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Grid refinement

NV
Nadine Vogel, modified 3 Years ago.

Grid refinement

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hello everyone,
I have a problem with the Grid Refinement Tab in the IDF Edit Window. I tried to use a rectangular shape and refine the grid there. I kind of get a refined Grid but it is located at the upper left corner of my former IDF. The rest of my refined IDF has the same value and is coloured white. I thought it would work that way, that if I have a 25m grid and use a shape somewhere in the middle to refine it and assign the value 5 or 1 to that shape, that my IDF remains the same except for that part in the middle where the shape is located which is refined then. But I just get this shape in the corner. Do you also get this when you do a grid refinement or did I do something wrong?
Kind regards,
Nadine
Peter Vermeulen, modified 3 Years ago.

RE: Grid refinement

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

We are looking into it, we will come back to you as soon as possible.

Kind regards,
Peter Vermeulen
NV
Nadine Vogel, modified 3 Years ago.

RE: Grid refinement

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hi Peter,
thank you very much.
I also recognized that if I have a 1 m grid and use a shape to get a coarser grid in the shape, that it just makes the whole grid coarser and not just the shape.
Kind regards,
Nadine
Peter Vermeulen, modified 3 Years ago.

RE: Grid refinement

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

At this moment we are finishing the improvement of iMOD on this particular topic. We expect to release a beta-version after the weekend, that version will be suitable to apply these form of grid-refinements.

If there was a work-around for you to try to create a local-grid refinement in an IDF file I would surely let you know, however, at this moment there is no alternative, sorry.

Thanks for your question.

Kind regards,

Peter Vermeulen
NV
Nadine Vogel, modified 3 Years ago.

RE: Grid refinement

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hi Peter,
okay thanks for letting me know.
I have another question. You know how my simulations look like with those two infiltration and three extraction wells.
If I infiltrate a certain amount of water, is it possible to let iMod calculate how much of the infiltration is captured by the extraction wells and how much of the infiltration is just flowing away? I didn't really find a way to use the compute waterbalance tool for that. Is there any possibility to get those watervolumes?
Kind regards,
Nadine
Peter Vermeulen, modified 3 Years ago.

RE: Grid refinement

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

We solved the issue with the IDF rescaling, it works fine now. I'll send Mario a link to update the newest iMOD Beta version for you to try.

You other question, what you could do is simulate a model without any wells and see how much water is flowing across the boundaries of your model. Thereafter, you could compute the model with the wells and check how the water balance is changing. Any change of flow over the boundary is caused by the wells.

Kind regards,
Peter Vermeulen
NV
Nadine Vogel, modified 3 Years ago.

RE: Grid refinement

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hi Peter,
thank you very much for solving the rescaling issue. I will try it as soon as possible. And thanks for the idea on how to quantify the amount of water that is not captured by the extraction wells.
Kind regards,
Nadine
NV
Nadine Vogel, modified 3 Years ago.

RE: Grid refinement

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hi Peter,
I have one other question concernig a model simulation with a refined grid. If I start a model simulation, I have to define the spatial model dimensions. There is that one point that says: Simulate model with cellsizes equal to: ...
I have a grid with 25 m cellsizes and a denser part in the middle, that has 1 m cellsizes. Which cellsize do I choose at the point where I have to define the spatial model dimensions? I would actually think that I should not have to choose any spatial dimensions at that point if I use the refined grid. Because from my understanding the value that I choose is then used for the whole grid. Then the whole refining would be useless. I think instead there should be a possibility to refer to the refined grid.
Anyway I tried to simulate the model with 25 m as soatial dimension first because it is faster then and got that weird picture that I attached for a head distribution. So maybe iMOD has a problem with simulating a model with a refined grid, or maybe it is due to having a refined grid and a determined spatial dimension. I will try it with 1 m now which will take a bit longer. But I don't think that this will change a lot. I thought I should already let you know.
Kind regards,
Nadine

Attachments:

Peter Vermeulen, modified 3 Years ago.

RE: Grid refinement (Answer)

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

Best thing to do is, to take the grid dimension from an IDF file instead. Therefore you need to specify NSCL=0 in the header of the runfile. As we did not tested this feature on our test-facility yet, I am not sure whether that works in the recent v3.4 however. Probably it is not working properly according to your experiences emoticon We have put this on our list of improvement for the coming release.

Question: from your latest model data, the interfaces of your model looked quiet smooth, you could use a 25 x 25 m IDF file and run a 1 x 1 m model, iMODFLOW will smooth your data for you.

Kind regards,
Peter Vermeulen
NV
Nadine Vogel, modified 3 Years ago.

RE: Grid refinement

Padawan Posts: 47 Join Date: 4/26/16 Recent Posts
Hi Peter,
sorry I totally forgot to answer. Thank you for your quick answer. I ran the 1 x 1 m model with the 25 x 25 m IDF files. But it took the same time as taking my 1 x 1 m files. So I can also just use those.
Kind regards,
Nadine Vogel