I am attempting to run a MT3DMS simulation (and eventually SEAWAT, too) with MODFLOW-NWT, and MT3DMS reports this error:

**Error Reading Flow-Transport Link File Possibly Caused by:**

**1. Incompatible Styles of Unformatted Files Used by MODFLOW and MT3DMS;**

**2. Unformatted Flow-Transport Link File Saved by Verison 1 of LinkMT3D**

** Package Which Is No Longer Supported by MT3DMS.**

Has anyone come across this before and has a suggestion on how to fix? It may be related to a GMS bug (I am using version 10.3.5, 64-bit) as I have tried an older model that successfully ran MT3DMS last year on an earlier version of GMS, but that model now reports the same error. I have contacted GMS support, but they are very busy and slow to respond, so I thought I’d ask the user forum to see if anyone had a solution.

Thanks.

]]>I would like to know if there is another way than manually assign transient recharge values from 2d array in the recharge package window. I have 120 raster (10 years of monthly recharge) of spatially distributed recharge to load in GMS. I'm thinking of going into MODFLOW input files.

Any ideas?

Regards

]]>I have imported a shapefile containing multiple polygons (553 polygons). When i tried to convert the shapefile to feature objects (command "shapes to features objects"), GMS creates more than 553 polygons-features (about 5000! polygons-features). For example, a single polygon with a specific ID, when converted, is split into multiple features with the same ID.

How can this issue be addressed? It is important that during conversion to keep the same number of features as the initial number of polygons of the imported shapefile.

Thank you in advance!

]]>
I am new to MODFLOW. I tried to set up the MODFLOW to measure the change of drawdown with time using the 3d grid. I am including the values I used here:

X dimension: 1000m

Y dimension :1000m

rows columns: 10,10

recharge:0.0027m/day

pumping 240 m3/day

horizontal K 10m/day

I set left and right column as constant head setting ibound<0. Here I have attached the screenshot of head change and drawdown. So, I have 2 questions:

1.The drawdown seems a bit off, can u tell the possible reason for it?

2.If I want to set the bottom cell as no flow boundary would I have to make the cells inactive?

[I have tried to set up the conceptual model and adapt it to the grid as well however sometimes it's

not showing the boundary condition correctly. That's why I tried 3D grid]

not showing the boundary condition correctly. That's why I tried 3D grid]

Please if anyone of you could solve the problem, it would be a great help.

Thanks

]]>I'm having some problems tracking particles in a USG groundwater model, because the particles stops in the edge of the cell and don't continue. Checking de mod-PATH3DU.exe file, the version in GMS is 1.0.6, but the latest one is 1.1.1. And if i replace it, GMS stop working and the sorfware close. What can i do?

Another problem is with display options, because i tried to activate label in contour options (Ugrid), but it doesn't appear in the model, so maybe is a bug of GMS

Thanks,

Bastian

]]>Using the option "use screen" for "wells" in sources/sinks, am I telling the model that the water extraction is only carried out in this interval?

When I turn on this option GMS transforms my extraction wells in injection wells!!

Why is that? Is it a software problem?

Best regards

Filipe Miguéns

]]>I have a serious problem. I am working GMS 10.2.6 64bit version in windows 7 (64bit) and in windows 10 (64bit). But I get different results using the same numbers in both version of windows. What should I do? Thank you very much

]]>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

]]>I am working on a MODFLOW and MT3DMS simulation set up. I have some constituent observations at different locations. I would like to create a 3D constituent plume using these observed data and use that 3D plume as the initial condition for MT3DMS model simulation. I am able to make the 3D constituent plume using these observed data with 3D Geostatistic methods. However, I don't know how to map this 3D plume to the MT3DSM grid as the initial condition. Would you please explain this to me?

Thank you,

Lalith

]]>can you paste some references on how to use SEAWAT in GMS.

Thanx in advance

]]>I am simulating model with 4 layers /top-clay, 2-aquifer, 3-clay, 4-aquifer/ which are all confined. Is it right about all layers confined?

I built conceptual model using the Borehole-Solid, Map-Modflow and 3D grid with Modflow 2000, LPF package, PCG solver. I think, aquifer is confined, so pressure water level in Layer 1. So, I could not understand transient computed head. Because, when ortho mode on and layer 1, around all pumping wells get dry, drawdown is very high /2000, 3000m/. Layer 2-head and drawdown is ok. Which layers head is correct? Initial head from Steady state head and using Starting head-3D dataset to Grid.

Thank you

]]>can any one tell me what is the wrong with this message and how to solve it please

Cell dimension change ..........

THANX IN ADVANCE

]]>I made a model with solids and materials in GMS and then I used HUF package to define uniform model layers (cells with same thickness in Z directions).

in eahc layer I have about 62500 cells (50 by 50 meter each).

now I want to add salt into model and run 2 simulation one with 200 year and one with 150 years.

