Delving deeper – groundwater modelling with AGE

The work of groundwater modellers is an increasingly important field in a world finally waking up to the environmental implications of a planet providing natural resources for 7 billion plus inhabitants.

In Australia, almost 17% of available water resources come from groundwater. So, understanding the environmental impact of that use is vital in ensuring access and usage of groundwater resources is safe, compliant, respectful of all stakeholders and considerate of the future.

For a range of sectors, from resource mining to agricultural and infrastructure projects, having an intimate understanding of groundwater-related operational issues is critical in ensuring safe practices and avoiding unforeseen risk. At Australasian Groundwater and Environmental (AGE) Consultants, our highly skilled team delivers robust and rigorously researched end-to-end groundwater and environmental advice to help clients understand the complexities of the underground environment whilst ensuring compliance with all regulations.

Groundwater modelling is a powerful methodical tool that creates computer simulations of underground water systems and helps predict impacts from mining, infrastructure and agricultural projects on aquifer conditions, vegetation, and ecosystems. These groundwater model predictions ultimately underline project and environmental risks relating to groundwater.

Developing a strong relationship with the client is the first step in understanding their specific needs and discussing areas of legal, environmental, or cultural significance which might impact the modelling. Data is then collected from the client and government databases. Armed with scientific and technical expertise, our groundwater modellers then begin the process of collecting and inputting data to develop predictive models:

  • A conceptual model provides a simple representation of the natural system, describing the direction of groundwater flow and the relationships between groundwater, climate, surface water and features of cultural and ecological significance.
  • Analytical modelling can be used to assess the impacts of smaller projects on water resources. If risks and uncertainties are low, these models may suffice in providing all necessary information.
  • Numerical models are expected for significant projects and include many parameters that are needed to replicate the groundwater system accurately. Calibrating the model facilitates the best match between the observed data and the model predictions.

Each member of our team of highly trained hydrogeologists and engineers brings not only a thorough understanding of the regulatory and legislative groundwater requirements to their modelling but is able to apply specialised calibration and uncertainty analysis methodology. When the modelling begins, the modeller takes the conceptual understanding of the groundwater system and uses it to first build the model structure, before assigning hundreds of parameters to the software. Calibration allows for fine tuning to optimise model predictions, and uncertainty analysis provides a range of potential impacts on the groundwater system. The calibrated model predictions and uncertainty analysis are used together when the project is reviewed and then assessed by the regulator.

End to end, large projects can take up to a year, while smaller projects may be delivered within a couple of months. Comprehensive groundwater modelling provides a deeper understanding of a groundwater system, facilitates the preparation of impact predictions, and quantifies uncertainty around the model predictions. This comprehensive analysis of the system benefits both the client and the regulator.

Environmental Impact Statements are an integral part of operations in multiple sectors, and governments require that they be taken seriously, not treated as a mere ‘tick-box’ exercise. Our team at AGE are proud to conduct groundwater modelling with rigour and integrity, not only for the success of projects but for the future of our environment.

Discover more > https://ageconsultants.com.au/our-services/groundwater-modelling/

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Delving deeper – groundwater modelling with AGE

The work of groundwater modellers is an increasingly important field in a world finally waking up to the environmental implications of a planet providing natural resources for 7 billion plus inhabitants. In Australia, almost 17% of available water resources come from groundwater. So, understanding the environmental impact of that use is vital in ensuring access and usage of groundwater resources is safe, compliant, respectful of all stakeholders and considerate of the future.

Read more

From China to the Cape: Australia’s specialist groundwater consultancy welcomes Dr Haili Jia

Experienced hydrogeologist and numerical modeller Dr Haili Jia joins AGE Consultants, helping expand our breadth of knowledge and expertise. As both a researcher and scientist working on commercial groundwater projects, Dr Jia brings both field and academic experience to her new role, as she acclimatises to AGE and a new life in Australia with her husband and two children.

Read more

Improved modelling of voids for mine closure planning

To date, mine closure recovery simulations have been too simplistic to accurately predict the long-term behaviour of pit lakes and voids. At AGE, our innovative approach and integration of granular data from various sources is building more reliable models. Queensland’s mine rehabilitation and closure reforms ensure that almost all active and closed open cut mines require a Progressive Rehabilitation and Closure Plan (PRCP). Until recently, void modelling has been quite unsophisticated, with annual average stresses, such as rainfall, used for modelling.

