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  1. Yesterday
  2. 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 you may not want a No Flow boundary in all locations, but I don't know everything about your model.
  3. Last week
  4. Hi all, I am currently looking at the impact of elevation on the hydraulic heads in a three layer model in Modflow 6 for elevations of 1, 5 and 10 degrees. To create elevation I am manually entering values within the top and bottom elevation packages. However when running the model the cells seem to flood substantially. I have investigated the effect of recharge and hydraulic conductivity however, despite using a wide range of values for these parameters the cells in the top layer still flood substantially. I wanted to check if the problem was related to how I constructed the model and input the elevation. Are there other methods of defining elevation within Modflow6? I have attached below images of the conceptual for flat and sloping scenario for reference. Any assistance would be greatly appreciated. Many thanks, Matthew Conceptual models.pptx
  5. Earlier
  6. I have a question, are data interpolation functions integrated in the normal GMS Modflow license or do I need Pro for it? Jeroen
  7. WIALLEN, are you possibly using a Community License? If so, one of the limitations is the inability to save a shapefile. https://www.aquaveo.com/software/sms-community -Calberts
  8. Shows up on mine when I tried to "save as" a map coverage, scatter data, and annotation layer. What layer are you trying to save?
  9. Are shapefile outputs no longer supported in SMS 13.0.13? I have a layer selected and am trying to export a shapefile via "Save As" but .shp is not one of the available file types.
  10. I am attempting to model a few road crossings in HY-8. When analyzing the results for a few of the crossings I noticed the water surface profile inside the culvert seems a little odd. For example, I have a headwater that rises above the top of the culvert, yet the culvert is only running about 3/4 full. Maybe I'm imputing incorrect data somewhere or maybe it is just how HY-8 calculates the water surface profiles. Can someone explain to me why this might be the case? Attached is a picture as an example. Thanks for the help! HY8 Example Pic.tif
  11. You put the "key" value in the material property input. Then it works just like any other calibration. The "Transient Calibration Pump Test" tutorial is a model where material properties are parameterized.
  12. Hi All, I am trying to calibrate a MODFLOW model using PEST. My model has multiple layers (12). However, I do not know how to parameterize the model. Aquaveo tutorials explain it as specifying hydraulic conductivity and recharge values are negative values in different areas. However, I am not able to do this because my model is developed in such a way that these Hydro-geological properties are specified as a properties of materials and these materials are assigned to different areas in each layer. Would you please help me to parameterize my model? Thank you, Lalith
  13. Hi All, I am trying to calibrate a MODFLOW model using PEST. My model has multiple layers (12). However, I do not know how to parameterize the model. Aquaveo tutorials explain it as specifying hydraulic conductivity and recharge values are negative values in different areas. However, I am not able to do this because my model is developed in such a way that these Hydro-geological properties are specified as a properties of materials and these materials are assigned to different areas in each layer. Would you please help me to parameterize my model? Thank you, Lalith
  14. MGage


    Hi I am running a two layer elevated aquifer in modflow with the hydraulic conductivity of the lower level reduced to a negligible value to explore the impact of elevation on the water table. The problem I am having is that water is leaking into the lower aquifer. Does anyone know of an alternative way to replicate this scenario in Modflow? Thanks
  15. Thanks Sean, You've done your best to resolve the problem. I hope the GMS developers can help me to solve this issue. Best regards,
  16. Sorry that my suggestion hasn't worked out - I haven't used UGrid before, so I don't have an answer for you.
  17. Dear Sean, Thanks for your reply. I’ve done your suggestion and the result was new UGrid. When I select layer 1 and select right mouse button, there is no option to redistribute and there are Refine and Split layer options which I tried the Split layer option and the result was new UGrid (attached figure). For the new UGrid, I need to initiate the MODFLOW again and re-do all the work I have done before again. I would appreciate it if you can give me a solution to split layer one without regeneration of UGrid. Best regards,
  18. I'm developing an AdH model and when I try to assign the boundary conditions only the Pressure option is available. The Flow tab is missing. I would like to assign an inflow hydrograph at the upstream and a WSE at the downstream. If I'm missing a step please let me know. Thanks.
  19. Hi, well, I think this feature that is not working properly. Here is an excerpt from MT3D manual, that describes how it handles units: "The MT3DMS code uses any consistent units for input and output variables. In the input file to the Basic Transport Package, the user decides the units for time, length, and mass. Then, any input variable or constant should be entered in units consistent with the three basic units. ..." [chapter 6.2 of Zheng, Wang (1998): MT3DMS A modular three-dimensional multispecies transport model for simulation of advection, dispersion and chemical reactions of contaminants in groundwater systems (Release DoD_3.50.A).] There is more in the chapter, so please read it. You can contact technical support for GMS and point them to the problem. I would treat the units specifed in GMS as purely informative for the user. I think the value for a given property you specify goes directly into the input files of MT3D. And therefore if you specify values of a mass rate in terms of different units compared to what your input concentrations are, your outputs will most likely be wrong (and cannot simply be rescaled). Also if there is any nonlinear process involved in the simulation the units must be consistent otherwise the results will be wrong.
