Specific Storage Specific Yield

[Francesca Moschini]

I'm running a simulation with Modflow-NWT, Using UPW & UZF . I have 3 convertible layers.

The specific Storage should always be > or >= than the specific yield from theory.
Now I have a problem assigning specific storage using modelmuse. It let me assign the specif storage only for a layer, I can't modify the rest.
Another thing is that it works when the SS is lower than SY, but if (for a specific area) I give SY=0.33 and SS=0.4 the model does not converge.
Am I missing something?

Thanks

[Richard B. Winston]

The following video shows how to assign values to different layers of
the same data set.
http://water.usgs.gov/nrp/gwsoftware/ModelMuse/DataSets/DataSets.html
You can change the selected layers with the "Model Cube" in the corner
of the top view of the model.

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[Francesca Moschini]

Hello Richard,
I've used this technique to assign values for HK etc but it doesn't work with SS. At least with my version of modelmuse  3.2.1 from may 2014.

Best regards

Il giorno martedì 27 gennaio 2015 10:56:18 UTC+1, RichardBWinston ha scritto:

The following video shows how to assign values to different layers of
the same data set.
http://water.usgs.gov/nrp/gwsoftware/ModelMuse/DataSets/DataSets.html
You can change the selected layers with the "Model Cube" in the corner
of the top view of the model.

Francesca Moschini wrote:
> I'm running a simulation with Modflow-NWT, Using UPW & UZF . I have 

[Richard Winston]

If you send your ModelMuse model to me at my work email (rbw...@usgs.gov), I'll try to figure out what's going wrong.

To unsubscribe from this group and stop receiving emails from it, send an email to modflow+u...@googlegroups.com.
To post to this group, send email to mod...@googlegroups.com.

[Ned Banta]

Francesca,

Specific storage generally is several orders of magnitude *smaller* than specific yield. Ss is unit-dependent, but even so, this is true for any length unit likely to be used in a model. A typical value for Ss would be about 1.0e-6/ft.

Ned

[Francesca Moschini]

Hello Ned,
thanks for your answer, you are right I mixed and confused the SS with the Saturated water content.

Now my SY ranges between 1E-6 to 0.33. 

So according to "As stated previously, mass balance is achieved by approximating the residual water content variable with the specific retention computed as the saturated water content minus the specific yield." from the UZF package, so I assume that My SWC should be higher than my SY.
However when I set SWC=0.5 for the whole catchment I receive the following error message: "42880: EXTINCTION WATER CONTENT FOR CELL AT ROW     2, COLUMN   134 IS LESS THAN RESIDUAL WATER CONTENT-- SETTING EXTINCTION WATER CONTENT EQUAL TO RESIDUAL WATER CONTENT
If I sent SWC= 1E-6, the models runs without errors.

Where am I wrong?