Groundwater Vulnerability Assessment of Sylhet Sadar Using GIS

Groundwater has been treated as a vital water supply because of its comparatively low vulnerability to pollution compared to surface water. Due to the health and economic impacts of groundwater contamination, steps to measure groundwater vulnerability are necessary for sustainable groundwater protection and management planning. In this study, an attempt has been made to assess groundwater vulnerability using the overlay index method and to prepare a groundwater vulnerability map using Geographic Information System (GIS) of Sylhet Sadar, a northeastern region of Bangladesh. Also, for the water depth-wise vulnerability assessment, the Water index was generated to observe the effect on chemical concentration for the depth of water. By assigning weight to each pollutant map in the overlay index approach, a combined hazard map was successfully created. The combined hazard map shows a total of 16.04%, 41.36%, and 42.59% of the studied area located in a less, moderate, and severely vulnerable zone, respectively. The combined effect of the chemical concentrations of water gradually decreases with the increase in water depth. Therefore, the developed map can be used as a tool for the management to take initiatives for sustainable use of groundwater.