Dear all,

I have a problem with my model and I hope that someone can give me a good advise:
WEAP (MAMBIA) requires information about effective precipitation ( % of precipitation available for evapotranspiration; the remainder is direct runoff or direct recharge to groundwater, unless constrained by Maximum Percolation Rate)
Since this is highly depending on the amount of precipitation and the frequency (which influences the saturation of the soil and therefor the losses) it requires to create a formula where this is respected.
Do you have an idea how I could solve this or is there a possibility to create the formula with the expression builder?

Thank you

Best wishes,

Pia