ABSTRACT
In order to understand the spatial and temporal variability of groundwater quality, it is imperative to have a perception of the groundwater flowpath and the travel time from the site of infiltration to the sampling point. Along the flowline, chemicals may become sorbed which retards their transport compared to the velocity of water. Furthermore, physical processes like diffusion and dispersion cause mixing and smoothen concentration changes. To achieve a conceptual understanding of the processes, we will in this chapter focus on hand calculations that provide insight in flowlines and residence times, in retardation, and in diffusion and dispersion.
