“…Despite the complications mentioned above, the SP method continues to receive considerable interest in hydrogeology as SP data are sensitive to contaminant transport (e.g., Maineult et al, 2004Maineult et al, , 2005Revil et al, 2009), redox processes (e.g., Linde and Revil, 2007), flow in saturated (e.g., Maineult et al, 2008;Bolève et al, 2009;Jardani et al, 2007) and unsaturated porous media (e.g., Thony et al, 1997;Doussan et al, 2002;Linde et al, 2007a), flow in fractures (e.g., Wishart et al, 2006), the water table elevation (e.g., Fournier, 1989;Revil et al, 2003;Rizzo et al, 2004), or the thickness of the vadose zone (Aubert and Yéné Atangana, 1996), etc. For example, the SP method might potentially be used to estimate water fluxes in the vadose zone (Thony et al, 1997).…”