Greg Bryce

I am trying to understand what Feflow uses for the variably saturated flow equation with respect to storage.  When fully saturated does it just use specific storage or does it still use porosity?  Thank you in advance - Greg

Hi,  I am reviewing a regional groundwater flow model.  I do not have the actual model but am reviewing it based on a report and shapefiles with model parameters.  The model has some very unique methods, one of them being how they used transfer boundaries.  They set up transfer boundaries to represent alpine streams.  The boundaries were assigned to the model based on a poly-line in the 1st and 2nd layer (7 layer coarse 30 thick min).  It is my understanding that transfer boundaries do not work without having three nodes that are connected by a single element.  However they reported flows to the river and the potentiometric wraps around the drainages so it appears the boundaries are working.  Can the TB work since they are coupled to the 2nd layer?  If so it is unclear to me how to calculate the proper inflow and outflow rates. 

Thank you to all who can provide input. - Greg

Thank you Pete,

I ended up stopping the simulation and importing the heads for all the nodes in a new simulation with the material properties changed.  This seems to work.  - Greg

Hi All,

I am working on a regional mine dewatering model.  There is very little data for the project, therefore we are approaching it as a hypothesis testing project and conducting a coarse sensitivity anlaysis.  I am running multiple hydraulic conductivity scenarios using an IFM to vary the K by depth.  I am running the model in batch mode to speed up the model and have continuous processing as the model takes 30+ hrs to run.  I have the model built and running from the start of the exploration adit to the end of mining, and now want to implement the mining recovery. 

If I use time variant material properties to change the K, porosity, and Ss can I have these just applied during the post-mining (recovery) and continue to use the IFM to set the initial material properties?  Essentially what I am asking can time variant material properties be applied to only a portion of the simulation time?

Thank you - Greg

I have a large regional variable saturated model that we are developing to evaluate effects of mine de-watering on springs and streams in a mountainous area.  There is about 5000 feet of relief in the model surface and the model ranges from ~1500' to 6000' in depth.  I have 30 layers in the model, and am having problems with stable flow to my transfer boundaries.  For example when I run the model at steady state I show ~9.8 cfs being discharged to the transfer boundaries in one drainage, then when I put the exploration adit into the model (using seepage faces along the decline) the discharge to the transfer boundaries in the same drainage is `10 cfs.  Although I can understand that there is numerical error and precision issues, it seems the model shouldn't be able to create more water when water is taken out of the model.  I am currently testing different closure criteria for both the inner and outer loop, as well as testing L2, L1, and Max error solutions to find and acceptable error/precision.  Does anyone have any other suggestions that I could try to eliminate/reduce this apparent error?

Thank you for your help - Greg