Hydrogeophysical Investigations Using DC Resistivity …
273
Fig. 10 Geoelectrical cross-sections C-C’ and D-D’ in the N-S direction. For location see Fig. 7
a total dissolved salt (TDS) around 135 to 300 mg/l. The thickness of this layer
increases towards the west at soundings no. 34 and 38 reaches the maximum values
of 117 and 122 m, respectively while its minimum thickness (93 m) is recorded at
sounding no 15. Also, some normal faults are inferred between the shallowest zone
of the Taref aquifer and the underlying aquifers. These faults control the occurrence
and recharge system of groundwater in the area. The optimum conditions for drilling
wells of good water quality and reasonable depths are located in the extreme western
portions of the sections. On the other hand, the N-S profiles (Fig. 10) are dominated
by brackish groundwater zones towards the central and southern parts as shown by the
lower resistivity values at soundings 8, 10 and 17 (15, 28 and 11 .m, respectively)
and can be interpreted as a result of infiltration of saline water from irrigation activities
273
Fig. 10 Geoelectrical cross-sections C-C’ and D-D’ in the N-S direction. For location see Fig. 7
a total dissolved salt (TDS) around 135 to 300 mg/l. The thickness of this layer
increases towards the west at soundings no. 34 and 38 reaches the maximum values
of 117 and 122 m, respectively while its minimum thickness (93 m) is recorded at
sounding no 15. Also, some normal faults are inferred between the shallowest zone
of the Taref aquifer and the underlying aquifers. These faults control the occurrence
and recharge system of groundwater in the area. The optimum conditions for drilling
wells of good water quality and reasonable depths are located in the extreme western
portions of the sections. On the other hand, the N-S profiles (Fig. 10) are dominated
by brackish groundwater zones towards the central and southern parts as shown by the
lower resistivity values at soundings 8, 10 and 17 (15, 28 and 11 .m, respectively)
and can be interpreted as a result of infiltration of saline water from irrigation activities