The Relative Importance of Compressibility and Partial Saturation in Unconfined Groundwater Flow

The flow of water in an unconfined aquifer is viewed within the framework of the Biot theory as extended for two‐fluid flow and for conditions of a vertical displacement with constant load. Order of magnitude inspection and an objective criterion, obtained from similitude considerations, are dealt with to estimate the relative importance of the compressibility of aquifer matrix and water and that of partial saturation. Finally, these are used to reconcile some apparently contradictory findings of past studies.