A Simple GoldSim Model
Lesson 3, page 2 of 12
In this Lesson, you will learn how to move around within the GoldSim interface by exploring a simple model. (In the next, Lesson, we will then build this same model from scratch).
This simple model simulates a pond of water that is used for forest fire suppression. A stream flows into the pond. The inflow rate varies from day to day, and this variation can be described statistically. There are no streams leaving the pond, but water seeps out of the bottom of the pond (so if the inflow stopped, the pond would eventually drain completely).
Over the next 100 days, the pond will need to be used for fire suppression. Fires are assumed to occur approximately once every 50 days. Whenever a fire occurs, a certain amount of water (100 m3) needs to be immediately removed (e.g., via helicopters) to fight the fire.
We want to know the likelihood that the pond will be emptied (and hence be unable to deliver the full 100 m3 of water when required) over the next 100 day period. The primary output of the model is simply the volume of water in the pond as a function of time.This volume, however, is uncertain (and must be simulated probabilistically) due to the variability of the inflow rate, and the random nature of the fires (i.e., they occur approximately once every 50 days).
Note: In order to keep this example simple and to avoid requiring you to have specific subject matter expertise (e.g., hydrology, fire occurrence) in order to understand the model, the key assumptions (e.g., the inflow rate to the pond, the rate at which fires occur) have been greatly simplified. You should not be concerned about this! The purpose of this Tutorial is not to teach you how to model this particular problem, but to introduce you to the basic features of GoldSim. At the end of the Tutorial, however, in order to illustrate some of GoldSim's advanced features, we will briefly discuss ways in which such a model could potentially be made more realistic.
This model (called TutorialExample.gsm) was installed along with the software. Since you opened this Tutorial from within GoldSim, you just need to locate and open the model, as discussed on the next page.