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7 Using GIS to Identify Social Vulnerability in Areas of the United Kingdom That Are at Risk from Flooding Tom Kieron Whittington CONTENTS 7.1 Introduction............................................................................................... 133 7.1.1 Background.................................................................................... 134 7.1.2 Requirement Study....................................................................... 135 7.1.3 Aims................................................................................................ 139 7.2 Methods...................................................................................................... 140 7.2.1 Index of Social Vulnerability ...................................................... 140 7.2.2 Index of Flood Probability........................................................... 144 7.2.3 Combined Index of Flood Vulnerability................................... 146 7.3 Results......................................................................................................... 146 7.3.1 Index of Social Vulnerability ...................................................... 146 7.3.2 Index of Flood Probability........................................................... 148 7.3.3 Combined Index of Flood Vulnerability................................... 150 7.4 Discussion.................................................................................................. 151 7.4.1 Evaluation of Results ................................................................... 151 7.4.2 Interface Potential......................................................................... 153 7.4.3 Modifiable Areal Unit Problem (MAUP).................................. 154 7.5 Conclusions................................................................................................ 155 7.5.1 Answering the Research Questions Posed............................... 155 7.5.2 Developing the Model for Use within the Flood Industry.... 156 References ........................................................................................................... 156 7.1 Introduction Around 5 million people in 2 million properties live in flood-risk areas in England and Wales (Environment Agency, 2000). Property worth over 2007 by Taylor & Francis Group, LLC. £200 billion and agricultural land worth approximately £7 billion are poten-tially at risk of flooding (HR Wallingford, 2000). The floods of Easter 1998 and autumn 2000 gave the United Kingdom an important reminder of a hazard that, though ever present, has been neglected by society in recent times. Many organizations are encouraged to deal with the problem, which is predicted to increase in frequency in the future due to climate change and continued urbanization of the floodplain (Price and McInally, 2001). There is a rise in the philosophical approach of ‘‘living with the hazard’’ (Smith and Ward, 1998) that focuses on flood warning and emergency planning, than flood prevention. Initiatives to help communities to help themselves are therefore high on the agenda but require a clear understanding of the social variability and different needs of communities at risk. It is the high profile of the field of research that motivates this project into establishing how geographical information systems (GIS) may be used to improve flood warning, and emergency planning and response in the United Kingdom. To determine how the technology could be best put to use with immediate effect, a requirements study has been accomplished from a literature review and interviews with the main organizations involved in flood warning, planning, and research in the United Kingdom. The conclusion of the requirement study identifies that the spatial distribu-tion of vulnerable groups living within the floodplain is a prime target for research, and this group would benefit greatly from GIS investigation. This research attempts to bring together social-vulnerability studies and flood-probability data with GIS technology to produce a high-resolution index of flood vulnerability (IFV). A number of applications demonstrate how the index and some of the data layers used in its creation may be used to improve the efficiency and quality of flood managers’ decision-making. During a flood emergency, planners can quickly identify different groups of people with different social needs and can thus disseminate resources appropriately. Alternatively, flood-warning education can be adapted for different communitiesidentified bytheirpostcode. The finalindexproduced is a prototype tool, which requires refinement, but demonstrates how exist-ing studies could be improved with the inclusion of GIS technology. 