HydPy-W currently only supports using evaporation submodels that comply with the PETModel_V1 interface, not the newer PETModel_V2 interface introduced for HydPy-PET-AMBAV-1.0. We have agreed to remedy this deficit.

Conceptionally, everything is clear (hopefully). Still, we have the situation that HydPy-W uses two submodels, one for potential evapotranspiration from the different HRUs and one for potential evaporation from the single surface water storage. Maybe this separation does not fit with an interface like PETModel_V2 that already calculates different evaporation values for water and land areas. So, the first step will be to check if we can merge both submodel usages into one without too much trouble. (We would lose some flexibility, of course, but increase consistency with other models and simplify using HydPy-W).