Groundwater Models to Improve the Ecology of a Saline Floodplain

Tuesday, December 5, 2017: 2:00 p.m.
Carl Purczel , South Australian Department of Environment, Water and Natural Resources, Adelaide, Australia
Tariq Laattoe, PhD , Flinders University, Bedford Park, Australia
Juliette Woods, PhD , Flinders University, School of the Environment, Adelaide, Australia
Virginia Riches , South Australian Department of Environment, Water and Natural Resources, Adelaide, Australia

Complex hydrological environments present management challenges where surface water-groundwater interactions involve interlinked processes at multiple scales. One example is Australia’s River Murray, which flows through a semi-arid landscape with highly saline groundwater. In this region, the floodplain ecology depends on freshwater provided from the main river channel, anabranches, and floodwaters. However, in the past century access to freshwater has been further limited due to river regulation, land clearance, and irrigation. A programme to improve ecosystem health at Pike Floodplain, South Australia, is evaluating management options such as environmental watering and groundwater pumping.

Due to the complicated interdependencies between processes moving water and salt within the floodplain, a series of inter-linked models have been developed to assist with management decisions. The models differ by hydrological domain, scale, and dimensionality. Together they simulate surface water, the unsaturated zone, and groundwater on regional, floodplain, and local scales. Outputs from regional models provide boundary conditions for floodplain models, which in turn provide inputs for the local scale models.

Two linked numerical groundwater models simulate floodplain processes in detail. One simulates 3D groundwater flow and solute transport across Pike Floodplain, while the other simulates density-dependent flow and transport in a cross-section through a riverine freshwater lens. The results are interpreted based on (i) ecohydrological requirements for key species of tree, and (ii) impacts on river salinity for downstream users. When combined, the models provide an integrated and interdisciplinary understanding of the hydrology and management of saline floodplains.

Carl Purczel, South Australian Department of Environment, Water and Natural Resources, Adelaide, Australia
Senior Groundwater Modeller


Tariq Laattoe, PhD, Flinders University, Bedford Park, Australia
Research Associate


Juliette Woods, PhD, Flinders University, School of the Environment, Adelaide, Australia
Dr Juliette Woods holds a joint position as the Principal Groundwater Modeller at the SA Department of Environment, Water and Natural Resources (DEWNR) and as a Research Fellow at the School of the Environment. She has worked in groundwater modelling in academia, government and industry since 1996. She was awarded a PhD in Applied Mathematics at the University of Adelaide in 2004 on the simulation of variable-density flow and solute transport, examining the numerical accuracy of different solution methods and simulating saline lakes. She was a research fellow at the Institute of Computational Engineering and Sciences at the University of Texas, Austin from 2001 to 2003, and later became Principal Groundwater Modeller at SA consulting company Australian Water Environments. She specialises in the salinity in the lower River Murray, but also works on regional-scale water resource models, surface-groundwater interaction and climate change impact studies.


Virginia Riches, South Australian Department of Environment, Water and Natural Resources, Adelaide, Australia
Senior Groundwater Modeller


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