7.1.1 Background The next century may see apparent increases in CO2 due to human activities resulting in climate change and consequently flooding from increased intensity and frequency of rainfall and sea-level rise (Price and McInally, 2001). Most flood-prevention schemes can be expected to fail if a high-level flood scenario occurs, and there are many locations where an engineering solution is impractical or could lead to considerable damage to the envir-onment (Borrows, 1999; Environment Agency, 2001). The expansion of urbanized areas can create the risk of more-frequent flood situations where increased precipitation results in greater runoff (Environment Agency, 2001; Price and McInally, 2001). Around 5 million people in 2007 by Taylor & Francis Group, LLC. 2 mi llion pro perties are vulne rable to flood risk in Engla nd and W (Env ironmen t Agenc y, 2000); the flood leve ls during the Oct ober 2 floods were the highest on record in many location s, and 10,000 proper t were affecte d (Enviro nment Agenc y, 2001). The Bette r Regul ation Task Force (2000) re commen ds that policy make consid er vulne rable peop le at all st ages of their work, with gre atest co eratio n to in clude vulnerabi lity im pact assessm ents. Knowl edge of wh social differen ces lie with in commun ities poten tially at ris k from flood and the general natur e of their circumst ances is needed to bette r tar publi c aware ness informati on and to resp ond appropri ately to emerge situat ions (Mor row, 1999; Tuns tall, 199 9; Blyth et al., 2001; Envi ronm Agenc y, 2001). On e of the mai n reasons for targetin g vuln erable gr is the desire to concen trat e on the worst affec ted areas and popu la (Jaspar s and Shoham 1999); emerge ncy plan ners need to know who th are and wh ere they are concen trated (Mor row, 199 9). Perform ance of f forecast ing and war ning syst ems appear s to be poor in the Un ited Kin (Hag gett, 1998; Horn er, 2000; Penning- Rows ell et al., 2000; Envi ronme Agenc y, 2001) but wil l contin ue to im prove, pro vided that the rig ht mation can be deli vered in advanc e to the right peop le (FHRC , 200 1) There is a need to devel op accura te flood- hazar d maps and flood- re action plans for hazard -prone areas (Rant akokko, 1999). The Environ ment Agenc y has created the ind icative floodpl ain map usin g historical a rainfal l catchmen t mode ls (e.g., ISIS and MIKE11) . The mapped floodpla boun daries are disaggr egated to unit postc odes to a ssist publ ic iden t tion of risk, but there is a mi smatch bet ween postc ode uni ts and iden flood- risk areas (Plough er, 2000). Boyle et al. (1998) discrimi nate the floo plain into uni ts def ined by the qua ntifica tion and spatia l variabi lity of hazard . Flood-pr obabili ty contours are create d with hydrol ogical mode li of flood flow rates assoc iated with differen t return-pe riods (the flood f quency in years). The use of GIS in this typ e of hazar d exposur e pro v efficient and accurate assessment for areas prone to flooding (Boyle et al., 1998), but it does not consider the socioeconomic variability that may also be associated with that location. 7.1.2 Requirement Study It is the intention of this research to enhance the flood-warning and emer-gency-planning industry with GIS technology. There are a number of organizations in the United Kingdom with different responsibilities within the flood indu stry (Table 7.1); consultant s and resea rch insti tutes a assigned projects to develop the roles of these organizations. As the industry does not have a single function, it was necessary to identify one aspect of technical research that could reasonably be undertaken with limited time and data, and yet provide a useful service. A GIS requirement study has been administered to evaluate the research needs of flood warning and emergency planning, but these particular needs are difficult to define 2007 by Taylor & Francis Group, LLC. TABLE 7.1 Flood Hazard Responsibilities in the United Kingdom Organization Legislative bodies Meteorological office Environment Agency (and the Scottish Environmental Protection Agency) Police and local authorities Responsibilities MinistryofAgriculture,FisheriesandFood(MAFF),nowDepartmentof Environment, Food and Rural Affairs (DEFRA) have policy responsibility for flood and coastal defense in England and administers the legislation that enables work to be carried out. The Flood and Coastal Defence Programme is aimed at reducing risk to people and the developed and natural land by financially supporting, advising,andguidingfloodandcoastaldefenseoperatingauthorities, and funding research programs. Following the 2000 floods, better definition of flood or erosion risk areas was identified as being of particular necessity to flood planning (HR Wallingford, 2000) Continuous monitoring of weather conditions and rainfall patterns from remote sensing and ground-based measurements falls under the authority of the meteorological office (MetOffice). Computer models simulate river discharge based on rain-gauge readings over time-periods in various parts of different catchments. If a flood situation arises, the MetOffice alerts the EA and local authorities to the possible threat The Environment Agency (EA) has the lead role in disseminating flood-warning messages