Estimation of intrinsic vulnerability of shallow groundwater in Jombang District, Jombang Regency, East Java, Indonesia based on Aquifer Vulnerability Index

The level of safety of groundwater to pollution hazards can be identified based on the level of vulnerability of the groundwater to pollution. Determination of groundwater vulnerability intrinsically can be done by using the Aquifer Vulnerability Index (AVI) method based on two physical parameters i.e. the thickness of each layer above the uppermost of saturated aquifer surface and the estimated hydraulic conductivity of each of these sedimentary layers. The objective of this study was to determine the level of groundwater vulnerability intrinsically based on the vulnerability index value of aquifers by using the AVI method. This study was conducted based on sample of 25 dug wells scattered in the Jombang District of Jombang Regency, East Java, Indonesia. Based on the results of the analysis using the AVI method, it can be stated that the hydraulic resistance logarithm in the study area were found to be in the range from -5.22 to 3.84 with the intrinsic vulnerability of groundwater to pollution hazards from extremely high to low. (paper)