How to use weir.res in SWAT+ and assign a weir to a specific reservoir?

[Damian Badora]

Hello,

I would like to model a small weir (jaz) in SWAT+ and I am confused about how the weir.res file is actually used by the model.

I am using:

• SWAT+ Editor v3.2.4
• SWAT+ rev. 61.0.2.61
• QSWAT+ 3.2.3

The Editor generates a weir.res file, for example:

weir.res name linear_c exp_k width height shape1 1.84 2.60 2.50 0.00

According to the documentation, the name field in weir.res is "a primary key referenced by the foreign key xxx in res_rel.dtl".

However, I cannot find how to actually assign a weir to a reservoir.

I checked:

• reservoir.res
• hydrology.res
• initial.res
• res_rel.dtl
• the Reservoir Release decision tables available in the datasets library.

The standard release tables (drawdown_days, flood_season) only use options such as:

days dyrt

I could not find any example using:

option = weir

or referencing the weir name (e.g., shape1).

My questions are:

1. How should weir.res be linked to a specific reservoir/subbasin?
2. Is there a special release decision table syntax required to use a weir equation?
3. Could someone provide an example of a working res_rel.dtl entry that uses weir.res?
4. Is the weir.res functionality currently implemented in SWAT+ rev. 61.0.2.61 and SWAT+ Editor v3.2.4, or is this feature not yet supported through the Editor?

Any example project or input file snippet would be greatly appreciated.

Thank you very much for your help.

Best regards

[Damian Badora]

I have one more issue.

I created two scenarios. The first scenario included ponds, but without assigning any parameters to them (essentially as if the ponds were not configured). In the second scenario, I defined pond parameters, even using exaggerated values.

However, when I compare the results from both scenarios, I do not see any differences in channel outflow or subbasin runoff. It seems as if both models are producing identical results.

What could I be doing wrong?

One additional note: the pond is connected to the corresponding channel.