show the complete set of the geoelectrical images of the measured
and the calculated apparent resistivity pseudosections
as well as the inverted resistivity model of the ERT profiles.
The geoelectrical ERT-P1 section includes a thin layer of
alluvial deposits which covers the first third of the section.
The center part of the section is completely composed of the
alluvial deposits to more than 45 m depth. At the last third
of the section, the thickness of this layer gradually decreases
until the end of the section. The alluvial deposits overly hard
and fractured limestones rocks which constitute the bedrock
of the dam reservoir floor. Several abnormal features such
as cavities, voids, and fractures were identified, along the
ERT section, within the limestone bedrock. These features
could be considered as anomalous structures that almost
play a significant role in the leakage processes from the dam
reservoir. The ERT-P2 profile was conducted in upstream
side of the embankment of the dam. The start point of this
ERT-P2 profile is located at 20 m before the beginning of the
ERT-P1 as illustrated in Figure 2. The difference between the
start points of the two profiles is related to the accessibility
and possibility of performing the field measurements. The
general structure of the ERT-P2 section seems to be similar
to the previous ERT-P1 section from where it includes a
superficial layer of alluvial deposits and cover hard fractured
limestones layer. The depth of this section is about 20 m due
to the 2 m interelectrodes separation used. This profile was
implemented in order to obtain more details of substructures
behind the dam body. The resistivity values of the various
geological structures and anomalies features, which have
been detected by the ERT sections, are shown in Table 1.