how to get cbc with BC output in flopy

Question

I'm trying to set up a model in "FloPy" (v'3.2.12'), but I'm having some trouble with the modflow output files. When following the "turorial2" available on the developers' website (https://modflowpy.github.io/flopydoc/tutorial2.html), everything seems to work. However, the cbc file doesn't contain information regarding the general head boundary condition. And I've had the same problem with a drain boundary condition. Is there some additional setting I need to change or set up before running a model? Or is there another way to read the rate information form the GHB boundary condition?

FYI- So far I've tried changing the ModflowOc-set up and I've also run the model with a different solver.

Thanks for the help,

Some additional information about the set-up (should be identical to the tuturial):

mf = flopy.modflow.Modflow(modelname, exe_name='mf2005')


ghb = flopy.modflow.ModflowGhb(mf, stress_period_data=stress_period_data)


oc = flopy.modflow.ModflowOc(mf, stress_period_data=stress_period_data,
                             compact=True)

Does the output unit number in the GHB and DRN package files match the output unit number of the cell-budget file? If you can post samples of your OC package, namefile, and the relevant boundary package file it would help others to troubleshoot your issue. — Jason Bellino, Jul 30 '19 at 15:32
Hi, thanks for the fast reply! No they don't match. So for the example from tutorial 2 the .cbc file has unit 53 and the .ghb has unit 23 (based on the listing file). Just like the online example, no unitnumbers were specified in the script. I take it, they should be specified? — Alizarin Red, Jul 31 '19 at 19:58

Jason Bellino · Answer 1 · 2019-08-01T18:41:34.553

Ok, given your reply to my comment let me expand a bit here. Given the following name file:

LIST               2  ss-kper60.list
DIS               11  ss-kper60.dis 
OC                14  ss-kper60.oc 
BAS6              13  ss-kper60.bas6 
NWT               32  ss-kper60.nwt 
GHB               23  ss-kper60.ghb 
RCH               19  ss-kper60.rch 
UPW               31  ss-kper60.upw 
DATA(BINARY)      51  ss-kper60.hds REPLACE
DATA(BINARY)      53  ss-kper60.cbc REPLACE

MODFLOW will storge the GHB package in memory on unit 23 and output to the cell-budget file on unit 53. The IGHBCB variable of the GHB package is used to push output to the cell-budget file; from the online guide to MODFLOW:

Therefore, inside of your GHB package file, the second entry on the first line should also be "53" to send the output to the cell-budget file:

# GHB package for  MODFLOW-NWT, generated by Flopy.
     43183        53  NOPRINT
     43183         0 # stress period 1

how to get cbc with BC output in flopy

1 Answers1