Multiple water sources (waterfalls and rivers)

What Feature would you like to see included within TaleSpire?
Multiple waterfalls and controlling different water levels

What situations would this Feature be useful?
Example; I want a waterfall in different levels of a sewers, the purpose of this is to flood floor 2 but not floor 1 kinda situation. Or say I build an archipealago of multiple mini islands. different heights.

Additional Thoughts/Details

I feel like adding waterfalls and river parts for the map, as a static item (like in construction under the decorations button, within nature, where all the trees and the leaves are) alone could fix this issue.