Lloyd R Townley

• BE MS PhD
• Nanjing Tech University

Many papers show that water, conservative solute, stable isotope and radon balances can be applied to the study of surface water – groundwater interaction. When undertaken simultaneously, such analysis provides an even more powerful method for estimating groundwater inflows and outflows, i.e. the exchange fluxes that for most people are hardest...

Our society is transitioning quickly into the digital age, spurred by the development of cheap and new sensing technology, breakthroughs in computing, and the development of efficient algorithms for optimization. This transition is also visible in the field of wastewater treatment and is driving new model developments, especially by exploiting the...

This dataset contains six Mathematica notebooks (.nb files, Version 13.3.0) and six printouts of those notebooks (.pdf files) corresponding to Examples 1 to 6 in a paper published by Townley (1995). An early version of Mathematica was used during preparation of the original paper. In 2021, starting with a set of old .ma files, the six solutions we...

Even though the original paper (Townley, 1995) contained no significant mathematical errors, this Addendum has been prepared (i) to give readers access to 3D graphics that are of much higher quality than are available online, (ii) to provide access to Mathematica notebook files in both .nb and .pdf formats, that demonstrate the use of Mathematica t...

Digital Twins (DTs) are on the rise as innovative, powerful technologies to harness the power of digitalisation in the WRRF sector. The lack of consensus and understanding when it comes to the definition, perceived benefits and technological needs of DTs is hampering their widespread development and application. Transitioning from traditional WRRF...

Recent studies of lake-aquifer dynamics have highlighted the diverse nature of groundwater flow regimes that may exist under the influence of nearby surface water bodies. For water resource managers, three-dimensional systems are often important. This work extends previous studies to descriptions of the effects on steady aquifer flows of fully thre...

New simulation software has been developed at the Nanjing University Yixing Environmental Research Institute, for use in training, and to facilitate the use of simulation software for improving the performance of water resource recovery facilities (WRRFs) in China.Computer simulation of WRRFs (formerly known as wastewater treatment plants or WTTPs)...

New simulation software has been developed at the Nanjing University Yixing Environmental Research Institute, for use in training, and to facilitate the use of simulation software for improving the performance of water resource recovery facilities (WRRFs) in China. Computer simulation of WRRFs (formerly known as wastewater treatment plants or WTTPs...

A key objective of water policy is to achieve equitable sharing of water resources between competing uses – both now and in the future. Predictive groundwater flow modelling currently provides the only means by which potential implications of current water management practices can be forecast and the effectiveness of management options assessed. Th...

CSG is fundamentally different from shale gas and tight gas, because water must be removed to reduce pressures until CSG is released by desorption. It is important to understand the differences, and at the same time to recognise challenges and risks, whether real or perceived. The emergence of a coal seam gas (CSG) industry in Australia has been a...

Groundwater modelling is not new. Modelling can be criticised for its weaknesses, yet modelling remains one of the only ways to predict the future behaviour of groundwater systems, in response to changes. While commercial software is readily available and models can be set up and run with only a few days of training, far more experience is required...

Extraction of coal seam gas (CSG) is a relatively new and emerging industry in Australia. Fields are developing in the Surat and Bowen Basins of Queensland and in the Gunnedah, Gloucester, Clarence-Morton and Sydney Basins in New South Wales. Considerable public interest currently surrounds the development of CSG resources. One focus of this intere...

The emergence of a coal seam gas (CSG) industry in Australia has been accompanied by concern about potential impacts on regional aquifers, including the Great Artesian Basin. The volumes of water withdrawn during production of CSG need to be understood in the context of water use from all sources, including both surface water and groundwater. Never...

Australian Groundwater Modelling Guidelines have recently been published by the Australian National Water Commission. The document was prepared by a team of authors drawn from the consulting industry, academia and government. The target audience includes modellers, model owners, environmental regulators and the community in general. The diverse nat...

The objective of the Australian groundwater modelling guidelines is to promote a consistent and sound approach to the development of groundwater flow and solute transport models in Australia. It builds on existing guidelines (Murray–Darling Basin Commission 2001) that have been adopted throughout Australia in recent years. While it is acknowledged...

Development of conventional and unconventional gas resources including CSG share many similarities; however, some important differences in CSG extraction may lead to potential impacts on groundwater supply. Conventional gas reservoirs are usually located at greater depths than commonly exploited groundwater resources. This contrasts with the situat...

Development of conventional and unconventional gas resources, including CSG, has many similarities; however, there are some key differences that may lead to potential impacts on groundwater supply. Conventional reservoirs are usually located at greater depths than commonly exploited groundwater resources and develop when gas becomes trapped by impe...

