Uncertainty Assessments of Flood Inundation Impacts: Using spatial climate change scenarios to drive ensembles of distributed models for extremes
Lead Research Organisation:
King's College London
Department Name: Geography
Abstract
Exploratory climate change studies for the UK indicate that an increase in the frequency of extreme events and associated flood risk is likely. Given that floods cause damage of over £1bn per year under present climatic conditions, climate change bears significant consequences for flood risk management. In order to evaluate these consequences, hydrological and flood inundation models are forced with projections of precipitation from atmospheric models for a range of Greenhouse gas emission scenarios to produce future flood predictions. However the validity and uncertainty of these model-based input precipitation fields are of key concern, as they potentially constitute a major source of ambiguity for hydrological and hydraulic modelling. Additionally, uncertainty is associated with the hydrological and inundation models themselves, such as for example the models ability to represent the dominating physical processes and to uniquely identify effective model factors (parameters and any other model variables) that will shape future forecasts. As the non-linear interaction of all model components will influence the total uncertainty associated with hydrological impact assessments these need to be comprehensively assessed. Therefore, a key and exciting challenge is to describe and quantify the origin and propagation of uncertainty from climate to hydrological to flood inundation models. This project aims to develop a novel holistic modelling approach for doing this. Our region of focus will be the River Severn catchment because of concerns about current and future flood risk. Specifically we will: (1) Quantify the 'top-end' uncertainties associated with climate change hydrological impact assessments by analyzing precipitation fields produced by two contrasting methods and assess how these affect the nature of flood and inundation predictions (2) Evaluate all uncertainties between and within a cascade modeling framework for flood inundation predictions in a fully coupled and dynamic way (3) Use novel techniques of uncertainty analysis including global sensitivity analysis and a new efficient functional similarity sampling approach to enable an effective evaluation of the uncertainties in the modeling cascade. (4) Assess the likely flood hazard change for the River Severn catchment over the next 100 years for various climate, landuse and soil moisture scenarios This project will deliver an insightful scientific methodology which can be used in future research assessments and catapult UK science to the forefront of an exciting, socially, and politically important international research area.
Publications
Cloke H
(2008)
Evaluating forecasts of extreme events for hydrological applications: an approach for screening unfamiliar performance measures
in Meteorological Applications
Cloke H
(2010)
Climate impacts on river flow: projections for the Medway catchment, UK, with UKCP09 and CATCHMOD
in Hydrological Processes
Cloke H
(2009)
Ensemble flood forecasting: A review
in Journal of Hydrology
Cloke H
(2013)
Assessment of a 1-hour gridded precipitation dataset to drive a hydrological model: a case study of the summer 2007 floods in the Upper Severn, UK
in Hydrology Research
Cloke H
(2012)
Modelling climate impact on floods with ensemble climate projections
in Quarterly Journal of the Royal Meteorological Society
Delrieu G
(2009)
Weather radar and hydrology
in Advances in Water Resources
He Y
(2009)
Tracking the uncertainty in flood alerts driven by grand ensemble weather predictions
in Meteorological Applications
He Y
(2010)
Ensemble forecasting using TIGGE for the July-September 2008 floods in the Upper Huai catchment: a case study
in Atmospheric Science Letters
Ivanovic R
(2009)
Science versus politics: truth and uncertainty in predictive modelling
in Hydrological Processes
Krueger T
(2010)
Ensemble evaluation of hydrological model hypotheses
in Water Resources Research
Krueger T
(2012)
Comparing empirical models for sediment and phosphorus transfer from soils to water at field and catchment scale under data uncertainty
in European Journal of Soil Science
Maraun D
(2010)
Precipitation downscaling under climate change: Recent developments to bridge the gap between dynamical models and the end user
in Reviews of Geophysics
McMillan H
(2010)
Impacts of uncertain river flow data on rainfall-runoff model calibration and discharge predictions
in Hydrological Processes
Mitchell S
(2011)
Processes influencing model-data mismatch in drought-stressed, fire-disturbed eddy flux sites
in Journal of Geophysical Research
Pappenberger F
(2008)
New dimensions in early flood warning across the globe using grand-ensemble weather predictions
in Geophysical Research Letters
Pappenberger F
(2010)
Global runoff routing with the hydrological component of the ECMWF NWP system
in International Journal of Climatology
Radcliffe DE
(2009)
Diffuse phosphorus models in the United States and europe: their usages, scales, and uncertainties.
