Adding data as condition variable for decision table

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Patit C.

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Mar 4, 2026, 6:02:08 PMMar 4

to SWAT+

Hi all,

I am working on a SWAT+ model and am looking to implement more complex, adaptive management logic in my Decision Tables.

Currently, I am using the standard reservoir release logic based on volume:

Condition: res_vol > p-vol
Action: release_target

I would like to know if it is possible to include external time-series data as a condition variable. Specifically, I want to use variables such as the accumulated rainfall forecast (3, 5, or 7 days) and SPEI indices stored in a CSV or text file to trigger management actions.

Example Logic:

IF res_vol > p-vol AND accumulated_rain_forecast_3d > 20mm
THEN release_target = X

My specific questions are:

Is it really possible to do it in SWAT?

I try to ask Gemini how to do it, but I get some advice in a roundabout way.

I also want to know if this is legit or some random things that are not related at all.

Is the best practice for this to use the decision_storage.det file to define internal pointers for these variables?
How do I correctly use the management.sch file with a chg_ds operation to "feed" these storage slots from an external daily text file?
Are there specific limitations on the number of chg_ds variables I can reference in a single .dtl file?

Any guidance or examples of .det and .sch formatting for this specific use case would be greatly appreciated!