Hi,
Just a couple of small bugs (if they even are bugs) i noticed. Removing a river is completely free, I think it should cost at least 1k like raise/lower terrain, maybe even 5k like the other forms of terrain change, since its a pretty substantial engineering effort.
Also building city roads is free even though according to the toolbar it should cost 30.
This is with the latest 32bit experimental for Linux.
Cheers,
Steffen