There are certain key datasets that are required to understand all groundwater systems. These include hydraulic conductivity, transmissivity and storage coefficients, hydraulic head distributions (including head gradients between aquifer layers, groundwater flow directions and velocities, rates and locations of recharge and discharge, and baseline salinity and water chemistry. Yet some of these characteristics can be difficult to quantify, particularly in areas of complex geology where rocks are folded and faulted rocks and flow can predominantly occur through fractures, or where wells are uncased or have long intake zones.

NCGRT researchers have worked on groundwater characterisation projects in most Australian States and Territories, in environments from the wet topics to the arid zone. As well as studies in the large sedimentary aquifers of the Great Artesian Basin and the Murray Basin, we have worked on highly complex groundwater systems associated with fractured and folded hard rocks. This has included major projects to understand the influence of faults and dykes on groundwater flow in both urban and mining environments.

NCGRT researchers have expertise in most areas of aquifer characterisation, including the use of environmental tracers to identify sources of groundwater recharge and quantify flow rates; artificial tracers for identifying preferential flowpaths in heterogeneous or fractured geological environments; and surface and downhole geophysics for understanding heterogeneity and mapping flow zones.

These ecosystems can be affected when groundwater extraction causes a decline in the water table.

NCGRT researchers have been working in field sites throughout Australia to examine water table depths accessed by vegetation, the magnitude of water table drawdown, and its influence on vegetation stress signs, and mortality. We have also been studying spring ecosystems in South Australia, Northern Territory and Queensland, and assessing sources of water for springflow and potential impacts of groundwater extraction, and mapping sites of submarine groundwater discharge to the South Australian coastline and to coastal lagoons in southern Europe. Our researchers are also examining groundwater management tools and how these can be used to protect GDEs.

Our researchers have expertise in measurement and interpretation of leaf water potentials for assessing vegetation health and access to water sources; isotope methods for assessing sources of water used by trees and sources of groundwater flow to springs and surface waters; sapflow, Bowen Ration and eddy covariance systems for measuring plant water use and regional evapotranspiration; and analysis of bore hydrographs for measuring tree water use in shallow water table areas.

Managed aquifer recharge using stormwater and treated wastewater is used to augment water supplies in major urban areas, including Adelaide and Perth. It is also used in rural areas to provide water for irrigation and in mining environments.

NCGRT researchers have been involved with design and evaluation of major urban MAR projects, including assessment of physical, chemical and biological clogging and transport of microorganisms and the risk of metal mobilisation through injection of oxidised source waters into reduced aquifers. In rural areas, we have been working in NSW and Queensland, examining the potential for MAR to increase water supplies for irrigated agriculture. We have also been examining the potential for MAR to improve mine closure outcomes, by reinjecting water that is pumped to dewater mine pits and is surplus to mine operations. The injected water will increase the rate of water table recovery after mining ceases and cause the pit lake to fill more rapidly thereby reducing the potential for oxidisation of minerals in pit walls and improving water quality.

NCGRT has expertise in linking groundwater flow and geochemical models in MAR context. We also have expertise in laboratory studies of transport of viruses and bacteria, and … (Still drafting)

Mining often takes place in areas of complex hydrogeology, and there is a strong financial and environmental imperative to understand groundwater flow and geochemical processes.

NCGRT researchers have been working with mining companies for more than 10 years to understand the groundwater resources of the eastern Pilbara region. Because many of the open pit iron ore mines extend below the natural position of the water table, groundwater surrounding the mines is extracted to provide dry mining conditions. Significant volumes of surplus groundwater are being pumped every year, and some of this is discharged into rivers and creeks. NCGRT projects include examining the fate of surplus dewater that is discharged to the environment, and using geochemical approaches to estimate the proportion of discharge water that travels back to the pit necessitating additional dewatering. We have also been modelling the rate of pit lake development post mine-closure and the interaction between pit lakes and the groundwater system. We are also examining the potential of managed aquifer recharge to improve mine closure outcomes and assist the recovery of groundwater levels and rapid filling of pit voids post mine closure. These projects are also examining the influence of faults and dykes on groundwater flow, and their implications for mine dewatering and water table recovery post mine closure. NCGRT also has significant expertise in geochemical processes that can lead to contamination of groundwater and surface water. Our researchers are examining both the processes controlling acid mine drainage, and contamination remediation options.

Groundwater modelling is the key tool used for predicting future groundwater levels and water chemistry. Our NCGRT researchers are at the forefront of developments and application of modelling technologies and have led the development of the Australian Groundwater Modelling Guidelines.

Our work centers around using modelling tools to improve the understanding and management of complex hydrogeological and geochemical systems. Many of our projects involve the integration of mathematical models in conjunction with either field work or laboratory investigations to facilitate an integral approach to many of today’s urgent water resources issues. We have considerable expertise in modelling of groundwater systems, including the interaction between rivers, lakes and groundwater; flow and transport through the vadose zone; modelling of seawater intrusion in coastal environments, and modelling of chemical reactions and geochemical processes. We also have expertise in parameter estimation, uncertainty analysis of model predictions with NCGRT researchers actively involved in the Groundwater Modelling Decision Support Initiative (GMDSI). NCGRT researchers are also frequently engaged as reviewers of developed groundwater models for a variety of clients.

NCGRT researchers are actively engaged in a diverse range of groundwater contamination studies. This includes work on groundwater salinity and its effect on usability of water resources; on geogenic contaminants such as arsenic and fluoride, which may be elevated due to natural geochemical interactions between groundwater and rock formations; on mining impacts on water quality, including acrid mine generation and pit lake water chemistry as well as projects on urban contamination, including emerging contaminants in groundwaters such as perfluoroalkyl and polyfluoroalkyl substances (PFAS).

Our work frequently involves the use of geochemical modelling and/or reactive transport modelling to quantify the mobility of pollutants (e.g. nitrate, arsenic, PFAS); to predict water quality changes during managed aquifer recharge or during passage through wetlands; to evaluate remediation options and/or to quantify feedback mechanisms between chemical reactions and physical flow in aquifer systems.

By integrating and quantifying both physical as well as geochemical aspects of complex natural aquifer systems, NCGRT researchers are facilitating an integral approach to managing and mitigating potential risks posed by pollutants.

Groundwater supplies almost one third of all water used for irrigation in Australia, but increasing future demand and climate change are likely to put groundwater systems under increasing pressure.

NCGRT researchers have expertise in estimation of sustainable yields of groundwater systems and estimating recharge beneath both dryland and irrigated agriculture. We are working with industry to examine the potential for improved water management, and to quantify and mitigate risks of groundwater contamination from agricultural developments, including nitrate contamination and land and river salinisation. NCGRT researchers have also been at the forefront of projects in the Murray Basin to study the effect of irrigation adjacent to the Murray River on river salinity and examining the potential for irrigation developments in central Australia to lead to salinisation of underlying groundwater resources.

We have also been undertaking studies in NSW, Queensland and Victoria to evaluate the potential of managed aquifer recharge (MAR) in agriculture catchments to provide additional water supplies and take pressure of stressed groundwater systems.