Abstract:
Numerous groundwater management concerns have arisen as a result of excessive
groundwater use. The yearly pumpage has already exceeded the annual safe yields in
certain regions, which has caused the water table to drop. Due to continuing, intensive
groundwater pumping in Punjab, Pakistan, the quality of the groundwater is declining.
Vertical Electrical Soundings (VES) were used to conduct geoelectrical resistivity
survey investigations at District Okara, Punjab, Pakistan. The tool used for the
collection of data was ABEM Terrameter SAS 4000, Sweden. To evaluate the spatial
inconsistency of soil and groundwater quality Schlumberger array was used. Overall
field data was collected from 28 different locations of the study area. The computer
software “Interpex IX1D” was used for the interpretation of field apparent resistivity to
true resistivity values and corresponding thickness of sub surface layers. Geographic
Information System (GIS) was used for the mapping of groundwater quality at 50 m
intervals by employing Inverse Distance Weightage (IDW) interpolation technique.
The results shows that the uppermost layer of 0 – 50m comprised of maximum potential
of fresh and useable quality water. In addition, as we increase the investigation depth
and move away from the river i.e. center of district Okara, the resistivity values shows
a decreasing trend reflecting the saline groundwater.
