The Scottish Government

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CHAPTER 2: EXISTING ASSET INFORMATION

Flood Prevention Schemes

2.13 The Scottish Executive provided a list of 78 schemes promoted as Flood Prevention Schemes under the Flood Prevention Act (Scotland) 1961. The list was reviewed, and 5 duplicate entries were found and one scheme which has been superseded by a new scheme, leaving a total of 72 schemes for inclusion within the database. These include:

• There are two schemes in Galashiels which are in separate parts of the town but both on the Gala Water
• There are four schemes in Perth. The North Muirton scheme has been superseded by the Perth FPS formed in three parts by Inveralmond, Bridgend and Lower City Mills respectively
• There are two schemes in Inverurie on the Strath Burn

2.14 There are therefore 72 schemes in 68 locations. There are currently proposals that will also supersede or alter schemes at:-

• The Roseburn Scheme in Edinburgh is likely to be superseded by the Water of Leith FPS currently under consideration
• The Waterside Scheme in Elgin is also likely to be superseded by a new Elgin FPS which is currently being developed and to be promoted by Moray Council

2.15 The location of these schemes is shown in Figure 2-1 showing a wide distribution across Scotland, with a concentration around the main urban conurbations. To allow grant aid approval, each Scheme would have 'approved' drawing(s) showing the scheme details with a horizontal and vertical deviation marked and an accompanying schedule detailing the scheme. The Scottish Executive had archive information relating to 52 of the schemes. An attempt was made to find records of the remainder from local authorities, but only a few were found.

Information supplied by the Scottish Executive

2.16 The amount and quality of information held in the Scottish Executive scheme files varied significantly. For some schemes there was only a file number and name, whilst others had detailed design reports, economic appraisals and flood maps. Factors contributing to the availability of information include the following:

• Size - large scale schemes such as those for the Perth and the River Kelvin schemes for instance tend to be better documented than smaller schemes
• Age - more recent schemes have the advantage of digital mapping and computerised assessment techniques for flood hydrology and hydraulics
• Cost of scheme - the more expensive schemes have greater amounts of information in their files than less expensive schemes

2.17 Files with the most useful information include detailed design reports, economic appraisals, description of operations, flood maps and as-built drawings, whereas some files provided only limited information.

2.18 Most of the files contain drawings of the schemes at different stages during their design. Typically, these include a location plan, plan of works and details of works. 'As-built' or Record Drawings were less common but are most useful as they often show differences between the design and what is constructed on site.

Figure 2-1 Location of Flood Prevention Schemes in Scotland

2.19 In order to map the flood prevention scheme extents, construction and as-built drawings were used, together with the Description of Works (or Description of Operations) that were supplied in the archive files.

2.20 The files also contain details of objections to the FPS and correspondence that covers how each objection was dealt with, which is not stored on the database.

2.21 Where available, design or Engineer's reports were a source of hydrological and hydraulic information, option appraisal and cost benefit analysis. Thirteen of the FPS files refer to schemes where computer hydraulic models were used in the design. Original design models were obtained for only three of these schemes. One further model was made available by the local authority for Fettercairn, constructed by EnviroCentre for a flood risk study undertaken after scheme completion. The general lack of models was due to either Intellectual Property Right issues where the modelling work was undertaken by consultants, or that the modelling software is now obsolete or bespoke.

Information supplied by the local authorities

2.22 Information held by local authorities varied significantly in extent and nature. Some local authorities were unable to find records relating to some or all of the FPS lying within their boundaries, whereas others had comprehensive records and information on additional schemes not held by the Scottish Executive.

2.23 Questionnaires were distributed to all 32 local authorities in Scotland. The questionnaires were also made available on a project website for the local authorities to enter information. It was intended that the local authority data would help fill the gaps in the information made available from the Scottish Executive file information. The local authorities were requested to provide any information relevant to the database, but with a focus on the present condition of the defences and availability of information. Requested fields included the following:

• Responsible officer for the Scheme
• Recent condition assessment
• Recent level survey
• Where information is held
• Consultant holding details
• Ex-employees with knowledge of the Scheme

2.24 Further information was sought through following up the questionnaire with telephone calls and visits to the local authorities. Some information was also made available following issue of the individual scheme draft reports to the local authorities.

2.25 Several local authorities submitted information on schemes that provided flood risk management but were not promoted under the 1961 Act ⁴. Information on these is shown in Table 2-1.

Table 2-1: Flood Defences reported by Local Authorities not promoted under the 1961 Act

Flood extents

2.26 Maps showing the extent of flooding - either historic or predicted are a useful source of information. A number of files contained information on flood extents, either in the form of historical flood outlines or in a few cases predicted flood outlines from modelling exercises.

2.27 The Scottish Executive files and local authorities supplied some flood outlines and these are summarised in Table 2-2. Most of those found related to historical floods; these have been digitised and are shown as historical flood outlines in the database. The data has also been passed to SEPA as they maintain a database of historical flood outlines.

Table 2-2: FPS with flood outlines

Local Authority Biennial Reports

2.28 The introduction of the Flood Prevention and Land Drainage (Scotland) Act 1997 introduced changes to the responsibilities and duties of local authorities in Scotland. The Act amended the Flood Prevention Act 1961 and repealed sections of the Land Drainage (Scotland) Act 1930 and the Land Drainage (Scotland) Act 1941.

2.29 Under the 1997 Act local authorities have a legal requirement to undertake the following duties:

• Requirement to assess watercourses
• A duty to maintain watercourses following assessment
• Reporting of flooding incidents in their area
• Notification of flooding to local authorities outwith their area
• Preparation and publication of reports on watercourse condition and flooding problems every two years. The most recent of these available for this study were published in November 2003

2.30 The November 2003 Biennial reports varied significantly in the amount of information on the assessment and maintenance of watercourses and flooding incidents.

2.31 The Biennial reports also report on schemes that are in their feasibility or design stages and these are shown in Table A- 1 of Appendix A.

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