Managing floods and droughts for a changing climate

44271droughtExtreme weather is becoming increasingly more common in the UK in recent years; for example, recent figures from the UK Environmental Agency (EA) showed that 1 in every 5 days saw flooding in 2012, but 1 in 4 days were in drought. The EA reported that rivers like the Tyne, Ouse and Tone went from their lowest to their highest flows since records began, in the space of only four months. These stats indicate the UK must work on dealing with such extremes. The Flood and Water Mangement Act (2010) and the Environment Agency Catchment Flood Management Plans promote working with natural processes where possible.

I attended a seminar last week, Wednesday 24 April 2013, entitled ‘Integrated Approaches to Managing Floods and Droughts for a Changing Climate.’ The event organised by the Parliamentary Office of Science and Technology (POST) comprised presentations by five prominent speakers that tackled the subject from different angles, which together elucidated the audience on flood and droughts in the UK, i.e. why we have been noticing changes in frequency of these natural events; what the future holds under climatic uncertainties; and how we are dealing with them so far and might continue in future.

Why are we experiencing an increase in floods and droughts frequency?

Man-induced changes to the landscape, such as extensive drainage of land, water bodies and wetlands, which removed natural water storage, and urban paving with concrete, tarmac, etc., which reduced natural infiltration of precipitation, not surprisingly, have made the UK less resilient to floods and droughts resulting from climate change. An increase in the frequency of floods and drought periods in the UK is expected in the future, as a result of climate change, which is also man-induced. In fact, we are already beginning to experience these climatic changes in the UK, in the form of more frequent and more intense weather extremes, such as floods and droughts, as I mentioned above. 

Professor Edward Maltby, Emeritus Professor of Wetland Science, Water and Ecosystem Management, from the University of Liverpool, and Visiting Chair of Research Innovation at Louisiana State University, talked about ‘Ecosystem approach to the management of land, water and living resources in the UK.’ He said that the new horn is floods and droughts and that we created a landscape that can’t withstand the new horn. He added that this is the challenge we are dealing with. He suggested that the important thing is to recognise how ecosystems work, i.e. the functional connectivity across the whole catchment, which we have lost. Now we need to achieve a balance, which is to provide a service and avoid risk.

What does the future hold?

Shorter droughts of up to 18 months may become more frequent by 2100, with a drought like that of 1976 perhaps occurring on average every 10 years by the end of the century, compared with a current frequency of perhaps 1 in 50 to 1 in 100 (Burke et al 2010).

Professor Jim Hall, Director of the Environmental Change Institute, University of Oxford and Member of the Adaptation Sub-Committee of the UK Independent Committee on Climate Change, presented on ‘Preparing for the impacts of floods and droughts’ and he said it is expected that annual damage from floods will increase from £0.7 billion currently to £0.9 – £6.9 billion in 2080.

Professor Alan Jenkins, Deputy Director of the Centre of Ecology & Hydrology and Science Director for the Water Research Programme, talked about floods, droughts and the future. He pointed out that another problem is the compounded effect of climate change together with the projected population increase. He added that we also need to worry about what is happening in other parts of the world.

Ian Barker, Head of Land and Water at the Environment Agency, who spoke about the role of the EA in managing water, said that the future will be different, which makes planning difficult, but that we must not stop planning. He added that the severity, duration and when cannot be predicted.

How are we dealing with weather extremes and how are we preparing for the future?

Richard Benyon, MP and DEFRA Parliamentary Under-Secretary for Natural Environment and Fisheries delivered a speech on flood and environment. He told us that £2.3 billion will be spent to protect the UK from floods by 2015. The plan is to use natural ecosystems or work with natural processes for flood alleviation, for example, the Natural Environment White Paper and the Water Framework Directive. He gave examples of current projects, such as Thames 2100, which is a project to provide more flood storage. He also mentioned the ‘Slowing the Flow Project’ in Pickering, North Yorkshire, and that the land management measures implemented by the Forestry Commission as part of the project, basically applying wood debris to slow the flow of water, has reduced flooding events. The community can see the difference too, he added.

Professor Hall summarised what the Committee on climate change has done, which includes responding to flood, i.e. reducing flood waters, reducing damage, taking properties out of risk areas and policy. With regard to the risk of water shortages, he said that a more adaptive approach is preferred, for example, reduce leakage, reduce per capita consumption from 150 litres/day to 133 L/day, which although seems to be a modest cut, will make a difference. The Committee is monitoring changes’ progress, he added, and the next steps are: publication of the Adaptation Sub-Committee (ASC) Annual report (June 2013), publication of DEFRA’s First National Adaptation Programme, and the ASC Statutory Assessment to Parliament on the progress so far.

Prof Jenkins said that the 2007 floods in the UK was a wake-up call to hydrologists. He added that we need to use existing data properly to produce warning, e.g. for surface flooding, the warning comes from the Met Office forecast of rain. There is a need for a set of consistent hydrological projections, and the hydrological outlook for the UK, which will tell where in the UK we may expect wetter conditions, is a work in progress.

Ian Barker pointed out that per capita water consumption is static and beginning to decline, due mainly to efficiency of modern appliances such as washing machines and dish washers. He also suggested that the use of effluent water for irrigation is another possibility.

The POST briefing on Natural Flood Management (NFM) concluded that collaboration between land-owners and communities is likely to be a key part of the success of NFM, and that long-term funding measures or incentives and better use of local knowledge will also be important.

CABI Environmental Impact internet resource search: [flood + drought + "climate change"]

Reference

Burke, E.J.; Perry, R.H.J.; Brown, S.J. (2010). An extreme value analysis of UK drought and projections of change in the future. Journal of Hydrology doi:10.1016/j.jhydrol.2010.04.035 (Met Office)

POST (2011). Natural Flood Mangement. POSTNOTE No. 396. The Parliamentary Office of Science and Technology, London.

 

Related articles

UN World Water Day 2013 – Water Cooperation
Drought Outlook: Spring 2013
Housing decisions ignore flood risk – Confused.com
The Drought-Stricken Midwest's Floods: Is This What Climate Change Looks Like?

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