Environmental Impact Analysis:
Scoping, Screening, Assessment
EIAxpert: rule-based screening-level EIA

EIAxpert is an interactive, rule-based expert system for environmental impact assessment. It is designed for a screening level assessment of development projects at a pre-feasibility stage.

The system can operate with a minimum of data and information about the project, its alternatives, and the environmental setting by drawing on a generic knowledge and rule base as well as a regional geographical information system and a set of data bases.

EIAxpert is a generic, completely data driven assessment tool that can easily be configured for a broad range of application domains and regions.

The original implementation was designed for the Lower Mekong Basin (commissioned by the Mekong Secretariat) for the assessment of water resources development projects, and uses checklists and assessment rules derived from the Asian Development Banks Environmental Guideline Series (Fedra et al, 1991). A related river basin management information system, that can be configured as a framework for EIAxpert is WaterWare.

The generic EIAxpert system includes:

  • A data base and interactive editor tools for water resources development projects, that allow to maintain (and compare) multiple alternatives for each project;

  • A two-layer, hierarchical geographical information system, covering the entire river basin as well as the areas immediately affected by individual projects. The GIS uses both vector data and satellite imagery;

  • A set of data bases, eg., on meteorology, hydrography, or water quality observations, but also environmental technologies such as waste water treatment;

  • A knowledge base with checklists, rules, background information and guidelines and instructions for the analyst;

  • The inference engine, that guides the analyst through a projects assessment in a simple menu-driven dialogue;

  • and a Summary Report generator, that summarizes and evaluates the impact assessment and provides a hardcopy report.

Through the rules of the expert system, external models (for batch execution or interactive, in this case again with a fully web-based interface and thus easily integrated) can be invoked as part of the inference procedure. Models can be used to calculate impacts of reduced flow, waste water discharges, land use changes, etc., or to estimate project parameters such as irrigation water demand, or changes to the groundwater table.

The Knowledge Base:
The expert system uses IF .... THEN rules for a qualitative assessment of potential environmental problems. The knowledge base of the Mekong system contains well above 1000 nested rules. The rule base is linked to a hypertext system that provides explanations of terms and concepts, background information, and instructions for the user.

A knowledge base browser allows inspection of individual rules, and a recursive explain function WHY can trace the symbolic reasoning of the system step by step.

EIAxpert is designed for incremental assessments; with more information becoming available during the various project preparation stages, a more refined analysis becomes possible. Different users can contribute to a projects assessment, and several versions of a project and project alternatives can be maintained simultaneously.

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