Modelling fracture flow

[Prathap Christoper]

Hello all!

I was wondering if there is a method/Package to introduce a dipping structure (Ex: a fracture) in to the groundwater flow model. As I m aware, vertical objects can be  introduced.

Thanks in advance!

[Richard Winston]

In MODFLOW version 6.7, the Horizontal Flow Barrier package has been renamed the Hydraulic Flow Barrier package because it now allows both horizontal and vertical barriers to flow. A dipping barrier could be simulated by a combination of horizontal and vertical barriers.

--
This group was created in 2004 by Mr. C. P. Kumar, Former Scientist 'G', National Institute of Hydrology, Roorkee. Please visit his webpage at https://www.angelfire.com/nh/cpkumar/
---
You received this message because you are subscribed to the Google Groups "MODFLOW Users Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email to modflow+u...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/modflow/821a6177-0fbf-4a20-8a0d-d809848be970n%40googlegroups.com.

[Randall Hanson]

These HFB  features are also a capability in MF-OWHM as well as transient barriers that have been used for mining applications and is not available in MF-6. So you can make any geometry you need and change them through time too!!

Sent from my iPhone

On Feb 16, 2026, at 5:55 AM, Richard Winston <winstonr...@gmail.com> wrote:



To view this discussion visit https://groups.google.com/d/msgid/modflow/CAMVFkVeB%3Dbto8HGdUr9DoZdXw5gbd%3DFDDEnKtmgF%2BYo%3DYguJew%40mail.gmail.com.

[Richard Winston]

The current version of MODFLOW 6 does allow the barriers to change in each stress period. In addition, I think the way MODFLOW OWHM allows connections between cells in different layers is different from what MODFLOW 6 does. Randy, please correct me if I'm wrong, but my Impression is that in OWHM, the barriers are always barriers to horizontal flow but if two layers have been juxtaposed by faulting, HFB barriers can be defined between horizontally adjacent cells in different layers, whereas in MODFLOW 6, barriers to vertical flow can be defined between cells at the same horizontal location but in different layers. 

To view this discussion visit https://groups.google.com/d/msgid/modflow/E79D4395-6FF5-48D0-A78D-FA9F33883AA9%40gmail.com.

[Randall Hanson]

Actually OWHM can have vertical barriers as well as interlayer flow.

Sent from my iPhone

On Feb 16, 2026, at 6:44 PM, Richard Winston <winstonr...@gmail.com> wrote:



To view this discussion visit https://groups.google.com/d/msgid/modflow/CAMVFkVc6ddj5%2B_GKCEi3PsONMnPcWPunsOdUxNy0imL2znu2Pw%40mail.gmail.com.

[franklin]

Hello All,

I need help with direction on how to calibrate a nitrate transport model with a tile as the loading source in GMS.

Thank you.

On Mon, Feb 16, 2026, 10:37 AM Randall Hanson <randyt...@gmail.com> wrote:

To view this discussion visit https://groups.google.com/d/msgid/modflow/E79D4395-6FF5-48D0-A78D-FA9F33883AA9%40gmail.com.

[Joseph Hughes]

HFBs in MODFLOW 6 can change by stress period. See https://modflow6.readthedocs.io/en/latest/_mf6io/gwf-hfb.html for information for specifying time-varying HFBs in MODFLOW 6.

[ashutosh singh]

Hi,

It is an interesting topic and I wanted to know why it is necessary to use something like a geological barrier. I think a low/high zone hydraulic conductivity can be used for cells to test how low/high conductivities can act like a barrier.

I have done it and I have seen exactly the same effects mentioned in research papers and textbooks.

//Ashutosh

To view this discussion visit https://groups.google.com/d/msgid/modflow/E79D4395-6FF5-48D0-A78D-FA9F33883AA9%40gmail.com.

[Philip Margarit]

To Ashutosh's point, structural overlay parameters are another option: https://gmdsi.org/blog/use-and-implementation-of-structural-overlay-parameters-2/

To view this discussion visit https://groups.google.com/d/msgid/modflow/CA%2BOP%2B8vfn%2B2n5Qe68S5R-F0vcU2PXP5kLhT8pzATPoRekNr0LQ%40mail.gmail.com.

--

Philip Margarit

Water Resources Science PhD Candidate

College of Food, Agriculture, and Natural Resources Science 

University of Minnesota, Twin Cities

651-262-3561

[Prathap Christoper]

Hello! Thank you for that information. What we are trying to do is model a dipping flow path along a fracture. Was thinking of introducing a vertical object and then assigning it a high hydraulic conductivity (preferential flow through a fracture )while assigning low or  near zero hydraulic conductivity to the surrounding cells (rock matrix).

Best Regards!

W.A.P.P. Christopher

Senior Lecturer

Department of Applied Earth Sciences

Uva Wellassa University.

To view this discussion visit https://groups.google.com/d/msgid/modflow/CAMVFkVeB%3Dbto8HGdUr9DoZdXw5gbd%3DFDDEnKtmgF%2BYo%3DYguJew%40mail.gmail.com.