Publication - Research and analysis

Mapping flood disadvantage in Scotland 2015: report

Published: 23 Dec 2015
Directorate:
Environment and Forestry Directorate
Part of:
Environment and climate change
ISBN:
9781785448478

This research identifies and maps the neighbourhoods in Scotland that would be most disadvantaged by flooding.

Mapping flood disadvantage in Scotland 2015: report
Executive summary

Executive summary

This report summarises the research into the assessment of social vulnerability to flooding and flood disadvantage, based on the assessment framework developed by Lindley et al. (2011). It is aimed at policy-makers and practitioners working in flood risk management, resilience, emergency services, public health, social care, housing, environment and other areas that would benefit from an improved understanding of vulnerable communities and flooding across Scotland.

Social vulnerability in this report is understood as the degree to which people's health and well-being would be negatively affected if they came into contact with flooding. Social vulnerability is a combination of:

  • Sensitivity (personal characteristics that increase the likelihood that a flood event will have negative health and well-being impacts on people),
  • Adaptive capacity (the ability of people to prepare for, respond to and recover after flooding, related mainly to their social and material situation), and,
  • Enhanced exposure (the aspects of the physical environment, such as housing and presence of permeable surfaces, which accentuate or offset the severity of flood events).

Flood disadvantage occurs where socially vulnerable areas coincide with areas which may be exposed to flooding, or in other words have high flood hazard-exposure. In this report, flood hazard-exposure is estimated spatially as the percentage of residential properties within flood risk areas.

This research updates an assessment of flood disadvantage carried out by Lindley and O'Neill (2013). However, the two assessments are not comparable as the following modifications have been made:

  • A revised set of indicators for socio-spatial vulnerability has been developed. The list takes account of the availability of new datasets, feedback from stakeholders and an additional evidence review.
  • Updated versions of indicators that represent the most up-to date picture of socio-spatial vulnerability. Sources of information include the Scottish census 2011 and Scottish Neighbourhood Statistics.
  • New flood maps produced by SEPA (version 1.1, March 2015) have been used to represent the likelihood of flooding across Scotland and the assessment has been carried out for different flood return periods than in the first assessment. The 'defended' flood outlines have been used in order to represent the risk of flooding taking into consideration the presence of flood defences.
  • Surface water flooding, as a substantial flood problem in Scotland, is included in the analysis alongside flooding from the rivers and the sea.

The assessment was carried out for the whole of Scotland at data zone level [1] . In total, 34 indicators relating to 14 thematic domains (Age, Health, Income, Information use, Insurance, Local knowledge, Social networks, Tenure, Mobility, Physical access, Crime, Access to services, Housing and Green space) were combined into the index of social vulnerability to flooding.

The index of social vulnerability to flooding was combined with the flood hazard-exposure index which took into account different sources of flooding (coastal, river, surface water) and different return periods [2] (1:25/30; 1:200, 1:200 including the impacts of climate change). This was then developed into the index of flood disadvantage. Social vulnerability and flood disadvantage are categorised into six classes, based on the deviation from average Scottish values, and range from extremely low to acute.

The key findings (for 1 in 200 year flood return period that accounts for climate change - a low probability-high damage flood scenario not including the impact of flood defences) are as follows:

Flood exposure:

  • Over 4% of residential properties in Scotland (just over 108,000) are estimated to be exposed to any type of flooding. At least some of these may be properties constructed since 1st January 2009.
  • Nearly half of all data zones in Scotland contain residential properties which may be exposed to any source of flooding.
  • Falkirk, the Orkney Islands and West Dunbartonshire have the highest proportion of residential properties exposed to coastal flooding.
  • Stirling, the Scottish Borders, Perth and Kinross and Moray have the highest proportion of residential properties exposed to river flooding.
  • Surface water flooding affects fewer properties. The highest proportion of residential properties exposed to surface water flooding is in Aberdeen City, Highland and Moray.

Just below 8% of the data zones are classified as having an extremely high or acute vulnerability to flooding. These are located mainly in the large Scottish cities, with Glasgow containing 191 such data zones, Edinburgh - 82; Dundee - 44 and Aberdeen - 27.

Flood disadvantage:

  • Considering any source of flooding, 3-4% of all data zones or 7-8% of data zones exposed to flooding can be classified as extremely or acutely disadvantaged.
  • Falkirk, West Dunbartonshire, Highland and Dumfries and Galloway have the highest number of extremely/acutely flood disadvantaged data zones in relation to coastal flooding.
  • With regard to river flooding, the highest number of extremely/acutely flood disadvantaged data zones is in Edinburgh, Stirling and Highland, followed by Falkirk and Aberdeen.
  • One-third of the acutely/extremely disadvantaged data zones in relation to surface water flooding are in Glasgow, followed by Edinburgh and Aberdeen.
  • At the national level, considering the low-probability flood scenario, the extremely and acutely flood disadvantaged data zones contain around 100,000 people. Over 28,000 people may be flood-disadvantaged in relation to coastal flooding; 60,000 in relation to river flooding and 14,000 in relation to surface water flooding.

