ASSESSMENT OF GROUNDWATER VULNERABILITY USING DRASTIC TECHNIQUE IN NARAYANGANJ DISTRICT, BANGLADESH

The groundwater vulnerability assessment in Narayanganj, an old industrial district in Bangladesh, highlights contamination risks considering natural and anthropogenic factors. Risk areas were identified using the GIS-based DRASTIC model, which integrated hydrogeological parameters. Narayanganj is home to almost 2,409 industries which can potentially contaminate groundwater and pose substantial ecological and human health risks. Narayanganj is one of the oldest industrial districts and significantly contributes to the growth of the local economy. However, recently it has been known to create severe environmental challenges, especially groundwater contamination from industrial and agricultural sources.

The assessment indicates varying levels of contamination risk across the district. The southeastern part is classified as a very-low vulnerable zone (14.58%), showing minimal susceptibility to contamination due to favorable hydrogeological conditions and limited anthropogenic impacts. The southwestern part, a low vulnerable zone (11.52%), has a slightly higher contamination risk, suggesting minor pollution sources constrained by protective geological features. The central region, identified as a moderately vulnerable zone (20.19%), exhibits a balanced risk, reflecting a mix of natural protection and moderate human activities. The northwestern part, classified as a highly vulnerable zone (29.99%), points to significantly increased contamination risk due to unfavorable geological conditions and substantial industrial or agricultural activities. The northeastern part is a very highly vulnerable zone (23.72%), exhibiting the highest contamination risk which indicates severe impacts from industrialization; waste disposal practices; and intensive agriculture, necessitating urgent intervention and protective measures.

This assessment reveals significant spatial variability in contamination risks and the urgent need for stringent environmental regulations and sustainable practices to be in place to safeguard groundwater quality and mitigate pollution, particularly in regions undergoing rapid industrialization; urbanization; and agricultural intensification.

Keywords: GIS, DRASTIC, Hydrogeology, Groundwater Vulnerability Index (GVI)