Operations managers responsible for mining, water resources, and environmental remediation projects are looking for tools that will help them find solutions to complex planning challenges. As diverse as these industries are, they share a need for an integrated simulationoptimisation approach capable of handling the physics of fully coupled surface...

A numerical model previously developed to systematically examine groundwater flow in vertical section near shallow surface water bodies such as lakes, wetlands and ponds is further developed to include simulation of the distribution patterns of hydrogeochemical and stable isotopic tracers in relation to the surface water body and the geometry of di...

Many studies of periodic forcing and response in aquifers have focused on describing the induced fluctuations in hydraulic head, without much consideration of the time-dependent flows. Visualization techniques presented in this paper can be applied to obtain a more physically intuitive impression of groundwater motion in aquifers that undergo perio...

Interaction between surface water and groundwater depends on the position of a lake within the regional flow system. The approach in this paper is to nest a local-scale two-dimensional (2-D) lake aquifer model within a 1-D regional aquifer model to examine the effect of the regional setting on surface water-groundwater interaction. This extends pre...

Wetlands can be classified as recharge, discharge or flowthrough water bodies, depending on the spatial distribution of flux across the interface between the water body and underlying aquifer. Modeling of steady groundwater flow in two and three dimensions allows this classification to be explored in great detail, as a function of wetland and aquif...

Recent studies of lake-aquifer dynamics have highlighted the diverse nature of groundwater flow regimes that may exist under the influence of nearby surface water bodies. For water resource managers, three-dimensional systems are often important. This work extends previous studies to descriptions of the effects on steady aquifer flows of fully thre...

The calculation of a water balance for a surface water body is often subject to large errors. These errors arise because of the uncertainty associated with individual components of the water balance, particularly the volumes of groundwater inflow and outflow. Coupling the water balance with balances for conservative solutes and environmental isotop...

Steady flow regimes for three-dimensional lake-aquifer systems are studied via idealized mathematical models that are extensions of earlier simplified vertical section models of interaction between shallow lakes and underlying aquifers. The present models apply to a shallow circular lake at the surface of a rectangular aquifer of finite depth, yiel...

Tailings management and rehabilitation have in recent years become issues deserving considerably more attention than in the past. The expectations of the community in terms of ensuring environmentally acceptable solutions for the long-term storage of this waste from mineral processing has required that the mining industry give the issue increased a...

Numerical models of dense solute transport in porous media can be classified based on dimensionality and assumptions used in constructing the models (e.g., three-dimensional, two-dimensional in plan). Each category has advantages and disadvantages. The larger the dimensionality of the model, the greater the expense in terms of both computer storage...

In June 1995, President Jacques Chirac of France unexpectedly announced that France would conduct a final series of up to eight underground nuclear tests at Mururoa and Fangataufa Atolls in French Polynesia, prior to signing the proposed Comprehensive Test Ban Treaty. A total of six tests were carried out between 5 September 1995 and 27 January 199...

An existing algebraic solution to Laplace's equation for the steady three-dimensional temperature distribution around an ellipsoid embedded in a uniform, isotropic medium is used to study the characteristics of porous/permeable media flow near a variety of objects. Symbolic-computation techniques are used to derive new closed-form algebraic express...

Assessment of groundwater - surface water interaction in estuaries that are tidally forced and in addition have transient density conditions in the surface water requires a multi-disciplinary approach. Such an approach has been undertaken in the Swan-Canning Estuary on the coastal plain of Western Australia. Here, the assessment of groundwater inte...

Assessment of groundwater - surface water interaction in estuaries that are tidally forced and in addition have transient density conditions in the surface water requires a multi-disciplinary approach. Such an approach has been undertaken in the Swan-Canning Estuary on the coastal plain of Western Australia. Here, the assessment of groundwater inte...

Shallow groundwater systems are those that occur nearest the earth's surface, bounded by a water table and an unsaturated zone above, and by bedrock or deeper aquifers below. Shallow groundwatrer systems are more likley than deeper systems to be in contact with surface water bodies, thus the interaction between surface water and groundwater, from b...

The members of Working Group 4 (Geosphere radionuclide transport) of Task Group B (Evaluation of potential long term radiological situation) who contributed to Section 6 of the Main Report were Fairhurst, C., de Marsily, G., Hadermann, J., Nitsche, H., Sastratenaya, A.S., and Townley, L. The Main Report is available online at https://www-pub.iaea.o...

The Members of Working Group 4 (Geosphere radionuclide transport) of Task Group B (Evaluation of potential long term radiological situation) were Fairhurst, C., de Marsily, G., Hadermann, J., Nitsche, H., Sastratenaya, A.S., and Townley, L.