in Journal of environmental quality
Stephens E
(2012)
The impact of uncertainty in satellite data on the assessment of flood inundation models
in Journal of Hydrology
Teutschbein C
(2011)
Evaluation of different downscaling techniques for hydrological climate-change impact studies at the catchment scale
in Climate Dynamics
Westerberg I
(2011)
Calibration of hydrological models using flow-duration curves
in Hydrology and Earth System Sciences
Wetterhall F
(2011)
Effects of temporal resolution of input precipitation on the performance of hydrological forecasting
in Advances in Geosciences
Wetterhall F
(2010)
Distribution-based scaling to improve usability of regional climate model projections for hydrological climate change impacts studies
in Hydrology Research
Wetterhall F
(2011)
Using ensemble climate projections to assess probabilistic hydrological change in the Nordic region
in Natural Hazards and Earth System Sciences
Wetterhall F
(2012)
Conditioning model output statistics of regional climate model precipitation on circulation patterns
in Nonlinear Processes in Geophysics
Description | A full assessment of the uncertainty in using RCM climate projections for use in flood impact modelling studies has been presented. Using these projections is not straightforward, as the spread in the uncertainty is very large and this is inflated through the modelling chain, leading to very uncertain flood projections. The research also provided the first evidence of the potential for improvements in flood forecasting through using ensemble forecasting and decision making techniques. The research included the first setup of a coupled atmospheric-hydrologic-hydraulic model cascade system which used a grand ensemble of weather forecasts to produce probabilistic flood inundation forecasts. By tracking the uncertainty through the model cascade, the dominating influence of the uncertainties from the rainfall could be understood, and the promise of such a tool for forecasting flood inundation demonstrated. |
Exploitation Route | Operational flood forecasters can use these new techniques to improve forecast skill and make better decisions. Methodologies for robustly understanding climate change impact on water resources including flooding and low flow at the catchment scale are of use to water resource modellers. |
Sectors | Environment |
Description | Since 2012 an operational EFAS now provides flood forecasting information two days or more before a flood event to the national authorities around Europe as well as the Emergency Response Coordination Centre of the European Commission. The skill of EFAS forecasts and warnings has been continuously improving (https://www.efas.eu/download/efasBulletins/2014/bulletin_dec-jan_14.pdf) and the system has demonstrated its early warning capabilities in several recent events (e.g. the Balkan floods in 2014 and the central European Floods in 2013), assisting with early flood preparedness for the ERCC, European national authorities and thus all European Citizens. Although citizen protection is of paramount importance in flood warning provision, floods are also harbingers of substantial damage costs, particularly in urban areas and although the exact cost-benefit ratio of EFAS flood warnings are currently being researched the system is very likely to have net economic value (Pappenberger et al, The Economic Value of Early Flood Warnings in Europe. Manuscript in Preparation.) The research provided scientific innovation, technical system developments and practical focus on enduser understanding which has contributed directly to these benefits, and costly and potentially contentious decisions are now made in a more consistent, risk-informed way. These knowledge transfer activities, supported by the strong scientific evidence from the research work and demonstrations of the value in systems such as EFAS, have led to a wider move in the UK (and beyond) towards ensemble flood forecasting. The Flood Forecasting Centre and the EA national forecasting centres have (or some cases very soon will have) implemented ensemble flood forecasting systems. Such an ensemble approach is likely to have improved the preparedness for the winter 2013/2014 flooding in the UK (Stephens & Cloke, 2014). In China, forecasts have been improved with the implementation of ensemble systems. |
First Year Of Impact | 2010 |
Sector | Environment |
Impact Types | Societal Economic Policy & public services |
Description | Training in interpretation of Ensemble Flood Forecast products |
Geographic Reach | Asia |
Policy Influence Type | Influenced training of practitioners or researchers |
Impact | Flood forecasters more confident to implement and use ensemble flood forecasts in their operational products |
Description | Applying probabilistic flood forecasting in Flood Incident Management. |
Amount | £200,000 (GBP) |
Funding ID | Science Project SC090032 |
Organisation | Environment Agency |
Sector | Public |
Country | United Kingdom |
