FD2321/TR1 the Flood Risks to People
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Defra /Environment Agency Flood and Coastal Defence R&D Programme Flood Risks to People Phase 2 FD2321/TR1 The Flood Risks to People Methodology Defra / Environment Agency Flood and Coastal Defence R&D Programme R&D OUTPUTS: FLOOD RISKS TO PEOPLE Phase 2 FD2321/TR1 The Flood Risks to People Methodology March 2006 Authors: HR Wallingford Flood Hazard Research Centre, Middlesex University Risk & Policy Analysts Ltd. Statement of use This is one of three final technical reports for FloodRisks toPeople Phase 2project.It describes the development of the final methodology including the methodology for mappingriskstopeople. Dissemination Status Internal:Releasedinternally External:Releasedtopublicdomain. Keywords Floodriskmapping; floodestimation,floodriskstopeople,floodriskmodelling Research Contractor David Ramsbottom, Technical Director, HR Wallingford Ltd, Howbery Park, Wallingford,Oxon,OX108BA.Email:[email protected] Project Manager Dr SureshSurendran,RiskAnalyst / FloodRiskProject Coordinator,Environmental Policy –RiskandForecasting,Environment Agency, Kings Meadow House,Reading, RG18DQ email: [email protected] ThisdocumentisalsoavailableontheDefra website www.defra.gov.uk/environ/fcd/research DepartmentforEnvironment,FoodandRuralAffairs FloodManagementDivision ErgonHouse HorseferryRoad LondonSW1P2AL Tel:02072383000 Fax:02072386187 www.defra.gov.uk/environ/fcd ©Crowncopyright(Defra);March2006 Copyright in the typographical arrangement and design rests with the Crown. This publication (excluding the logo) may be reproduced free of charge in any format or medium provided that it is reproduced accurately and not used in a misleading context. The material must be acknowledged as Crown copyright with the title and source of the publication specified. The views expressed in this document are not necessarily those of Defra or the Environment Agency. Its officers, servants or agents accept no liability whatsoever for any loss or damage arising from the interpretation or use of the information, or reliance on views contained herein. Publishedby the Department for Environment,FoodandRural Affairs. Printedinthe UK (March2006) onrecycledmaterial containing 80% post-consumer waste and20% chlorine-freevirginpulp. PB NO.11545 R&D OUTPUTS: FLOOD RISKS TO PEOPLE: PHASE 2 FD2321/TR1 ii Acknowledgements The authors are grateful for David Murphy (Environment Agency’s FloodRiskPolicy Manager - Strategy,Planning & Risk) for his chairmanship of Project Boardandfor his commitment andownership towards this project.This project benefitedfrom the Project Board and a large group of consultees, who participated in several consultation activities.We acknowledge their valuable contributions to the project that went beyond our expectations and,therefore,really made a difference tothe success of the project. Special thanks are extendedtoJohnGoudie (Defra) andIanMeadowcroft (EA).Thanks alsotoanextensive team of technical staff at HR Wallingford,Middlesex University’s FloodHazardResearchCentre andRisk& Policy Analysts Ltdfor whom supportedthis project. Core Project Team DavidRamsbottom HRWallingford(ContractorProjectDirector) StevenWade HRWallingford(ContractorProjectManager) Valerie Bain HRWallingford PeterFloyd Risk&PolicyAnalysts Ltd EdmundPenning-Rowsell FloodHazardResearchCentre,MiddlesexUniversity TheresaWilson FloodHazardResearchCentre,MiddlesexUniversity AmaliaFernandez FloodHazardResearchCentre,MiddlesexUniversity MargaretHouse FloodHazardResearchCentre,MiddlesexUniversity SureshSurendran EnvironmentAgency(ClientProjectManager) Project Board DavidMurphy EA(FloodRiskPolicy - Strategy,Planning &Risk) SureshSurendran EA(EnvironmentalPolicy –Risk& Forecasting) MervynPettifor EA(FloodRiskProcess –Regulation) TonyAndryszewski EA(FloodRiskProcess –FloodEventManagement) Roger Lewis/ IanHope EA(FloodRiskManagementReservoirSafety) PeterBorrows EA(Thames2100) PhilIrving EA(EnvironmentalPolicy –Risk& Forecasting) JohnGoudie Defra(FloodManagement) DavidMoses LocalAuthority(EmergencyPlanning) Other Key Consultees RichardHorrocks EA(RegionalFloodRiskManagement/REUUTAG) PaulaOrr EA(EnvironmentalPolicy –SocialPolicy) SarahLavery EA(FloodRiskManagement -ThamesEstuary) DavidRichardson Defra(FloodManagement -Policy) AndyDickson NorthamptonshirePolice(Emergencyservices0 PeterBye LocalAuthority(Planning) DavidCreighton Insurance RobinSpence CURBE PeterVonLany Halcrow (REUUTAG) JimHall University of Newcastle-uponTyne (REUU TAG) ColinGreen Middlesexuniversity(REUUTAG) R&D OUTPUTS: FLOOD RISKS TO PEOPLE: PHASE 2 FD2321/TR1 iii EXECUTIVE SUMMARY Flooding from rivers, estuaries and the sea poses a risk to people as well as causing significant economic impacts.Inthe last decade of the 20th century floods accounted