Introduction to Regression¶ This tutorial proves an overview of linear regression. It illustrates fitting a polynomial to noisy data, including the role of SSE (reponse curve), degrees of freedom, the gradient of that surface (Jacobian) and overfitting. We use a very simple model (a polynomial function) to illustrate these core concepts and the maths […]
Introduction to Regression Read More »
GMDSI is preparing a two-part book. A draft of the first part of this book is now available. Authored by John Doherty, it provides a comprehensive conceptual framework for decision-support groundwater modelling. Based firmly on scientific principles, it suggests ways in which modelling can better serve the imperatives of environmental management than it does now.
Scientifically-Based, Decision-Support Groundwater Modelling Read More »
Locating sources of groundwater contamination is an inverse problem on steroids. It is, in fact, two inverse problems. Source locations must be back-calculated from field measurements. The hydraulic properties of aquifer material through which groundwater flows, and contaminants are transported, must also be inferred from these same measurements. Another spice in the inverse problem soup
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This is the second of a two-part series recorded by John Doherty. The first video is philosophical. The second video provides real-world examples of the philosophy at work. Two examples are discussed. Both of these are the subject of GMDSI worked example reports. The first example illustrates how, through simultaneous history-matching of six aquifer tests,
Groundwater Modelling and the Scientific Method: Part 2 Read More »
This is the first of a two-part series recorded by John Doherty. The first video is philosophical. The second video provides two real-world examples of the philosophy at work. This first video begins by examining the scientific method. It then examines the way in which decision-support groundwater modelling is commonly undertaken. It demonstrates that differences
Groundwater Modelling and the Scientific Method: Part 1 Read More »
This game illustrates ideas presented in an accompanying interactive video. Like the video, it was developed by Ty Ferré of University of Arizona. The game is simple but powerful. It resides in an Excel spreadsheet. So you don’t need an expensive video card to play it. And perhaps it is marginally (but only marginally) less
Decision-Support Groundwater Modelling: A Game Read More »
Management of coastal aquifers is unforgiving. If too much fresh water is extracted, salt water takes its place. Depending on the location, measurements of historical system behaviour may be scarce or plentiful. However assimilation of these data using a numerical model that attempts to simulate salt water intrusion is nearly impossible because of long run
Worked Example: Coastal Management Modelling Read More »
These videos were prepared as lectures for the Groundwater Modelling topic of the Groundwater Hydrology course at Flinders University. They aim to introduce history matching and uncertainty quantification in the context of groundwater modelling for decision-support and provide a starting point for those who are new to the field. The videos provide an overview of
Intro to History Matching and Uncertainty Analysis Read More »
Groundwater modelling needs a context to make sense. This context is set by a decision that must be made, by those who must make that decision, and by those who are affected by it. The context for the decision itself is set by adverse consequences that groundwater management seeks to avoid. Ty Ferré from University
For this worked example, we rebuild an old USGS model. The focus of the original model was protection of water supply wells that serve a small town in New Hampshire. Those who built the original model did a good job – given the technology that was available at the time. We show how modern data
Worked Example: Probabilistic Capture Zone Analysis Read More »
GMDSI is managed by the National Centre for Groundwater Research and Training (NCGRT) and administered by Flinders University.
