Flood disadvantage in Scotland: mapping the potential losses in well-being

1. Introduction and Aims

1.1 Formulating a just response to the problem of flooding requires consideration of both the potential for flood exposure and an assessment of the potential impacts of flooding on people's well-being. Much analysis to date has centred on understanding the characteristics of exposure. There has been less emphasis on the personal, environmental and social factors which help to explain why people and communities exposed to the same flood events can experience very different outcomes in their longer term well-being.

1.2 The Joseph Rowntree Foundation recently published the report Climate change, justice and vulnerability (Lindley et al., 2011). The associated project involved an inter-disciplinary team seeking to explore how climate change may differentially impact people's health and well-being across the UK. The work had conceptual and empirical elements. It developed core ideas and then implemented them to create mapped results. The project used the context of heat- and flood-related events as its basis. Three key concepts developed within the study were vulnerability, socio-spatial vulnerability and climate disadvantage. These are explained below.

• Vulnerability - The vulnerability of individuals is characterised by the degree to which an event such as a flood or a heat wave converts into losses in their well-being. A variety of personal, environmental and social conversion factors affect how far an individual is able to respond to stresses placed on well-being. Personal factors include features associated with individuals such as disability, age and health. Environmental factors include features of the physical environment such as the extent of built up areas, quality of housing stock and building elevation. Social factors include features associated with the wider social and institutional context such as levels of inequality and income, the strength of social networks and neighbourhood cohesion.
• Socio-spatial vulnerability - Socio-spatial vulnerability is understood as 'the geographical expression of the degree to which an external event has the potential to convert into well-being losses' (Lindley et al., 2011:7). In other words, considering how the characteristics of people and places can affect the chance of the people within any particular neighbourhood to be negatively affected by an event, irrespective of whether they come into contact with one. Socio-spatial vulnerability has five dimensions, each of which has a number of domains populated by a number of indicators (Appendix 1, Table A1.1). In the context of flooding, the five dimensions can be explained as follows:
  • Sensitivity - factors which describe personal biophysical characteristics such as age and health. These affect people's underlying susceptibility to health-related outcomes of flood events.
  • Enhanced exposure - factors which describe aspects of the physical environment, such as the extent of built-up zones or housing characteristics, which tend to accentuate or mitigate the severity of flood events.
  • Ability to prepare - factors that describe the extent to which people within a neighbourhood are able to prepare for floods, such as income, insurance and local knowledge.
  • Ability to respond - factors that enable people within a neighbourhood to immediately respond to floods such as income, community networks and personal mobility.
  • Ability to recover - factors that enable people within a neighbourhood to recover from floods (and thereby overcome direct and indirect impacts) such as income, insurance, housing mobility and social networks.
• Climate disadvantage - A combination of '(a) the likelihood and degree of exposure to a hazard and (b) individual or group vulnerability with regards to such hazards' (Lindley et al., 2011: 7). In the original report, assessing climate disadvantage involved mapping neighbourhood scale socio-spatial vulnerability against measures of hazard-exposure, such as temperature patterns and flood likelihood (chance of occurring). The method used in this report is broadly the same, but with a few technical differences and with a specific focus on flood disadvantage^[3]. The flood hazard measures used in the current study are explained in paragraph 2.5.

Figure 1 below shows how these key concepts fit within a research framework. This model includes exposure, both in terms of potential flood likelihood (hazard) and features of the environment that may accentuate the impact of flooding (enhanced exposure). This model illustrates how socio-spatial vulnerability and hazard exposure maps - both useful data in their own right - are particularly powerful when combined to map climate disadvantage.

Figure 1: Conceptual framework used in the study (from Lindley et al., 2011)

1.3 The original report produced neighbourhood-scale maps of socio-spatial heat vulnerability and heat disadvantage for the whole of the UK. Socio-spatial flood vulnerability maps were similarly produced for the whole of the UK. Appendix 1 (Table A1.2) lists the set of indicators used to map Scottish socio-spatial flood vulnerability. It was only possible to map flood disadvantage for neighbourhoods in England and Wales due to a lack of available flood hazard-exposure data for Scotland and Northern Ireland. Flood hazard-exposure measures for England and Wales were derived from the Environment Agency's Nafra Spatial Grid 09/10 dataset, which was purchased for use in the project. Equivalent data were not available for Scotland within the time frame of the initial project.

1.4 The overall aim of this follow-on study is to produce flood disadvantage maps for Scotland that take into account estimated flood exposure as well as underlying socio-spatial vulnerability. This brings the Scottish data in line with maps already produced for England and Wales, though results are not directly comparable for reasons outlined in Chapter 2 (paragraph 2.4). This work uses available data for potential flood hazard-exposure supplied by the Scottish Environment Protection Agency (SEPA), through the Scottish Government. Directly equivalent data to that used for England and Wales were not available.

1.5 A map of flood disadvantage for Scottish neighbourhoods^[4] has been produced (Chapter 3), by combining socio-spatial flood vulnerability with an estimate of hazard-exposure, represented by the percentage of residential addresses which are potentially affected by coastal or fluvial flooding within each neighbourhood. This is an improved flood exposure metric to that produced for England and Wales, because it gives a better representation of the proportion of people potentially affected. The flood exposure metric used to produce flood disadvantage maps for England and Wales combined socio-spatial flood vulnerability with an estimate of hazard-exposure, represented by the proportion of the land surface of the neighbourhood potentially affected by coastal or fluvial flooding. A neighbourhood may have a large land area potentially affected by flooding but this land area may not be associated with housing.

1.6 Additional work compared the historical flood event data used within the socio-spatial flood vulnerability assessment, against SEPA's current historical flood event database. In the original study, the database was used to construct a proxy indicator of potential insurance access problems (see Appendix 1, Table A1.2). The supplied data were noted as being under review, so close examination of the most recent version of the data was carried out to explore opportunities to improve the existing indicator (see paragraph 2.7 for findings).

1.7 The results are related to four case study examples taken from the south west, the north and the central lowlands. The case studies discuss the specific sources of flood disadvantage and socio-spatial vulnerability in each selected location.

1.8 The Scottish Government is keen to explore how this work and its underlying model can be used to inform policy and planning. The mapped results for Scotland are presented here for discussion, with a view to future development. Although this work used the best available flood hazard exposure data at the time of writing, the absence of data on pluvial flooding and flood defences means conclusions should be treated with some caution and used in conjunction with local knowledge. SEPA is due to publish improved flood hazard exposure maps by the end of 2013 which, along with forthcoming neighbourhood level data from the 2011 Census, could enable the current work to be updated. Those interested in using the data to inform flood and adaptation planning can request the data via envstats@scotland.gsi.gov.uk. Feedback on the report and data can also be made to the same address.

1.9 A short summary of the data and key points of the method, as applied to Scotland, are provided in Chapter 2.