You mean someone well versed in machinery drawing its energy from river currents?
Forests nulify the +1 commerce bonus of rivers. Preserves and lumbermills just nulify this nulification.
Something's wrong in this save:
https://www.dropbox.com/s/9onuydqh2npsoz9/Washington AD-1876 Turn 385.CivBeyondSwordSave?dl=0
The waiting for other civs never ends, but I would like to play the rest of the game.
What SVN revision is it?
Sorry, haven't had a lot of time to look at these things.
Because the Carthaginians have founded Carallis on Sardes, my Roman Empire do not have a fleet at start. And how do I can invade Carthago now? Where are my those wonderfull ships?...
You could probably just worldbuild it back in, but that is pretty odd. I thought it would just push your navy outside their culture at spawn, or at least push their culture back so you'd have a square around Rome's starting area.