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Sean Czarniecki

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Everything posted by Sean Czarniecki

  1. I have Build 10.4.10 installed and I see the Horizons -> 3D Mesh option come up when I look for it. My only guess is that your license doesn't include the 3D Mesh module. The pop-up box you show on your screen shot actually covers up the view of the available module icons, so I can't answer that by looking at your screen. However, the location where the 2D Mesh module would normally be (between the solids module and the 2D grid module) does not show the icon for the 2D Mesh module, so I'm guessing that you don't have either of the 2D Mesh or 3D Mesh modules. You can figure this out by l
  2. If I have this right, multipliers for Recharge in MODFLOW are not applied on a cell-specific basis, but rather by stress period across the entire grid. Therefore, if you want different multipliers for each stress period, you can do this in a spreadsheet (one column), copy the cells, and drop them into the GMS recharge input box. If you need to multiply different areas of your grid, you will have to do that manually, but creating data sets (one for each recharge and one for the multipliers) and multiplying the data sets before pulling them into the recharge rate input. Right now, that's
  3. If your river stage is below the river bottom, then you definitely want to switch to one of the stream packages. The stream packages allow the river/stream to go up and down based on the surrounding groundwater elevation and flows in the stream.
  4. Okay - so the way your first post was worded, it sounded like you were getting different head results in the NWT than the USG runs. Your latest post suggests that what you are comparing are "observation" results (which is probably why the topic is titled as it is). Can you confirm that? Can you also confirm that by manually checking cells in the NWT and USG simulations that the heads are similar? I know that I had issues with observations in my USG simulations (and seem to recall asking about it as well - there might even be a post on this board about it), so I managed it in other ways (se
  5. I think the difference may be in the MODFLOW build itself. While working with MODFLOW-USG a couple of years ago (which, if I understand correctly, would use similar code to MODFLOW-NWT), an updated version came out which changed how calculations were performed for "dry" cells (due to users who didn't agree with how the solver handled those cells). It changed my model results and would have negated the work I had done for half a year. Working with the GMS developers, we solved it by using the older MODFLOW executable during my model runs. It is easy to do this by directing GMS to run the ol
  6. Well, based on what I'm seeing, you have one side of your model that has a constant head boundary condition and the other 3 are No flow boundaries. If this is the case, the only way for the water (which you are adding through recharge) to leave the model is through the constant head boundary. Therefore, the groundwater elevation has to get high enough for the gradient to want to flow towards the constant head. At a minimum, it will need to be at the elevation of the constant head boundary. If the conductivity of the peat layer is too low, this will create quite a mound. I'm thinking that y
  7. Sorry that my suggestion hasn't worked out - I haven't used UGrid before, so I don't have an answer for you.
  8. An excellent question. I don't know if the GMS tools will work to do this or not with the Ugrid (I haven't tried it in your situation). In other cases, I would take a side view of the grid (general mode), select the layer with the layer select tool, right mouse button, redistribute from 1 to 2 layers.
  9. To simulate it exactly as you show it, you would have to split Layer 1 into 2 layers, so that the HFB goes up to the elevation you choose. The other way to do it (without splitting layers) could be to allow flow through the HFB that is equivalent to the fraction of layer thickness that is open (the HFB is across the full thickness, but not totally impermeable).
  10. The 3 sides with rock don't need anything. The 4th side needs some condition to allow water to leave (or enter), such as a constant or general head boundary...river/stream, etc.
  11. Tough to describe here, but I'll try to do it briefly. You actually have to set it up to have 2 values for the same time. The first value would be zero and then second will be one. Then when you want to end having it be one, you make another entry for that same time and make it zero. It ensures that there is no averaging from one time step to the next.
  12. Interesting. I don't really have time to look into it further, so I'll brainstorm with you. I'm wondering if setting IPHDRY to a positive number could be causing the problem, depending on what you are setting HDRY at. Try putting IPHDRY to 0 to see what happens. The cell would then clearly not be available for particles. " IPHDRY is a flag that indicates whether groundwater head will be set to HDRY when the groundwater head is less than 1×10-4 above the cell bottom (units defined by LENUNI). • If IPHDRY=0, then head w
  13. Is that output line at the end showing top and bottom elevation of the specified cell (which appears to be reversed), or the head and the bottom elevation in the cell?
  14. You can just select cells manually and change the conductivity in the properties dialog....or set up a coverage with polygons to change just small areas when it maps over to MODFLOW. Test it out so that you can confirm everything else remains the same when you map it over.
  15. So let me tell you something that might help you to figure out what is going on. I had built a model using MODFLOW-USG....one of the reasons was because it managed dry cells without actually making them dry (model converged with no issue). Well, after months of working with this model, a newer MODFLOW-USG executable came out (and was being used in GMS) that eliminated that part of the programming (I guess it was not helpful to some people - enough complaints got the programming changed). Well, that certainly messed up my modeling. It wouldn't converge anymore. The solution was ultimately
  16. It would only use it during transient runs.
  17. Open up your output file and see if it gives you more details about the issue. It could be that you've got more time steps than the variable allows. I'm not sure what that array value is, but it sounds like that could be the issue.
  18. The only ways you can fix this is to either add more layers or change the thickness of your layers.....neither of which you probably want to do. If you read up on MODFLOW, you will see that it prefers if you don't make big transitions, but it will still be okay if you have them. We often have a thin confining layer (e.g., 1 m thick) above a thicker layer. For that warning to go away, you would have to make the next layer below no greater than 1.5 m thick, then another below that no greater than 2.25 m thick.....etc. You can see that this is often not practical. I suggest you don't worry a
  19. Warnings are not always a problem. The Cell Dimensions warning is telling you that the model results will be better if you have a smoother transition from smaller cells to larger cells (this will often come up based on layer thickness differences). The model will still work - this isn't usually a big concern. The second set of warnings is pretty clear - you need to establish hydraulic conductivities in layers 4 through 8....check your materials. You can also make these changes in other ways by opening the LPF package and editing layers individually, or by making coverages for each laye
  20. The entire layer is blocked. If you need it to stop at a certain elevation, you need to set the bottom elevation of the layer at that elevation.
  21. Under the Grid menu, there is an option for MODFLOW Layers -> 2D Scatter Points. Under there, select the flow package properties.
  22. You have to go under display and go into General Mode instead of Ortho Mode. You will then be able to rotate the display in all directions. Note that if you are in a multi-layer model, you may need to select other layers and hide them as all layers become visible at the same time in General Mode.
  23. http://www.aquaveo.com/software/gms-learning go into the tutorials under the Conceptual Model modules (by going through 1 and 3, you should be able to figure out how to define different layer extents).
  24. Yes. However, if it is bigger than the current extent, you will have to expand the overall grid and then inactivate the cells outside of the current extent in your current layer. You can cut the layer using the grid tools and then change the extent of the second layer as necessary by inactivating cells beyond whatever extent you are looking for. You can do a lot of this by making a boundary polygon for each layer (see the GMS tutorials).
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