Accounting for Climate Change Uncertainty in Flood Hazard Prediction

Floods are the most common and widely distributed natural risk to life and property worldwide, causing over £4.5B worth of damage to the UK since 2000. Managing flood risk therefore presents a substantial challenge to this and future governments. Arising from the requirements of the EU Floods Directive (2007/60/EC), flood hazard maps for the UK must be delivered by December 2013. Due to limitations in current methodologies these maps take a deterministic approach to mapping catchment scale flood hazard, and do not incorporate climate change projections. Climate projections are predicted to result in the increase of UK properties at risk from flooding and coastal erosion: understanding the uncertainty these bring to flood hazard is therefore of vital economic significance to the UK.
Different methods to assess or determine flood hazards have evolved through research and practice. However, these do not allow for uncertainty estimates to be explicitly included within the process. While uncertainty analysis has been an area of research over a number of years, it has not yet achieved widespread implementation in flood modelling studies and decision making for a number of reasons. With developments in the field, such as improved computational power and newly available standardised climate datasets, incorporating uncertainty into assessments is becoming increasingly possible and indeed essential.
It is clear that a gap currently exists in uncertainty estimation in flood hazard prediction, particularly in relation to climate change projections, and that this area of research is critical to current policy and operational drivers. This proposal has been developed to comprehensively address this gap. The project will develop a novel probabilistic modelling framework to assess the impact of uncertainty arising from climate change on flood hazard predictions, generate exemplar probabilistic flood hazard maps for selected case study catchments and attempt to quantify the change to flood hazard as a result of climate projections.

The potential beneficiaries from the outcomes of the proposed research include regulators and statutory consultees (including the Environment Agency (EA), the Scottish Environmental Protection Agency (SEPA), policy makers (specifically the EA, SEPA, the UK and Scottish Governments), engineering and environmental consultants, academic researchers (universities and research institutes) and in the longer term members of the public living in flood prone areas. These beneficiaries will be interested in both the scientific outcomes of the project as well as the technique development.
As set out in the Case for Support, flood hazard poses a significant on-going economic burden to the U.K. with potential impacts from the uncertainty arising from climate predictions adding extra pressure. Regulatory and policy requirements arising from the EU Floods Directive and national legislation (such as the Flood Risk Management (Scotland) Act 2009) necessitate the development of flood hazard maps for the UK. At present these maps do not account for the potential impact posed by climate uncertainty to flood hazard. Hence the output of this research will be of direct interest to regulators and statutory consultees (EA and SEPA) as it will provide quantitative projections of the change to flood hazard (velocity, floodplain extent and depth) resulting from climate projections (UKCIP 09). This information will be of direct benefit when developing strategies to manage flood risk in particular areas allowing prioritisation of economic resources, as well as policy development. It is this point regarding policy development which will be of interest to the UK and Scottish governments, as being able to quantify the potential change to flood hazard in vulnerable areas will allow policy makers to assess, and adjust policy accordingly.
The recent UK Flood and Coastal Erosion Risk Management (FCERM) research strategy highlights that 'uncertainty propagation associated with all forms of flooding', as well as the need to understand the response of hazard to climate change, is critical to current policy and operational drivers. Consequently, regulators (EA and SEPA) and engineering and environmental consultancies are likely to be interested in the development of the method as well as the end products (maps, software and quantitative understanding of change to hazard). Through the different engagement activities described in the Pathways to Impact document the project will seek to maximise the utility and clarity of developed techniques and outputs. These will provide a methodology which will be applicable for any catchment in the UK. While developed for the UK the method will also be applicable more widely and therefore of interest to consultants who work internationally.
Once developed across the UK, this information will be of direct benefit to members of the public residing within flood prone areas. From the outputs potential quantitative changes to flood hazard over the 50-80 year time period will be available. This will allow greater understanding of the threat posed by flooding which can feed into flood policy development, flood defence/alleviation strategies and management plans.