The solution to the forward pro-
blem uses the finite element method to compute the potential electrical response in the soil due to the current source. The final products of the process are images (tomographs) showing the distribu-
tion of resistivity in the plane be-
tween the two boreholes used. By interconnecting a network of bore-
holes, a three-dimensional repre-
sentation of the area being inves-
tigated can be developed. By ana-
lyzing the resistivity images be-
fore, during, and after a remedia-
tion process, 3-D subsurface satu-
ration changes can be inferred.

Technology Needs

Many remediation processes can interact with a contaminated area

in ways that are difficult to predict. It is advantageous to be able to monitor this interaction so that the effectiveness of the remediation process can be assessed, and pro-
cess parameters can be modified to improve the effectiveness of the remedial process. There are no alternative methods currently available to image the fluid satu-
ration distributions in two- and three-dimensional cross-sections of the subsurface. Point sampling of fluid saturation can be perform-
ed by acquiring core samples, and line measurements of fluid satura-
tion along boreholes can be per-
formed by using well-logging techniques.

Electrical resistance tomography is being developed as a tool to allow