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Pathline simulation, missing extraction well

NV
Nadine Vogel, modified 3 Years ago.

Pathline simulation, missing extraction well

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hello,
I came across a problem during a pathline simulation.
I have to do a pathline simulation for three extraction and two infiltration wells. They are arranged in a row next to each other. The three extraction wells are both at the outsides and in the middle. The infiltration wells fill the two places in between. If I start the pathline simulation in my wells and do it backwards, it works fine and both infiltrations are shown. And if I start my pathline simulation at the border of my model I can see the pathlines for the extraction wells. But just for the two wells at the outside (see pictures attached). The one in the middle is not shown in the pathline simulation. So the last thing that I tried was to delete the two extraction wells at the outside and just have the two infiltration wells surrounding the extraction well in the middle. When I started the pathline simulation at the border of my model I could see the pathline simulation for the well in the middle.
I was wondering now why this one well in the middle is not shown at all when I use all three extraction wells. Does anyone know why this happens?
Best regards,
Nadine
FR
Frans Roelofsen, modified 3 Years ago.

RE: Pathline simulation, missing extraction well

Padawan Posts: 87 Join Date: 11/11/13 Recent Posts
Dear Nadine,

You write in your post: "If I start the pathline simulation in my wells and do it backwards, it works fine and both infiltrations are shown".
If that works fine, one should expect to see in the 'backward picture' the path lines from the 3 extraction wells to their origin instead of path lines from the 2 infiltration wells.
Please check that. If you see 3 plumes to the 3 extraction wells, your path line calculation seems to work fine.

In the first picture you attached to your post I see the path lines to the two outer extraction wells only.
These path lines you started at the border of the model.
My conclusion for now is that the path lines to the middle extraction well not originate at the model boundary but for instance in the infiltration wells.
That is what I expect to see in the 'backward picture'.

Kind regards,

Frans
NV
Nadine Vogel, modified 3 Years ago.

RE: Pathline simulation, missing extraction well

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hi Peter,
thanks for answering. I actually was thinking that, too, when I read my Post again. Anyhow I was confused then and thought you might have an idea. But I think that there is some problem with the pathline simulation then.
I did the pathline simulation again for different cases to see the differences. First I did foreward simulations for the infiltration wells and second for the extraction well in the middle. Then I did two backwards simulations, one for the infiltration wells and the other one for the extraction well in the middle. I attached the pictures and also marked the wells from which I started the pathlines (all cases were point isd files) and wrote in the pictures themselves if it was foreward or backwards. Unfortunately in no case the pathlines between the extraction well in the middle and the infiltration wells are shown. Then I did two simulation with line isd files. One foreward simulation from the right border and one backword simulation from the left border of the wells. I think these two pictures would then show the best pathlines, but still without considering the middle one. And they give the impression, that most of the infiltration is flowing away not being captured by the extraction wells.
I also attached a picture with the equipotential lines. I substracted the groundwater head of the underlying aquifer from the groundwater head of the upper one. The pathlines should be perpendicular to those. This picture gives the impression that the extraction wells capture most of the infiltration. So if I put my last two pathline iff files, that were generated with the line isd files, above the picture with the equipotential lines then the pathlines seem to be not accurate enough leading to a wrong interpretation. So maybe there is a way to improve that. Or maybe I understood something wrong and made a mistake.
Kind regards,
Nadine
Peter Vermeulen, modified 3 Years ago.

RE: Pathline simulation, missing extraction well

Jedi Knight Posts: 135 Join Date: 11/11/13 Recent Posts
Hi Nadine,

I must say that your pathlines look a bit strange to me, maybe I can run your simulation myself, therefore you need to send me the runfile for imodpath, the fluxfiles (bdgfff, bdgfrf, bdgflf) and sdf-file?

Kind regards,
Peter Vermeulen

Ps, You wrote: "I substracted the groundwater head of the underlying aquifer from the groundwater head of the upper one. The pathlines should be perpendicular to those." I do not understand this, the pathline need to be perpendicular to the groundwater head (whenever isotropic conditions are valid), not perpendicular to the difference, or maybe I misunderstand you.
NV
Nadine Vogel, modified 3 Years ago.

RE: Pathline simulation, missing extraction well

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hi Peter,
thanks for your PS, I actually don't know what came to my mind there. I think I thought that I need to calculate a difference to see the potential lines. Long day at work maybe...
I changed the legend now of my groundwater head from the second aquifer to show the potential lines and it actually fits better to the pathlines now.

Still you are right, the pathlines look a bit strange. So I will upload a zip folder from my model results and the run file. But I did not create an sdf file for the model simulation. I thought that I could feed the wells in through the project manager. I created an ipf file with the extraction and infiltration rates. Then I assigned this ipf to the second aquifer in the project manager. Does it work this way or do I need an sdf file? If you need anything else from me to upload to check the pathline simulation, let me know.

And although the pathlines fit better now, I still miss the ones between the wells. I would have expected to see those if I start a pathline simulation in the injection well and do it forward. But this didn't work.

Thank you very much,
kind regards,
Nadine
Peter Vermeulen, modified 3 Years ago.

