Initial Screening Tool

Initial Screening Tool (IST) pilot area

The BGS Initial Screening Tool (IST) was developed to assist the planning community in the assessment of the potential risk to ground and surface waters from contaminants mobilised as a consequence of development.

The initial research area selected for the application of the IST was the Olympic Park site, London.

Through use of GIS techniques such as network analysis, generation of zones of influence, geoprocessing and the incorporation of surfaces extracted from 3D geological and hydrogeological models, the IST aims to build on previous contaminated land screening tools by identifying, modelling and scoring individual potential pollutant linkages.

This capability and the ability to identify how many potential pollutant linkages are present, is unique among many currently available screening tools.

New methodologies

Modelling a pollutant linkage in the Initial Screening Tool (IST)

Significant improvements have been achieved in the identification of pollutant linkages over previous GIS based scoring systems.

The combination of detailed 3D data, identification of individual pathways and improved scoring of evaluation factors has clear benefits in assisting the planning community in the assessment of the potential risk of contaminant mobilisation to groundwater and surface waters.

It is recognised that there are limitations on how widely the techniques implemented by the IST can be applied, based primarily on the availability of detailed digital 3D geological and hydrological data.

This data is available for the Thames Gateway region and some other urban areas, but not at a national scale.

The future

Initial Screening Tool (IST) report extract. OS Data · Crown Copyright. All rights reserved. BGS 100017897/2010

To more accurately model pollutant linkages, a key development will be the generation of groundwater zones of influence in 3D.

Other areas being explored, include making region or site specific changes to evaluation factors. For example, consideration will be given to generating an additional evaluation factor to take account of the potential for contaminant mobilisation as a result of the groundwater draw-down that will be required to construct proposed foundations.

A further improvement would be the addition of a groundwater evaluation factor to represent the permeability of the receiving aquifer.

The incorporation of a foc evaluation factor would align the methodology more closely with numerical approaches to determining remediation values (Marsland et al., 2003). Additionally more analysis of the effect of mobilised contaminants on human receptors could be addressed leading to the identification of remediation requirements.

References and further reading

Marchant, A P, Banks, V J, Royse, K R, Quigley, S P and Wealthall, G P.  In press.  An Initial Screening Tool for water resource contamination due to development in the Olympic Park 2012 site, London.   Environmental Geology.

Royse, K R, Banks, V J, Marchant, A P and Quigley, S P.  2010.  Development of a ranking tool to prioritise potential hazards to groundwater in urban environments.  in Restoration and recovery : regenerating land and communities, pp. 150–158, eds. Moore, H. & Fox, H. Whittles Publishing.

Royse, K R. 2008.  Unlocking the potential of 3D geology.   Geoconnexion, 1, 11–13.

Contact

For further information contact Dr Katherine Royse or Enquiries