Geographical distribution of social vulnerability to flooding and flood disadvantage:

  • Urban areas are more likely to contain the extremes of social vulnerability to flooding: 73% of the extremely or acutely vulnerable data zones were located in large urban areas and a further 23% in other urban areas. However, extremely low vulnerability also tends to focus in urban areas: 29% of data zones classed as having extremely low vulnerability were in large urban areas and nearly 50% in 'other urban' areas.
  • Remote small towns and remote rural areas emerge as having potential issues with social and physical isolation and mobility of people, especially older populations, which may raise issues with regard to responding to flood events.
  • Flood disadvantage in Scotland (any type of flooding) tends to concentrate in urban areas; in particular the smaller urban areas contain a high proportion of extremely and acutely disadvantaged neighbourhoods.
  • Both social vulnerability and flood disadvantage are concentrated in coastal areas.
  • The results of the flood disadvantage assessment are consistent with the SEPA's 2011 National Flood Risk Assessment. Nearly all acutely/extremely vulnerable data zones were located within Potentially Vulnerable Areas ( PVAs); 97.5% of the extremely vulnerable neighbourhoods were located within PVAs. Only one of 98 acutely flood disadvantaged neighbourhoods and five of 138 extremely flood disadvantaged neighbourhoods fell outside PVAs. This compatibility allows for the use of this assessment alongside PVAs to differentiate between communities with different characteristics.

Case studies with local authorities (Dumfries and Galloway, Dundee City and Scottish Borders):

  • The participants were supportive of the framework used and of the explicit links made between the vulnerability of communities and the hazard of flooding, as these issues tend to be considered in separation in local authorities' work.
  • The data broadly reflected the participants' experience of where exposure and vulnerability are located and coincide. However, in one case-study rural local authority there were fine-grained differences that were not picked up by the level of assessment at the data zone level. This indicates the need for further investigations into vulnerability and communities at the level of smaller spatial units or individuals.
  • The potential uses of the results included: supporting cross-departmental working; identifying priority areas for emergency services; and, communicating flood risk issues to local communities.
  • A strong recommendation emerging from the meetings with local authorities is to develop a spatial portal which would allow selected layers of information to be displayed and would bring together the underlying spreadsheets, containing the data, with the maps.

Recommendations:

  • For local authorities, mapped flood disadvantage provides a useful framework for planning actions in anticipation of the increased risk of flooding ( e.g. redevelopment that alters the use of the ground floor to minimise damage if a flood happens) and developing recovery strategies in the aftermath of flooding ( e.g. targeting financial assistance to groups least likely to have flood insurance).
  • It is recommended that local authorities collaborate with third sector organisations in particular in remote rural areas but also in inner-city areas to increase the self-help potential of communities, facilitate development of social networks and provide support in the case of flooding.
  • Raising awareness of flooding and actions to be taken among landlords and tenants is needed as the private rented sector continues to grow.
  • The extensive set of indicators compiled in the vulnerability assessment may be used by various local authority departments to identify areas for actions unrelated to flooding ( e.g. adult and social care).
  • The information on the concentrations of residential properties and neighbourhoods characterised by acute and extreme flood disadvantage can be used by SEPA to provide additional information to support the implementation of Flood Risk Management Strategies for Local Plan Districts.
  • The dataset may be used by SEPA in future flood risk management cycles to inform the delivery of actions such as provision and method of delivery of flood warnings and flood prevention schemes. The highly vulnerable and disadvantaged data zones located outside PVAs identified in 2011 NFRA could be considered against candidate PVAs for the next cycle NFRA.
  • The spatial distribution of flood disadvantage can be used to support or evaluate decisions made on flood risk investment. Requiring particular attention are areas with acute and extreme disadvantage in coastal and urban areas, and reducing the risks associated with physical and social isolation of communities in remote towns and rural areas.
  • Future research could focus on: developing more direct indicators of social vulnerability to flooding; exploring the future dimension of vulnerability alongside climate projections; and, investigating localised, fine-grained variability in social vulnerability to flooding and flood disadvantage. Mapping the provision of emergency services, rest centres and other social infrastructure that could be used in response to flooding and in the recovery phase would offer additional layers of information.

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