Rivers will be in the local maps, yes.
You can't build bridges at the moment; considering that. The rivers are fordable at many places thought.
If you add bridges and the ability to expand rivers through digging ditches, that'd add a whole new level of base setup strategy.
Would a river running through a desert deposit soil on its banks to make an oasis? Like along the Nile river.
And, dare I ask, fishing?
As of now, still absolutely amazing. Continous credit to you for making the most entertaining game I've played in years.