Using remotely sensed evapotranspiration to identify groundwater discharge areas in northern Australia

Study region The study region is the catchments that overlie, and are adjacent to, the Cambrian Limestone Aquifer in northern Australia. Study focus The Cambrian Limestone Aquifer is the largest water resource in the Northern Territory, and the only reliable water resource in the region. Water resources development has historically only occurred in the Daly and Roper catchments, but there are now increasing development pressures on the water resources in other catchments. The groundwater discharge through springs is culturally, ecologically and economically important and protected through water allocation plans. The springs in the Daly and Roper have been well characterised but the other sparsely populated, undeveloped catchments, have not had the same level of investigation. This study aims to use remotely sensed evapotranspiration to identify groundwater discharge areas across ∼750,000 km 2 of northern Australia. New hydrological insights for the region The current conceptualisation of the CLA has discharge occurring in the Roper, Daly and Nicholson catchments. This study has identified small groundwater discharge locations at the basin margins in the Victoria, Limmen Bight, McArthur, Robinson and Calvert catchments. These additional groundwater discharge locations need to be assessed for their source aquifer before development occurs in these regions to ensure the protection of their cultural, ecological and economic values.