Hi, great mod! Although I do not even have time to build the first road.

First idea :
Why not add addon / mod channels for boat mods? (Canals of the Rim?)

Irrigation Canal (Little Stream) - Tribe
Small Canal (Narrow River) - Medival
Middle Channel (Middle River) - Industrial
Wide Channel (Wide River) - Space
SItu Canal Resources Gatherer (Industrial) and Advanced SItu Canal Resources Gatherer (Space)

For generation (construction) together with roads - channels are parallel to the road.

Second idea :
When you build a road through a settlement cell, generate maps on the non-adjustable edges (because the game does not allow you to build ♥♥♥♥♥♥♥ floors on the edges) so that the players themselves, as they like, build the road through their settlement.