Abstract:
In this research work, attempts were made to evaluate the intrinsic
vulnerability of shallow aquifer system of Sialkot using a well known overlay and
index method, naming DRASTIC, in a GIS environment. Sialkot is one of the
important cities of Punjab famous for its industrial, agricultural and commerce
activities. Because of increase in anthropogenic stresses, the groundwater of Sialkot
is under threat. Keeping in consideration the importance of groundwater and
difficulties lying in remediation and restoration of subsurface water reservoirs, it was
decided to take an initial step for its prevention. Due to its incorporation of all
important hydrogeological parameters and its comparatively easily implementation,
DRASTIC method was selected. Data of various types in different formats was
collected from many government, semi government and private organization. The
information required as input for all seven parameters i.e. depth to water table, net
recharge, aquifer media, soil media, topography, impact of vadose zone and hydraulic
conductivity was deducted from collected data as well as from literature surveys.
Maps were developed for each of these seven parameters individually using GIS as a
tool and a cumulative vulnerability map was developed using the Indices obtained as
a result of DRASTIC methodology. The values obtained from DRASTIC model for
the study area were between 112and 151. For ease, the DRASTIC index range was
divided into five classes i.e. 112-119 (low), 120-127 (medium), 128-135 (moderate),
136-143(high), and 144-151(very high). The area of each vulnerable zone was
delineated by different colors. The area was found dominated by medium and
moderate vulnerable zones covering area of 448 km2 and 444 km2 respectively. Area
of 81 km2 was covered by Low vulnerable zone while the high vulnerable zone
encompassed total area of 40 km2. Least area i.e.11 km2 was found in vicinity of very
high vulnerable zone.
