vegetation; even beaver dams (or man-made ‘leaky dams’) – can all increase the “sponge effect”: the ability of the land to hold onto water and release it slowly.
Research[1] has found infiltration rates up to 60 times higher under young native woodland compared to grazed pasture, with follow up research[2] indicating that strategically placed, small scale planting of trees for shelter can be used to improve the infiltration capacity of extensive areas, with positive impacts on run-off rates, erosion and stream water quality at both farm and landscape scales. SEPA has just published (21 January 2016) a new handbook on for how to put in natural flood management measures in practice[3], but not enough of it is being done.
Tree planting, peatland restoration and other green-engineering measures to prevent flooding need to happen, and communities can take the lead. Scene has developed expertise and relationships in the community energy sector, which can be used by communities for wider climate change adaptation – community empowerment; regulatory knowledge, relationship building between communities and landowners; engagement with policy makers; sourcing funding and preparing the applications to secure the permissions to allow projects to go ahead.
With SEPA publishing its Flood Risk Management Strategies in December 2015, and Local Flood Risk Management Plans due to be published in June 2016, now is the time for communities across the UK affected by flooding, or just interested in securing an integrated solution to this growing problem, to engage.
For more information or to discuss this further, please contact Alex Schlicke at Scene Consulting.
ALEX SCHLICKE
Partner @ Scene Consulting Ltd.
Phone: +44 (0)131 651 4556 M: +44 (0)7535 325 205
Web: sceneconsulting.com
[1] Bird, S.B; Emmett, B.A; Sinclair, F.L; Stevens, P. A; Reynolds, A.; Nicholson, S. & Jones, T. (2003) PONTBREN: Effects of tree planting on agricultural soils and their functions. Centre for Ecology and Hydrology Bangor, Deiniol Road, Bangor, Gwynedd.
[2] Carroll, Z.L., Bird, S.B., Emmett, B.A., Reynolds, B. and Sinclair, F.L. (2004), Can tree shelterbelts on agricultural land reduce flood risk?. Soil Use and Management, 20: 357–359. doi: 10.1111/j.1475-2743.2004.tb00381.x
[3] http://www.sepa.org.uk/media/163541/sepa-natural-flood-management-handbook.pdf