Within GoldSim, the definition of what is meant by a “source” is completely determined by the user. A “source” may represent an entire landfill, or a single buried drum; a group of leaking underground tanks or a complex engineered facility. In a given system, multiple sources may exist.
The key point is that a Source element inputs contaminant mass to the pathway network (which subsequently transports mass through the system), as shown below:
This Source element “Buried_Drums” provides mass input to the Cell pathway called "Soil".
In effect, a Source can be viewed as a “black box” whose outputs are release rates for each species in the system to one or more transport pathways.
A Source allows you to define the properties and characteristics of the various contaminant sources in your system, and based on these, computes the resulting release rates to specified transport pathways. The properties and characteristics that you must specify for each Source are as follows:
•Containment: Is part or all of the species mass at the Source initially present within barriers of some sort (e.g., drums, boxes) which must fail before any of the contaminants can be released? If so, what is the rate at which the containers fail?
•Inventory: What is the initial quantity of each species at the source? Where is it located within the Source (relative to any barriers that may exist)?
•Waste matrix: Is part or all of the contaminant mass at the Source bound within one or more matrix materials of some sort (e.g., grout, metal) which must degrade to some extent before any of the contaminants can be released? If so, what are the degradation rates of these materials?
•Mass Transfer: What are the physical and chemical characteristics of the Source which control the rate at which contaminant mass (once it is liberated from any containers or matrix materials) can be transported through and away from the source?
•Connections to the Pathway Network: When mass leaves the Source, to which pathways does it discharge?
Once the nature of each Source is specified in this manner, the resulting mechanisms controlling release can be simulated.