MT3DMS run in each takes about 1.5 hour for each one.

for SEAWAT I set transport time step to 365 days (one year) but it changes to one day and it takes for ever to be finished! (it does not even give me how long would it take for the model to reach the resullts!)

I thought having uniform layers will help SEAWAT to be faster!

And one more thing, each model is about 20 to 30 GB!

**is there any way to make it faster? and lighter?**

I wanted to run SWI for faster calculation time but it gives me an error which says HUF layers are not compatible with SWI!

**is there a problem with my model layers? or HUF and SWI don't work together? is it possible to run SWI with HUF?**

is there any way to export the HUF layer data and use it in LPF? because the input files with HUF are different. there is only one big text file with all the data for HUF and it does not have data of cells!

I could not find if they are compatible or not in Moflow USGS site ( https://water.usgs.gov/ogw/modflow-lgr/MODFLOW-LGR-Guide/index.html?package_incompatibilities.htm ).

]]>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.

]]>For an excavation I used the LAK package and defined the bottom with a TIN ("bathymetry") at -7 m.

Unfortunately it gets intersected with two layers despite of assigning the Lake from the conceptual model after the horizons.

My final Lake bottom fits for half of the excavation and for the other half the surface looks like as it's truncated by the layers below.

I've tried several concept models and grids but same result.

]]>For an excavation I used the LAK package and defined the bottom with a TIN ("bathymetry") at -7 m.

Unfortunately it gets intersected with two layers despite of assigning the Lake from the conceptual model after the horizons.

My final Lake bottom fits for half of the excavation and for the other half the surface looks like as it's truncated by the layers below.

I've tried several concept models and grids but same result.

]]>I am using Seep2D to simulate the stable flow condition across earth dike. I would like to print out the model configuration and result in text file , however, I can not find such menu in the GMS/Seep2D . Can somebody advise me, it is very appreciated.

Thank you.

]]>

I am trying to compute Darcy velocity out at the end of my model. I know I can get the flow from the Flow Budget. However, because the water table did not saturate the entire depth (z-direction) of my model's end, I can't just use the full cross section area of my model to compute Darcy velocity.

I can count the cells and go that route but I want to make sure there is no easier way.

Thanks.

]]>
I would like to ask about the length of the* computational time of the transient model*. I have built already several more complex models, but my transient models never exceeded 1 or max 2 hours to be finished. Not this time.

I had built (I have to admit rather big model) with the number of the cells around 3 000 000. As flow package there is used **HUF **and as the solver **PCG2**. For the steady state my model finishes somewhere at the 10^{th} iteration with the total computational time around 7 min.

Built on that is the transient model with 27 stress periods. From previous experience I would guess the maximum time around 1.5 hour – stress periods usually are getting faster to be run. What surprised me is that I am getting to the time more than 4 hours. Changing convergence criteria doesn’t help me, as the problem is not the convergence of the model itself – at least for outer iterations (for each stress period I have convergence within 3 – 5 iterations). Neither changes of the solver had helped me.

In my model occurs several bigger places with dry cells – but I am not allowing rewetting – could it be the problem?

I had built similar model in with NWT solver – there was the time around 1.5 hour to complete transient model. Is there any reason why HUF should cause longer computation?

Thanks for any kind of the tips or ideas to get this model faster ;-)

]]>

Kind regards,

Jonas

]]>Are observations not set up to work in MODFLOW-USG?

]]>when converting a steady state model to transient I initialize the stress periods and import transient boundary conditions via MAP to MODFLOW. This seems to work.

But for Recharge the following error occurs when looking at RCH or RCH rate:

Within the properties of RCH rate all stress periods seem to be in the right format (identical to what has been defined under "Global options - stress periods" and same as for other boundary conditions like transient pumping rates e.g.).

Can you help?

Am using version 10.3

Mark

]]>

I'm building a multilayer model with GMS (MODFLOW-USG) for a region in Portugal and i start the calibration fase.

Can anyone tell me the best way to calibrate my model?

I'm thinking about to using the pilot point method, but i cant find a tutorial on how to proceed for calibration of multilayer models...

Can anyone help me?

Thanks in advance

]]>

I noted GMS has values for porosity in both MODFLOW and MT3D. In MODFLOW menu (MODFLOW options) one can enter values for porosity, although porosity is not used in flow computations as far as I know. Also in MT3D menu it is essential to enter porosity value.

In the model I have (which is a SEAWAT model) I entered values for porosity in the MT3D options, but I noticed there are different values -by default- in the MODFLOW options. Which values does the model consider in this case? and why is there an option for porosity in MODFLOW?

Thanks

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