Directional Variography and Assessment of the Characteristics of a Contamination Source of an Aquifer: Is It a Possible Task?

The geometric characteristics of a contamination source in an aquifer are a very important element for managing, monitoring and cleaning polluted groundwater. This paper outlines a methodology to evaluate the configuration of the sources using a geostatistical approach, based on the directional variography. The proposed method has been tested using the results of three simulated cases and the values of concentration of several pollutants sampled in 36 wells. Directional experimental variograms have been plotted, for each variable, and theoretical models with their parameters (range and sill) have been fitted. The radar plots of the values of the sills explain the different typology of the sources. In particular, linear sources produce a butterfly shape radar plot, punctual sources produce a rounded shape radar plot and sparse, punctual sources produce an almost irregular shape radar plot. The analysis of directional variography can have practical usability in screening field measurements aimed at the identification of contamination sources.