Publication - Research and analysis

Mapping flood disadvantage in Scotland 2015: report

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

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

Mapping flood disadvantage in Scotland 2015: report


1. Data zones 2001 were used rather than data zones 2011, as most of the data underpinning the assessment was originally collected for the data zones 2001.

2. The return periods estimate the average length of time between flood events of similar magnitude ( e.g. 1 in 200 years).

3. Whilst the flood maps used as a basis of flood disadvantage assessment in this research allow for identification of areas not exposed to flood hazard, in practice, there is no situation where there is "no" likelihood of flooding, only very to extremely low likelihoods. There may always be a chance of flooding although it might be extremely remote. This is particularly true in the case of surface water flooding caused by intense rainfall events, which are hard to predict but could occur anywhere.

4. Defended extents were not available for surface water flooding and the low probability scenarios for river and coastal flooding.

5. All references to local authorities in this report pertain to the entire area of a local authority.

6. Where no bars are present, no residential properties are at risk from a given type of flooding.

7. Where no bars are present, no residential properties are exposed to coastal flooding.

8. 'Acute disadvantage' refers to standardised disadvantage index values that are larger than the mean (Scottish average) value by more than 2.5 standard deviations. 'Extremely high disadvantage' relates to standardised disadvantage index values larger than the mean (Scottish average) value by between 1.5 and 2.5 standard deviations (see also Table 3).

9. Local authorities not containing extremely or acutely disadvantaged data zones are not presented in the figures.

10. Some inconsistencies in SEPA flood map data mean that no extremely/acutely disadvantaged data zones have been identified in Orkney Islands for high probability surface water flooding. The flood maps are currently being improved by SEPA.

11. Population-weighted centroid is a summary single reference point which represents how the population at census time was spatially distributed and grouped within the census unit.

12. SFVI Score = ((Unemployed + Overcrowding + Non-car ownership + Non homeownership) / 4) + Single Parents + Over 75s + Long Term Sick)) ( SEPA, 2011b after Tapsell et al., 2002).

13. The spatial coincidence of data zones and PVAs was determined based on location of the data zone population-weighted centroid within the spatial extent of PVA.

14. Freeboard is often defined as the difference between the flood defence level and the design flood level. It can also however be the difference between the design flood level and the finished floor levels of any development.

15. The map colour scheme was revised in the final report.

16. This has been addressed to some extent - web maps were created, presenting social vulnerability to flooding, flood disadvantage and hazard-exposure for the flood types and return periods considered in the project.