no, but you can set up batch runs

*Pete*


www.aquageo.us



hydrogeomatt wrote:
>
>
> Hi,
>
> Is there any way in FEFLOW to set up a model so that it runs in steady
> state (to provide initial conditions) and is then followed by transient?
>
> I'm currently doing this as a manual iterative process, but I thought
> there may be correct way to do this.
>
> Thanks,
>
> Matt

Hi,

Is there any way in FEFLOW to set up a model so that it runs in steady state (to
provide initial conditions) and is then followed by transient?

I'm currently doing this as a manual iterative process, but I thought there may
be correct way to do this.

Thanks,

Matt

Hi Pete,

I see that you work with Feflow, can you please help me?
 I am proposed to simulate the exchange between river and the aquifer, can you
help me to do a mesh for this problem taking into account vadoze zone.

Do you have publications for this problem, ( or Diersch,...)

Thanks.


________________________________
De : Pete Sinton <psinton@...>
À : gwmodel@yahoogroups.com
Envoyé le : Sam 21 Novembre 2009, 18 h 15 min 20 s
Objet : Re: [gwmodel] Mass balance problem in FEFLOW.

 
Hi Matt,

In transient, the "imbalance" term for each time step is a combination
of the change in fluid storage and fluid balance error left remaining
after the convergence criteria has been met or the maximum number of
time steps has been reached. In my experience with FEFLOW, the error is
quite small, so the imbalance essentially equals the change in storage
(for models that are logically configured!) .

Problems with convergence (large error, bad numerical solution) may be
solved by using smaller time step, using a finer mesh, using more
layers, specifying boundary conditions (and constraints) that do not
result circular flow patterns or conflicting inflow/outflow at a node or
adjacent nodes, applying more gradual changes in material properties,
etc. The usual types of problems with any numerical model apply to
FEFLOW. However, note that FEFLOW's solver is more rigorous than
typical (e.g. transmissivity of an unconfined layer can vary _within_ a
time step, whereas it cannot in MODFLOW), and so more prone to ill posed
model configuration (the up side is that FEFLOW's solution is more
reliable than typical).

*Pete*
www.aquageo. us

hydrogeomatt wrote:
>
>
> Hi,
>
> My model balances ok with a constant recharge rate, but upon changing
> this to one which varies over time the mass no longer balances
> satisfactorily. What are the common ways of addressing mass balance
> issues in general in FEFLOW?
>
> Thanks.

You might be able to use PHAST to model the leaching.
http://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phast/
http://water.usgs.gov/nrp/gwsoftware/ModelMuse/ModelMuse.html

Noble Jacob wrote:
>
> Dear Groundwater modelers,
>
> I wish to model (3D) fluoride contamination in a regional aquifer.
> From the field observations and geochemical studies, I understand that
> the fluoride in groundwater is due to leaching from the aquifer
> materials. How to conceptualize the leaching process (accumulation of
> fluoride along the flowpath) and which software can I use to model
> this (MODFLOW was used for flow simulation)?
>
> Also, I appreciate some references/reports on regional scale pollutant
> transport modeling (preferably geogenic sources)
>
> Thanks in advance
>
> With kind regards
> Noble
>
> Noble Jacob
> Isotope Hydrology Section
> HIRUP, Bhabha Atomic Research Centre
> Mumbai 400085, INDIA
>
>

Dear Groundwater modelers,

I wish to model (3D) fluoride contamination in a regional aquifer. From the
field observations and geochemical studies, I understand that the fluoride in
groundwater is due to leaching from the aquifer materials. How to conceptualize
the leaching process (accumulation of fluoride along the flowpath) and which
software can I use to model this (MODFLOW was used for flow simulation)?

Also, I appreciate some references/reports on regional scale pollutant transport
modeling (preferably geogenic sources)

Thanks in advance

With kind regards
Noble

Noble Jacob
Isotope Hydrology Section
HIRUP, Bhabha Atomic Research Centre
Mumbai 400085, INDIA

http://hydro.geo.ua.edu/mt3d/

*Pete*

www.aquageo.us


olayinka_oladeji wrote:
>
>
> Hi,
> Please advise whether the USGS 3-D ground-water flow and
> solute-transport model integrated with MODFLOW-2000 (mf2k_gwt) has
> capability to develop transport model for a continuous pollution source.
>
> If possible, how can this be conceptualised?
>
> If not, which existing model (preferably freeware, but can also
> consider proprietary) has this capability?
>
> Kind regards.
>
> Yinka.

