Posted by Matthew Hardwick on 15 December 2014
The recent Treasury announcement of £2.3 million investment into flood defences is likely to be welcomed by many people who were left devastated by the winter floods at this time last year. Between December 2013 and March 2014 the UK witnessed heavy and prolonged rainfall. The East Coast was affected by the worst coastal surge since 1953. Around 6,500 properties were flooded, key transport infrastructure was damaged and approximately 85,000 hectares of agricultural land was flooded, including the Somerset Levels.
This flooding of vast swathes of prime agricultural land in Somerset caused much debate as to who or what might be to blame. One of the most heated debates attributed the flooding to the lack of river maintenance, in particular the cessation of dredging (the removal of sediment from rivers for navigation purposes, to reduce the risk of flooding and aid the drainage of low-lying land). It was progressively phased out during the late 1990s due to a combination of EU legislation such as the Water Framework Directive and Habitats Directive and evidence proving dredging was ineffective and uneconomical.
We have become accustomed to artificial interventions such as draining wetlands, reclaiming salt marshes, dredging rivers, straightening river channels and building concrete walls to reduce the impact of flooding. However, these are no longer the answer to reducing flood risk and mitigating the impacts of climate change, and over the last decade we have seen a greater focus on developing and implementing more cost-effective and sustainable ways of managing land-use for the benefit of reducing flood risk to people, property and the environment.
We are witnessing a return to natural methods in flood-risk management, ‘working with natural processes’ and ‘making space for water’ (terms coined by Defra) within our river catchments to reduce the threat of flooding. This is referred to as ‘Natural Flood Management’. River and sea-defences are now being deliberately allowed to breach, allowing flood water to inundate fields, wetlands and marshes, as it once did centuries ago, and in doing so slowing the rush of water inland, allowing sediment to be deposited and reducing the need to intervene with our rivers through techniques such as dredging.
Natural Flood Management can be described as the alteration, restoration or use of landscape features to assist in storing, slowing and holding back water (Parliamentary POSTnote 396). There are many opportunities where the natural landscape can be utilised to manage water and reduce flood risk, such as the creation of wetlands or woodland, use of river bends or old channels to store and hold back water. Natural features along the coast, such as saltmarshes or beaches, together with the use of Green Infrastructure or Sustainable Drainage Systems in towns and cities, can all be classed as a form of Natural Flood Management, and used effectively to mimic natural processes of slowing, storing and holding back water.
Natural Flood Management strategies can provide obvious benefits such as avoided costs of damage to society, human health, economic activities, infrastructure, cultural heritage and the environment. However, this approach often delivers multiple benefits including:
These processes have been around for decades, so why are we still debating whether such approaches are appropriate and worthwhile investing in? There seemed to be a general consensus among the scientific community at two recent CIWEM events that we need to act much faster to overcome the financial and political barriers currently preventing Natural Flood Management being implemented on the ground, especially as the impact of climate change becomes ever more apparent.
Those barriers will only be overcome if hard engineered measures and natural flood management approaches are brought together, to work hand-in-hand, and enable stakeholders to work in partnership to deliver long-terms solutions, much more quickly and cost-effectively. I also believe that in order to gain more buy-in and uptake of such strategies, there is an urgent need to further promote studies supporting Natural Flood Management, in order to overcome the perception that such measures will not prevent flooding due to their scale or a lack of supporting evidence. Furthermore, we need to develop more tailored and targeted information about Natural Flood Management and its benefits to major landowners, farmers and their advisers. This should provide user friendly advice on where landowners and farmers can go to find support and advice, with viable funding schemes that are simple to access.
Ricardo Energy & Environment is already working with many of our clients in developing the thinking behind Natural Flood Management, supporting initiatives which promote the wider benefits. For more information on Ricardo Energy & Environment’s capabilities in terms of flood risk reduction through catchment-wide management, Sustainable Drainage Systems and Water Sensitive Urban Design, please follow this link: http://energyandenvironment.ricardo.com/cms/catchment-based-approaches
Register for our free flooding webinar: building a compelling business case to secure partnership funding.