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Found 27 results

  1. Dear members, I am trying to generate velocity vectors in a density dependent model. The GMS is displaying error, pic of which is attached below. I have been generating velocity vectors and never faced any such problem. I am not able to work out solution to this problem. Any help would be appreciated. Thank You
  2. Tom said to mention this here on behalf of technical support. When exporting native text MODFLOW files, the files are not updated with new information. For example put new information into the MODFLOW | Global Options | Optional Packages | RCH package and click OK. Unless the project is manually saved after making the edit and before exporting the native text file those changes aren't saved, but users may not realize clicking OK doesn't update the files. It may be helpful for the user to receive a reminder that 'You have not yet saved your changes to the model. Would you like to save these changes before exporting the native files?' or something along those lines.
  3. Hi everyone, I am currently doing a project regarding in-situ chemical oxidation of BTEX using persulfate solution, and trying to use RT3D to represent the process. As reading the literature the reaction should be a pseudo 1st-order kinetic reaction model, but the only relevant option I found in the reaction package is the inst. aerobic degradation of BTEX which only offers oxygen as the electron acceptor. In this case, could someone familiar with the persulfate or other similar oxidation mechanisms tell how to construct the RT3D model? convert the persulfate concentration to an equivalent oxygen concentration? or should I try more options other than MODFLOW? Regards Dylan
  4. Hi all, I have come up with some errors when running the tute model of TUTE: MODFLOW – Generating Data from Solids that indicate “changing heads are below the bottom of cell xxx". It is so weird that a tute brings up a problem like this. Having read a thread in the forum suggesting to remove the BC of constant heads from the sources sinks coverage, I found many cells dry out with red triangular flags after a modflow run. I knew it was different from what is instructed in the tute sheet, but it seems plausible for me that without those BC these cells could dry out. A further question is, i was constructing a more complex multi-layer solids model and tried to convert to modflow. My BCs are constant heads set on the arc of the coverage boundary, kind of surrounding my small catchment of interest, and they are definitely all below the bottom of my first, second and part of the third layer, so how to define the default layer range? (i.e. from 1 to 1, 3 to 12 as I have 12 layers in total, or 1 to 12?). PS: in this coverage I define wells, specific head, layer range for source sink and layer range for areal properties, and tick used for BC option. The first trial I have set was 1 to 12 (dont know if appropriate), converted map to modflow, and could see the blue dots assigned from layer1 to 12 of my conceptual model. All of them indicate the some heads I define in the coverage. (Really? Does it have to be a 58 m head in the even very bottom of my rock layer of 30 m elevation?). As expected, the model warned that lots of heads were below cells' bottom. When removing all of them in sources sinks and running the model in steady state, I found it never converge. A feeling was that I did it wrong when defining BCs. This is where I got confused. Could anyone kindly help? I am using GMS Version 10.0 Thanks for any help Rgds Dylan
  5. Hi, I've been trying to calibrate my transient model using PEST, however I'm experiencing some difficulties. It executes the estimation process and finishes the parameter estimation but it fail's to give me any new values for the chosen parameters. This only happens when I try to calibrate it as a transient model. When I run it in steady state there are no problems and it estimates new values for my parameters. When I run it as a transient model there is a message in the PSLAVES windows that pops which states that the "Total sum of squared, weighted residuals: NaN", and I think the problems lies here. However I'm not sure how to fix it. If anyone has any idea what's causing this and could help me with a solution I would be very grateful. Jonas
  6. I am using GMS 10.1.3 and trying to import a MODFLOW NWT model obtained from the USGS. The model appears to import okay, but when I run MODFLOW, it quits after several seconds with the note "MODFLOW terminated with error!" The OUT file states "model stopping due to reach altitude error." Upon further examination of the OUT file, there are warnings for each stream segment that "upstream elevation is equal to or lower than downstream elevation" and the streambed properties listed in the file indeed streambed elevations all set to zero. Looking at the SFR2 package through GMS shows all stream segments ELEVUP and ELEVDN set at zero for stress period one. For all other stress periods, there is data provided for ELEVUP, but ELEVDN remains universally set at zero. I can copy the ELEVUP data from a later stress period and apply this to stress period one, but without ELEVDN data, the altitude errors still occur, terminating MODFLOW. It appears that when importing the file, GMS does not pick up the streambed elevation data. Any help will be much appreciated.
