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Found 23 results

  1. 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
  2. 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
  3. Often when I initiate a PEST run with SVD-assist and NOPTMAX = -2 or -1 the process ends with the message "cannot find Jacobian array file". The process starts with a calculation of the Jacobian matrix: But ends like this: It always works when I run the model without pilot points. A forward run with the pilot points also works. I have managed to run both a parameter estimation and NSCM with SVD-assists before with the same model constraints but when experience this problem when I attempt to make changes in the model. Ideas on how to solve this issue?
  4. Please consider adding support for drawdown observation data - particularly as it would pertain to parameter estimation simulations. For MODFLOW-2000/2005/NWT where the observation process is being used, this change would be relatively easy to implement via a change to the ITT flag value. For MODFLOW-USG, the change may be even easier to implement through an additional call to usgmod2obs that extracts relevant simulated drawdown values. It would also be useful to provide an option to pause PEST execution following creation of the input files - the control file, in particular. -Mike
  5. Hello dear users and the developers, I am having a problem with Transient PEST calibration (GMS version 10.2.3). My model consists of 1 layer UGrid and have boundary conditions of specified head (along the coast, 0) and GHB. I have done several PEST runs with 90 pilot points in steady state condition. It worked and got results. In the calibration window, it was showing the flow of parameters changing, the graph was being drawn. Then, I changed it to 7 years long transient model. The forward transient run with MODFLOW-USG was successfully done. But when it comes to transient PEST calibration with 90 pilot points, there is nothing going on in the window. No parameters showing up, just the time passes and it says parameter estimation finished. But no results. When I close it with "read the solution", it gives an error saying that: boost::filesystem::remove: The process cannot access the file because it is being used by another process: "C:\Users\user\AppData\Local\Temp\GMS_10980\ppest\slave1\GMS FILE NAME.ba6" During the Parallel PEST run, several cmd.exe are working besides pslave.exe. In the cmd.exe, there is something written by the developer: "Note: This program reads a MODFLOW-USG unformatted file. Sometimes there are problems in reading files of this type due to incompatibilities between different FORTRAN compliers. If there are any such problems please contact ... and I will send you an alternative copy of this program." Can this be the problem of mine in my case? Should I contact the person to ask for the alternative copy? Or what do you recommend? Thank you! Best, Cansu
  6. Hello, For a very long time, I have been trying to create a numerical model of an aquifer with complex hydrogeology (by using borehole-to-Ugrid option). I had several layers of 4 different materials. But all my efforts were trash. Because, I have never obtain a successful Modflow-usg run. They never converged. Although wetting option was on, the aquifer had so many dry cells. And these dry cells were always at same locations (not near/at the location of wells). It was meaningless. I couldn't run the PEST. So I decided to make my system more basic and created a one-layer model with HK zones. It worked well without the wetting. I have applied pilot points approach for the calibration. And pest is working because the forward run has a successful result. However, this time the calculated residual is too high. I have done many things to decrease the error. But the best result until now is about 7000 (Sum of Squared Weighted Residual Head+Flow) and for Root mean squared residual it is 16. These values are so big. Interestingly, the computed vs. observed head plot (attached) looks not so bad that there should be a way to fit them to the line. I only have head observations in my hand and I don't have any flow observations data. May this be the problem? Or what may be the problem? Could you please help me on this? I would be so happy to hear your recommendations to lower my calibration error to an acceptable value. Note: The computed heads are higher than the measured heads. The boundary conditions are ; specified head along the coast and GHB condition was assigned to some part of the boundary. The model is steady-state. Thank you! Best, Cansu