RE: Pathline simulation, missing extraction well

Jedi Knight Posts: 135 Join Date: 11/11/13 Recent Posts
Hi,

Thanks, can you send the following files as well:

"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\DBASE\ASC\BND_BOUNDARYCONDITIONS_NEU_SC1.IDF", !## ibound layer 1
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\IMOD_USER\SOLIDS\Splitlayer\INT_L1.IDF", !## top layer 1
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\IMOD_USER\SOLIDS\Splitlayer\INT_L2.IDF", !## bottom layer 1
"0.3", !## porosity aquifer layer 1
"0.1", !## porosity aquitard layer 1
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\DBASE\ASC\BND_BOUNDARYCONDITIONS_NEU_SC1.IDF", !## ibound layer 2
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\IMOD_USER\SOLIDS\Splitlayer\INT_L2.IDF", !## top layer 2
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\IMOD_USER\SOLIDS\Splitlayer\INT_L3.IDF", !## bottom layer 2
"0.3", !## porosity aquifer layer 2
"0.1", !## porosity aquitard layer 2
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\DBASE\ASC\BND_BOUNDARYCONDITIONS_NEU_SC1.IDF", !## ibound layer 3
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\IMOD_USER\SOLIDS\Splitlayer\INT_L3.IDF", !## top layer 3
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\IMOD_USER\SOLIDS\Splitlayer\INT_L4.IDF", !## bottom layer 3
"0.3", !## porosity aquifer layer 3
"0.1", !## porosity aquitard layer 3
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\DBASE\ASC\BND_BOUNDARYCONDITIONS_NEU_SC1.IDF", !## ibound layer 4
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\IMOD_USER\SOLIDS\Splitlayer\INT_L4.IDF", !## top layer 4
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\IMOD_USER\SOLIDS\Splitlayer\INT_L5.IDF", !## bottom layer 4
"0.3", !## porosity aquifer layer 4
"0.1", !## porosity aquitard layer 4
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\DBASE\ASC\BND_BOUNDARYCONDITIONS_NEU_SC1.IDF", !## ibound layer 5
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\IMOD_USER\SOLIDS\Splitlayer\INT_L5.IDF", !## top layer 5
"W:\hydrogeologie\grundwassermodellierung\data\W4-Masterarbeit\iMOD_Masterarbeit\iMOD\IMOD_USER\SOLIDS\Splitlayer\INT_L6.IDF", !## bottom layer 5
"0.3", !## porosity aquifer layer 5

Regards,
Peter Vermeulen
NV
Nadine Vogel, modified 3 Years ago.

RE: Pathline simulation, missing extraction well

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hi Peter,
yes, I attached a folder that contains all the files you listed.
Kind regards,
Nadine
Peter Vermeulen, modified 3 Years ago.

RE: Pathline simulation, missing extraction well

Jedi Knight Posts: 135 Join Date: 11/11/13 Recent Posts
Hi Nadine,

Okay, thanks! I will be in Wiesbaden coming Wednesday, maybe we can meet and discuss the issues you face shortly.

Kind regards,

Peter Vermeulen
NV
Nadine Vogel, modified 3 Years ago.

RE: Pathline simulation, missing extraction well

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hi Peter,
yes that would be great. Thanks for the offer!
Kind regards,
Nadine
NV
Nadine Vogel, modified 3 Years ago.

RE: Pathline simulation, missing extraction well

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hi Peter,
on Wednesday you said that I could change the closure criterion to get nicer pathlines. It was 0.1E-02 by default and I changed it to 0.1E-04. Unfortunately it didn't change a lot. I attach a picture where you can see the old lines in grey and the new ones in red. I also tried to simulate the model with a closure criterion of 0.1E-05 or 0.1E-06. But I got an error message then (it just said that an error occurred). So I was wondering if it just doesn't work with smaller values or if there are any other parameters that are dependent on the closure criterion which I would have to change as well?
Kind regards,
Nadine
Peter Vermeulen, modified 3 Years ago.

RE: Pathline simulation, missing extraction well (Answer)

Jedi Knight Posts: 135 Join Date: 11/11/13 Recent Posts
Hi Nadine,

Probably the pathlines have been slightly improved by increasing the closure-criterion, but the issue you are facing is the fact that the pathline iff file, rounds the coordinates to meters, which give you these "abrupt" changes in pathlines, you see this in the startpoint locations as well. I've to see whether I can improve this. Below is an example of your IFF file in bold the coordinates of your pathline which are expressed in 7 significant digits only.

1 4 0.4735476E+06 0.5526334E+07 0.9906818E+02 0.0000000E+00 0.0000000E+00 695 1112
1 4 0.4735479E+06 0.5526334E+07 0.1001267E+03 0.8182381E+00 0.4046638E-02 695 1113
1 4 0.4735485E+06 0.5526334E+07 0.1012868E+03 0.2494865E+01 0.2358915E-02 696 1113
1 4 0.4735489E+06 0.5526334E+07 0.1019254E+03 0.3745312E+01 0.1868866E-02 696 1114
1 3 0.4735496E+06 0.5526333E+07 0.1026846E+03 0.5721467E+01 0.1597278E-02 696 1114

Alternatively you might use the IPS (those pathlines looked very smooth) or change to coordinate system (divide everything by 100) to increase the number of significant digits. The latter is off course more work.

Kind regards,

Peter Vermeulen
NV
Nadine Vogel, modified 3 Years ago.

RE: Pathline simulation, missing extraction well

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hi Peter,
thanks for your answer. I was just wondering if there is any other parameter that I would have to change with the closure criterion. But I will just use the IPS instead.
Kind regards,
Nadine
Peter Vermeulen, modified 3 Years ago.

RE: Pathline simulation, missing extraction well

Jedi Knight Posts: 135 Join Date: 11/11/13 Recent Posts
Hi Nadine,

Well, maybe that is your best option for now. Good luck.

Greetings,

Peter Vermeulen