How to assign Darcy Discrete Feature?

This might be a simple question, but I haven't found any material that discuss this in details.

For ex. if I would like to simulate a fracture with Transmissivity  1e-6m/s and aperture of 1e-4m, how could I assign parameters in Darcy discrete Feature?

There should be three parameters to be specified: [b]Thickness, conductivity and porosity[/b].
1: Thickness=aperture=1e-4m; porosity=1; conductivity=????
2: Thickness=0.1m, conductivity=1e-5m/s, porosity=0.001 (this is actually a thin layer of 0.1m thickness to be equivalent)

Could anyone give me some advice which method is the right way? or there is a third choice?

Thanks,
Tana