Jump to content
GMS, SMS, and WMS User Forum

All Activity

This stream auto-updates     

  1. Yesterday
  2. Hi Sakura, I didn't get a chance to read the forum in a while. Sean has given you all the correct advice. You are in good hands. In summary, I would try running the model and would not worry about the warning at this stage.
  3. We are about to start a 3D dam seepage model. We have done several similar models over the last few years in a finite element, unstructured mesh model code similar to FEMWATER. This time, we've decided to start with a MODFLOW model due to funding and scheduling issues. I've been wondering if a MODFLOW-USG model will meet our needs, and eliminate the need to switch to an FEM model sometime in the future. I took a MODFLOW-USG class several years ago, and have been looking for an opportunity to use it, but have not stayed up to date with the current condition of the interface in GMS. I've done a little testing over the last few days, and I see two possible hindrances. I think I've got workarounds for both, but wanted to see if anyone else had additional ideas. 1. We definitely need to be able to look at a cross-section of the dam and show head contours on the cross-section. With a regular grid, this is straight forward as long as your cross-section is along a row or column. I don't see any cross-section cutter in the USG model. With an unstructured mesh, we are used to using the control key to select a line of elements to isolate. I do not see that that hotkey is available with an unstructured grid, but it looks like we can select and isolate a group of cells and get a similar effect - either draw a box or select with a polygon. Is that our best bet? 2. Once we have the model solution, we compute a factor of safety against uplift at all the surface nodes in the FEM model - basically we need the gradient for upward flow. We have an external code that will automatically do this for an unstructured mesh by comparing heads and elevations at nodes located at the same x,y location. If we use a regular structured gridded MODFLOW, the computation is pretty trivial using the MODFLOW arrays for the centroid elevations and computed heads and the data calculator. I am not finding the same options in the unstructured grid. I realize that the grid is not required to have layers and that the computational points are not necessarily at exactly the same x,y locations, but it seems that the only way to build the unstructured grid in GMS is with layers, so if you're using the GMS interface, it's likely a layered USG. At this point, I'm thinking writing an external code or maybe an excel macro may be my only option here and I can probably steal code from the routine we use on unstructured meshes. Is there anything I'm missing in the GMS interface that could help me here? Thanks for your advice.
  4. Hi, Is it possible in SMS as a post-processor to visualize the output results at the cell-centered for mesh using Dataset format (link below)? I know it is possible for cell-centered grid but I was wondering if for mesh it was possible. I tried to use VECTYPE to be 1 for mesh but it did not work and ND must be the number of nodes and not the number of cells. Here is the link of the format of the dataset used in SMS: https://www.xmswiki.com/wiki/SMS:ASCII_Dataset_Files_*.dat Thank you, Elodie M.
  5. Last week
  6. Is Coastal Modeling System (CMS) have the option to simulate cohesive sediments or it is only for non-cohesive sediments?
  7. Hello! I use the Hec-GeoHMS 10.1 extension in ArcGIS 10.1. After merging 65 subbasins into one basin, I'm trying to river merge all individual streams unsuccessfully. The message from the above action is: disconnected rivers or rivers meeting at confluence can not be merged. I notice that all individual streams are meeting at a confluence. I would like to ask if I'm doing something wrong or if there is an alternative methodology in order to merge all rivers in one.
  8. Dear Sean Czarniecki, Thank you very much for your kind reply. If these warnings do not influence the accuracy of modeling results I will go to the next steps. Kind regards, An,
  9. 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 about that warning. Other people may feel differently.
  10. Dear Sean Czarniecki, Thank you very much for your kind reply. I would like to fix the Warning: Cell dimensions change more than 50% between cells i=1, j=1, k=3, and i=1, j=1, k=4. Could you please give a solution to fix it? Kind regards, An,
  11. 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 layer.
  12. Dear Lalith, Thank you very much for your reply. I solved the problem but I got other errors as the attached figure. Would you please give me advise on solving these errors? Kind regards, An,
  13. Hello, Does anyone know if there are any tricks to getting SRH's pressure flow BC to run stable with overtopping? I am working with very large (>100,000 cfs) flows and have already tried varying the grid cell size in the vicinity of the bridge from 5'x5' to 20'x20'. I don't get any errors but when I plot weir flow it oscillates over a magnitude of a few thousand cfs. I am using holes in the mesh to represent piers. I have gotten the model to run stable for a few simulations, but whenever I make some changes to the mesh it's a trial and error process of trying to get the overtopping stable again. Are there any tricks or bugs I should know about? Thanks
  14. Earlier
  15. When using Modflow NWT and the UZF package and MT3DUSGS the following bug is present in GMS 10.3.7: Specifying the source concentrations in Constant Head cells and NOT as Recharge Concentration The parameters INCUZF and INCUWET (Items 7 and 9 in the input manual for sum package in Mt3DUSGS) must be specified in the SSM package for each recharge period as negative numbers otherwise as it is MT3DUSGS crashes because when they are missing it expects to read recharge concentration Here is a zip file of the model in which the correct sum package has been renamed sim.good and the one resulting from the file save in GMS is named ssm To fix this as GMS is now, one has to map the conceptual model to MT3dUSGS, save the model, manually add the two records for each stress period and run without saving
  16. Lalith

