Hydrogeology

The basic theory and concepts of hydrogeology will be discussed in this chapter. Sections 4.2–4 will deal primarily with the definitions and equations of ground-water flow in the saturated and unsaturated zone. Section 4.5 will examine the geology of hydrogeology, and is especially important because the movement of fluid through the subsurface and the equations that describe this movement are dictated by the geology of the subsurface materials. Geologic characteristics such as permeability, porosity, anisotropy, and homogeneity, are functions not only of the type of rock or soil material, but also of the depositional environment, diagenesis, and tectonic processes such as folding and faulting that may have occurred after deposition. This information is needed to build a geologic framework in which hydrogeologic principles may be applied before ground-water flow and contaminant transport can be evaluated.