irrigation time

dalfa...@ut.ac.ir

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Dec 29, 2023, 3:12:43 AM12/29/23

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Hi everyone,
I hope all who are struggling with this model be success and well doing.
Is there a way to set more than one-time cycles in defining irrigation start and stop time? for example running for one year and having 4 irrigation time cycles in every season. defining 8-time cycles (on winter, on spring, on summer, on autumn, off winter, off spring, off summer, off autumn) but just 1 time cycle irrigation i found in parflow manual.
I will appreciate any experience or help or other way.
Best
Sadegh Dalfardi

Stacie DeSousa

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Feb 19, 2026, 2:14:44 PM (9 days ago) Feb 19

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Hello, I am also trying to model seasonal irrigation cycles. I am wondering if you found an answer to this.

Thank you,

Stacie

Reed M. Maxwell

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Feb 19, 2026, 2:59:54 PM (9 days ago) Feb 19

to Stacie DeSousa, ParFlow, Nicholas S. Jadallah

Nick, can you send an example script out to the group on this?

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Nick Jadallah

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Feb 19, 2026, 4:20:01 PM (9 days ago) Feb 19

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Hi Everyone,

I use ParFlow-CLM to run transient simulations and have an "irrigation season" during which irrigation is turned on (the rest of the year it is turned off). The way I get around the constant irrigation timing issue you describe is by restarting my run midway through the year. So, for example, I start my simulation with irrigation turned on. Then pause. Turn irrigation off. And restart the simulation. Can repeat or customize as-needed. I know it's tedious to restart runs this way, but it does work effectively for the irrigation season issue.

One useful setting I find is the RUN.Solver.PrintInitialConditions = False setting, which prevents ParFlow-CLM from printing the initial condition files (which is default behavior). Changing this setting to False helps me a lot when I run irrigation cycles with NetCDF output, but I'm not sure if it would help the same way for .pfb outputs. Might be something worth testing, though.

If you know how to restart runs, then you should be in good shape. If you don't, just reply to this and I'm happy to provide a descriptor to help you get started.

Cheers,

Nick

Nick Jadallah

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Feb 19, 2026, 9:34:16 PM (8 days ago) Feb 19

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I will also share the irrigation keys that I use in case it is helpful:

    Run.Solver.CLM.IrrigationType = "Spray"
    Run.Solver.CLM.IrrigationCycle = "Constant"
    Run.Solver.CLM.IrrigationRate = [some irrigation rate, mm/s] 
    Run.Solver.CLM.IrrigationStartTime = [start time, 24H, float, GMT]
    Run.Solver.CLM.IrrigationStopTime = [end time, 24H, float, GMT, value must be > start time) 

Also, remember that you have to set the irrigation flag setting in your vegp.dat file to 1 (instead of the default 0) for the land cover type you wish to irrigate.

Hopefully this helps! Again, please let me know if you have trouble with the restarts (or anything else).