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Adam

Importing from Modflow

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Hallo,

has anyone ever imported flow field from Modflow to X2t?

I have a one-layer groundwater flow model in GMS 5.1 (Modflow 2000) and I‘m not able to import output files from GMS to X2t.

I acted in accordance with the Reactive Transport Modeling Guide. The problem is, that I don’t understand what does it mean - specify the unit identifier for the budget file :unsure: . Where and how have I to set the unit identifier?

Do you have any experience with this problem ?

Adam

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Hallo,

has anyone ever imported flow field from Modflow to X2t?

I have a one-layer groundwater flow model in GMS 5.1 (Modflow 2000) and I‘m not able to import output files from GMS to X2t.

I acted in accordance with the Reactive Transport Modeling Guide. The problem is, that I don’t understand what does it mean - specify the unit identifier for the budget file :unsure: . Where and how have I to set the unit identifier?

Do you have any experience with this problem ?

Adam

Hi Adam:

Have you already looked at the Appendix "Importing from Modflow" in the v7 Reactive Transport Modeling Guide? It gives the following information regarding the unit identifier in section B.2:

When you run Modflow, you supply various input files, including a discretization file. When it runs, the program can write among other datasets a budget file. You should give the discretization file a suffix .dis, the budget file, .bud.

The discretization file contains information about the finite difference domain and the time stepping in the Modflow model. The budget file is a binary dataset containing information about the flow field. In setting up yourModflow simulation, observe the following guidelines:

  • The budget file needs to contain data describing flow among the nodal blocks. Specify the unit identifier for the budget file as the value for the IxxxCB variable, where “xxx” is the flow package in use. The variable, for example, might be
    IBCFCB, ILPFCB, and so on.
  • The budget file also should contain data for nodal block flows resulting from the external stresses, such as wells, recharge, evapotranspiration, and so on in the simulation.

To set Modflow to write these data, you specify in the input file for the package in question the unit identifier for the budget file. For a package “xxx”, set variable IxxxCB (e.g. IWELCB, IRCHCB, IETSCB, etc.) to the unit identifier.

Let me know if that is of help.

Regards,

Tom Meuzelaar

RockWare, Inc.

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Hi Tom,

I have looked at the Appendix B.2, still I’m not sure, where I have to change unit identifier (– in Modflow’s output budget file?). I have open example script for import from Modflow to X2t called Example 1. I have looked in Example’s files, but I haven’t seen e.g. IBCFCB unit identifier there.

My problem consists also in the following guideline:

The budget file needs to contain data describing flow among the nodal blocks.

Specify the unit identifier for the budget file as the value for the IxxxCB variable,

where “xxx” is the flow package in use. The variable, for example, might be

IBCFCB, ILPFCB, and so on.

Can you give me advice?

Best regards,

Adam

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Hi Tom,

I have looked at the Appendix B.2, still I’m not sure, where I have to change unit identifier (– in Modflow’s output budget file?). I have open example script for import from Modflow to X2t called Example 1. I have looked in Example’s files, but I haven’t seen e.g. IBCFCB unit identifier there.

My problem consists also in the following guideline:

The budget file needs to contain data describing flow among the nodal blocks.

Specify the unit identifier for the budget file as the value for the IxxxCB variable,

where “xxx” is the flow package in use. The variable, for example, might be

IBCFCB, ILPFCB, and so on.

Can you give me advice?

Best regards,

Adam

Hi Adam:

Sorry for the delay in response- your reply slipped past my notice.

If you look at some of the other MODFLOW output files in the Example1 folder, you'll notice a file called Example1.bc6. This file has the Unit Identifier. It's usually specified in one of the input files that is the flow 'package', which usually contains an 'F' as one of the last letters- in this case BCF6 (all of the packages and corresponding output files are listed in Example1.nam).

The other thing to note in the .nam file is the unit number for the budget file ... in Example1.nam the unit number is 50. I *think* this can be any number really -- it's just an identifier for the DATA(BINARY) package. That identifier - 50 - is what then needs to be put into the flow package file, Example1.bc6.

If you look in the Example1.bc6 file you will see some numbers followed by the variable names the numbers correspond to. Since this is a BCF package one of the variables is named IBCFCB. Now what you need to do is set that variable's value to the identifier used for the budget file -- in this case 50. This basically tells the flow package to put its output in the budget file.

I hope that helps,

Tom

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Hi Adam:

Sorry for the delay in response- your reply slipped past my notice.

If you look at some of the other MODFLOW output files in the Example1 folder, you'll notice a file called Example1.bc6. This file has the Unit Identifier. It's usually specified in one of the input files that is the flow 'package', which usually contains an 'F' as one of the last letters- in this case BCF6 (all of the packages and corresponding output files are listed in Example1.nam).

The other thing to note in the .nam file is the unit number for the budget file ... in Example1.nam the unit number is 50. I *think* this can be any number really -- it's just an identifier for the DATA(BINARY) package. That identifier - 50 - is what then needs to be put into the flow package file, Example1.bc6.

If you look in the Example1.bc6 file you will see some numbers followed by the variable names the numbers correspond to. Since this is a BCF package one of the variables is named IBCFCB. Now what you need to do is set that variable's value to the identifier used for the budget file -- in this case 50. This basically tells the flow package to put its output in the budget file.

I hope that helps,

Tom

Hi Tom,

the importing from GMS to X2t is finally working. Thank you very much for your help :rolleyes: ! The problem did not consist only in unit identifier. Next problem was caused by formulation of model cell extend along y and z axis in a model output file with suffix .dis (marked by red color):

# MF2K DISCRETIZATION FILE

#

#

# NLAY NROW NCOL NPER TIMEUNITS LENUNITS

1 50 50 1 1 2

0

INTERNAL 1.0 (free) 0

20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0

INTERNAL 1.0 (free) 0

20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0

CONSTANT 500.0

CONSTANT -700.0

1.0 1 1.0 SS

The import of flowfield from GMS was successfull after rewrite (blue marked part):

# MF2K DISCRETIZATION FILE

#

#

# NLAY NROW NCOL NPER TIMEUNITS LENUNITS

1 50 50 1 1 2

0

CONSTANT 20

CONSTANT 20

CONSTANT 500.0

CONSTANT -700.0

1.0 1 1.0 SS

Best regards

Adam

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...the importing from GMS to X2t is finally working.....

Adam:

Glad to hear it! Thanks for providing the additional detail that led to a succesful model- others will greatly benefit from this.

Regards,

Tom

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