Mixing

This chapter discusses different aspects of mixing in groundwater, and reports ap- proaches for the description and quantification of mixing in heterogeneous media. Mixing may be characterized as a process that leads to the homogenization of het- erogeneous concentration distributions, the dilution of concentrated solutions. Thus, it may help to attenuate water contamination through the decrease of maximum con- taminant concentrations. On the other hand, mixing may compromise groundwater quality through the blending of freshwater and brackish water in coastal aquifers, for example. The blending of waters with different chemical signature plays a central role for for the quantification of chemical reactions because it brings segregated species into contact.