The objective of this study was to improve the conceptualisation: of the active and potential intrusion and up-coning of saline water from the Southern Ocean and the northern saline-hypersaline lake system to the fresh groundwater resource; and increase the understanding of the aquifer geometry of the Esperance groundwater system, Western Australia. Esperance town is almost wholly reliant on groundwater for public and private water supplies, making it an extremely important resource.
Hydrochemistry sampling, aerial electromagnetic survey, down hole geophysical logging and bore hole lithological logs were used to develop a 3D conceptual hydrogeological model. The aquifer layers and groundwater contours were used to identify a potential future groundwater resource. Saline groundwater was identified through hydrochemistry sampling and the aerial electromagnetic survey. The aquifer layers and saline groundwater mapping were then used to develop a 3D layer of the saline interface.
Definition of the saline interface intruding the fresh water aquifer from the saline lake system to the north and the ocean to the south provide information about the risk of saline intrusion to the fresh water resource. New interpretation of the aquifer geometry from the development of the 3D conceptual model enabled the identification of potential future groundwater resources.
This study supports management of saline interface to ensure the fresh groundwater resource is not degraded. Additionally the study allowed for the ability to identify a potential future groundwater resource.