with the help of local authorities; flood defense accounts for about 50% of the Agency’s annual budget (EA, 1996). There are a number of departments within EA to deal with various aspects of flood warning. The National Flood-warning Centre continuously monitors changes in the conditions of rivers, such as the effect of development on channel flow; and it is the interface between the agency and the public. The Emergency Management Team develops contingency planning policy on which it advises local authorities and coordinates the information flow during an emergency. The EMT liase with weather service providers and issue warnings and press releases during an emergency and are responsible for education campaigns prior to any particular event. EA regional offices deal with more localized issues with respect to flood-alleviation schemes and flood warning. There is some variation between EA regions in the scope and sophistication of the facilities available to support operational decision-making (Haggett, 1998) Local planning and emergency considerations: It is the role of the police to organize localized planning and response on behalf of LA and EA guidelines. Once alerted to the onset of a flood event a command-and-control center is set up by the police, local warnings are issued, and emergency response teams dispatched. The police have roles in the evacuation of people at-risk and traffic management (Smith and Ward, 1998). Without detailed information on the social characteristics of different threatened communities, emergency planners and services can have great difficulty in reaching specific communities in need (Haggett, 1998). The police have endeavored to improve reliability and speed of flood-warning dissemination and focus on emergency response through the use of technology (Horner, 2000) 2007 by Taylor & Francis Group, LLC. TABLE 7.1 (continued) Flood Hazard Responsibilities in the United Kingdom Organization Insurance companies Responsibilities In different European countries, there are varying methods for insuring against flood damage. Countries with a high risk of flooding have responded in different ways. Austria and Belgium have state-funded schemes; Italy has insurance available that is rarely bought; and Netherlands has no insurance cover available other than for some industrial risks. The United Kingdom, with medium risk, is the only countryinEUwith100%privateinsurancesolutions(Ebel,1999).Flood aid and insurance do nothing to mitigate and reduce the risk of future disasters, and such measures may be counterproductive if they continuetoencouragesettlementintohigh-riskareas(SmithandWard, 1998). The insurance industry has recently discovered the value of flood-riskmapsthatcombineflooddepthwithinformationonbuilding typeswithinagivenarea,usuallydefinedbyitspostcode(Rodda,2001) owing to the dearth of a ppropria te litera ture. To overcome this problem series of intervie ws has been condu cted with man y of the key organizat from the flood ind ustry in the United Kingdom to supp lement finding from releva nt litera ture. The object of the inte rviews are twof old: to co an audit of curren t GIS to co nsider how the techn ology is used in warning and emerge ncy planning, and iden tify areas where GIS are no meeting their potenti al; a nd to conside r the opi nions of some of the le practitio ners in these areas, wh ich would significant ly ben efit the floo warning and emerge ncy-plan ning pro cess. The audit shows that most system s deal with flood war ning and p ventio n, or emergency planning, but very few syst ems are used for em gency resp onse that re quires pre cise and up- to-date inform ation for effic decisio n-maki ng on how to respon d to chang es in ci rcumst ances (Table No system s-in-use consi der all a spects of the flood indu stry, and ne ar the use of GIS is onl y involv ed with research , possibl y indicating deficien cy of actual running syst ems. Over all the system s are spar se utilizi ng soc ioeconom ic data and as sessing fl oods accordi ng to popu la and commodity risk . Advan ces of GIS may invo lve more soc ial consid ations of floodin g as the nece ssity for monitorin g flood- risk comes from effect it may have on soc iety. It may also be fruitf ul to conside r a syst not on ly provides flood war ning but a lso assists in the emerge ncy plan and respons e of a flood in real time, anoth er use of GIS which is not optim ally exploited . Real-tim e GIS may be useful in modify ing emerge plans appr opriate ly duri ng a flood event as new da ta bec omes avai la Interviews included advances for research in the flood industry that organizations felt were important, and these were found to generally concur with ideas expressed in the literature. The so-called ‘‘living with hazards’’ philosophy (Alexander, 1997; Smith and Ward, 1998) has created the need for more effective initiatives to be researched within the roles of warning, 2007 by Taylor & Francis Group, LLC. ... - tailieumienphi.vn
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