Thesis: Quantifying changes in groundwater flow dynamics within mining-impacted groundwater systems through numerical modelling of multiple age tracers.
Quantifying groundwater flow rates and residence times is critical for the sustainable management of a groundwater system, yet remains a difficult challenge, particularly in heterogeneous geologic environments. Environmental dating tracers are increasingly used to gain an improved quantification on recharge rates, flow processes and groundwater ages within an aquifer system. Calibrating numerical groundwater models with environmental tracer data, in addition to hydrologic data, provides an opportunity to improve model uniqueness by providing an independent measure of groundwater fluxes. In this study, environmental tracer data collected from a research site within the Pilbara region in Western Australia, where open pit mines are a widespread feature of the landscape, will be employed to develop regional groundwater flow and transport models that examine the hydrological interactions between aquifers and open mine pits. The study will investigate physical and chemical controls on the mixing and distribution of multiple environmental tracers that are used as identifiers for groundwater ages reaching from tens of years to tens of thousands of years. This will provide a basis for both an improved conceptual understanding and quantification of groundwater flow rates using numerical models.
Why my research is important
The proposed research will improve the ability to be able to construct better constrained flow models of groundwater systems and develop an understanding for interpreting environmental tracer data for heterogeneous and transient aquifer systems. The project will provide new and urgently required hydrogeological understanding of open pit mines that will underpin closure planning for Pilbara mines that reach the end of their productive life. The outcomes will be used to improve predictions of the hydrology and chemistry of open mine pits and to understand the dependency of the chemical evolution on recharge rates.