Natural flood risk management

This, the final seminar in the Oxford Water Network’s Hydroclimatic extremes series, brings together two leading experts to explore Natural Flood Management: Louise Heathwaite, Professor of Land and Water Science in the Lancaster Environment Centre, Lancaster University and Enda O’Connell, Professor of Water Resources Engineering, Newcastle University. It will be followed by refreshments at Christ Church.


Natural Flood Management – Prof Louise Heathwaite
NFM has gained traction recently as an upstream solution to a downstream problem. What advocates of this approach (perhaps) choose to forget is that catchments are systems: changes in one part effect other parts of the system, sometimes with unintended consequences. Analysis of the scientific evidence base for targeted catchment interventions to reduce flood risk is robust only at very small scales. As a scientific community, we remain challenged in developing appropriate – and joined-up – measurement and modelling tools to scale-up. As long as this persists, policy interventions are likely to be extrapolated out of context – and natural flood risk management is no exception.

We can, however, move forward in other ways. River restoration, for example, is usually undertaken to meet biodiversity goals with, in principle, the assurance of no net increase in flood risk downstream. Creation of riparian woodland buffer zones may deliver co-benefits of reductions in diffuse pollution, water discolouration and soil erosion and enhanced carbon storage, aquifer recharge and river water temperature control (through shading), generating economic gain in terms of reduced water treatment cost. Co-benefits deliver broader environmental gains than the initial problem definition: I will develop the arguments and discuss the opportunities further in my presentation.

Whilst there is no silver bullet solution to flood risk based on natural flood management, except perhaps at small scales and for smaller flood events, we do have before us an unprecedented opportunity. Michael Gove recently challenged all to “accelerate change as the new normal” and to develop the adaptability to shape change rather than resist it. In my view, this is a real opportunity to deliver innovative land-based science that quantifies the co-benefits of integrated land use planning in order to influence future policy that seeks to pay for environmental enhancement of natural capital.

Assessing the Potential of Natural Flood Management: Scale, Process and Modelling Considerations – Prof Enda O’Connell
Over the past sixty years, significant changes in UK land use and management practices have occurred, driven by UK and EU agricultural policies. There is substantial evidence that modern land-use management practices have enhanced surface runoff generation at the local scale, frequently creating impacts through ‘muddy floods’. Such local impacts can be avoided or mitigated through the adoption of better land management practices and/or small scale surface runoff control measures. However, analysis of rainfall runoff records at the larger catchment scale has failed to find evidence of significant impacts on the flood hydrograph. Moreover, recent multiscale catchment experiments allied to new modelling developments for predicting impacts have also not provided evidence of impacts, but have enhanced our understanding of catchment functioning in transmitting local scale impacts to the large catchment scale. These findings do not imply that catchment scale impacts are absent, but suggest that they are small and not easily detectable in the presence of natural hydroclimatic variability.

Natural Flood Management (NFM) seeks to restore the natural hydrological functioning of the landscape through various measures that can reduce runoff generation at the local scale and slow its propagation downstream. Against the above background, the importance of scale in predicting the impacts of NFM measures in larger catchments will be demonstrated. As scale increases, the river channel network plays an increasingly dominant role in transmitting impacts downstream, and in dispersing the multiple small scale benefits that can result from NFM measures. The role of modelling in predicting such impacts will be discussed.

About the speakers
Professor Louise Heathwaite BSc. PhD. FRSE

Louise is a hydrochemist with more than 30 years research experience and >160 ISI-listed publications. She is recognised internationally as an authority on understanding the sources and hydrological pathways of diffuse agricultural pollution from land to water, and for work developing the Critical Source Areas (CSA) concept, which forms the cornerstone of many models of diffuse pollution risk worldwide.
Louise was elected Vice President of the International Association of Hydrological Sciences in 2004 – the first woman to reach this level of office. IAHS has nearly 5,000 members drawn from 130 countries worldwide. She was appointed Chief Scientific Adviser to the Scottish Government for Rural Affairs and the Environment from 2012 to 2017, and is currently Cross-Faculty Associate Dean for Research at Lancaster University. She has previously served on Defra’s Science Advisory Council and on NERC Council.

Louise has a strong interest in interdisciplinary science kindled during her Environmental Sciences BSc. at the University of East Anglia, where she gained 1st Class Honours. She is an advocate for science applied to practical yet complex challenges, illustrated by her PhD. in wetland hydrochemistry from the University of Bristol. Here, her research on the impact of pump-drainage on water quality in the Somerset Levels on the first SSSI to be declared in England, met head-on the need to balance conservation and farming interests for sustainable water use.

In 2004, she joined Lancaster University as founder and Director of the Centre for Sustainable Water Management – one of four interdisciplinary research centres that were precursors to what is now the Lancaster Environment Centre. Louise was elected a Fellow of the Royal Society of Edinburgh in 2015, and President of the Freshwater Biological Association in 2017.

Professor Enda O’Connell FREng
Enda O’Connell is Professor of Water Resources Engineering (part-time) at Newcastle University, and was founding director (1985-2009) of the Water Resource Systems Research Laboratory in the School of Engineering at Newcastle University. Prior to this, he worked at the UK Institute of Hydrology, and in the Civil Engineering Department of Imperial College London.

For more than forty years, he has contributed extensively to the international literature in the areas of stochastic rainfall modelling, distributed physically-based modelling of river basins, climate change impact assessment, flood risk estimation and management, and water resources management. In the field of flood risk management, he has been engaged for several years in assessing the impacts of land use management changes on flood generation at a range of scales. In the water resources management field, he led a major programme of capacity-building in Palestine over the period 1999-2005 based on a holistic Integrated Water Resources Management approach. More recently, he has launched a new research programme in Earth Systems Engineering at Newcastle University, an evolving field based around a multidisciplinary approach to adaptation to climate and socio-economic change, with a focus on understanding and modelling coupled human and natural systems.

He is/has been a member of the editorial boards of several leading international journals, and has acted as a consultant on many national and international hydrology/water resources projects. He is the founding past President of the Hydrological Sciences Section of the European Geosciences Union, and a Fellow of the UK Royal Academy of Engineering. In 2017, he received the European Water Resources Association’s Certificate of Honour.

In the period 2009-2011, he has been an Honorary Professor in the Water Resources Department at the Institute of Water Resources and Hydropower Research (IWHR) in Beijing. In 2013, he was appointed a De Tao Master of Hydrology and Water Resources Management, and in 2014, an Honorary Professor at NHRI.