Environmental Remediation and Restoration: Hydrological and Geophysical Processing Methods

Remediation and restoration of sites contaminated by hazardous organic chemicals has become an increasingly critical problem as the dissolution and transport of these compounds by groundwater threatens many aquifers providing drinking water to populations worldwide. The characterization of these sites prior to remediation and the monitoring of the restoration progress rely on the processing of data provided by geophysical sensing technology and direct groundwater measurements collected over sparsely distributed wells. Many of the tools and techniques developed within the context of geophysical signal processing (GSP) have a role to play in this domain. In this article, we discuss environmental restoration and remediation (ERR) problems and review the state of the art in the modeling and inversion of geoelectrical and groundwater concentration data, including a discussion of recent work in the area of joint inversion. While methods such as electrical impedance (EI) tomography are well known within the GSP community, the models and inverse methods associated with subsurface flow and transport of contaminants represent a relatively new area. We conclude with an overview of opportunities for collaborative activities among signal processors, geophysicists, and environmental engineers.