A leaking point source located in an urban area has resulted in a dense plume composed mainly of ammonium sulfate. The contaminant has accumulated in the bottom of a regional unconfined sandy limestone aquifer system. With a current conventional single-pump system of four recovery bores it would take 17 years to remediate the aquifer. The main limi...

We consider a two dimensional model for dynamic interaction between an unconfined aquifer and an open water body in which the water level is a function of time. We formulate the problem mathematically, isolating the governing equation, boundary and initial conditions. We present an accurate numerical solution to the problem. The numerical approach...

Final voids are the mine pits remaining after mineral resources have been extracted by open-cut mining operations such as coal mining. In order to determine the most appropriate post-mining use for final voids, a number of issues need to be resolved concerning their long term stability and how they will interact with the surrounding environment. In...

Cyclic responses to periodic sinusoidal forcing are well documented in the study of groundwater systems, however there are few results in 2D or 3D. The objective of this research is to understand the dynamics of groundwater flow in a 2D vertical section beneath a wide shallow lake in a regional aquifer.

Modifications to lake hydrology and chemistry due to stormwater discharge Shenton Park Lake, Perth, Western Australia, is a urbanised wetland with a primary role as an infiltration basin for the recharge of stormwater. The lake displays a range of environmental management problems common to shallow wetlands of the Swan Coastal Plain, including eutr...

Lake Jasper is a freshwater lake located within the D'Entrecasteaux National Park in the south west of Western Australia. It is located on a low-lying coastal plateau, is relatively deep (10m) and has a surface area of about 4 km 2 making it one of the larger freshwater lakes in Western Australia. The relationship between the lake and the shallow a...

This paper presents a functional formulation of the groundwater flow inverse problem that is sufficiently general to accommodate most commonly used inverse algorithms. Unknown hydrogeological properties are assumed to be spatial functions that can be represented in terms of a (possibly infinite) basis function expansion with random coefficients. Th...

This report describes the development and application of two tools based on particle-tracking techniques. The first, PTRACK, is a simple Eulerian particle-tracking code designed to handle input velocity distributions calculated by standard finite-difference codes. The second, STREAMv2.0, is a superset of PTRACK with built-in logic for locating divi...

THE ISSUES: Groundwater use in the Eastern Goldfields: Previous work, carried out in Stage 1 of this project demonstrated that groundwater use in the Eastern Goldfields significantly exceeded the natural rate of groundwater recharge, and that the groundwater resources were effectively being mined. Given this understanding, it was recognised that t...

In the analysis of aquifer behavior, it is common to distinguish between steady-state and dynamic or unsteady behavior. A special case of the latter is periodic behavior, in which an aquifer responds to forcing that varies sinusoidally in time. This paper presents an efficient method for obtaining analytical solutions for periodic aquifer flow, bas...

Summer water levels in East Lake, within the Perry Lakes Reserve have been artificially maintained over the past two summers by pumping from the unconfined aquifer. Bores within the reserve are used for lawn irrigation during the week, while on weekends a portion of the pumping capacity is used to maintain lake levels. West Lake is not artificially...

One day someone can check my recollection of events. My Comment may be the only "comment" on a paper in WRR to which the original author did not "reply". John was asked by the Editors to reply, but he refused. He simply said "Lloyd's right". I have not checked to see how many authors have cited the original paper. I don't think anyone has cited my...

In 1995, I led Project a group of about 12 research scientists in Project CA01 within CSIRO Land and Water. We were actively working on a wide range of projects that involved surface water - groundwater interaction. At the end of 1996 or early in 1997, the Chief of CSIRO Land and Water came to me one day and announced that he was shutting down our...

A numerical model is used to examine groundwater flow in vertical section near surface water bodies, such as lakes, wetlands, ponds, rivers, canals, and drainage and irrigation channels. Solutions are generated partly by superposition to achieve computational efficiency. A large number of flow regimes are identified, with their characteristics cont...

FlowThru provides a general framework for classifying groundwater flow patterns near elongated surface water bodies. The program recognises a large number of distinct flow regimes (seventeen flow-through, eleven discharge and eleven recharge flow regimes), which can occur under different regional flow and recharge conditions. Although developed wit...

Steady seepage through a levee or a dam separating reservoirs with different levels and densities is shown to result in five possible flow configurations. If densities are equal, the problem reduces to the classical problem of flow through a dam. If the lower reservoir is less dense, a stationary wedge may or may not form inside the levee near the...

Hydraulic properties of bounding formations: Measurements of hydraulic conductivity of low permeability aquitards overlying the paleochannels has been completed using slug tests. Results of the slug tests indicate an overall range of values for hydraulic conductivity from 10-6 to 10-9 m/s. Several factors dictate that care should be taken not to o...