Interaction between sea water, groundwater flow systems, the occurrence and direction of buoyancy forces under hydrostatic conditions [A], the direction of equivalent forces under hydrodynamic conditions [B] in groundwater flow systems, and the occurrence of buoyancy reversal

It is a part of normal scientific evolution that widely accepted scientific opinions are eventually supplanted by new insights. Naturally, the change of such basic scientific insights may ruffle the feathers of established proponents of previous held opinions. This situation has now arisen with respect to some of the basic assumptions of groundwater flow calculations. It presently also occurs in the basic physics of groundwater flow, namely the conflict between the application of velocity potentials and force potentials and, in addition, the application of pressure potential force directions within such calculations. Unfortunately, based on the physics involved, the necessary changes require a rewrite of some aspects of groundwater flow programs. It is clear that such changes will not be accepted without substantial resistance. However, these changes are, nevertheless, necessary for improving the knowledge and understanding of groundwater flow and its role in environmental sciences. The present shortcomings occur in two areas: (a) our understanding of the physics of variable density flow and (b) our choices on how to program codes for groundwater flow calculations. This paper deals with the field situation of variable density flow in Florida and in particular with the Cutler site. A physics-enhanced application of force potentials is dealt by Weyer (Environ Earth Sci, 2019) submitted to Environmental Earth Sciences. A selected collection of papers dealing with the physics of groundwater flow and the application of force potentials is contained in Weyer and Ellis (Subsurface investigation and simulation of fluid flow systems by means of force potentials. Springer Publications, New York, 2019).