  20. Hi, i have a point source with tracer mass loading of 0.17 kg/day. mass input units can be kg, grams or milligrams, as in the GMS unit’s menu. if i use grams, the mass loading input should be 170 g/day, and respectively for mg. the problem is with the output concentration units. i can chose between g/lit, mg/lit, ppm or ppb. if i use concentration units of mg/lit, and change the mass units while updating the source value, i get different values for the solution. it seems that the model is ignoring the input units, and take into consideration only the mass value itself. for example - using 0.17 kg/day doesn't multiple with the correction factor for the output units, and i get very low concentration. i would appreciate any advice. Thanks, Yoni
  21. 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.
  22. Dear Sean, Thanks for your reply. I have a very sophisticated MODFLOW 6 model with Octree grid and I’ve calibrated and validated the model (attached figures). If I want to split layer 1, the Ugrid will be regenerated again and I need to define again the materials and probably calibrate the model. How I can split layer 1 without regenerating the Ugrid? Thanks,
  23. Hi, my model terminated with the error below "allocation of arrays x y z and xhs failed returned. error message number 41" How can I solve this? Thank you
  24. 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).
  25. Dear all, I am trying to model a “subsurface dam” using the Horizontal Flow Barrier (HFB) package which simulates thin low-permeability geologic features to impede the horizontal flow of groundwater. I have a model with two alluvium layers which are shown in the attached schematic figure. In the HFB package, the cell boundary represents a vertical face between two adjacent cells. The question here is how I can define a barrier within one cell (layer) up to a specific level rather than the whole cell thickness (like layer 1 in the figure). Your help and insight would be highly appreciated. Best regards,
  26. Hi forum! I'm a first-time user of SMS and SRH-2D. My question to group is, has anyone had trouble getting obstructions to apply to their model run, or know special tricks to get program to recognize and apply the obstruction? I started with a feature line stretching part-ways across a channel in order to divert more water into another, to represent a jumble of beaver-cut logs that I observed in the field which are generating a new flow pattern. That didn't cause any effects. I began playing with the obstruction layer until it consisted of a long solid 50-ft tall wall across the main branch of the channel, plus several point obstructions with large diameters around it to see if I could generate a change. It had zero effects. I have completely deleted the obstruction layer and tried building a new one in a different location. I also tried it at very low (to match a field measurement Q) and at very high (Q100) flood values, still to no effect. The obstruction coverage is definitely associated to my SRH simulations. I believe I have set my Z elevation correctly (represents bottom of the obstruction), set a wide obstruction width, set Z thickness higher than WSE, included an appropriate drag coefficient, and played with porosity values between 0-1. What am I missing? Do I need to line up obstructions on mesh nodes, completely regenerate a new mesh, or is there some other trick to getting program to recognize it? Do I need to delete output files somewhere so that program knows it should rewrite them? I have read the SMS user manual on this topic which doesn't say much about troubleshooting. After adding the obstruction with no effects, I also went back and took the tutorial on this subject and the features that I created in the tutorial worked just fine when I ran that simulation. Screen capture below showing z elevation, obstruction parameters, approximate elevation of WSE, and obstruction location provided. This is just one scenario I've tested in order to just try to elicit a response from the model.
  27. Hi, I agree it is poorly documented. I had to dig into the source codes to figure it out. It seems to be an excess infiltration volume rejected by the model. It can be routed to other packages as described in the ModelMuse documentation: "If the applied infiltration rate is larger than the vertical hydraulic conductivity, the actual infiltration will be reduced to the vertical hydraulic conductivity. Any remaining potential infiltration will be available to the MVR package as rejected infiltration." So I guess if you lower your infiltration rate this term should approach zero. I have no idea why the text description in the budget file states "HORT+DUNN". Maybe somebody else could clarify that.
  28. Hi, I have created MODFLOW model for a region near the coastline and It ran successfully in both steady and transient state. Currently there is no sink or source terms to make the model simple. Once the model achieve a stable solution, they will be added later. Then, I tried to run it in with SEAWAT and model shows the error that Memory is not enough. I tried both Parallel, 64Bit options as well as both of them in combination but did not get any luck. The way that I ran the SEAWAT model is as follows. I assume that I did it correct but please let me know if you have any alternative ways. 1. Run MODFLOW in steady state. 2. Change the model and output to transient state. 3. Assign steady state heads in step 1 above as the initial heads for the run. 4. Map MODFLOW to the grid. 5. Map MT3DMS to the grid. 6. Run SEAWAT. My model grid has 512 x 646 x 12 cells (12 layers). Number of total and active cells are 3,969,024 and 1,416,464 respectively . Since I did not have any success in running the model in GMS, I decided to run the SEAWAT model in text based USGS format. I exported the MODFLOW model from GMS to the regular text based USGS format. However, I do not see such a format change for either MT3DMS and SEAWAT option in GMS. 1. I assume that either MT3DMS or SEAWAT does not require such a conversion. Please correct me if I am incorrect. 2. Also, I think that the SEAWAT name file in the SEAWAT folder that GMS produces (.swn file) may not be the correct one to run SEAWAT in USGS format because the type, format, number of files and the content in the files are different. Please see the files and sizes of GMS and USGS formats of MODFLOW in the screen shots below. Can you please advise me how to make the name file to run in USGS format using these GMS files? I am planning to use the USGS version of SEAWAT executable and/source code to run the model since Aquaveo executable might have been customized to its data file types and may not match the requirements. Please let me know if you have any suggestion on this. I very much appreciate all your thoughts, suggestions and help to resolve this issue. Best regards, Lalith
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