Read more

From China to the Cape: Australia’s specialist groundwater consultancy welcomes Dr Haili Jia

Experienced hydrogeologist and numerical modeller Dr Haili Jia joins AGE Consultants, helping expand our breadth of knowledge and expertise.

As both a researcher and scientist working on commercial groundwater projects, Dr Jia brings both field and academic experience to her new role, as she acclimatises to AGE and a new life in Australia with her husband and two children. With a keen interest in groundwater evaluation, numerical modelling, GIS, data analysis and programming, and as a former member of the Council for Geoscience in South Africa, her skills complement and bolster the strength of our multidisciplinary team.

Relocating to Australia via China and South Africa, Haili completed her PhD in Hydrogeology at the University of the Western Cape in 2007 and has accumulated over fourteen years of experience, including recharge estimation on the Table Mountain aquifer. Her involvement in long-term mine water management programs in the Witwatersrand Gold Basin, and responsibility for numerical modelling of the flooded basins there saw her successfully respond to complicated hydrogeological conditions. Dr Jia is keen to face some Australian challenges and bring that prior knowledge and experience to assist AGE clients in her new role.

With government legislation ensuring environmental sustainability is at the forefront of industry thinking, and robust groundwater investigations critical in determining project outcomes, the skills of Dr Jia and the AGE team will undoubtedly be in high demand.

Transitioning with her family to a new country and a new work environment has been challenging, but Haili has found the AGE team to be incredibly supportive and she cannot commend the collaborative work environment highly enough. Having previously been expected to work in isolation on some projects, she finds sharing collective knowledge and ideas with her AGE colleagues invigorating.

The team at AGE is thrilled to be working with and learning from Dr Jia’s diverse experience.

Dr Haili Jia’s husband Dr Lixiang Lin is also a highly experienced hydrogeologist. Some of their research papers and publications can be accessed via the links below:

The development of GIS-PMWIN and its application for mine-water modelling in the Far West Rand, South Africa

A typical groundwater storage assessment in the Tugela area, South Africa

Optimisation of representative elementary area (REA) for the preparation of lineament density map of fractured rock aquifer

Latest posts

Read more of our news, insights and updates from the team.

View all

Delving deeper – groundwater modelling with AGE

The work of groundwater modellers is an increasingly important field in a world finally waking up to the environmental implications of a planet providing natural resources for 7 billion plus inhabitants. In Australia, almost 17% of available water resources come from groundwater. So, understanding the environmental impact of that use is vital in ensuring access and usage of groundwater resources is safe, compliant, respectful of all stakeholders and considerate of the future.

Read more

From China to the Cape: Australia’s specialist groundwater consultancy welcomes Dr Haili Jia

Experienced hydrogeologist and numerical modeller Dr Haili Jia joins AGE Consultants, helping expand our breadth of knowledge and expertise. As both a researcher and scientist working on commercial groundwater projects, Dr Jia brings both field and academic experience to her new role, as she acclimatises to AGE and a new life in Australia with her husband and two children.

Read more

Improved modelling of voids for mine closure planning

To date, mine closure recovery simulations have been too simplistic to accurately predict the long-term behaviour of pit lakes and voids. At AGE, our innovative approach and integration of granular data from various sources is building more reliable models. Queensland’s mine rehabilitation and closure reforms ensure that almost all active and closed open cut mines require a Progressive Rehabilitation and Closure Plan (PRCP). Until recently, void modelling has been quite unsophisticated, with annual average stresses, such as rainfall, used for modelling.

Read more

Improved modelling of voids for mine closure planning

To date, mine closure recovery simulations have been too simplistic to accurately predict the long-term behaviour of pit lakes and voids. At AGE, our innovative approach and integration of granular data from various sources is building more reliable models.

Queensland’s mine rehabilitation and closure reforms ensure that almost all active and closed open cut mines require a Progressive Rehabilitation and Closure Plan (PRCP). Until recently, void modelling has been quite unsophisticated, with annual average stresses, such as rainfall, used for modelling. Traditionally a number of discrete methods are used to model surface water, groundwater and contaminant transport. These systems do not communicate or align closely. This compromises the reliability of recovery predictions.

