The primary input to a network pathway is the fracture network. Each Network pathway requires at least one fracture network. Very simple fracture networks can be entered by hand, but complex fracture networks would typically be generated by a discrete fracture network generation and flow simulation code. (Golder Associates’ FracMan library of codes for fractured-rock systems includes a program, called PAWorks, which can generate fracture network files that can be directly imported into GoldSim).
This fracture network identifies all of the “pipes” making up the pathway, and the manner in which they are interconnected. In addition, for each pipe, it identifies:
•the geometry (length, cross-sectional area, and flow-wetted area);
•the flow rate; and
•the fracture set, which identifies the transport properties of the pipe (e.g., porous infill material, coating material, properties of matrix diffusion zones, etc.).
Finally, the fracture network identifies which of the pipes are associated with "sources" (mass flux links into the pathway) and which pipes are associated with "sinks" (mass flux links out of the pathway) and/or "watch groups" (collections of pipes within the network whose mass fluxes can be added together and monitored).