OR/14/010 Technical information

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Dearden, R A, Tye, A M and Marchant, A. 2014. User guide for the Pipe Leakage Impacts. Nottingham, UK, British geological Survey. (OR/14/010)

Pre-requisite requirements

To use the Pipe Leakage Impacts map, a computer with vector-based GIS software is required.

It is highly beneficial to have a topographic GIS layer. If unavailable, see the Ordnance Survey website (http://www.ordnancesurvey.co.uk/) for the provision of OpenData.

Creation of the dataset

The ‘Leakage’ dataset is directly derived from the datasets listed in Table 8. The polygons in the original datasets were reclassified with five attributes (e.g. see Tables 2 to 7) and neighbouring polygons with the same attribute were merged. A summary map was generated by reporting the greatest potential for an increase in ground movement.

Scale

The Pipe Leakage Impacts map is produced for use at 1:50 000 scale providing 50 m ground resolution. The mapping scales on which the original geological linework are based are shown in Appendix 1.

Dataset history

BGS is strategically surveying and resurveying areas of Great Britain, improving and updating the geological maps. It is anticipated that a new version of the dataset will be released once a significant proportion of the underlying dataset has changed. This report describes the first version of the Pipe Leakage Impacts map, generated during 2013.

Coverage

The data covers Great Britain, but not the Isle of Man.

Data format

The Pipe Leakage Impacts map has been created as vector polygons, which are available in a range of GIS and CAD formats, including ArcGIS (.shp) and MapInfo (.tab).

Limitations

  • The Pipe Leakage Impacts map has been developed at 1:50 000 scale and must not be used at high resolution.
  • The Pipe Leakage Impacts map is based on, and limited to, an interpretation of the records in the possession of the British Geological Survey at the time the dataset was created.
  • The dataset does not consider the pressure of the water leaking from a pipe; it considers the impact of leaking water on stability hazards.
  • This dataset is not an alternative for a ground investigation.
  • Site observations represent the properties of the ground more accurately than the data provided by the Pipe Leakage Impacts map.
  • Other more specific and detailed ground instability information may be held by BGS, and an assessment of this could result in a different outcome.
  • An indication of potential natural ground instability does not necessarily mean that a location will be affected by ground movement or subsidence. Such an assessment can only be made by inspection of the area by a qualified professional.