Jump to content
GMS, SMS, and WMS User Forum

Time Step in Modflow


Hydrology
 Share

Recommended Posts

Has anybody been able to get MODFLOW to run with a timestep less than 13 minutes using GMS 7.0? I am not able to get it to go lower than this, although in previous versions of GMS we were able to go to very small time steps. GMS 6 and GMS 7 use the same version of MODFLOW, so I think that it is a GMS problem.

Link to comment
Share on other sites

I was able to modify the MODFLOW transient tutorial in the GMS installation using the latest release of GMS 7.0 to have both time steps and stress periods that were less than 13 minutes.

Maybe something strange is going on with your particular simulation. Try having support@aquaveo.com look at it.

Link to comment
Share on other sites

I was able to modify the MODFLOW transient tutorial in the GMS installation using the latest release of GMS 7.0 to have both time steps and stress periods that were less than 13 minutes.

Maybe something strange is going on with your particular simulation. Try having support@aquaveo.com look at it.

I sent it in to support and they said that yes there is a bug in GMS 7.0 that wont allow you to use small time steps. They have reported it to the developers and it should be fixed in a later release. So I am not sure if you are using the same version of GMS 7 that I am using. I downloaded the latest version from the web site and the same problem exists.

The model we developed was fairly complex pumping model. When it didn't work, we gradually simplified it until we ended up with a simple rectangular grid with a constant head boundry condition on either end. This simple model still didn't work. We finally found by trial and error that it would work with a 1 day time step or a .1 day time step, or a .01 day time step, but anything from a 0.0089 day time step (12.96 min) or less will not run. You don't get any errors, but you can see in the computation window that the model is not running through any time steps. Plus, the model output file is blank.

I have attached a copy of the simplified model. Maybe there is something else that we have done wrong, but I dont see it. Any help would be appreciated, because we really need to have small time steps for the pump test calibration.

Edited by Hydrology
Link to comment
Share on other sites

Hydrology,

Can you please Email Tech Support and just give and overview of the problem. We want to make sure that this is being taken Care of.

Thanks

Joel Bennett

Aquaveo Tech Support

I will send it again. I spent about a half hour on the phone with tech support originally. They then asked me to send them the input files. I called them back later to see what they found, and they ( I think that it might have been someone named Nate? but that could be another support case) said that they were getting the same results. But I will try emailing them again.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...