ARC Linkage - River Murray Freshwater Lenses

Collaborating Organisations: Flinders University, Monash University, SA Department of Environment and Water

Researchers: Prof Adrian Werner CI, Prof Ian Cartwright CI, and Dr. Graham Green PI

This project brought together groundwater researchers from Flinders University, Monash University and the Department for Environment and Water to study fresh groundwater in otherwise salty aquifers within the floodplains of the River Murray. Field measurements, computer modelling and laboratory sand tank experiments were used to unravel the factors controlling 'lenses' of fresh groundwater abutting the river that are thought to sustain fragile and often degraded ecosystems. New tools were developed to rapidly determine the extent of these lenses and guide management. The complexities of fresh groundwater floating on salty water within Murray floodplains were reproduced in laboratory experiments, scrutinising lens physics for the first time.

The project has contributed to substantially improving the management of rivers in semi-arid zones worldwide. It provides a tool for understanding the relative importance of natural conditions and human actions on freshwater lenses, enabling targeted monitoring plans, risk assessments, and successful management strategies. The selected field sites were the critically endangered River Murray and associated wetlands, floodplains, and groundwater systems from Wentworth to the Murray Mouth.