The Scottish Government

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EXECUTIVE SUMMARY

1 Flooding is a natural occurrence, but one which can result in economic losses, human hardship and environmental damage. The Scottish Executive is investing in improving understanding of flooding in Scotland as part of the need for development of a sustainable approach to flood risk management.

2 Recommendations made in recent studies on the possible effects of climate change identified a need for a register of fluvial and coastal defences containing detailed records of all Flood Prevention Schemes ( FPS), the defended areas and number and value of properties protected. In addition, the new SEPA flood map "the Indicative River and Coastal Flood Map (Scotland)" was made available to the public in 2006 by SEPA. In accordance with standard practice, these will show areas of undefended flood risk.

3 The Scottish Flood Defence Asset Database provides a national repository for information relating to flood risk and flood defences. At present information on the flood prevention schemes has been determined and recorded. For each scheme the following information has been collected and summarised within the database:

• for each flood defence element the location, structure, material, physical details and condition
• the standard of protection expressed as a flow or water level and as a return period
• an estimate of the standard of protection in 2080 reflecting current estimates of climate change
• flood maps for the floods currently assessed as 100, 200 and 1000 year
• details of modelling at each cross section including a rating curve, photograph, map at each modelled section
• the number and values of properties defended
• the original design standard

4 The review has used national methodologies and each scheme has been assessed using standard criteria to allow an overall picture of how well defences perform across Scotland.

5 Many of the schemes constructed under the Flood Prevention (Scotland) Act 1961 were not designed to incorporate for future changes in river flows. The current scheme analyses have shown that even without the incorporation of climate change, the design flows and standard of protection have varied significantly owing to additional river flow data and revised methodologies. The standard of protection of existing schemes may therefore change although their performance against a defined flow is likely to be maintained.

6 The review of costs and benefits allows an assessment of the value of defending properties and has implications for national planning, expenditure and the financial sustainability of flood management. Of the 72 Flood Prevention Schemes built since the 1961 Flood Prevention (Scotland) Act, 39 were reviewed in detail. In total the schemes provide 61km of defences. Present day costs of £82 million were found for 54 FPS with present day damage avoided for 39 schemes in the order of £240 million. Of assets surveyed 87% are in good and very good condition as defined by the National Sea and River Defence Surveys Condition Assessment Manual.

7 The number of properties currently protected by the 39 assessed flood prevention schemes is some 4580. Of these 1570 are protected to a standard of protection lower than 100 years. There is a significant benefit that could be derived from improving the performance of some of these defences to the 100 year standard. The ratio of commercial/industrial and residential properties protected is approximately 1:4.

8 The number of properties protected by flood prevention schemes in Scotland has followed a trend of gradual increase until the mid to late 1990's, at which point several schemes have significantly increased the total number of properties protected.

9 At present a FPS can only be promoted if it will defend to at least the 100 year flood and this research demonstrates that many of the schemes providing defence against frequent flooding are economically viable at their current standard of protection which is often much lower than 100 years. At the time of writing there are at least 48 schemes under preparation in Scotland which represents a considerable increase in interest and resource allocation to flood management, ensuring this information is captured will assist maintenance and planning at a national and local level.

10 The Scottish Flood Defence Asset Database is a major investment and provides an exceptional tool in managing flood risk on a national basis. The database has been designed to allow new schemes to be readily entered. The database has also been designed to allow information on all flood defence assets to be recorded including information on flooding from Coast Protection schemes, flood prevention assets that are not part of schemes promoted under the 1961 Act and historical flooding. It is envisaged that the database can be built upon to form a central source of information on flooding and flood risk.

11 The study database is geo-referenced (i.e. linked to maps) and is currently available to the Executive, local authorities and SEPA by means of a web-based GIS application. In a number of locations local authorities have made or are planning improvements identified as part of this study.

12 The database will also allow planners and other stakeholders to readily determine whether the standard of protection afforded is adequate to meet current Planning Guidance ( SPP7 Planning and Flooding).

13 The Scottish Flood Defence Asset Database provides a unique opportunity to consolidate information held on flood risk and flood defence in one location and thus provide a valuable tool in providing sustainable flood management.

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