Mapping of Groundwater Vulnerability Index in the Alluvial Plain of Semarang City Using the Susceptibility Index MethodAdetya Arga Marjuanto, Thomas Triadi Putranto and Denny Nugroho SugiantoE3S Web Conf., 125 (2019) 01010DOI: https://doi.org/10.1051/e3sconf/201912501010