  7. I'm a newer user building a MODFLOW model that I will then need to teach others how the model was constructed, I am establishing a coverage for the WEL package that will use a point shapefile from another model to inform the location and pumping/abstraction rates. One of the attributes in the shapefile is "Layer", identifying the layer of the well in the 10 layers of the model. I was shown how to create the coverage but I wanted to understand the rationale for selecting the Layer Range item in the Source/Sink/BCs list. I'm guessing this allows the use of the Layer attribute to map the points to specific layers in the Solid and Grid models, assuming they appear within layers 1 to 10, as specified. Also, I had a question about the "Use to define model boundary (active area)" check box. I have conflicting information as to when that should be checked in a coverage. My intuition tells me that is would only apply to feature objects that define the model boundary and not necessarily other boundary conditions that are applied to the model boundary conditions. For example, given one coverage (a polygon) that defines the extent of the active region of the model across all layers is create with the "Use to define..." item checked. If separate coverage was created that defines a constant head on layers along one edge of the active model domain, already identified as active in the other coverage, does the box need to be checked? When should it be check and not? Is there a danger in checking the box when it shouldn't. Any insights are appreciated Ted
  8. Hi, I need to know if it's possible (and how) to export with GMS grid parameter data of a model into shapefile such as : - Ibound - Hydraulic conductivity, Anisotropy - Porosity, Ss I've already exported CCF file with the Export function (see my previous topic) but it didn't include all the modflow code/parameters. Can you help ? Thanks
  9. Hi everyody, I work with GMS 10.1. I need to export the information of flows of a steady state model realised on Modflow 2005 with GMS. Is there a way to recuperate a file in ASCII form (or equivalent) with flow values of every faces of the mesh's of the grid ? Thanks for your help
  10. I've a Local Model of a site that include a slope from 300 to 350 m asl. A cross-section is attached to the post. I set up a Modflow Ugrid model with only 1 layer. Now I'm asked to insert a Barrier, so I need a new layer because Barriers don't reach the bottom of the aquifer. Is it correct to insert a new layer with constant top elevation (320 m abs) and set inactive the cells where the top elevation is less than 320? The Coverage for the Boundary condition (CHD at elevation 300 m asl, see attached cross section) is to be set to Autoassign BC including lower cells? How can I set the same boundary condition if it starts at an elevation of 325 m asl and ends at 300 m asl? Thank you aquaveo-h1.pdf
  11. I've create a multi layer Modflow model (3 layers) converted from a Solid Model (LPF, material ID). The idraulic properties are assigned by means of material ID, one for each layer. a. HK_a for layer 1 b. HK_b, for layer 2 c. HK_c, for layer 3 Now I need the to include a new building with foundations below the ground elevation and above layer 2. The building foundation has a different HK_d << HK_a, HK_b, HK_c. I create a new coverage with material properties and layer range. I assign the new HK to the polygon representing the buiding. I try Map to Modflow but when I query the Modflow cells the HK value is not changed. How can I assign it to cells inside the polygon representing the buiding area? My workround is to select intersecting cells by polyon and manual assign the material ID. Thank you Daniele
  12. I've create a multi layer Modflow model (2 layers). I've a coverage (coverage 1) defining the domain. The coverage is divided in two polygons ( polygon A e B ) for setting the HK: a. HK_a, for polygon A, layer 1 to 2 b. HK_b, for a polygon B, only layer 1 c. HK_c, for the same polygon B, only layer 2 I duplicate coverage 1, coverage 1.1 e coverate 1.2. I make these assignments: -coverage 1.1 to layer 1 -coverage 1.1 to layer 2. Is it correct or there is a different approach? Thank you Daniele
  13. hello, i am trying to compare head value datasets from two models. the x and y dimensions and cell sizes are the same, however the second model has 4 layers instead of one. i just want to compute the head difference of the two models. thanks
  14. Hi, I am trying to simulate a scenario where the boundary head is gradually varying with time. Another scenario I am trying is to simulate coastal aquifer with seaside boundary head varying as per tidal variations of sea level. As far as I know, in given stress period the specified head remains constant. Therefore continuous head variation cannot be achieved and it has to be approximated by series of step changes. This will result in huge number of stress periods. Is there any alternate more efficient way to simulate such scenario? Thanks in advance. Saubhagya
  15. I'm working on a model using GMS, and I need to convert the modflow hdf5 files from GMS to original modflow files (from HDF5 to ASCII) so I can use it in GW Vistas. I found a link which provide a way to do that, but I can't run gms2mf2k.exe provided in this link. How can I convert the HDF5 files? thank you
  16. Hello. I have a MODFLOW model developed using GMS. The model domain is like a rectangle rotated about 30degree clockwise. the north and south boundaries are no-flow boundary. But, the east and west boundaries are defined as general head boundary (GHB). The flow direction in the domain is always from northwest to southeast. I want to run the model as steady-state, I have quarterly measurements of water levels in couple wells inside model domain. My question is where should I get the head, and conductance to set-up my GHBs in the west and east boundaries? Is there any general rule that I should follow? Thanks, bk
  17. Aloha, I have been trying to use the horizontal anisotropy function to model an area that has many dikes of similar strike. I'm not exactly sure what GMS is doing, however, becaue I can not find any documentation, on forums or the wiki, about how this feature works with the MODFLOW LFP package . For example is the anisotropy always aligned with grid cells? Is there anywhere else to access the feature besides the LPF dialog? If anyone can point me to documentation about this, or can explain it I would be much appreciative! Thanks,
  18. Hi everyone, I'm trying to run MODFLOW, using ModelMuse. My goal is running GSFLOW after I get some results from the ModelMuse. However, Whenever I try to run the ModelMuse, the ModelMonitor indicates me the "Errors and Warnings in Listing File". It says that 24:Illegal File Type in Name File: NWT or UPW. (I'm using MODFLOW-NWT). What should I do to fix this problem?
