GW-SW Pty Ltd provides a range of "resources", describing studies and technologies that
have contributed to the state of the art in groundwater modelling and groundwater-surface water interaction.
Additional information about publications related to these resources can be found at
a personal website,
under the headings Research interests and Publications.
One of the first two-dimensional finite element groundwater flow codes to be used by third party users was AQUIFEM-1, developed at MIT in 1977-80 under the guidance of John L Wilson.
An early version was written by Antonio Sa da Costa in 1977-78, based on the code CAFE written by John Wang and
Jerome Connor at MIT in the mid 1970s for circulation in coastal environments
(cf. Wang and Connor (1975), Mathematical modelling of near coastal circulation,
TR 200, Ralph M Parsons Laboratory for Water Resources and Hydrodynamics, MIT, April).
Lloyd Townley rewrote AQUIFEM-1 and prepared all documentation between October 1978 and February 1980.
While never promoted as "open source" software, the Fortran source code was
provided in the user's manual.
Two reports were published:
(i) a 114-page manual describing the
theory of the finite element method and verification
that the finite element method is able to reproduce analytical solutions, and
(ii) a 294-page user's manual,
including a "programmer's guide".
Both reports were published twice: as Technical Reports 248 and 252 of MIT's Ralph M Parsons Laboratory for Water Resources and Hydrodynamics,
and as TAP Reports 79-2 and 79-3 of MIT's Technology Adaptation Program.
The well-known reference book entitled
Applied Groundwater Modeling: Simulation of Flow and Advective Transport
by Anderson and Woessner (1991) used AQUIFEM-1 to explain finite element models,
in contrast to finite difference models such as MODFLOW, first released in 1983 but better known since 1988.
Many illustrations in the reference book come directly from the AQUIFEM-1 manuals.
AQUIFEM-1 has no relationship with AQUIFEM developed by Pinder and Voss in Sweden in 1979,
or AQUIFEM-SALT developed by Voss for the USGS in 1984.
The name was chosen independently as a logical name for an AQUIfer Finite Element Model.
CDM Smith evolved from
the same roots, from Antonio Sa da Costa's first version at MIT in 1978.
A brief history of the 30 years of evolution of DYNSYSTEM was presented at the 2013 NGWA Summit in San Antonio TX.
One of the first published applications of AQUIFEM-1 was to the
Nile Valley in Egypt in 1986.
The source code and a collection of example data files will soon be made available.
AQUIFEM-N is a multi-layered extension of AQUIFEM-1.
It was distributed in Australia and internationally from the mid 1980s until
the early 1990s. It has many similarities with early versions of MODFLOW, in
that it was designed as a quasi-3D model, with vertical flow represented by a
conductance or leakage coefficient. However development ceased after addition
of conservative solute transport in the early 1990s.
AQUIFEM-N was developed in 1984-85 at the request of Richard Evans of the
State Rivers and Water Supply Commission of Victoria. The SRWSC had an HP 3000 mainframe,
which allowed 64 KB of RAM per user/process. The agreed specification was for a
multi-layered finite element model with up to 10 layers, each with up to 400 nodes
and 600 linear triangular elements, to run on the available hardware.
AQUIFEM-N was developed on an XT PC with a single floppy drive and 128 KB of RAM.
The software was uploaded and tested remotely using the AUSTPAC network operating at 15 baud.
The user's manual and other documentation will soon be made available.
AQUIFEM-P is a periodic version of AQUIFEM-1, developed in
1985 and documented in 1993. Many hydrogeological systems have piezometric
heads and flows that fluctuate
in response to fluctuations in forcing, such as seasonal variations in recharge,
evapotranspiration and pumping (due to wet and dry seasons), tidal oscillations at boundaries and diurnal variation in plant water uptake.
The purpose of AQUIFEM-P is to simulate the dynamic behaviour of fluctuating
systems without time-stepping.
