Developing Groundwater Flow Nets Using Electrical Resistivity

Flow nets provide an understanding of groundwater flow built on strong theoretical and numerical models. The simplest version is the solution to the Laplace equation and illustrates flow lines moving vertically and converging near discharge locations. In field settings, the amount of field data utilized to support these conceptual models is generally limited due to a small number of piezometers being used to structure the field flow net. Multielectrode electrical resistivity data in 2D can provide a strong addition to piezometers as it can illustrate flow lines in 2D with continuity unavailable from piezometer data. Utilizing contrasts in salinity, varying rock properties, or biological growth patterns, flow lines can be observed in systems to develop conceptual models of discharge and convection based on 2D data. These models would be difficult to impossible to build using piezometer data. Examples will be provided from porous and fractured media flow systems and contaminated sites near streams.