River Beaver (Faction)
A different faction of beaver, that forgoes living on the land. Land is only used for harvesting and farming trees. Maybe food if water crops do not become a thing. If water crops become a thing, then they would use water based crops for food. They only construct items in the river, or stacked on items in the river - never land. Unlike other factions, their buildings only work when the base of the stack is in water. So if you redirect the water and dry land out, it may become unusable. this would require flooding more areas of the map in order to grow, and potentially walling off land to preserve trees. Another consideration would be to go with only trees that grow in water, in which case last harvesting of trees would be limited to only 1 or 2 tiles from shore.