Bug Report? Sediment Parameters (exp_sed, lin_sed) Missing in Toolbox v3.0.7

[Ridwaan Siciid]

Hello SWAT+ developers and group members,

I am working on a sediment yield model for a large catchment (~127,000 km²) in the Horn of Africa and have encountered a persistent issue with the latest SWAT+ Toolbox where I cannot access the sediment routing parameters for calibration. I believe this might be a bug, and I wanted to share the details.

My Software Details:

• SWAT+ Toolbox Version: 3.0.7 (from Editor v3.0.8, released May 17, 2025)
• SWAT+ Revision: 61.0.1
• Operating System: Windows

The Problem: The primary sediment routing parameters, exp_sed.bsn and lin_sed.bsn (the new names for SPEXP and SPCON), do not appear in the parameter list for sensitivity analysis or calibration. The process seems to be inactive.

Troubleshooting Steps I Have Already Taken: I have worked through a long troubleshooting process and can confirm the following:

1. My project setup uses a stream network "burn-in" due to the large catchment size.
2. My weather station definitions, daily data files (.PCP, .TMP, etc.), and master list files (pcp.cli, etc.) are all correctly formatted and linked.
3. I discovered that the sediment routing process was not active. I searched for the ised_rout flag in rout_unit.con and other files but could not find it. A search for "bagnold" or "sediment routing" in the entire TxtInOut folder returns no results, suggesting the project was created without these configuration lines.
4. I then located the parameters.bsn file, which correctly contains the headers for exp_sed and lin_sed, but their values were set to null.
5. I manually edited parameters.bsn to replace null with standard default numerical values (1.5 and 0.0001).
6. Even after saving the file, closing the project, performing a "Write-Run-Read" cycle, the parameters still do not appear in the calibration list.

The Key Finding: When I open the graphical editor for parameters.bsn within the SWAT+ Editor interface, the input fields for exp_sed and lin_sed are not displayed at all. It seems the graphical interface itself is not recognizing these specific parameters from the text file's header, which prevents me from setting their values through the GUI and prevents the calibration tool from seeing them.

My question is: Is this a known issue with recent versions of the Toolbox? Is there a different configuration step required to "activate" these parameters so the Editor GUI can recognize them, perhaps one that is not being written correctly during project creation for large catchments?

Any help or insight would be greatly appreciated.

Thank you,

Ridwan Saed

Adama Science and Technology/MSc Student

[Flavien DAMIBA]

Hello, even mine of 900 km2, I cant find these 2 parameters for calibration:  exp_sed.bsn and lin_sed.bsn

It is disappointing

[Celray James]

The current list of parameters that can be calibrated is based on the current official release of the cal_parms.cal file which excludes these parameters for both SWAT+ Editor and SWAT+ Toolbox. These parameters should be available in the next release of SWAT+ Tools.

However, if you need to 'activate' them in SWAT+ Toolbox (SPT), you can enter them in the "...SWATPlus\SWATPlusToolbox\assets\config\status\cal_parms.cal" file in your SPT install location. The next time you start SPT, they will be available. However, I cannot guarantee that they will work as expected.

C. James