here you will (hopefully !) find a solution to address the question in the topic title.
Last year I did not pose the question to myself, since I did not have the evapotranspiration corrections available.
In these days, where my local Zimmermann corrections are in the 150 % range, I was forced to answer to the question !
In fact, some days ago in the morning, I noticed that, after one hour or so from the last irrigation session, the flowmeter of the water supply was still running.
I made an R script (sorry. It’s the only program language I know) to calculate the possible water deficit.
Since I think that R (https://cran.r-project.org/) is not much known in this community, the script is commented, to help you in the customization process.
It’s a matter of fluxes: the very large one for some stations (38 lt/min) and the very small flux from the water supply (3lt/min).
The two fluxes are the combined with the frequency of the irrigation sessions.
I realize that is not easy to modify the backup.json file.
If needed, I can modify the script to:
export the data into a more readable and editable form as csv.
modify the data (by the user)
reimport the modified data and get the results for simulated programs