Radiocarbon dating of groundwater in tertiary sediments of the Eastern Murray basin

Abstract

The Tertiary sediments located in the eastern part of the Murray Basin contain one of the most important low salinity groundwater resources in New South Wales. This has been especially apparent during recent years as increasing demands on the resource are being made by irrigators and municipal water suppliers. It is therefore imperative that the hydrogeoloical environment in which the groundwater occurs be thoroughly understood to allow adequate management of the resource. As part of a systematic exploration of the Tertiary aquifer systems, the Australian Atomic Energy Commission, in association with the Water Resources Commission of New South Wales, carried out a radiocarbon dating project on 37 groundwater samples from bores screened in these unconsolidated sediments. The results indicate water ages in the range 'modern' to 15 800 years. Groundwater recharge areas are indicated and rates of groundwater recharge and movement determined. The latter shows close correlation with velocity values quantitatively determined by Darcy's law.