GNGTS 2016 - Atti del 35° Convegno Nazionale

GNGTS 2016 S essione 3.2 525 Results. Of the 10 conducted ERT/IP profiles only one ERT/IP section (ERT-4/5, Figs. 2 and 3) shall be discussed in the text as the other models provided analogous information, hence, their interpretation is similar to the ones being discussed (Figs. 2a and 2b). Contrary to the 2D resistivity image, which shows a smooth variation of resistivity with depth, the chargeability inversion model provided detailed information about: 1) the location of themain distribution channels where permeable sediments are concentrated (arrows in Fig. 2); 2) the base of these channels do not exceed 10 to 12 m below ground level; 3) low chargeability values at depths > 15 m correspond to low resistivity values which indicates permeable sediments saturated with saline groundwater. Based on these achievements, it was decided to locate the activities of AR in the SW sector of the artificial lake, where surface water, from a nearby canal, was diverted, through a pipe, to supply fresh-water directly into the lake. Fig. 2 – 2D inversion model of profile No. 4: a) resistivity and b) chargeability (induced polarization); dashed blue arrow: base of the paleo-river ridge, continuous red arrow: top of the confined aquifer. Fig. 3 – 2D resistivity inversion models of profile No. 5: a) April 2013 and b) June 2014; dashed blue arrow: base of the paleo-river ridge, continuous red arrow: top of the confined aquifer. a) b) a) b)