Assessment of groundwater intrinsic vulnerability using GIS based drastic model in Sialkot, Punjab, Pakistan (T-1311) (MFN 4266)

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.