    Sarath

    http://gmstutorials-8.0.aquaveo.com/SEEP2D-SheetPile.pdf this is another similar approach
  17. http://gmstutorials-8.0.aquaveo.com/SEEP2D-SheetPile.pdf this is another similar approach
  18. Hi Sarath, My understanding about your actual condition is limited. With the understanding I grabed from your text, a simple rectilinear modflow model will do this. Diaphragm walls can be represented using a barrier with appropriate HC, (https://www.xmswiki.com/wiki/GMS:HFB_Package). I would start with single 2 layer model (1 above the excavation level and other one below that level). Best regards, Lalith
  19. Lalith

    Sarath

    Hi Sarath, My understanding about your actual condition is limited. With the understanding I grabed from your text, a simple rectilinear modflow model will do this. Diaphragm walls can be represented using a barrier with appropriate HC, (https://www.xmswiki.com/wiki/GMS:HFB_Package). I would start with single 2 layer model (1 above the excavation level and other one below that level). Best regards, Lalith
  20. Hi, Why are your horizons so much off from the solids? Where is your grid? is it completely inside your solids? Can you make only the solid edges and remove the solid faces and also add the grid with a different specified color. I would like to see both the grid and solids frames in the same figure. best, Lalith
  21. Sarath

    Sarath

    Hello, I am trying to model a support of excavation (SOE) with diaphragm walls along the perimeter of the site and install wells for dewatering within the site. We would like to see the drawdown curves inside and outside the site. Can anyone please give me a direction on this? We don't have a toe cut-off. Thanks
  22. Global Options (among nearly everything else as well) is dimmed. I am trying to export a "Native Text" MODFLOW model. Any solution to this problem.
  23. Dear Lalith, Thank you very much for your help. Unfortunately, I cannot solve this problem. You can see in the Figure after extending the boundary of the study area the Model created another error. Could you or everybody please help me to solve it. If you don't mind I could send my model to your email then you could check it easily. Again, thank you very much for your great help. Yours sincerely, An,
  24. Thanks aghamiri, I can't find any thing helpful!
  25. Thanks Bri, I am using version 10.1.11.
  26. Please make the boundaries that are used to create solids little bit larger than the boundaries used to make the modflow grid so that solids would cover the grid sufficiently (make a buffer). Sometimes, grid cells are created that crosses out the boundaries (when using specified heads for example). If the same boundaries are used to create solids, then those solids do not cover these boundary cells and provide this error.
  27. Please make the boundaries that are used to create solids little bit larger than the boundaries used to make the modflow grid so that solids would cover the grid sufficiently (make a buffer). Sometimes, grid cells are created that crosses out the boundaries (when using specified heads for example). If the same boundaries are used to create solids, then those solids do not cover these boundary cells and provide this error.
  1. Load more activity
×
×
  • Create New...