Dear All,
I hope you are doing well. In my WEAP model, the simulated flows are much lower than expected during the dry months, while the peaks are too high during the wet season. How can I reduce the wet-season peaks and increase the dry-season flows so that the simulation better matches the observed flows?
I would also appreciate it if anyone could share code for calibration and validation. I wasn’t able to get it to work using the R calibration/validation model or the WEAP Model Inspector.

Thank you.
Kind regards,
Selam

If you are seeing lower flows than expected during the dry months and too high during the wet months, then your simulated model is too "flashy" compared to observed. You will need to make your system more steady by decreasing runoff and increasing baseflows. Basically, your land will need to hold on to the water for longer and release it more gradually.

Now, for how to implement this in your model, you can do the following (Assuming you are doing soil moisture method catchments):
- Decrease runoff resistance factor
- Increase soil water capacity
- Decrease preferred flow direction
- Decrease root zone conductivity
- Consider decreasing deep water conductivity and increasing deep water capacity (study your soil moisture results in your upper and lower buckets).

This information above is from our WEAP Tutorial in the catchment calibration chapter on page 221. Our best resources for learning more about calibration are pages 212, 221, and 222-226 in the catchment calibration chapter of the Tutorial, plus our YouTube lessons on calibration: https://www.youtube.com/watch?v=Notx1vfeRCk. Study your results for soil moisture (z1 and z2)- make sure that the soil moisture levels follow a believable trend and are not consistently at 0% or 100%. It's hard to give very detailed advice on this topic without having worked on your specific model, but I hope the above helps.

-Doug