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Scottish Vacant and Derelict Land Survey 2004

Annex: Considerations when interpreting the data

A.1 Data Quality Local authorities may not update all historic site information every survey, consequently some site information may not be current. For example, a site may be sold and change ownership type or sites might change contamination status. Such changes could happen without the local authorities knowledge.

A.2 Removal and Addition of Sites. The means by which new sites are detected are largely centred on the expert knowledge of local authority planning officers. It is very important to note that Table 19, which shows new sites added since the previous survey, show only entirely new sites. Sites that have increased in size since the previous survey are not shown. Similarly, when part of a site is brought back into use, that part is detailed in the 'B' data set, and the part not brought back into use remains in the survey 'A' data set.

A.3 Changes in Site Details. Changes in site details can also cause other difficulties in interpreting the data. The most notable are when two separate sites become joined by the inclusion of a further piece of vacant or derelict land, and alternatively when a single site has a central area brought back into use, such that the remaining disused area does not form a single contiguous site. The first of these scenarios is the most awkward from a statistical viewpoint, as data regarding previous use etc. for both sites are unlikely to be compatible. Where this happens, details from the largest contributing site are used to describe the new, compound site.

A.4 Definition of Contamination. The SVDLS bulletin reports on sites, which are available for, re-use, and as such, contamination is defined in terms of its potential impact on development, either as a direct result of the contamination itself or through the costs of remediation prior to re-development. This differs considerably from the definition of contamination set out in Part IIA (Contaminated Land) of the Environmental Protection Act 1990, which refers to land causing a threat to human health or the wider environment. It seems likely that all derelict sites, which are contaminated under the Part IIA definition, should also be regarded as contaminated under the SVDLS definition, but not necessarily vice versa. Another issue lies in the measurement of contaminated land, in that it can only be confirmed to be contaminated after it has been tested. Although this is obvious, it implies that the amount of recorded contaminated land bears a direct relationship with the amount tested for contamination, and as such, the availability of resources for testing might have a strong influence on the data presented.

A.5 Ownership. Details of ownership are not always readily available to local authorities, and this is reflected by the large amount of land of 'Unknown' ownership shown in Table 6. Annex Chart A illustrates the relationship between unknown ownership and the length of time sites have lain vacant or derelict. Each column represents the percentage of all sites in that category for which ownership is unknown. Using the percentage values gives a clearer picture of the extent of the problem by standardising the 'number' of sites in each age category. Ownership was unknown for 17 per cent of the sites that had lain vacant or derelict since 2001, representing 111 hectares of land.

Annex Chart A: Percentage of sites where principal owner is unknown by period since which they have lain vacant or derelict, 2004

A.6 Previous Use and Length of Time Vacant or Derelict. Knowledge of the use to which a site was formerly put is important in assessing it for potential contamination. The triple of previous, intended and actual usages of reclaimed derelict land and urban vacant land brought back into use is also important in determining the success of local plans. In order to carry this assessment through, it is necessary to have information about the previous use of sites. However, there appears to be a relationship between the length of time a site has been vacant or derelict and the information available about its previous use, as shown in Annex Chart B. For each time period, the percentage of sites for which there is no available information about previous use is given. The longer a site has been disused, the less likely is the possession of information about its previous use. The exception to this is in the very oldest class of sites, which is also the single largest class, containing 804 sites out of a total of 4,174.

Annex Chart B: Percentage of sites where previous use is unknown by period since which they have lain vacant or derelict, 2004

A.7 Land area eligible. Although local authorities are asked to note all derelict land for the survey (see Annex A10 regarding Highland council), the recording of vacant land is restricted to urban areas where the resident population exceeds 2,000 people, and the 1 km band, which surrounds them. Consequently, the actual land area surveyed for vacant land is often considerably smaller than the total land area of each local authority, especially in the case of the more rural areas. The figures contained in this bulletin should thus be interpreted as showing derelict land throughout Scotland, but only urban vacant land. In 2004, a pilot survey of vacant sites in small settlements (GRO(S) identifies 264 settlements with a population of between 500 and 2000) was carried out. Seven authorities volunteered to take part and 22 sites, covering an area of 26 hectares, were identified in 67 such settlements. (The area of individual settlements can be found on the GRO(S) website see http://www.gro-scotland.gov.uk/grosweb/grosweb.nsf/pages/scotcen8).

A.8 Definitions of location. The existing definition of "urban" allows local authorities some flexibility when defining the location of a site. It is hoped to introduce a new standardised definition for the 2005 survey, this will allow a consistent percentage of urban area which is derelict to be calculated for each local authority.

Annex Table A: Derelict Land as a percentage of total area by local authority area, 2004 ^{1, 2}

1. Figures may not sum due to rounding
2. 2003 data have been used for the following council areas: Aberdeenshire, Argyll and Bute, Scottish Borders and South Ayrshire.
3. Total Area of local authority is based upon high water mark

A.8 Definitions/Interpretations. The SVDLS guidelines clearly state the definitions for the recording of derelict and urban vacant land. Where difficulties are encountered, the guidelines have been modified to assist in the provision of uniform returns, but ultimately the survey relies on the consistent application of definitions between local authorities and through subsequent years. Some of the changes reported in Annex Table B (sites removed for 'definitional' reasons) come about following a reappraisal of the survey guidelines, and the introduction of GIS systems has allowed planning officers to improve data quality. Since the last survey, 173 hectares of land were removed from the survey for definitional reasons, of which 113 hectares (16 sites) were located in North Lanarkshire. Since the last survey only two sites were removed due to naturalisation, both of these sites were in West Dunbartonshire.

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