  7. Hello everyone, Can someone tell me if there's a limited number of observation points using MODFLOW USG? I have 77 observation points for my model, but when I create the files in GMS it considers only 7 of them! I started my model from scratch using MODFLOW-USG, so I cannot import the 3D Grid files as exemplified in the tutorial. Another thing that occurs in my model after running it, is that the observation targets don't show the same value as the generated head surface?! Can you help me? Best regards Filipe Miguéns
  8. Hello, I have encountered a problem with exporting native modflow files from GMS. Some of the model parameters are defined using Pilot points. Lets say that I would like to use different version of MODFLOW to calibrate the model. I have succesfully exported the MODFLOW native files and I was able to start USGS version of modflow. The input data are read correctly, first stress period is solved, however during the second period MODFLOW stops. Here is the end of the output file: PERCENT DISCREPANCY = -0.03 PERCENT DISCREPANCY = -0.03 TIME SUMMARY AT END OF TIME STEP 1 IN STRESS PERIOD 1 SECONDS MINUTES HOURS DAYS YEARS ----------------------------------------------------------- TIME STEP LENGTH 2.67840E+06 44640. 744.00 31.000 8.48734E-02 STRESS PERIOD TIME 2.67840E+06 44640. 744.00 31.000 8.48734E-02 TOTAL TIME 2.67840E+06 44640. 744.00 31.000 8.48734E-02 1 1 STRESS PERIOD NO. 2, LENGTH = 29.00000 ----------------------------------------------- NUMBER OF TIME STEPS = 1 MULTIPLIER FOR DELT = 1.000 INITIAL TIME STEP SIZE = 29.00000 PARAMETER "sc1v1 " IN PARAMETER INPUT FILE HAS NOT BEEN DEFINED -- STOP EXECUTION PARAMETER "sc1v2 " IN PARAMETER INPUT FILE HAS NOT BEEN DEFINED -- STOP EXECUTION PARAMETER "sc1v3 " IN PARAMETER INPUT FILE HAS NOT BEEN DEFINED -- STOP EXECUTION PARAMETER "sc1v4 " IN PARAMETER INPUT FILE HAS NOT BEEN DEFINED -- STOP EXECUTION .... PARAMETER "GHB_3405 " IN PARAMETER INPUT FILE HAS NOT BEEN DEFINED -- STOP EXECUTION PARAMETER "GHB_3409 " IN PARAMETER INPUT FILE HAS NOT BEEN DEFINED -- STOP EXECUTION PARAMETER "GHB_3406 " IN PARAMETER INPUT FILE HAS NOT BEEN DEFINED -- STOP EXECUTION When modflow starts no interpolation is performed for the pilot points. I assume there is some custom routine in the GMS version that handles the interpolation from PP to the MF grid array. Please advice how this is supposed to be handled or what am I doing wrong.
  9. I have problems running PEST NSMC with fixed pilot points. Both in my own model and in the NSMC tutorial files, I get the same error message "Cannot open parameter value file nsmcII_200_random_nul.par." and the simulation finishes without completing any iteration. Is this a bug i in GMS? Kind regards, Jonas
  10. Hello, it is often the case to treat WEL package data (e. g. well pumping/injection rate or specified flow BCs) as adjustable parameters when doing inverse modelling for parameter estimation or optimisation. I would like to see a better GMS handlig of this. One cannot use conceptual model at all when trying to define specified inflow BCs as parameters, because GMS treats the Key value as flow rate and distribute it between the cells intersected by the BC conceptual model geometry. In the case of pumping well it is possible to specify Key value in the conceptual model and map it to MODFLOW (hopefully) correctly. However there is no check whether this exact Key value does not appear in the regular pumping data. This could easily lead to an error. Especialy when the model is continuosly used and the pumping data with some key values are reasigned over and over during the model application. I would consider wise to be able to specify in GMS whether a particular value is Key value or not and to treat it accordingly in GMS. Also a model checker should check for conflicts in the WEL package for the reasons described above. This obviously extends to MNW package as well. I am wondering if anybody else experienced this problem and would like to see this implemented.
  11. I often experience problems when running a PEST parameter estimation model with SVD-assist. I find it quite arbitrary when it work and when it does not work. For some occasions it seems to work just by moving the modelling files to another computer and run the model on that workstation. For my current model, SVD works but SVD-assist does not. To reach reasonable results with NSMC is even more problematic, in particular for transient models. I run the latest nightly build and NWT as solver. Someone with similar experiences or suggestions to a more streamlined and stable model procedure?
  12. PEST has the ability to calculate the Jacobian once and use the same Jacobian for subsequent parameter estimation for faster simulations, but less-accurate results. This is a request for an option within GMS to run PEST with only a single Jacobian Calculation, but for more than one run. This should enable large calibration projects to be much more efficient where accuracy is relatively less important due to the size of the project.
