Aquifer Transmissivity from Surficial Electrical Methods

ABSTRACT Recent advances in the automatic inversion of vertical electrical sounding data offer the opportunity to describe the relationship of the resistivity of a granular aquifer to its hydraulic conductivity. This type of relationship, together with aquifer thickness, can be used to determine the transmissivity of the aquifer. Vertical electrical soundings and pump‐test data along the axis of a glacial outwash aquifer in central Illinois have indicated an inverse relationship between aquifer resistivity and hydraulic conductivity. This relationship has been attributed to differences in sorting of the outwash sediments. But studies of granular aquifers deposited in other geologic environments are needed before meaningful generalizations can be made.