Abstract:
Study was conducted to assess the intrinsic susceptibility of the groundwater system
using a weighted overlay – index approach known as GIS based DRASTIC model in
GIS setting in District Haripur. Haripur is a major district of Pakistan’s Hazara
division, which is famous for its agriculture. The district Haripur has a major
industrial state i.e. Hattar Industrial State which contributes to needs of whole
country. Due to the increasing population, rapid industrial growth and other human
activities the groundwater is under risk of contamination. Therefore, study was
designed to avoid the exposure of population to contaminated water by identifying
areas vulnerable to groundwater pollution. For this purpose, GIS based DRASTIC
model was applied because of its efficiency, accuracy and easy execution. The data
and information needed for assessing the vulnerability of the area was gathered from
numerous organizations and from literature survey. Using GIS, seven thematic map
layers were generated from the data gathered which are Depth to water, Net Aquifer
Recharge, Aquifer Media, Soil Media, Slope/Topography, Vadose zone and
Conductivity (Hydraulic). A weighted overlay- index analysis was carried out using
these seven layer to obtain a susceptibility map of the study area. Results of the
Weighted overlay analysis indicates a range (88-190) of DRASTIC Indices. Which
was further classified into five smaller classes i.e. Low vulnerable zone (88 - 109),
Medium vulnerable zone (110 - 129), Moderate vulnerable zone (130 - 149), high
vulnerable zone (150 - 169) and very high vulnerable zone (170 - 190). Each zone
was allotted a distinctive color on the map for easy identification. A dominant area of
965 kilometers square was covered by moderate vulnerable zone. Both medium and
high vulnerable zone covers an area of 506 kilometers square. Low vulnerable zone
covers an area of 118 kilometers square. Lastly very high vulnerable encompass the
least area i.e. 66 kilometers square. The study recommends that the susceptibility map
and assessment should be incorporated while making policies regarding land use.
