This model has been tested extensively against the known behavior of certain discharges and found to be accurate. For a particular analysis, one might want to know what effects will result from a new wastewater treatment plant that is in the planning stage. Using the model, one could find what downstream sections of a river will be affected and how the dissolved oxygen curve will respond. This model could account for the other discharges that are already being released into the river and calculate the cumulative effect. As you can see, there is quite a difference between simulation and predictive models.
Simulation models deal with extracting more information from what is already known about a feature.
Predictive models deal with changes that will occur if certain variables of a feature change. Both these types of models can apply to groups of features or whole coverages, as well. These both have a variety of applications for managing environmental problems. One area that has made good use of models is groundwater pollution. There are many models that deal with groundwater flow and the transport of pollutants in groundwater.