mcarlson

Hello
I am a fairly new FeFlow user looking for advice on unsaturated, vertical flow modeling. The goal of the model is to more effectively model perched water tables in the unsaturated zone. I am attempting to model a pit slope using the modified Van Genuchten modeling. The model has constant head boundaries on either edge, 2nd order flux recharge BC at the dumps and seepage face boundaries along the pit slope. Values for unsaturated porosity, residual saturation and hydraulic conductivity are assigned by unit. The following modified Van Genuchten parameters were recommended to me for dealing with the pit slope as values for “fractured, porous rock”:

Sr = (n-Sy)/n 
? = 1.10
A = 40 (my max element size, although it sounds like other posts suggest to lower this value? Does lowering this value below element size maintain accuracy?)
n = 1.15 
m = 0.145

Using these values I am having some trouble obtaining convergence during steady-state calibration. The stability of the model has been decreasing significantly with any introduction of anisotropy or increased in recharge flux boundary condition.

Has anyone attempted a similar scenario and has any insight into more effective mod VG parameters for pit slopes, particularly values for fractured, hard rock that might improve convergence?

Any insight on increasing the stability of the model, with reasonable parameters would be extremely helpful. Or any literature on this specific topic would be of great interest, especially regarding parameter estimation for n, m and ?. I am also open to trying other approaches as well.

Thank you in advance for any help.

Hello,

I am trying to make a vertical 2-D unsaturated model based on seasonal recharge data. When I looked up where to input my data for storativity into the FeFlow model, it said that the input parameter, was Drain/Fillable porosity. But, I cannot find this as a parameter option in the 2-D model options. Has it been renamed to something else?

Thanks