Extending Darcy's concept of ground-water motion

The tensor nature of permeability and its effect in a given ground-water flow regime have been acknowledged by various investigators. The effect on the spread of a given dissolved substance can be qualitatively discussed on the basis of the tensor characteristic of the permeability coefficient. The correlation between the dispersion coefficient and the tensor characteristic is one possible means of defining the flow regime within a given aquifer. Because of the large-scale changes in magnitude and direction of the tensor components of permeability, the concept of a mean line of dispersion may produce a more significant statement on the characteristics of flow than does the present concept of hydraulic potential and the streamline.