  13. Jonas

    PEST and Kriging

    Hi, When i customize the variogram for the pilot points of the HK-field in the nsmc I and II tutorials, and also in my own models, I encounter the problem showed in the attached figure. It seems like the whole field is generated from only one point and not all available ones. I also edited the already set up variogram in the tutorials, and then changed back to its original form and still got the same problem. Any ideas on how to solve this issue? Kind regards, Jonas
  14. Hi, I am trying to get GMS to calibrate a specified flow boundary that I assigned to my model. The boundary was created by using a coverage polygon. However, when I try to initialize the boundary to PEST, I can't get PEST to recognize the specified flow boundary. Does GMS support PEST calibration of specified flow boundaries? Is there a step that I'm missing? -Josue
  15. Hi again! I attempt to use Null Space Monte Carlo in a similar manner as presented in PEST - Null Space Monte Carlo I tutorial (http://gmstutorials-10.1.aquaveo.com/MODFLOW-StochasticModeling-NullSpaceMonteCarloI.pdf) As presented in the attached text file I have some model that converge although most models does not converge for some reason (Ideas on how to adress this are also appreciated). As seen in the text file, there are different calculated values for the pilot points between the four converged solutions. The bpa files for the different solutions are also different. All good so far. My issue is that there is no difference between the grid files of the HK parameter for the four different solutions. Any ideas on how to solve this issue? Could it have something to do with the Kriging process? Best regards, Jonas T40_nsmc.txt
  16. Hi! I have set up a model for a municipal water supply in an glacifluvial esker. I want to calibrate the hydraulic conductivity (HK) against steady-state heads in the esker material with PEST and pilot points. I also have other materials in the model but with a fixed HK. The recharge is also calibrated with PEST in three different polygons. The picture below shows layer four (of five). Left shows materials (only bedrock and esker in this layer) together with locations of the pilot points. The middle part shows calibrated heads after PEST has been running. Right shows HK after calibration with PEST. My issue is that the area with esker material (left) does not overlap the area that is calibrated with pilot points in the rightmost picture (non red area). Something that looks strange in particular is the straight paths from the middle to the south of the model that get the same HK as the bedrock although the material is set to esker. It is the same issue in the other layers of the model. Ideas on how to solve this issue are appreciated. Kind regards, Jonas
  17. 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
  18. When running PEST in parallel, it would be good if you could specify where the PSLAVE directories are saved to. In cases of large projects, it would allow the ability to save the files to a different drive to avoid crashing due to lack of room on the C drive.
  19. I am running a model and refined it using the pilot points and am using the HUF package rather than the LPF package as suggested in the tutorial. I am trying to import the optimum values back to the model and do not see a way to attach them to the associated material. I have tried running the model after importing the optimal values and I again get my initial huge errors as the pilot points were never imported. If you have any advice on how to import these values it would be much appreciated. Version is 10.0.11 Greg
  20. Hi, When I try to merge multiple coverages that have specified observed flow to a specific arc group, the merged coverage does not contain all arc groups from the original coverages, but only some of them (not the same arcs every time). Any suggestions how to deal with this, or a different approach to assigned multiple instances of observed flow to complex arc groups? I know there are ways to manually group the arcs in a single coverage and take it from there, but I have an intricate system of streams that is classified according to stream width. The 'observed flow' is used as a workaround by setting its weight to 0, as I need the jacobian matrix calculated by PEST for further analysis; manually grouping all these arcs is not really a workable option. Any advice is appreciated, thanks in advance. Pytrik
  21. I am running a transient PEST model with pilot points, using HK and RCH values. However, during the run I notice that the RCH values are not changing between optimization iterations. None of the points are defined as fixed. I created the RCH scatter points by duplicating the HK scatter points then editing the values. Could the additional "Active" field (populated with "1"'s) in the new RCH scatter point file be causing the problem? Both pilot-point-defined Parameters are referencing the correct scatter point sets. I am using 18 pilot points, but have over 100 Observation Points so I do not think I am violating that ratio. Thanks for your help! Chris
  22. Dear All, I have been using PEST for calibrating my project using GMS. I have defined a set of pilot points for HK and want to assign a different min. & max. for each point in the calibration process. Does GMS support such idea? Any insights/helps would be appreciated. I look forward to hearing from you soon.
  23. Hi All, I am tyring to calibrate a steady-sate MODFLOW model using PEST in GMS 8.0. Does anyone know where can the initial Marquardt lambda (RLAMBDA1) value be specified? I have performed an initial (unsuccessful) run and it seems that the default value is set 0.01. However, I would like to increase this value somewhere in between 1 to 10. Yet, I can't seem to find any input dialog for this option. Any help is much appreciated! Cheers Bernard
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