Traditionally, these predictions were calculated in isolation, with no sophisticated feedback loops between climate, surface water interactions, the final landform, and surrounding groundwater systems. Data needed to be simplified to integrate system predictions, which limited our ability to predict how stresses interacted. Furthermore, the ability to view the true cumulative effects was inadequate.

Neil Manewell, Technical Modelling Lead at AGE Consultants, describes this method as ‘problematic’, especially when there are significant volumes of dry coal seams and spoils, with varied permeability, that surface water models often misrepresent. This can have the effect of overstating future water levels in the pit lake and surrounding strata and can speed up the expected recovery of the groundwater system and pit lake.

A 3D groundwater model is the best way to assess the complex nature of groundwater flows patterns and contaminant transport. At AGE, when simulating post-mining recovery, we have devised an alternative method to simulate pit lake recovery. Using the 3D groundwater model, so that groundwater can be accurately simulated, a ‘reservoir node’ is built into the pit void. The reservoir node is where information is integrated from the surface water model. The inflows and outflows prescribed to the reservoir node are calculated from other analytical models, such as AWBM or SWAT+. We can also make use of particle tracking (mp3du), basic contaminant transport (BCT), and reactive-active transport simulators (BCT + PHT-USG).

By integrating surface water, groundwater and possibly geochemical data onto one platform, the data and outputs can be managed consistently over time. Detailed daily representations of climate (rainfall, surface water, and evaporation) and the impacts of short, sharp incidents can be simulated as a system. Landform disturbances or a major climatic event, are automatically updated throughout the model. High-level chemical reaction modelling can be embedded to manage the risks of salinity and other contaminant interactions with the aquifer. These models could be used to calculate the probability of various risks to groundwater dependent assets, prompting proactive redesigns of mine plans to avoid future impacts and ensure compliance.

When the data is integrated, the risk of errors is reduced, saving time in meeting PRCP reporting requirements. AGE has used this modelling in feasibility studies of various landform configurations, and future applications could include comparative analysis of various closure and rehabilitation options.

We have applied this new modelling method to models of the Glendell, Mt Owen, Hunter Valley and Liddell operations.  We successfully implemented a reservoir node into a MODFLOW USG model, and particle tracking for several different scenarios was simulated to confirm contaminants would not migrate to local groundwater dependent assets.

Future modelling will work on increasingly complex systems and simulate the interactions between systems with live monitoring data. We will continue to work at the forefront of this technology to improve the information and analysis required for optimised decisions and planning.

Ultimately, this new method of integrated water level predictions in mine voids, surrounding groundwater systems and connected streams helps our industry improve rehabilitation outcomes, leading to better financial assurance after the closure of a mine. The reservoir node approach maintains consistency with the surface water modelling, enabling reliable predictions of groundwater drawdown, thus improving governance and planning decisions.

Latest posts

Read more of our news, insights and updates from the team.

View all

Delving deeper – groundwater modelling with AGE

The work of groundwater modellers is an increasingly important field in a world finally waking up to the environmental implications of a planet providing natural resources for 7 billion plus inhabitants. In Australia, almost 17% of available water resources come from groundwater. So, understanding the environmental impact of that use is vital in ensuring access and usage of groundwater resources is safe, compliant, respectful of all stakeholders and considerate of the future.

Read more

From China to the Cape: Australia’s specialist groundwater consultancy welcomes Dr Haili Jia

Experienced hydrogeologist and numerical modeller Dr Haili Jia joins AGE Consultants, helping expand our breadth of knowledge and expertise. As both a researcher and scientist working on commercial groundwater projects, Dr Jia brings both field and academic experience to her new role, as she acclimatises to AGE and a new life in Australia with her husband and two children.

Read more

Improved modelling of voids for mine closure planning

To date, mine closure recovery simulations have been too simplistic to accurately predict the long-term behaviour of pit lakes and voids. At AGE, our innovative approach and integration of granular data from various sources is building more reliable models. Queensland’s mine rehabilitation and closure reforms ensure that almost all active and closed open cut mines require a Progressive Rehabilitation and Closure Plan (PRCP). Until recently, void modelling has been quite unsophisticated, with annual average stresses, such as rainfall, used for modelling.

Read more