A simple idealisation is to consider sinusoidal fluctuations
superimposed on long-term average behaviour. After linearising, the steady
and sinusoidal components can be decoupled, simulated separately and recombined. Rather than representing
sinusoidal fluctuations as a combination of sines and cosines (to represent
phase lag), AQUIFEM-P is based on the use of complex variables, a technique used frequently in
wave mechanics and in analysis of structural vibrations.
The user's manual and other documentation will soon be made available.
We would love to find opportunities to demonstrate how this approach can help in analysis of the response time of hydrogeological systems.
CERT is a two-dimensional finite element groundwater flow
code that includes parameter estimation and uncertainty analysis. CERT was written between June 1982 and April 1983, as part of Lloyd Townley's PhD research.
It was documented in April-June 1983 as part of a project by INTERA Environmental
Consultants for the US Office of Nuclear Waste Isolation (ONWI), documenting codes that could
be applied to the design of radioactive waste management facilities.
CERT is based on the concept that all model parameters can and perhaps
should be considered to be uncertain. Parameter estimation is implemented using
both gradient-based and extended Kalman filter (EKF) search algorithms, minimising an objective function that combines
measurements of heads and either measurements of or prior information about
model parameters. This objective function can be justified based on Bayesian,
Maximum Likelihood (ML), Maximum a Posteriori (MAP) or heuristic (weighted least squares) arguments. The gradient-based search uses
adjoint methods and a novel (under-utilised) method to estimate the curvature of
the objective function along the direction of each line search. Uncertainty analysis is implemented using the first order second moment (FOSM) method, later extended to include a second order correction to the mean, and also using Monte Carlo (MC) simulations.
One of the few examples of an application of CERT is in Neil Blandford's
(1987) MS Thesis (7.7 MB).
While not specifically related to CERT, a
by McLaughlin and Townley (1996) presents the groundwater inverse problem
in the language of maximum-a-posteriori (MAP) estimation.
In particular, the paper shows relationships between linear Bayesian methods,
nonlinear least squares and maximum likelihood methods, the pilot point method and
extended Kalman filtering, all of which have been applied in groundwater studies.
The CERT user's manual and other documentation will soon be made available.
FlowThru was developed by Lloyd Townley and Tony Barr at
CSIRO during the period 1989-92, significantly extending the results of MSc
research undertaken by Simon Nield at UWA. An
interactive version of FlowThru is provided here.
FlowThru generates flow nets that show groundwater flow patterns
beneath and near shallow water bodies such as lakes, wetlands, rivers and streams.
The flow nets are automatically analysed to find stagnation points and dividing streamlines.
Although this work was initially motivated by studies of shallow wetlands on the
Swan Coastal Plain near Perth,
Western Australia, the principles can be applied to every kind of surface water - groundwater interaction.
The FlowThru code allows the geometry of a vertical section to be defined
in physical units, and also using non-dimensional ratios.
Non-dimensional ratios allow the results to be applied to a wide range systems
with the same ratios. We would love to embed FlowThru in other software, but would need support to do so.
user's manual explains how flow regimes are identified based on the number
and location of stagnation points (singularities) in the flow domain.
FlowThru was an outcome of years of research, summarised at
under the heading "Research interests --> Surface water - groundwater interaction".
The report by Townley et al. (1993a) was scanned in June 2015, 22 years after the
report was completed and submitted as a Final Draft. It is now available for download.
Animations based on AQUIFEM-P
A number of animations are provided to illustrate the impact of seasonal fluctuations of recharge,
rainfall and evapotranspiration on groundwater flow patterns in a 2D vertical
section through shallow surface water bodies. The results combine the concepts of
FlowThru with seasonal fluctuations, simulated using the periodic finite element model
AQUIFEM-P. This work formed the basis for Tony Smith's PhD thesis, completed in 1999.
Most of the animations show flow-through regimes rather than recharge or
discharge regimes, because this was the focus of our research at the time.