Fellow modelers:
Last time, I posted the message with wrong URL.

I sincerely apologize for the mistake.

This time, I have tested the URL and is as follows:

http://www.gisunlimited.net/forms/reviewer_application_form.htm


The Journal of Spatialhydrology: JoSH (http://www.spatialhydrology.com/journal)
has been serving the hydrology community since year 2000. The JoSH is an on-line
open access journal with no publication fee.

The Journal of Spatialhydroloy needs reviewers like you who can contribute to
their profession with full enthusiasm.

If you interested in becoming the reviewer of an esteemed on-line open access
journal, please submit your application at the following URL:

http://www.gisunlimited.net/forms/reviewer_application_form.htm

After receiving your application, your will contacted by the Managing Editor for
further details.

Sorry for cross posting.

Is the pollution source associated with a source of fluid such as a
constant-head boundary or a well. If so, the source can be simulated in GWT by
specifying the concentration associated with the source.

If the pollution source is not associated with a source of fluid, you can use
MT3DMS instead of GWT and in Data Set D8 specify ITYPE = 15.

"For a special type of sources (ITYPE = 15), CSS is taken
directly as the mass-loading rate (MT^-1) of the source so
that no flow rate is required from the flow model."

-----Original Message-----
>From: olayinka_oladeji <olayinka_oladeji@...>
>Sent: Nov 21, 2009 4:23 PM
>To: gwmodel@yahoogroups.com
>Subject: [gwmodel] Simulation of continuous pollution source using coupled
modflow and moc3d models
>
>Hi,
>Please advise whether the USGS 3-D ground-water flow and solute-transport model
integrated with MODFLOW-2000 (mf2k_gwt) has capability to develop transport
model for a continuous pollution source.
>
>If possible, how can this be conceptualised?
>
>If not, which existing model (preferably freeware, but can also consider
proprietary) has this capability?
>
>Kind regards.
>
>Yinka.
>

Hi Matt,

In transient, the "imbalance" term for each time step is a combination
of the change in fluid storage and fluid balance error left remaining
after the convergence criteria has been met or the maximum number of
time steps has been reached.  In my experience with FEFLOW, the error is
quite small, so the imbalance essentially equals the change in storage
(for models that are logically configured!).

Problems with convergence (large error, bad numerical solution) may be
solved by using smaller time step, using a finer mesh, using more
layers, specifying boundary conditions (and constraints) that do not
result circular flow patterns or conflicting inflow/outflow at a node or
adjacent nodes, applying more gradual changes in material properties,
etc.  The usual types of problems with any numerical model apply to
FEFLOW.  However, note that FEFLOW's solver is more rigorous than
typical (e.g. transmissivity of an unconfined layer can vary _within_ a
time step, whereas it cannot in MODFLOW), and so more prone to ill posed
model configuration (the up side is that FEFLOW's solution is more
reliable than typical).

*Pete*
www.aquageo.us


hydrogeomatt wrote:
>
>
> Hi,
>
> My model balances ok with a constant recharge rate, but upon changing
> this to one which varies over time the mass no longer balances
> satisfactorily. What are the common ways of addressing mass balance
> issues in general in FEFLOW?
>
> Thanks.

Hi,
Please advise whether the USGS 3-D ground-water flow and solute-transport model
integrated with MODFLOW-2000 (mf2k_gwt) has capability to develop transport
model for a continuous pollution source.

If possible, how can this be conceptualised?

If not, which existing model (preferably freeware, but can also consider
proprietary) has this capability?

Kind regards.

Yinka.

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Fellow modelers:

The Journal of Spatialhydrology: JoSH (http://www.spatialhydrology.com/journal)
has been serving the hydrology community since year 2000. The JoSH is an on-line
open access journal with no publication fee.

The Journal of Spatialhydroloy needs reviewers like you who can contribute to
their profession with full enthusiasm.

