Hydrogeological Research Transforms Groundwater Management in Northern Territory

Anita Doig’s hydrogeological research is helping bridge gaps in understanding how groundwater moves through tropical regolith, shaping better management for Australia’s most remote regions.

When Anita began studying geology, she was drawn to the idea of reading the Earth’s story through rocks. Each mineral, fracture, and layer hinted at an ancient environment, piecing together what the planet looked like millions of years ago. Years later, that same curiosity has taken her beneath the surface, into the complex world of hydrogeology and groundwater management. 

Doig’s journey from minerals to water was born partly from circumstance and partly from curiosity. After working in petroleum exploration, the downturn that followed COVID-19 prompted her to reassess where she wanted to direct her skills.  

“I wanted a challenge that would keep me engaged and offer some stability,” she said. “Groundwater seemed like the perfect fit. I could still use my geological background, but in a way that directly supports communities.” 

Now based in the Northern Territory with WGA, Doig recently earned the Student Water Prize at the Northern Territory Water Awards for her research at Flinders University on the hydrogeology of lateritic regolith profiles. Her work applies fundamental geological principles to a setting that remains understudied but critically important: the deeply weathered, iron-rich layers that overlie much of northern Australia. 

Understanding how tropical regolith forms

Lateritic regolith forms through intense tropical weathering, where soluble minerals are dissolved away over time, leaving behind layers of ironstone and clay. These regolith profiles can extend tens of metres below the surface. While they may look solid and impermeable, Doig found that groundwater interacts with them in surprisingly dynamic ways. 

“In the tropics, laterite is prevalent,” she said. “It covers around a quarter of the Northern Territory, particularly in the Top End, where most people live. But there was very little published data explaining how groundwater moves through this environment. I wanted to write the paper I wished already existed.” 

Her research combines case studies from around the world, supplemented by local fieldwork, to develop a conceptual model that explains how groundwater behaves in these environments. This model identifies key hydraulic parameters, such as hydraulic conductivity and storativity, and examines how they vary depending on the underlying parent rock. 

“The big surprise was how much the parent rock type influences the regolith’s properties,” Doig said. “Different rocks weather in different ways, and that affects how clays form, how fractures develop, and how water can move. It sounds simple, but no one had pulled that together into a usable model before.” 

New findings on flow and hydraulic conductivity

One of her most significant findings challenges a long-held assumption. Clays, she found, are not always impermeable barriers. When clays form in situ through tropical weathering, they can create preferential flow pathways, allowing some groundwater to move through even dense layers.  

“Hydrogeologists often think of clay as impermeable,” she said. “But in these tropical systems, the clays can actually let small amounts of water through. It is not fast, but it changes how we think about recharge and contaminant movement.” 

That insight is particularly important for the Northern Territory, where 90 per cent of water use comes from groundwater. Understanding how water travels through lateritic regolith helps improve the protection of drinking water bores and refines how recharge into deeper aquifers is modelled. 

“The top part of the regolith, the laterite cap, can be very permeable,” Doig said. “During the wet season, water can move rapidly through it. If a bore is screened in that upper section, contaminants from the surface can enter quickly. Knowing that helps us design and manage bores more safely.” 

Regional applications for hydrogeology and groundwater management 

Her findings also provide a foundation for future studies and engineering projects in other regions with similar geological conditions. Western Australia’s ancient Yilgarn Craton, parts of northern Queensland, and areas around the Gulf of Carpentaria all feature lateritic profiles that are likely behave in comparable ways. 

“Getting a reliable map of where these profiles exist is a challenge,” Doig said. “But the methods I used can apply anywhere. The key is starting with the geology. If you understand the geological setting, you can fill data gaps with much more confidence.” That focus on first principles defines Doig’s approach.  

She said working in the Northern Territory often means interpreting systems with limited data.  “You cannot always get more data,” she said. “You have to take what you have and work from there. That is where geology comes in. It gives you the framework to make sense of what is happening underground.” 

At Flinders University, Doig found mentors who helped her translate that instinct into structured research. Supervisors Associate Professor Okke Batelaan and Dr Eddie Banks guided the project’s design and encouraged her to explore new questions.  

“They let me run with my ideas but were always there with good feedback,” she said. “That support made the research so much stronger.” 

From theory to real-world application 

At WGA, Doig is applying the same thinking to consulting projects across the Territory. Her dual experience in research and industry gives her a unique perspective on the persistent gap between academic studies and applied science.  

“Both research and industry are essential, but they have different goals,” she says “Research aims to discover something new, while applied science aims to solve a problem. The two can support each other, but it helps when people understand those differences.” 

Her award-winning research is already being used by hydrogeologists, engineers, and planners working in tropical environments. For Doig, that is the most rewarding outcome.  

“When I presented at the Australian Water Association’s Water in the Bush, a few people came up afterwards and said they could use my data in their work,” she said. “That meant a lot. It showed me the project was not just a thesis to finish a degree. It is something that will actually help people working on the ground.”

A deeper understanding of Australia’s groundwater 

For someone who views rocks as pieces of ancient history, Doig’s focus has shifted to how the unseen movement of water shapes the future. Her work highlights the importance of understanding the smallest details of geology in enhancing how communities manage and protect their most vital resource. 

“There is always more to learn about groundwater,” she said. “We cannot see it, so we have to imagine it. The more we understand how it moves, the better we can look after it.” 

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