We share these animations is not to provide answers, but to illustrate features of
surface water - groundwater interaction that we understand well. We believe
dynamics has an enormous influence on apparent mixing in groundwater, and hope to be able to explain more in the future.
The Perth Urban Water Balance Study (PUWBS) was a landmark study of the groundwater
resources near Perth, Western Australia, undertaken during the period 1982-87.
Lloyd Townley was a member of both the Steering Committee and the Project Team,
guiding the direction of the project while at the same time involved in hands-on modelling.
The final report has been scanned, 25 years after publication, to illustrate
the level of technology available at that time.
See Volume 1 (194 MB) and Volume 2 (10 MB).
The study was unique in a number of ways. The report was far more
colourful than many modelling reports at the time, being targeted at a
broad audience keen to understand the groundwater resources.
Extensive use was made of GIS, using the first licence for ARC/INFO in
Western Australia. The concept of a vertical flux model, coupled to an underlying
regional scale single layer finite element model, was not unique,
but may have been attempted in more detail than ever before in an urban environment.
Underground nuclear testing at Mururoa
and Fangataufa Atolls in French Polynesia
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 1996.
Responding to concerns and protests, the President invited two international
groups to conduct separate independent investigations of the consequences of the underground tests.
Professor Charles Fairhurst was asked to select and lead a
team of independent international experts, known as the International
Geomechanical Commission (IGC) to study issues related to stability and hydrology.
The International Atomic Energy Agency (IAEA) undertook a separate study of radiological issues.
The IGC's stability studies were led and coordinated by
Professor Emmanuel Detournay, with detailed analysis being undertaken by
Branko Damjanac, Peter Cundall and other staff from ITASCA in the USA.
The hydrology studies were coordinated by Lloyd Townley and
Professor Ghislain de Marsily, with detailed analysis being undertaken by
Pierre Perrochet and Laurent Tacher of the Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland.
The IGC's findings were published in 1999 in hard copy,
with additional files on an accompanying CD. The printed report is
divided into three "parts". Part 1 is entitled General Results.
Part 2 is entitled Technical Analyses, but includes only Chapter 1, which provides an overview of the IGC's analyses.
Part 3 contains French Translations of Parts 1 and 2. The CD contains
a number of files in PDF format, in this case entitled "volumes".
Volumes 1 and 3 correspond to Parts 1 and 3. But Volume 2 is 480 pages in length,
with Chapters 1 to 7 and Appendices A to V; it contains all of the technical analyses undertaken by the IGC.
A modified version of the IGC's final report (24.9 MB) has been assembled,
13 years after publication in hard copy. This version includes Volume 2 in place of Part 2.
Of particular interest to hydrologists and hydrogeologists are
four sections in Volume 2: Chapter 6 on "atoll hydrology prior to nuclear testing", Chapter 7 on "hydrological impacts of underground nuclear tests",
Appendix U on "analysis of periodic groundwater flow", and Appendix V
on "effective dispersion in a periodic flow field". Appendix U builds on similar
periodic analyses published separately by Lloyd Townley. Appendix V improves
an earlier solution by Okubo (1973), and was developed by Pierre Perrochet in collaboration with Lloyd Townley.
A slightly different compilation (784 pp.) has been
prepared and archived by the University of Minnesota.
Even though the IAEA study relied on the geotechnical and
hydrogeological simulations undertaken by the IGC, its report was
published earlier. The IAEA main report (31.2 MB) is entitled "The Radiological Situation at the Atolls of Mururoa and Fangataufa".
Lloyd Townley was a member of the IAEA's Working Group 4 (geosphere
radionuclide transport) of Task Group B (on evaluation of the potential
long term radiological situation), and contributed to preparation of Chapter 6 of the main report.
Working Group 4 prepared a Technical Report entitled "Releases to the
biosphere of radionuclides from underground nuclear weapon tests at the atolls" (270 pp.),
being Volume 4 in a series of 6 reports supporting the main report.
For more information about the history of nuclear testing in
French Polynesia, see www.mororua.org.
If you have any questions, please ask.