If you interested in becoming the reviewer of an esteemed on-line open access
journal, please submit your application at the following URL:

http://www.gisunlimited.net/forms/forms/reviewer_application_form.htm

After receiving your application, your will contacted by the Managing Editor for
further details.

Sorry for cross posting.

Hi,

My model balances ok with a constant recharge rate, but upon changing this to
one which varies over time the mass no longer balances satisfactorily. What are
the common ways of addressing mass balance issues in general in FEFLOW?

Thanks.

Hi Matt,

1. surface elevation or elevation of river stage are approaches I have
used depending on the scale of the river.  Setting hundreds of river
elevations is tricky.  What I do: Set up the mesh using a map of the
river bed and assign elevations to the top slice (this assumes the river
is on the top slice).  Export the xyz locations of the nodes to a shape
file, use a GIS program (I use Didger) to separate out the nodes (with
their node number and elevation data) that will be used to model the
river (tedious!).  Use a text editor to prepare a listing of river nodes
with elevations that you then edit into an ascii formatted fem file (in
section FLOW_I_BC).  There are ways to use feflow's capabilities to
avoid editing the fem file via the regionalization menu, but I find
editing to be faster and more reliable; but I am that type of modeler!

2. to stop leakage from a river into groundwater system when head falls
below river stage, set the "max" to zero.

3. attempting to stop leakage either in or out using transfer rates
generally does not work due to averaging of material properties, etc;
you'll usually see some leakage.  Setting min or max to zero will stop
leakage (but may still see a very small amount).  Use transfer rates
that are consistent with hydrogeology; in many cases in xfer = out xfer.

4. phreatic model with natural surface: are you thinking of applying a
blanket of 3rd-type nodes to remove water wherever the water table
exceeds the top?  That would be similar to the "natural contraints"
option.  Such approaches might make sense, for example, for a wetlands,
bog or swamp.  However, if the water table is exceeding the top and it
shouldn't, that may mean you need to adjust parameters to match the
model to observed conditions rather than setting a bunch of arbitrary
discharge points.

Best of luck,

*Pete*




hydrogeomatt wrote:
>
>
> Hi,
>
> I want water to be able to exit the model when it exceeds the top
> slice elevation in an unconfined mountain region. Transfer boundaries
> seem like right option, but I'm not confident selecting the correct
> settings. So I have a few questions (sorry!) that I hope someone can
> help shed some light on:
>
> 1. Should the reference head required for the transfer BC be equal to
> the surface elevation for each node? And how would I go about
> assigning these given that there are hundreds?!
>
> 2. I want no water to re-enter the model from these nodes so do I need
> to define a constraint of min = 0 to prevent them acting as a source?
>
> 3. What value would need to be applied for the transfer rates in the
> flow materials menu? Would 'in' = 0 and 'out' = something arbitrarily
> large suffice?
>
> 4. I'm developing two models of the same scenario to compare the results:
> - variably saturated. unconfined z-elevations = true surface
> elevations in that region.
> - saturated phreatic with confined conditions applied when the water
> table exceeds the top slice. Surface elevation in the unconfined
> region is set arbitrarily high to force unconfined conditions in that
> region.
>
> Would it be better in the phreatic model to set the surface elevation
> equal to the true surface and then used the transfer BCs to simulation
> water leaving through a spring? Or will this cause conflicts with the
> assumption of confined conditions when the water table is greater than
> surface elevation?
>
> Any other comments on aspects I may not be considering will be much
> appreciated!
>
> Many thanks.

Hi,

I want water to be able to exit the model when it exceeds the top slice
elevation in an unconfined mountain region. Transfer boundaries seem like right
option, but I'm not confident selecting the correct settings. So I have a few
questions (sorry!) that I hope someone can help shed some light on:

1. Should the reference head required for the transfer BC be equal to the
surface elevation for each node? And how would I go about assigning these given
that there are hundreds?!

2. I want no water to re-enter the model from these nodes so do I need to define
a constraint of min = 0 to prevent them acting as a source?

3. What value would need to be applied for the transfer rates in the flow
materials menu? Would 'in' = 0 and 'out' = something arbitrarily large suffice?

