Sensitivity analysis of groundwater vulnerability using DRASTIC method: A case study of National Capital Territory, Delhi, India

The assessment of groundwater vulnerability to contamination has proved to be an effective tool for water resource management. The primary objective of the present study was to evaluate the vulnerability of aquifer by using the DRASTIC method. This was followed by a secondary objective of assessing the effect of each DRASTIC parameter on the final vulnerability map by applying sensitivity analysis. DRASTIC assigned highest vulnerability to the eastern border of the NCT of Delhi and lowest values were observed in the southern part of the study area. Thereafter, sensitivity analysis was conducted to validate the scores used in DRASTIC and it was found that the theoretical weights were in agreement with effective weights. This analysis further suggested that net recharge, depth to water table and impact of vadose zone were the key factors determining vulnerability. It was concluded that the final recommendation derived from the combination of DRASTIC with senstivity analysis could be used as an efficient tool for local authorities and policy makers to manage groundwater resources.