That sounds awesome! Would we be able to pick how many rivers we want to go through the city or would that be random?
I don't know how exactly parametrization is going to look. Most likely a couple of new options will be added (e.g. "island", "confluence", maybe something else) in addition to existing "river" and "coast". For anything more exotic (including multiple rivers) there will be an option to upload a "water map" image. I just hope the UI won't be too complex, I hate spending time on buttons and checkboxes...