Start | 01/2009 |
End | 05/2011 |
Description | DEFRA Catchment Modelling call |
Amount | £50,452 (GBP) |
Organisation | Department For Environment, Food And Rural Affairs (DEFRA) |
Sector | Public |
Country | United Kingdom |
Start | 07/2014 |
End | 09/2015 |
Description | Industrial CASE PhD: Uncertainty in future flood risk for insurance markets |
Amount | £78,000 (GBP) |
Funding ID | NE/H017836/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 08/2010 |
End | 08/2014 |
Description | Interdisciplinary PhD studentship: Developing a Risk-Based and Participatory Approach to Reducing the Uncertainty in Modelling Climate Impact on Flood Inundation |
Amount | £78,000 (GBP) |
Funding ID | 1014118 |
Organisation | Economic and Social Research Council |
Sector | Public |
Country | United Kingdom |
Start | 08/2010 |
End | 08/2015 |
Description | Partnership Grant: Novel early flood warning system. |
Amount | £50,721 (GBP) |
Organisation | Queen Mary University of London |
Department | Innovation China UK |
Sector | Private |
Country | United Kingdom |
Start | 01/2009 |
End | 12/2009 |
Title | Ensemble Flood Forecasting |
Description | A modelling methodology for representing uncertainty by implementing probabilistic ensembles in flood forecasts, particularly in the medium range. |
Type Of Material | Computer model/algorithm |
Year Produced | 2009 |
Provided To Others? | Yes |
Impact | The method is now integrated into the European Flood Awareness System and has been emulated in other operational systems, including those int the UK. |
Description | Environment Agency |
Organisation | Environment Agency |
Country | United Kingdom |
Sector | Public |
PI Contribution | Working on understanding flood risk in flood susceptible catchments and improving flood forecasting. |
Collaborator Contribution | Provision of data, expertise, forecast systems. The context of the flood risk framework. |
Impact | EA/DEFRA technical report |
Start Year | 2007 |
Description | European Flood Awareness System |
Organisation | European Commission |
Department | European Flood Awareness System (EFAS) |
Country | European Union (EU) |
Sector | Public |
PI Contribution | Scientific innovation, technical system developments and practical focus on enduser understanding for the EFAS: e.g. The research provided the first evidence of the potential for improvements in flood forecasting through using ensemble forecasting and decision making techniques. |
Collaborator Contribution | Provision of expert advice, computing resources and expertise, data, methods, stakeholder network. Research secondments. Willingness to co-test new ideas within the operational system. |
Impact | The EFAS now provides flood forecasting information two days or more before a flood event to the national authorities around Europe as well as the Emergency Response Coordination Centre of the European Commission, and has been operational since 2012. The skill of EFAS forecasts and warnings has been continuously improving (https://www.efas.eu/download/efasBulletins/2014/bulletin_dec-jan_14.pdf) and the system has demonstrated its early warning capabilities in several recent events (e.g. the Balkan floods in 2014 and the central European Floods in 2013). This has provided an earlier flood preparedness, days earlier than conventional flood forecasting systems, and thus greatly improving flood preparedness for the ERCC, European national authorities and all European Citizens. Hannah's scientific innovation and technical system developments has provided an evidence base for implementing early warning from ensembles and contributed directly to the improved flood warning from EFAS. Hannah's work with social scientists on improving communication of EFAS flood alerts has allowed EFAS forecasters to change their practice both in the way alerts are given and the way that they engage with forecast recipients, allowing costly and potentially contentious decisions to be made in a more consistent, risk-informed way. In addition, the EFAS system with an estimated development cost over 10 years of 20 million Euros, is now estimated to provide net economic benefit. |
Description | Joint Research Centre |
Organisation | European Commission |
Department | Joint Research Centre (JRC) |
Country | European Union (EU) |
Sector | Public |
PI Contribution | Working on using ensemble forecasts and uncertainty analysis in their operational modelling systems. |
Collaborator Contribution | Expertise, access to computers, research visits, access to data, models and stakeholders. |
Impact | Development of EFAS |
Description | Met Office |
Organisation | Meteorological Office UK |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Improving flood forecasting, land surface hydrology for seasonal forecasting, interpretation of climate projections for water resource impacts |
Collaborator Contribution | Provision of data, expertise, models. Co-producing methods. |
Impact | Several research articles |
Start Year | 2007 |