how to get drawdown in Modflow 6?

[Mike IT Expert]

I came accross the below paragraph in page 31 of MF6.4.2 doc.

Calculation and reporting of drawdown for the model grid is no longer supported, as this calculation is easily performed as a postprocessing step. Calculation of drawdown is supported as an observation type by the OBS Package; drawdown is calculated as the difference between the starting head specified in the IC Package and the calculated
head.

I am wondering how I can activate OBS package in MF6. I tried adding it in the nam file as below:

BEGIN OPTIONS                          

  LIST VIP2.out                        

  PRINT_INPUT                          

  PRINT_FLOWS                          

  SAVE_FLOWS                            

END OPTIONS                            

                                       

BEGIN PACKAGES                          

  DIS6  VIP2.dis                        

  OC6  VIP2.oc                          

  RCH6  VIP2.rch                        

  WEL6  VIP2.wel                        

  GHB6  VIP2.ghb                        

  NPF6 VIP2.npf                        

  STO6 VIP2.sto                        

  IC6 VIP2.ic      

  OBS VIP2.obs                  

END PACKAGES

But it outputs the below error:

MODFLOW 6 U.S. GEOLOGICAL SURVEY MODULAR HYDROLOGIC MODEL VERSION 6.4.2 06/28/2023 MODFLOW 6 compiled Jul 05 2023 20:31:54 with Intel(R) Fortran Intel(R) 64 Compiler Classic for applications running on Intel(R) 64, Version 2021.7.0 Build 20220726_000000 This software has been approved for release by the U.S. Geological Survey (USGS). Although the software has been subjected to rigorous review, the USGS reserves the right to update the software as needed pursuant to further analysis and review. No warranty, expressed or implied, is made by the USGS or the U.S. Government as to the functionality of the software and related material nor shall the fact of release constitute any such warranty. Furthermore, the software is released on condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized use. Also refer to the USGS Water Resources Software User Rights Notice for complete use, copyright, and distribution information. Run start date and time (yyyy/mm/dd hh:mm:ss): 2023/09/07 13:40:12 Writing simulation list file: mfsim.lst Using Simulation name file: mfsim.nam ERROR REPORT: 1. Model package type not supported [model=GWF_MODEL, type=OBS]. UNIT ERROR REPORT: 1. ERROR OCCURRED WHILE READING FILE 'VIP2.nam'

[Richard B. Winston]

Put "OBS6" instead of "OBS" in the name file.

[Saul Montoya]

Its OB6 or OBS6 i guess.

MF6 only exports heads at cells, the you have to compare with the observed.

Viva el software libre!

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[elnazb...@gmail.com]

Dear Richard

I hope this email finds you well. First and foremost, I want to express my sincere appreciation for the valuable assistance and time you have provided me with thus far. Your guidance has been invaluable.

Unfortunately, I’m still facing issues importing my observation wells data into my model, even after following your method. Could I send you observation well data for review? Your expertise could help identify any potential issues.

I will change the OBS in file name right now.

Thank you for your continued support.

Best regards,

elnaz

Sent from Yahoo Mail for iPhone

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.

[Mike IT Expert]

Thanks, Richard!

OBS6 it is!

BEGIN PACKAGES

...

  obs6  VIP2.obs

END PACKAGES

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[Mike IT Expert]

Thanks Richard, 

OBS6 works like a charm. 

BEGIN PACKAGES

...

  obs6  VIP2.obs

END PACKAGES

Just curious what the time column is for:

time,L1DDN,L2DDN

39.00000000000,2.023049941,2.022936737

69.00000000000,2.022438580,2.022325874

97.00000000000,2.021333402,2.021220669

133.0000000000,2.020622994,2.020510306

165.0000000000,2.025589785,2.025477491

195.0000000000,2.072172028,2.072062335

225.0000000000,2.160251562,2.160143949

255.0000000000,2.253832204,2.253723644

288.0000000000,2.373406258,2.373297068

318.0000000000,2.501806557,2.501696895

348.0000000000,2.641811925,2.641701248

382.0000000000,2.761247668,2.761131923

[fil...@gmail.com]

Good morning,

but how to have the same file produced with previous version? the ".bdd"?

I am using modelmuse and I don't find a way.

Thanks in advance

F.

[rbwinston]

Import the heads for the desired time. Then, subtract those heads from the initial heads.

MODFLOW 6 does not compute drawdown unlike previous versions of MODFLOW. 

See my free book

Getting Started with MODFLOW.

https://gw-project.org/books/getting-started-with-modflow/

On Apr 30, 2024 at 12:04 PM, fil...@gmail.com <fil...@gmail.com> wrote:

Good morning,

but how to have the same file produced with previous version? the ".bdd"?

I am using modelmuse and I don't find a way.

Thanks in advance

F.

Il giorno venerdì 8 settembre 2023 alle 05:04:15 UTC+2 Mike IT Expert ha scritto:

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