Jump to content
GMS, SMS, and WMS User Forum

Sean Czarniecki

GMS Experts
  • Content Count

    226
  • Joined

  • Last visited

  • Days Won

    2

Sean Czarniecki last won the day on August 4 2009

Sean Czarniecki had the most liked content!

Community Reputation

8 Neutral

1 Follower

About Sean Czarniecki

  • Rank
    Senior Member

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. Sean Czarniecki

    draining water to the ground using canals

    Increase the recharge in the cells where you are simulating the canals. Just an option - may not be exactly what you are looking for.
  2. Sean Czarniecki

    Head is computed for dry cells (below bottom of the cell)

    What version of MODFLOW are you using?
  3. Sean Czarniecki

    Changes to MODFLOW-USG?

  4. Sean Czarniecki

    Changes to MODFLOW-USG?

    Hi Bill - I contacted the MODFLOW-USG developers and have sent them my native text files. I'll send a set of GMS files to tech support. Maybe you guys will see something. Thanks!
  5. Sean Czarniecki

    Changes to MODFLOW-USG?

    Thanks for the suggestion - I may need to go down that path as I try to get through the problem. This is certainly frustrating, as I've done hundreds of runs which now don't work. I'm checking to see which well fields are causing the solution to not converge (and am narrowing it down), but the bigger problem is that the solution is now totally different in areas without wells because of what appears to be that change in the minimum saturation value.....
  6. Sean Czarniecki

    Changes to MODFLOW-USG?

    I'm running the model with some wells pumping (in areas that shouldn't go dry even in low recharge times). Seems to work....but I wanted to provide a screen shot of the progress window. You will see that the error values just don't make sense (in the older version, they were reasonable).....and a weird text item came up during SP 18, TS 1. Doesn't make me feel too good....
  7. Sean Czarniecki

    Changes to MODFLOW-USG?

    I've looked a little further at the version notes and think I see what may be the problem. GWF2BCF-LPF-U1 -- Removed the minimum saturation value. Difficult problems behave better by allowing saturation to go to zero and letting the solver handle it. Revised the way CLN-GW flows are written to the budget file. CLN2BASU1 -- Removed the minimum saturation value. So something that caused problems for other people appears to have been changed…..and this is likely what now doesn’t allow my model to solve properly. I just ran the model with no wells pumping and it converges. The model had been crashing when it got to the period of zero recharge, which would be when wells may be in cells which could go dry due to pumping due to lack of water. This is not good. If anyone has insight into if I'm interpreting the issue correctly, I would love to hear from you. To the GMS developers, if you can confirm that there wouldn't be any other reason for my non-convergence (e.g., any chance that it is actually some coding issue related it input files generated for the new MODFLOW-USG?), I would appreciate it. It would be great if there were an option to still keep the minimum saturation value for some models, but not for others. Based on the release notes, it doesn't look like that is an option.
  8. Sean Czarniecki

    Changes to MODFLOW-USG?

    I looked into the version notes on MODFLOW-USG and can't tell if anything they updated would cause my particular model to crash. It would be sad if they corrected a bug which previously allowed my model to converge and now won't allow it. Nothing jumps out as fitting their bug corrections. Any chance that it is something related to merging the newer version into GMS? I do note that the progress window used to show what unit the CLN Heads were supposed to write to ("CLN HEAD UNIT 767") after every time step. It no longer does that, but that shouldn't have any impact on the convergence...I'm just noting a difference.
  9. Sean Czarniecki

    Changes to MODFLOW-USG?

    I hope someone can help me out here. I finished a complex model back in February (I had used GMS 10.3.05). I have been asked to provide model files to someone else who will be using the most recent version of GMS (currently 10.3.07). I thought it was a good idea to do a test run using that latest version. The model didn't work....and the window showing modeling progress was showing some extreme errors that I definitely hadn't seen before. The model crashed after a few stress periods. I thought that it might be the software change (I hadn't changed anything else). Sure enough, I loaded the older version and it worked like it did before. In the progress window, I can see that the MODFLOW-USG version is different. 10.3.05 used Version 1.3.00 from 2015, whereas 10.3.07 uses Version 1.4.00 from 10/27/2017. Can anyone tell me what changes occurred that would result in my model not converging any more? This is bad news to me.....
  10. Sean Czarniecki

    Modflow List File

    Go into the output control under MODFLOW. This information is also included in the .out file. After running the model and opening in GMS, these files will show up in the Project Explorer, where you can double click on them and open with a text editor.
  11. Sean Czarniecki

    RCH output

    Can you select them, copy to your clipboard, and then paste in a spreadsheet?
  12. Just for kicks, you might try lowering your specified head to see if you can achieve a reasonable calibration. Have you accounted for evapotranspiration? Could your recharge be too high? Are your calibration measurements being influenced by any tidal effects (you said "coast," but are running steady state, which is an average condition....perhaps your measurements were taken under a lower tidal influence)? Just some things to consider.
  13. Sean Czarniecki

    Water level change with recharge

    Not knowing what your boundary conditions are, I'll assume that the cell goes dry in an area which isn't impacted by boundary conditions (even if no-flow). Your starting head may be too different than what the final elevation is going to be. The calculations will do an interation which may come to a solution below the bottom of the cell (think of the iterative process as a wave where the model goes up and down at smaller amplitudes until it gets to the solution). If the low value is below the bottom of the cell and there is no rewetting, the cell is dry and won't rewet. You might have to try starting heads that are actually lower to be closer to the final solution. Just my initial thinking.
×