The development of a knowledge-based system for the preliminary investigation of contaminated land
Large areas of the UK have witnessed intense industrialisation since the industrial
revolution in the latter part of the 18th Century. Increased environmental awareness and
pressure to redevelop brown field sites, have resulted in the majority of civil engineering
projects undertaken within the UK encountering some form of contamination.
In order to collect the vast amount of information required to assess a potentially
contaminated site, a multi-stage site investigation (preliminary investigation, exploratory
and detailed investigation) is usually undertaken. The information collected during the
investigation allows the three components of the risk assessment process to be identified.
These components are the source of contamination, possible pathways for the movement
of contaminants and vulnerable targets on and off site.
A prototype knowledge-based system (ATTIC Assessment Tool for The Investigation of
Contaminated Land) has been developed to demonstrate that knowledge-based technology
can be applied to the preliminary stage of the investigation of contaminated land. ATTIC
assesses information collected during the preliminary stage of an investigation (past use,
geological map, hydrological maps etc.) and assists with the risk assessment process, with
the prediction of potential contaminants, hazards and risk to neighbouring areas.
The system has been developed, using CLIPS software. It consists of four knowledgebases
(source, pathway, target and health and safety knowledge-base), containing 1600
The knowledge within the knowledge-bases was obtained from two main sources. The
initial and main source was the technical literature. Obtaining knowledge from technical
literature involved reviewing published material, extracting relevant information and
converting information into rules suitable for the knowledge-base system. The second
source of knowledge was domain experts via a knowledge elicitation exercise. The exercise took the form of a questionnaire relating to the rules and parameters within the
A Visual Basics interface was also developed in conjunction with the knowledge-based
system, in order to allow data entry to the system. The interface uses a series of forms
relating to different components within the risk assessment process.
On completion of compiling the prototype, the system was validated against a number of
case studies. The system predicted the likely contaminants with a reasonable match to
those observed, even though the input data for the case studies was limited. The
assessment of risks to neighbouring target areas was generally in agreement with the case
study reports, matching similar risk values and directions.
In addition to the development of the prototype system, a database modelled on the
Association of Geotechnical Specialists electronic format for the transfer of ground
investigation data was also developed to store preliminary investigation information. The
data structures were implemented using Microsoft Access relational database management
system software. This allowed the database to be developed within a Microsoft Windows