4. I'm developing two models of the same scenario to compare the results:
- variably saturated. unconfined z-elevations = true surface elevations in that
region.
- saturated phreatic with confined conditions applied when the water table
exceeds the top slice. Surface elevation in the unconfined region is set
arbitrarily high to force unconfined conditions in that region.

Would it be better in the phreatic model to set the surface elevation equal to
the true surface and then used the transfer BCs to simulation water leaving
through a spring? Or will this cause conflicts with the assumption of confined
conditions when the water table is greater than surface elevation?

Any other comments on aspects I may not be considering will be much appreciated!

Many thanks.

Dear Dr Peter,

Thank you , but could I have more precision about discretizing streams??

 I have to do that with vertical configuration taking into account slices, so
in the first slice I have for example two transfer condition and transfer rate
exactly like what you have said, in the second slice I have also  two
transfer condition, in the third only one onde  ........., or it will be taking
as a single node in the first slice where I affect a transfer condition an d a
transfer rate??? In these case where can I mention  h_water table= h in
Feflow????

How will feflow calculate the exchange between streams and groundwater, would
it take the vadoze zone into account or not???
Thank you for these presicions , can you please advise me some
publications about simulating streams with FEFlow???? 
Sana.


________________________________
De : peterschaetzl <p.schaetzl@...>
À : gwmodel@yahoogroups.com
Envoyé le : Mar 10 Novembre 2009, 14 h 15 min 02 s
Objet : [gwmodel] Re: Stream-Aquifer interaction in FEFLOW

 
Dear Sana,

there are different options for this. Basically, you can distinguish approaches
where the stream is considered as a boundary condition from approaches where
surface water is simulated, too, and the simulations are coupled.

In the first case, mostly 3rd kind boundary conditions are used, putting a
reference water level (= water level in the stream) and a so-called transfer
rate (a conductance corresponding to the properties of the clogging layer).
Please note that in FEFLOW the area of the river bed is not part of the
conductance, thus the boundary condition setting has to include an area. In
cases with a river disconnected from groundwater, it might be good to limit the
infiltration. In FEFLOW, this can be done by applying a so-called constraint
condition, in this case a minimum head at the elevation of the river bottom.
For coupled simulation, FEFLOW can be linked to the hydrodynamic simulation
system MIKE 11 by a coupling module called IfmMIKE11.

Please see www.feflow.info for further details.

Peter

--- In gwmodel@yahoogroups .com, Sana Ounaies <sana.ounaies@ ...> wrote:
>
> Hi,
>
> I am a phd student, I want to simulate the exchange between stream
/groundwater via vadoze zone, but I don'f find how does Feflow set flux in this
case??
>
> The stream will be set as many nodes where I must affect a flux in every node
or It will be set as one node??
>
> Help me please!!
>
> Sana

Dear Sana,

there are different options for this. Basically, you can distinguish approaches
where the stream is considered as a boundary condition from approaches where
surface water is simulated, too, and the simulations are coupled.

In the first case, mostly 3rd kind boundary conditions are used, putting a
reference water level (= water level in the stream) and a so-called transfer
rate (a conductance corresponding to the properties of the clogging layer).
Please note that in FEFLOW the area of the river bed is not part of the
conductance, thus the boundary condition setting has to include an area. In
cases with a river disconnected from groundwater, it might be good to limit the
infiltration. In FEFLOW, this can be done by applying a so-called constraint
condition, in this case a minimum head at the elevation of the river bottom.
For coupled simulation, FEFLOW can be linked to the hydrodynamic simulation
system MIKE 11 by a coupling module called IfmMIKE11.

Please see www.feflow.info for further details.

Peter

--- In gwmodel@yahoogroups.com, Sana Ounaies <sana.ounaies@...> wrote:
>
> Hi,
>
> I am a phd student, I want to simulate the exchange between stream
/groundwater via vadoze zone, but I don'f find how does Feflow set flux in this
case??
>
> The stream will be set as many nodes where I must affect a flux in every node
or It will be set as one node??
>
> Help me please!!
>
> Sana
>
>  
>

Hi,

I am a phd student, I want to simulate the exchange between stream /groundwater
via vadoze zone, but I don'f find how does Feflow set flux in this case??

The stream will be set as many nodes where I must affect a flux in every node or
It will be set as one node??

Help me please!!

Sana