Representing Spatial Variability

All real environmental systems are variable to some extent. For example, aquifers are generally heterogeneous with respect to flow and transport properties, chemical conditions vary spatially throughout the environment, and flow rates vary spatially within a stream. Such variability can have a large influence on the behavior of the system, and it is therefore very important to represent this in your model.

Much of this variability can be directly represented within GoldSim using the basic structure and features of transport pathways and sources. For example, variability in transport pathways can be represented by defining multiple pathways with differing properties, and barrier failure distributions in contaminant sources typically reflect spatial variability in chemical and/or hydrologic conditions.

How would one represent, however, the fact that the decay rate or partition coefficient for a contaminant is spatially variable? In this case, the solution is to define separate Solid, Fluid or Species The chemical (or non-chemical, such as bacterial or viral) constituents that are stored and transported through an environmental system in a contaminant transport model. In GoldSim, the Species element defines all of the contaminant species being simulated (and their properties). elements in each location where the properties vary.

This is discussed in greater detail in the topics below.