SEDL / STP / STP963-EB / STP44851S

An Application of Impedance-Computed Tomography to Subsurface Imaging of Pollution Plumes

Tamburi, A
Head, E. J. Faraci and Associates Ltd., Winnipeg, Manitoba

Roeper, U
Hydrogeologist, Saskatchewan Water Corp., Regina, Saskatchewan

Wexler, A
Professor of electrical engineering, University of Manitoba, Winnipeg, Manitoba

Pages: 15    Published: Jan 1988

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Abstract

An impedance-computed tomography (ICT) algorithm and system, known as the Electroscan system, for impedance imaging with surface measurements is described. The algorithm determines the current flow paths iteratively and employs sparse-matrix techniques. The measurement system uses a grid of electrodes over the ground surface and introduces controlled currents into a subset of electrodes in a prescribed sequence. Voltage measurements (using high-impedance equipment) are taken at passive electrodes only. Tests are reported for controlled saline plumes injected into a porous media flow field in a laboratory plume, and an uncontrolled leachate plume coming from a sanitary landfill located in floodplain alluvium.