I support. Duplicate of mine #3931 by the way.

A double-edged sword. Rivers in early game can be devastating - especially for PCs trying to forge their way through SMC and UD where return back through SMC is not necessarily reasonable. Lategame they are more or less an irrelevant speedbump if even that. Chance of getting blocked by aquatic monsters on water tiles would make them even more lethal early game, but hardly any more difficult for higher level characters who likely have access to water breathing and/or rings of fish and/or staff of parting water and/or levitation and/or controlled teleportation and/or ice bolt and/or wands of cold.

Voting yes, because increased variety is good, but this should be implement with consideration towards more mid/lategame challenge. Perhaps only start spawning water type monsters beyond a certain DL.

Seconded. It's a nice flavour item, but rivers in UD / PC / early CoC are devastating enough as-is.

I second it too. No Dragon Turtles in PC dungeon please...