The western suburbs of Melbourne, Australia are underlain by a thick sequence of Cainozoic age basalt rocks (Newer Volcanics Province), which resulted from multiple phases of volcanic activity. Historically, most industrial development occurred in these suburbs, which resulted in several contaminant plumes within the area. A hydrogeological conceptual model was developed for one of the industrial sites to understand impacts of the site on groundwater and evaluate remedial options. Three main phases of lava flows were recognised under the study site. The time breaks between the phases were sufficiently long to allow for inter-phase deposits (palaeosols) to develop over extended areas. Within each of the main lava flow phases, a number of individual flows occurred leading to a complex structural profile of the basalt unit. A number of aquifers and sub-aquifers occur through the basalt unit resulting in a complex inter-relationship and lateral movement of contaminants.