Modelling Future Streamflow

[Erika]

If cross-posting is an issue, please delete. 

Dear SWAT Group,

I would like to ask for your advice regarding a modelling workflow I am currently working on.

I set up my model in SWAT+ Editor and performed the calibration using SWATrunR. From the calibration, I identified a set of parameters corresponding to the best-performing runs. During the model setup, I used the Hargreaves method for evapotranspiration estimation, as streamflow is my main variable of interest. The calibration and validation were based on observed data up to 2024.

My current objective is to use climate projection data together with the calibrated parameter set to simulate future streamflow. To do this, I created copies of my baseline model and replaced the observed climate inputs with projected climate data, creating separate model versions for each ensemble. I then attempted to run these models in SWATrunR using the calibrated parameter set to obtain future streamflow projections for the catchment.

However, the resulting streamflow does not appear reasonable, which makes me question whether my conceptual approach is correct.

Could you please share your opinion on this workflow? In particular:

• Is it appropriate to use copies of the calibrated baseline model with projected climate inputs in this way?

• Are there any common pitfalls when applying calibrated parameters to future climate scenarios in SWAT+ / SWATrunR that I should be aware of?

If you have experience with a similar workflow, I would greatly appreciate any guidance or suggestions.

Thank you very much for your time and support.

Have a nice day :) 

Erika