for 12% of all deaths from natural disasters, claiming about 93000 lives across the world(OECD International Disasters Database).In1953the NorthSea floods caused approximately 2500 deaths across the UK, Netherlands, Belgium and Germany and concentrations of fatalities have beenassociatedwithflashfloods suchas Lynmouthin Cornwall (1952,over 30 deaths) andVaisonla-Romaine inFrance (1992,38deaths). Inthe UK,there were a small number of fatalities associatedwiththe Easter 1998and Autumn2000floods.InAugust 2004,a major airborne rescue operationwas requiredto rescue victims of the Boscastle flood and in January 2005, the media reported 3 fatalitiesinfloodinginCarlisle. A key Government objective for the Environment Agency is “to reduce the risks to people and to the developed and natural environment from flooding.” Environment Agency indicator: “No loss of life attributable to flooding in areas receiving a full flood warning service.” EnvironmentAgencyCorporateStrategy,2002-07. Flood forecasting and warning, emergency planning, land use planning and the operation of flood defence systems have all contributed to reducing risks in the UK. However, flood risks cannot be completely eliminated and to support Government targets for flood risk management there is a requirement for methods to estimate the risks topeople,as well as risks of economic andenvironmental damage.As shownin Figure ES1the project is focusedonpeople andprovides measures of annual average riskthat canbe usedalongside annual average economic damage andother social and environmentalcriteriatoimprovefloodriskmanagement. Figure ES1. The Risks to People project in the context of the source-pathway- receptor model of flood risk. Drivers Processes that change the state of the flooding system (including climate change and socio-economic change) Risk Model The flooding system Based on:- Flood Hazard Source Pathways Receptors Area Vulnerability People Vulnerability Rainfall Channels People Fluvial flood Flood defences Houses Tidal flood Urban surfaces Infrastructure Risk Estimate Floodplains Environment Annual average individual and societal risk (of harm or loss of life) R&D OUTPUTS: FLOOD RISKS TO PEOPLE: PHASE 2 FD2321/TR1 iv The “Risks toPeople Phase 2” method is a form of multi-criteria assessment based on the concepts of floodhazard,area vulnerability andpeople vulnerability. The method was tested using seven case studies including the flooding in Carlisle in 2005. These examples demonstratedthat the method works well,providing sensible estimates of the fatalitiesandinjuriesfor arangeofdifferentfluvialandtidalfloodevents. Improving flood risk management The researchhas a wide range of potential applications from raising awareness of the dangers of flood water, targeting flood warning, emergency planning, development control and flood mapping. The approaches developed can make use of information from other projects, such as the National Flood Risks Assessment (NaFRA) and be incorporated into the overall Risk Assessment for Strategic Planning (RASP) framework as well supporting Catchment Flood Management Plans and more local initiativestounderstandmanagefloodrisks. This report (FD2321/TR1) describes the Risks toPeople Methodology that is basedona multi-criteria assessment of factors that affect FloodHazard,the chance of people inthe floodplainbeing exposedtothehazard(AreaVulnerability)andability ofthoseaffected torespondeffectively to flooding (People Vulnerability). The report describes the key concepts,provides an overview of how the methodwas developed andshows a number ofexampleapplications. A secondTechnical Report (FD2321/TR2) is a guidance document that explains how the overall methodor its component parts canbe appliedinfloodriskmanagement for land use planning, the management of flood defences, measures for responding to flooding andfinally,inongoing andnew research projects.The outputs of consultation, workshopsandbackgroundresearchareincludedintheProjectRecord(FD2321/PR). A comment on the concepts of 'tolerable' and 'acceptable' risks In the UK there have been various Government reports that have developed the concepts of 'tolerable' and 'acceptable' risks, most notably the Health and Safety Executive reports 'Tolerability of Risk' (HSE, 1992) and 'Reducing risks, protecting people' (HSE, 1999). These advance upper limits of tolerability for annual individual riskfor workers in'risky' occupations andfor the general public.If the annual riskof fatalityorseriousharmislessthanthe'tolerable' riskitisdeemed'acceptable.' Suggestedthresholds for 'tolerable' and'acceptable' riskhave beenusedin several case study examples inthis report andwere discussedinPhase 1of the research project (HR Wallingford,2003).While these concepts are valuable,current Government policy for floodriskmanagement