  19. Hi everyone, I am trying to build a transient model to model lake-aquifer interaction using LAK3 package. At first, I’ve built a steady model without any problem. But when I change this model into the transient one, it can't run. I also checked my model. There is no error. If I inactivate the lake package, the transient model works correctly. I don’t know why this happens to my model? Does LAK3 package have a problem with transient modeling or special settings are needed? Thank you guys,
  20. When viewing a MODFLOW model using the Lake package (LAK), the Lake cells cannot normally be selected, unless either viewing the Ibound dataset or changing 3D Grid Display Options for Inactive cells. Note that the cells in Ortho mode appear to be missing (empty fill), as they are inactive, but still have a Lake MODFLOW BC Symbol in the center. The error message when attempting to select a Lake cell is "You must first select a gridcell(s) in order to change its attributes." This is because the cells are coded as inactive (IBOUND = 0), as specified by the LAK Package. It would be nice to allow the the "Select Cells" tool to be allowed to select cells that use the Lake BC, without needing to change the inactive cell option in the 3D Grid Display option or when viewing the Ibound dataset.
  21. With the "Grid Overlay" method of the "Solids -> MODFLOW" operation, I would like to have a thickness bias option. This would be easy to add to the existing dialog (underneath Minimum Thickness): The purpose of allowing a thickness bias option of, e.g. 0.75, would create thinner grid cells near the top, and thicker grid cells near the bottom. This bias principle is the same when creating a 3D Grid for MODFLOW, and should not be difficult to enable. Currently there isn't a bias control, so it is effectively 1, which creates equal cell thicknesses for all layers at a given grid location. Simply put, there is better geologic data and more interesting GW interactions near the surface, so I would like the grid to be refined near the surface. As a result of more geologic information near the surface, my Solids data are often more detailed near the surface, and less detailed and with less certainty at depth. This level of detail near the surface is neglected with no bias control.
  22. Hi, I'm trying to run a transient flow model for 28 days. I have constant head arcs (stresses) that turn on and off during various times during 28 days (for example 7 to 14 days or 14 to 21 days). When i run the flow model GMS is assigning the constant head to the grid cells at the location of arcs for the entire duration (28 days) when the constant head has been assigned for only few days. Not sure why GMS is extending the constant head stress to the entire duration. If i go into grid source/sinks and look at various stress periods, GMS autimatically uses data from previous stress periods. I have stress periods setup correctly. Any suggestions would be greatly appreciated.
  23. Dear all I am new with GMS. and have trouble modeling multiple pumping well to see the total drawdown. I have three layer of clay, silt and sand. I wanna see how much water I should pump and from which layer to get certain drawdown. so I worked backward. giving discharge I checked the result drawdown. I am interested to use wellpoint system in the silt layer (instead of deep well in sand layer) now the question is, why in modflow I can assign any discharge to the well? I expected MODFLOW to give error saying because of low pearmiability this much discharge is not possible to be taken from clay/silt. but that's not the case. any discharge I put in, the modele solve the problem and give me drawdown for it! I used FEMWATER as well, for the same question, and it also solve for any discharge I define!!! That looks wiered to me this can't recognize the layer can't provid a lot water?!! any help is highly appreciated, Zara
  24. Dear all, I do appreciate if you can help me with this problem: I had a square area with 4 cutoff walls around it. and some wells are going to be inside the area to dry it. first I modeled a cross section in Seep2D to see how the wells dry the area. I attached a picture of results. the results looks fine. but I wonder why when I model it in Modflow, as 3D model, the seepage (vertical gradient) is not as continuous as it was in SEEP2D . I attached image here. it sounds like any cell in one aquifer layer has almost the same head pressure along its depth!!! so should I divide my aquifer to multiple layers to get more accurate results? Thank you for any help.
  25. Dear all I have trouble modeling a square site with different BC. at one side I have river (I put constant head as BC) and no problem in that for modeling. now, 1) at one side I have rock (no flow coming in or out from site at this side) and 2) at other side of square area I have no BC (I mean the water can flow out of area etc) what is the difference in modeling number 1 and 2? how to difine them in my model? my model currently have active cells in coverage so I think it means all sides I have rock, right? Thank you, Zara