Vol.:(0123456789) 1 3 Earth Systems and Environment https://doi.org/10.1007/s41748-018-0051-0 ORIGINAL ARTICLE Groundwater Resource Assessment and Conceptualization in the Pilbara Region, Western Australia Rodrigo Rojas 1  · Philip Commander 2  · Don McFarlane 3,4  · Riasat Ali 5  · Warrick Dawes 3  · Olga Barron 3  · Geof Hodgson 3  · Steve Charles 3 Received: 25 January 2018 / Accepted: 8 May 2018 © Springer International Publishing AG, part of Springer Nature 2018 Abstract The Pilbara region is one of the most important mining hubs in Australia. It is also a region characterised by an extreme climate, featuring environmental assets of national signifcance, and considered a valued land by indigenous people. Given the arid conditions, surface water is scarce, shows large variability, and is an unreliable source of water for drinking and industrial/mining purposes. In such conditions, groundwater has become a strategic resource in the Pilbara region. To date, however, an integrated regional characterization and conceptualization of the occurrence of groundwater resources in this region were missing. This article addresses this gap by integrating disperse knowledge, collating available data on aquifer properties, by reviewing groundwater systems (aquifer types) present in the region and identifying their potential, and propos- ing conceptualizations for the occurrence and functioning of the groundwater systems identifed. Results show that aquifers across the Pilbara Region vary substantially and can be classifed in seven main types: coastal alluvial systems, concealed channel iron deposits, inland valley-fll aquifers, karstifed dolomites, sandstone aquifers (West Canning Basin), Permian/ Cenozoic Paleochannels, and Fractured Rock aquifers. Coastal alluvial systems show the greatest regional potential as water sources and are currently intensively utilised. Conceptually, the main recharge processes are infltration of precipitation associated with cyclonic events and the interaction with streamfows during summer season, whereas the main discharge mechanisms correspond to evapotranspiration from riverine and coastal vegetation, discharge into the Indian Ocean, and dewatering of iron-ore bodies to facilitate mining activities. Important gaps in the knowledge relate to aquifer connectivity and accurate quantifcation of recharge/discharge mechanisms. Keywords Pilbara · Regional review · Paleovalley aquifers · Channel iron deposit (CID) aquifers 1 Introduction and scope The Pilbara region in Western Australia is one of the most important mining hubs of the country. Total iron-ore pro- duction in Western Australia alone in the period 2012–2013 represented a quarter of the world’s production (AUD$56 billion) and amounted to 73% of the total value of the West Australian mineral and petroleum sales (Kneeshaw and Morris 2014). This region is also one of the World Wildlife Fund’s Global 200 Ecoregions selected for its unique and rich biodiversity, containing highly valued environmental assets intrinsically connected to groundwater systems (DoW 2010). Moreover, riverine pools sustained by groundwater discharge, groundwater-fed wetlands, and groundwater- dependent vegetation have an intrinsic cultural value to the indigenous communities inhabiting this region (Brodie et al. 2012; Alaibakhsh et al. 2017). These aspects are all * Rodrigo Rojas Rodrigo.rojas@csiro.au 1 CSIRO Land and Water, EcoSciences Precinct, 41 Boggo Rd, Dutton Park, Brisbane, QLD 4102, Australia 2 DP Commander Hydrogeology, Perth, Australia 3 CSIRO Land and Water, Private Bag No. 5. Wembley, Perth, WA 6913, Australia 4 Present Address: School of Agriculture and Environment, University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia 5 3 Landra Loop, Perth 6155, WA, Australia