ABSTRACT
This chapter addresses the hydrodynamic processes that affect the subsurface transport and fate of fluids and dissolved constituents. Hydrodynamic processes include those phenomena that result from the physical movement of fluids in the subsurface. To understand the basic hydrodynamic processes affecting subsurface transport and fate, several subtleties related to ground water flow and Darcy's Law need to be highlighted. The influence of hydraulic conductivity on contaminant transport is evident in Darcy's Law. Spatial variability in hydraulic conductivity is a critical factor controlling mass transport. Similar to many of the ground water flow equations, several forms of the solute transport equation can be found in the literature. Subsurface contaminant transport processes are interesting in that they can be approached and analyzed, and they manifest themselves, at various scales. R. N Bhattacharya and V. J. K. Gupta give a good comparative description of three different space-time scales regarding dispersion during solute transport. They are kinetic scale, microscopic scale and Darcy scale.
