Originally posted by TyresTyco:

Well if you build on water for bridges or making a port or something.. even in my few 15 hours I'm getting annoyed by the constant rock throwing by dwarfs that swim around me trying to get in.

"Just don't fight on water" really doesnt help at all besides you if you like being a captain obvious.

I'm as vulnerable to confirmation bias as anyone*, but after hundreds of hours of play, I am fairly sure the game simulates depletion of mobs in an area. It would be easy to do using RNG techniques.

So if you're 15 hours in the game and you need to build a bridge in the Black Forest, go dwarf hunting. Look for spawners, and kill as many dwarfs as you can. After that, they will spawn only at the background replenishment rate and you should be able to finish your bridge.

*Verbose version of "imho."