A spatial decision support system for the risk-based management of contaminated sites: The DESYRE DSS

Abstract

A GIS-based Decision Support System (DSS) called DESYRE (Decision Support sYstem for the REqualification of contaminated sites) was developed in order to address the integrated management and remediation of contaminated megasites. The DESYRE DSS supports decision makers during the main phases of a remediation process, i.e. analysis of social and economic benefits and constraints, site characterization, risk assessment, selection of best available technologies, creation of sets of technologies to be applied, analysis of residual risk and comparison of different remediation scenarios. Within the DESYRE DSS these functionalities were implemented in six interconnected modules. In the characterization module, chemical and hydrogeological data are organized in a relational database in order to support the definition of the conceptual model of the site and to provide information regarding contaminant distribution and transport through the different environmental media. Georeferenced information system tools are used for handling spatial data. The socio-economic module addresses the socio-economical constraints though a Fuzzy Logic analysis, in order to provide decision makers with a tool that compares the different land use options outlining possible scenarios linked to alternative uses of the considered site, on the basis of socio-economic considerations and local characteristics. In the pre-remediation phase, an original risk assessment methodology (risk assessment module) allows the evaluation and estimation of the spatial distribution of risks posed by contaminants in soil and groundwater, providing a risk-based zoning of the site in support of the definition of the remediation technologies plan. The latter phase is performed in the technology assessment module, where a selection of suitable technologies and the creation of different technology sets are carried out by experts supported by Multi-Criteria Decision Analysis tools. The selection takes into account both technical features and requirements of available technologies, as well as site-specific environmental conditions of the site of concern, such as chemical contamination levels and remediation objectives. A simulation of the selected technologies application is performed in the post-remediation risk assessment (residual risk assessment module) in order to provide residual risk maps with related uncertainty maps. Finally, the decision module provides a methodology for the description and comparison of alternative remediation scenarios by defining a set of aggregated indices. In this chapter, the structure and the functionalities of the software DESYRE are presented. The application of the whole system to a case study gives an explanation of the flow of information within the system and the presentation of the outputs of all the above mentioned modules. © 2009 Springer Science+Business Media, LLC.