Lesson 1 - Unit 3 Overview

Since all models are wrong the scientist cannot obtain a "correct" one by excessive elaboration… Just as the ability to devise simple but evocative models is the signature of the great scientist, so overelaboration and overparameterization is often the mark of mediocrity.

George Box

As pointed out in Unit 1, this is a “hands-on” Course.  That is, while you are taking it, you are expected to simultaneously use the software. In fact, you have already done so in Unit 2.

However, before continuing to work directly with the software as we did in the previous Unit, it is necessary to pause here and introduce a few fundamental concepts to set the stage for the remaining Units.  The remaining Units will discuss all of these concepts in great detail and provide many Examples and Exercises for you to learn in a “hands-on” manner.

In particular, this Unit provides an overview of the overall philosophy and approach to environmental modeling embodied in GoldSim and the Contaminant Transport Module. As we shall see, the quote provided above is particularly salient to this discussion, so take note!

As part of this discussion, this Unit will describe some basic concepts (many of which you are likely already at least somewhat familiar with).  As a result, you may be tempted to skim over this material.  However, it is highly recommended that you carefully work your way through the entire Unit, as it provides the fundamental underpinnings for the remaining Units.

Lessons 2 through 7 provide some introductory material on contaminant transport modeling in GoldSim:

• What are the key decisions required before building a contaminant transport model?
• What are the key physical and chemical processes that can be represented in GoldSim?
• How are the mass transport equations representing these processes solved in GoldSim?

Lesson 8 then discusses a critical issue associated with contaminant transport modeling that is often overlooked or ignored:

• The Problem of Uncertainty in Contaminant Transport Models

This then leads directly into a discussion of the modeling philosophy embodied in GoldSim and the Contaminant Transport Module, which is introduced in the next two Lessons:

• GoldSim Modeling Philosophy
• Basic Concepts of Contaminant Transport Modeling Using GoldSim

As you work your way through this Unit, you may think it is taking a rather circuitous route and covering a number of conceptual issues instead of discussing the practical “hands-on” use of the software.  However, the background information provided is necessary in order for you to fully understand why GoldSim is designed the way it is. That is, in order for you to build effective contaminant transport models in GoldSim, it is necessary for you to fully understand (and “buy into”) the philosophy on which GoldSim is based. As such, this Unit provides the necessary foundation for understanding the actual contaminant transport modeling features of the software that will be described in detail in the remainder of the Course.

This Unit has a total of 11 Lessons (including this overview and a summary at the end).